Genetic Influences on Parental Expressed Emotion. A Novel Approach to the Nature of Nurture
1. 1
Genetic Influences on Parental Expressed Emotion: A Novel Approach to the
Nature of Nurture
Florence Walsh
Abstract
By treating measures of the family environment as phenotypes in a child-based twin
design genetic effects can be inferred. The present study is the first we are aware of to
use maternal expressed emotion as a measure of the non-shared environment to
examine the nature of nurture of parent-child relationships. The sample consisted of
279 mothers who completed a questionnaire that examined self-reports of parenting.
230 mothers completed a subsequent phone interview in which expressed emotion
was measured using the Five Minute Speech Sample (5MSS). The average age of
twins was 3.7 years. Findings showed some moderate associations between self-
reports of parenting and the 5MSS for negative perceptions but not positive
perceptions of the parent-child relationship. Bivariate correlations also showed a
strong genetic effect on mother’s self-reports of parenting and mothers reported
treating twins very similarly. The 5MSS measure showed no significant genetic
effects and mothers spoke about twins very differently. However patterns of findings
did show that children exerted some genetic effects for both measures. Thus the
present study demonstrates how the 5MSS can provide a new window through which
to view parental differential treatment and offers a nuanced perspective regarding the
nature of nurture.
2. 2
Acknowledgements
I would like to thank Dr Alison Pike, Dr Bonamy Oliver, Katie Shaw and Rachel Lee
who designed the initial Twins, Family and Behavior (Tfab) study and collected the
data. Thank you to Katie Shaw and Rachel Lee for their time spent training myself
and other students using the data how to code the Five Minute Speech Samples.
Special thanks to my project supervisor Dr Alison Pike for her continuous guidance,
support and advice throughout my project and who gave me the inspiration that drove
my enthusiasm to examine the data from a behavioral genetics perspective. Dr Alison
Pike also assisted with some initial analysis and offered guidance regarding further
analysis. Transcription and coding of the Five Minute Speech Samples (5MSS) was
conducted jointly by myself and other undergraduate students who used the Tfab data
in their projects. Enormous thanks to the parents who took the time to complete the
Tfab study questionnaires and telephone interviews.
3. 3
Introduction
Three decades of research have demonstrated that children are not passive receptacles
for environmental influence; rather they modify, select and shape their environment,
in part, for genetic reasons (Anderson et al, 1986;, Waldman et al, 2002; O’Connor,
2007). Behavioral genetic designs can provide leverage in understanding the interplay
of genetic and environmental influence (or the nature of nurture) by treating measures
of the family environment as phenotypes (McClearn et al, 2001). Estimating how
genetics influence individuals shaping of their environment is integral to
understanding bi-directional characteristics of parent-child relationships, or put
simply; who influences who. An understanding of these characteristics is also of
practical importance as it could contribute to the efficacy of interventions that aim to
ameliorate child behavior problems and negative maternal behavior. Past research has
explored children’s genetic influence on parenting using either observational or self-
report measures. This study is the first we are aware of to employ the Five Minute
Speech Sample (5MSS) within a child-based twin design to examine parental
expressed emotion as a measure of the non-shared environment.
Origins of Expressed Emotion and The Preschool Five-Minute Speech Sample
The 5MSS method was originally utilized within adult psychiatry to examine
expressed emotion between a caregiver and their mentally ill relative (Gottschalk &
Gleser, 1969). Asking respondents to speak for five uninterrupted minutes is
presumed to maximize an individual’s tendency to project actual intrapsychic
qualities and internal states rather than just reactions to cues from an interviewer
4. 4
(Gottschalk & Gleser, 1969). Caregivers are typically asked to speak for five minutes
about their mentally ill relative and statements of criticism and emotional over
involvement are coded and assessed (Brown et al, 1972; Magna-Amato, 1993).
Although brief, the 5MSS has proven highly effective at indexing the climate of
caregiver-relative relationships and predicting the relative’s adaption (Kim- Cohen et
al. 2004; Hooley, 2007). Adapted versions such as the Preschool Five Minute Speech
Sample (Daley, 2003) (used within the present study) have since been employed
within developmental research to examine parent-child relationships.
These studies have demonstrated that compared to a control group of mothers,
mothers of children with behavioral disorders express fewer positive comments, more
critical comments, and less warmth towards their children within the 5MSS (e.g.
Asarnsow et a, 1994; McCarty & Weisz, 2002; Peris & Baker, 2000; Scott &
Campbell, 2001). Additionally, mothers who express more warmth towards their
children have been associated with greater adaptive family functioning, parental
affection during interactions and better child adaption (Psychogiou et al, 2013;
Cartwright et al, 2011). There is also growing evidence that expressed emotion is a
bidirectional construct. Some studies have documented parental criticism predicting
child behavior problems above and beyond prior levels of child symptomology
(Garber et al, 2005; Peris & Baker, 2000). Whilst others have found child-effects on
expressed emotion such as infants fussy temperament being associated with high
parental criticism (Barnes et al, 2007) and adolescents externalizing behavior
problems predicting an increase in parents criticism after controlling for prior levels
of criticism (Frye et al, 2005). Thus measures of expressed emotion might reflect
5. 5
parenting in which the child reciprocates but may also be a reaction to a child’s
genetically determined characteristics (McCarty et al, 2004).
The Nature of Nurture
Although the majority of these studies have implemented measures of expressed
emotion using ‘2-children-per-family’ designs, they have not been genetically
sensitive (Turkeimer & Waldron, 2000). Thus, differential expressed emotion elicited
by the parent will be confounded by genetic differences between siblings, making it
difficult to distinguish the gene-environment interplay (Plomin, 1994). Twin designs,
however, provide a natural experiment to examine the nature of nurture. Monozygotic
(MZ) twins share all of their genes whilst dizygotic (DZ) twins share approximately
half. Thus, if heredity affects a trait, identical twins should be more similar for the
trait than fraternal twins, a phenomenon known as an ‘evocative genotype-
environment correlation’ (Plomin et al, 1977). If there is no difference between MZ
and DZ twins we can assume that there is a greater influence from the environment.
A number of seminal studies have examined the nature of nurture using self-report
and observational measures. In the Nonshared Environment in Adolescent
Development (NEAD) study (Reiss et al, 2007), parent-child interactions were
videoed during a session where problems were discussed. Findings showed that
heritability was found for 54 out of 72 measures including expressions of affection,
conflict tactics and monitoring. Interestingly studies examining twins reared apart
(although showing lower correlations than twins reared together) also show
significant correlations when reporting on different families (Bouchard & McCue,
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1990; Plomin et al, 1988). Findings have been interpreted to support an evocative
genotype-environment correlation; members of the different families respond
similarly to genetically influenced characteristics of the separated twins. Genetic
effects have also emerged in a multitude of studies comparing nonadoptive and
adoptive siblings using a range of methodology including videoed observations of
mother-infant interactions (Dunn & Plomin, 1986; Fulker et al, 1992) and maternal
interviews (Plomin et al, 1992).
It is evident that some dimensions of the parent-child relationship are more heritable
than others. Measures of parental control consistently show lower heritability than
measures such as closeness (Kendler & Baker, 2007; Rowe, 1981; McGue et al,
1997). Additionally findings generally demonstrate that parental negativity is due
primarily to genetic influences whilst positivity is under greater influence from the
environment (Feinberg et al 2001; Neiderhiser et al, 2007; Boivin et al, 2005; Taylor
et al, 2004). Heritability of parental negativity may be because negative reactions are
more conditional upon a child’s behavior; when a child behaves badly they are likely
to evoke a negative response from the parent (an example of an evocative-gene-
environment correlation) (Hooley, 2000). Contrastingly this is less likely to occur
with regard to a child’s positive behavior (Knafo & Plomin, 2006). Heritability of
parental negativity towards children has been identified as a factor that may
contribute to coercive cycles of interaction between parents and children (Patterson &
Reid, 1989). This is evident in studies that show that mothers are less warm towards
anxious children (Sigman et al, 2004) and more maternal negativity is directed
towards conduct disorder boys regardless of a mother’s genetic relatedness (Romney
et al, 1986).
7. 7
The Non-Shared Environment: Parental Differential Treatment
Within studies examining the nature of nurture, similarity that is beyond genetic effect
can be attributed to the environment shared by twins and any further differences are
ascribed to the non-shared environment. (McGuffin et al, 2001). Factors in the non-
shared environment include peer relationships (Harris et al, 2001) and parental
differential treatment (Plomin et al, 2003). Parental differential treatment is evident in
multiple twin studies that show that despite sharing the same genes, parents treat MZ
twins differently (e.g. Moffitt et al, 2004; Hetherington et al, 1996; DiLalla & Bishop,
1996). Reasons for differential treatment must therefore be a result of environmental
influences. A quantitative study by Caspi et al (2004) identified some reasons for
parental differential treatment in interviews with mothers. These included one twin
being ill and thus requiring differential parenting, or mothers identifying more with
one child being like herself and as a consequence responding differently (either
positively or negatively) towards that child. Additionally parental differential
treatment is more likely in families with lower socio economic status, higher
household chaos and maternal depression (Asbury et al, 2003). This may be because
parents living in stressful situations may be less vigilant in monitoring the ways they
treat each of their children following temporary behavioral discordance such as one
twin having a problem at school. (Brody et al, 1992).
One important finding within these studies is that reports of parental differential
treatment differ depending on the source used. Parents generally yield higher
correlations of treatment between children whilst child reports and observations
typically only show modest correlations (Reiss et al, 2000). Higher correlations from
8. 8
parent self-reports are likely to be due to social desirability to report ‘fait treatment’
of children, especially when the children are twins (Kim-Cohen et al, 2004). Thus it is
often difficult to get parents to reveal through direct questioning that they treat
children differently. Asking children about parental differential treatment can also be
problematic because (although an important source of information) results can be
confounded by genetic influences on adolescent’s perceptions rather than actual
differential treatment (Nedirchiester et al, 1998). Expressed emotion used within this
study is an alternative measure to self-report questionnaires that might capture more
accurately the emotional atmosphere and differences between parent-child
relationships. Furthermore, because single method associations have been shown to
inflate findings between variables (Bank et al, 1990) this study used both self-report
measures of parenting and the 5MSS. Using different methodology to examine similar
measures allows for a nuanced understanding of different dimensions of the parent-
child relationships from alternative perspectives.
The Present Study
Although one longitudinal study by Caspi et al (2004) used the 5MSS within a MZ-
differences design, the present study uses the 5MSS within a child based twin design.
Caspi et al’s (2004) longitudinal study offers valuable findings regarding the effects
of parental differential treatment on the development of behavioral problems. The
present Twins, Family and Behavior (Tfab) study focuses more heavily on the nature
of nurture approach. By making direct comparisons between MZ and DZ twins we
gain a greater understanding of how expressed emotion differs between those who
share 100% of their genes, compared to those who share only 50% of their genes.
9. 9
Additionally by examining associations between mother’s self-reports of parenting
and the 5MSS we can examine how different methodology reflects parental
differential treatment. Based on previous research I hypothesized that there would be
a moderate association between mother’s self-reports of parenting and the 5MSS
measure. Additionally I hypothesized that mothers’ perceptions of twins would be
genetically influenced for both the 5MSS and mothers self-report measures of
parenting.
10. 10
Method
Sample and Recruitment
803 families with twins born in England or Wales in 2009 and 2010 were contacted
on behalf of researchers at the University of Sussex via the Office of National
Statistics. 346 mothers allowed contact by TFab, and from these 279 completed the
initial questionnaire and 230 completed a subsequent telephone interview. The
average age of the mothers at completion of the questionnaire was 37.5 years (SD =
4.66) and 86.6% of the sample were either married or cohabiting with the parent of
the twins. 56.9% of the mothers had a degree or above and income per household
was between £30,000- 39,999 pa. The average age of twins at the time of the study
was 3.7 years (SD = .40). Within the sample 35.5% of the twins were monozygotic
and 44% of these were male and 56% were female. 64.5% of the twin sample were
dizygotic and of these 49.2% were dizygotic and of the opposite sex, 23.7% were
dizygotic male twins and 27.1% were dizygotic female twins. All twins were
biologically related to their mother.
Procedures and Measures
The Preschool Five Minute speech sample (5MSS) (Daley et al, 2003)
The 5MSS was conducted via a telephone interview with mothers. Researchers
flipped a coin to determine which twin the mother would speak about first to avoid
order effects. The following instructions were then read to mothers:
11. 11
‘This part will feel a little bit odd, but I’d like to hear your thoughts and feelings
about [name of twin] in your own words and without me interrupting with any
questions or comments. When I ask you to begin I’d like you to speak for 5 minutes,
telling me what kind of a person [name of twin] is and how the two of you get along
together. After you begin to speak, I prefer not to answer any questions until after the
5 minutes are over, but I’ll tell you when your time is up. Do you have any questions
before we begin? Okay great, whenever you’re ready’.
The Speech samples were audio recorded, transcribed and coded according to an
adapted version of Daley’s 5MSS coding manual (see appendix 1). All coders
received training in this coding system. This included 1) a detailed review of the
manual and familiarization of coding rules and definition 2) coding a series of training
tapes until acceptable inter-rater reliability was achieved and maintained and 3)
discrepancies in coded tapes were discussed and jointly agreed upon. To avoid bias
coders only coded one twin per family and did not code speech samples that they had
previously transcribed. Inter rater reliability (recorded below following descriptions
of each measure) ranged from moderate to very good. Findings are strengthened by
the robust method used in which all samples were coded in pairs and all discrepancies
were discussed and agreed upon. Additionally pairs were continually rotated to avoid
rater drift.
The 5MSS was coded after every minute on 4 different scales:
12. 12
Warmth was defined in the manual as ‘the intensity of sentiment or feeling which
parents express about their child during the 5 minute speech sample’. Warmth was
coded as a global rating and mothers were coded as expressing high, moderate or low
warmth. Coders were instructed to consider mothers tone of voice, spontaneity,
concern and empathy when rating warmth. Mothers expressing high warmth showed
signs of enthusiasm with positive changes in tone. For example ‘ She likes drawing,
she’s always bringing me home pictures from play school, in fact last week she drew
me this picture of a castle, it was very well drawn. I was very proud of her so I stuck
it up in the kitchen and I’ve been showing it to everyone who has called”. Mothers
expressing moderate warmth demonstrated some evidence of change of pitch when
talking about their child and displayed some evidence of affection and empathy. For
example ‘He’s good at football, I think for his age, he’s got better co-ordination than
most children and is probably more athletic’. Mothers expressing low warmth spoke
about their child in a monotonic voice with an absence of spontaneity and lack of
empathy. For example ‘She grabs her toys from children and then gets upset when
they won’t play with her, why does she do that when I tell her not to, it does my head
in’. Inter rater reliability for this measure ranged from .64** to .72** (p < .01).
Relationship was defined in the manual as ‘the quality of relationship and joint
activities undertaken between parent & child’. Relationship was a global rating coded
as positive, neutral or negative. Coders were instructed to consider reports of the
relationship and reports that the mother enjoyed and valued time with her child. A
mother expressing a positive relationship made a direct statement that they get along
together. For example ‘Charlotte and I get on really well together’. A neutral
relationship was coded if the relationship wasn’t addressed as part of the speech
13. 13
sample, if there was unclear evidence, or if the parent gave details of joint activities
but did not indicate if they enjoyed or valued them. For example ‘we go to the park all
the time’. A negative relationship was coded if the mother made a direct statement
about their relationship with the child that was not contradicted elsewhere in the
speech sample. For example ‘We just don’t seem to get along, he ignores me’. Inter
rater reliability for this measure ranged from .77** to .88** (p < .01).
Critical comments were defined as negative comments about the child’s behavior
and/or personality. These were recorded using a frequency code and qualified and
unqualified comments were coded separately. For example ‘Libby is a selfish girl’
would be coded as a critical unqualified comment. Inter rater reliability for critical
unqualified comments ranged from .50** - .68** (p < . 01). ‘Sarah is sometimes a
nightmare to put to bed’ would be coded as a qualified comment. Inter rater reliability
for critical qualified comments ranged from .58** - .74** (p < . 01).
Positive comments were defined as statements of praise, approval or appreciation
about the child. These were recorded using a frequency code and qualified and
unqualified comments were coded separately. For example ‘David is a very
thoughtful boy’ would be coded as a positive unqualified comment. Inter rater
reliability for positive unqualified comments ranged from .78** - .89** (p < .01).
‘When she is in the right mood Charlotte has a great sense of humor’ would be coded
as a positive qualified comment. Inter rater reliability for positive qualified comments
ranged from .59** - .79** (p < .01).
14. 14
Factor analysis was conducted and variables were subjected to a rotated varimax
factor solution. Based on a scree plot and following an examination of factor loadings,
the rotated component matrix reflected a two-factor solution of ‘negative perceptions’
and ‘positive perceptions’. The factor called ‘negative perceptions’ explained 20.45%
of the variance after rotation and was loaded with two measures; critical qualified
comments (.73) and critical unqualified comments (.62). The factor called ‘positive
perceptions’ explained 23.63% of the variance after rotation and was loaded with
three variables; relationship (.35), warmth (.75) and positive unqualified comments
(.80). The positive qualified measure did not load onto either factor presumably
because of ambiguity of coding these comments and was thus excluded from further
analysis. Based on these results an average was taken from warmth, relationship and
positive unqualified comments to create a scale ‘positive perceptions’ and an average
of critical qualified comments and critical unqualified comments was taken to create a
scale of ‘negative perceptions’.
Questionnaires
Parent-Child Relationship Scale. On the Parent-Child Relationship Scale
(Hetherington & Chingempeel, 1992) parents were asked to rate 15 items about
aspects of their relationship with their children. For example ‘how much do you enjoy
spending time alone with your child’ and ‘is it easy to be affectionate towards your
child’ on a 5-point scale ranging from 1 (not at all) to 5 (extremely). Two subscales
were derived from this measure; Parent-Child Relationship Positive and Parent-Child
Relationship Negative. (Note for Ali. I need data to get the alphas for the subscales)
15. 15
Parental Feelings Questionnaire. On the Parental Feelings Questionnaire (Deater-
Deckard, 2000) parents were asked to rate how true seven statements regarding their
feelings towards each child were. These included statements such as ‘sometimes I feel
very impatient with himher’ and ‘sometimes I am amused by him/her’. These were
rated on a 5-point scale ranging from 1 (definitely untrue) to 5 (definitely true). Two
subscales were derived from this measure: Positive Parental Feelings and Negative
Parental Feelings.
Ethical Issues
The TFaB study was conducted in compliance with the ethical standards of research
with human subjects of the University of Sussex (see appendix A). Informed consent
was gained at every stage of the study and participants were told that they could
withdraw from the study at any time and ask for their data to be destroyed and/or
removed from the project. Code numbers were used so that names of mothers and
their twins could not be identified.
16. 16
Results
Descriptive statistics for the study variables can be seen in table 1. These illustrate
that on average parents reported having positive feelings towards their children and
very positive relationships. T-tests indicated that there were no significant differences
in mean scores for all measures between older and younger twins.
Table 1. Means and Standard Deviations for all Study Measures
Measure Older twin
M (SD)
Younger twin
M (SD)
Parental Feelings
Positive 3.79 (.35) 3.81 (.32)
Negative 2.48 (.95) 2.52 (.95)
Parent-Child Relationship
Positive 3.26 (.40) 3.27 (.38)
Negative 1.34 (.68) 1.31 (.68)
5MSS
Positive Perceptions
Warmth 2.14 (.33) 2.15 (.33)
Relationship 2.11 (.21) 2.10 (.15)
Positive unqualified 1.12 (.75) 1.09 (.68)
Negative Perceptions
Critical Qualified .31 (.32) .27 (.27)
Critical Unqualified .16 (.27) .14 (.19)
Hypothesis 1: Associations between the 5MSS and mothers self-reports of parenting
To address the first hypothesis and examine whether expressed emotion captured a
novel aspect of perceptions of the parent-child relationship, I calculated bivariate
correlations between traditional self-report measures of parenting and the 5MSS for
both older and younger twins.
17. 17
Results (see Table 2) show that the 5MSS positive perception measure was not
associated with self-report measures for either older or younger twins. This indicates
that the 5MSS captured a novel dimension of the parent-child relationship when
examining positive expressed emotion, which differed from findings when examined
with self-report measures.
In contrast, the 5MSS negative perceptions measure was moderately associated with
self-report measures of parental feelings for older and younger twins. The 5MSS
negative perceptions measure was also moderately associated with self-report
measures of the parent-child relationship for the younger twin, but not for the older
twin. This indicates that the 5MSS and mothers self-reports of parenting capture only
moderately similar dimensions of the parent-child relationship.
Thus, findings support our first hypothesis of some moderate associations between
mothers’ self-reports of parenting and the 5MSS.
Table 2. Correlations between mothers Self-Reports of parenting and the 5MSS
measures
Note. OT = Older twin; YT = Younger Twin
* p < .05, **p < .01, *** p < .001.
5MSS
Self- Report Questionnaires Positive
perceptions
OT
Positive
perceptions
YT
Negative
perceptions
OT
Negative
perceptions
YT
Parental Feelings .13 .15 .30** .23*
Parent-Child Relationships .11 .07 .01 .28**
18. 18
Hypothesis 2: Genetic influences on measures of the parent-child relationship
To address the second hypothesis interclass twin correlations were calculated for
5MSS measures and self-report parenting measures separately for both monozygotic
and dizygotic twins (see Table 3). Fisher’s z-transformations were calculated to
examine whether there were significant differences between interclass correlations as
a result of zygosity. Results show that correlations for positive and negative
perceptions of expressed emotion were non significant for both monozygotic and
dizygotic twins. Z values indicated that the difference between correlations was non-
significant. This suggests that measures of parental expressed emotion are influenced
more by the non-shared environment than by genetics.
All correlations for self-report measures were significant indicating that parents
reported that they treated twins similarly. Z values also indicated a genetic influence
as monozygotic twins were treated more similarly than dizygotic twins for all self-
report measures apart from positive parental feelings.
Despite non-significant findings for the 5MSS measure, it is worth noting that the
consistent pattern of correlations for all measures indicates that monozygotic twins
were always treated more similarly than dizygotic twins. Thus both measures
demonstrate some genetic influence, but this effect is larger for self-report measures
of parenting than measures of expressed emotion. Thus the second hypothesis that
mother’s perceptions of twins would be influenced genetically was supported for self-
report measures of parenting, but only partially for the 5MSS measure, which
indicated a greater influence of the environment.
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Table 3. Correlations between Self-report measures and twin zygosity and 5MSS
measures and twin zygosity
Note. MZ = Monozygotic; DZ = Dyzygotic
*p < .05, **p < .01, *** p <.001
MZ r DZ r Z
5MSS
Positive
.24 -.07 1.16
Negative .25 .15 0.39
Parent- Child
Relationship
Positive .94** .81** 4.79**
Negative .92** .78** 4.28 **
Parental-Feelings
Positive .69** .61** 0.97
Negative .94** .77** 5.65**
20. 20
Discussion
Within the present study findings show that there were some moderate associations
between measures of expressed emotion and mothers self-reports of parenting for
negative perceptions of the parent-child relationship, but not for positive perceptions.
Additionally mothers self-reports of parenting were influenced by the child’s genetic
propensity and mothers reported treating twins similarly thus supporting a child-
effects model (Larsson et al, 2008) and an evocative genotype-environment
correlation (Plomin et al, 1977). However no significant genetic effect was evident for
measures of expressed emotion and this methodology reflected parents treating twins
very differently. Thus measures of expressed emotion offer a unique perspective into
the nature of nurture of parent-child relationships and an exciting and novel window
through which to view parental differential treatment.
Hypothesis 1: Are there associations between expressed emotion and mothers self-
reports of parenting?
Negative perceptions of the parent-child relationship were moderately associated
between measures. This was evident for both the older and younger twin for negative
parental feelings. However it was only evident for the younger twin for negative
perceptions of the parent-child relationship. Although this could be interpreted to
suggest an effect of birth order, discrepancies between the older and younger twins
were more likely to be influenced by methodological factors. Examination of means
showed no significant difference between older and younger twins, moreover the
order in which parents discussed twins was randomized to avoid order effects. Thus
21. 21
this finding is likely to be due to factors such as the small sample size of mothers who
completed the 5MSS. Correlations consistently showed no significant associations
between self-report and 5MSS measures of positive perceptions. The robust
methodology of coders rating all 5MSS together (which yielded good inter rater
reliability) supports findings as legitimate reflection of parent’s perceptions rather
than rater bias.
Thus the 5MSS may in fact capture a unique dimension of positive perceptions of the
parent-child relationship that self-report measures do not. Within he 5MSS mothers
that demonstrated high positivity were coded as showing spontaneity and elaboration
when speaking, changes in tone of voice, and an ability to see things from the child’s
perspective (Daley, 2003). However, scales used within self-report measures of
parenting had a limit of 5 responses and thus did not have the capacity to measure
subtle aspects of positive expression such as tone of voice. Therefore the 5MSS
captured the more expressive and spontaneous aspects of positive expression that
structured self-report measures with limited responses did not.
Furthermore positive perceptions within self-report measures and the 5MSS may not
have been associated because the coding of positive comments was often ambiguous.
This was evident following factor analysis in which qualified positive comments did
not load onto either factor and were thus excluded from further analysis. However
when parents spoke negatively, responses were much more salient (especially in
regards to qualified and unqualified critical comments). Additionally mothers who
spoke negatively about their twins were coded as speaking in an unexpressive and
monotonic voice with limited responses (Daley, 2003). Thus negative responses were
22. 22
more equivocal with the limited format of self-report measures and this might explain
associations between negative perceptions in self-reports and the 5MSS.
Despite associations between measures of negative perceptions, correlations were
only modest. Thus the 5MSS captured a novel aspect of both positive and negative
perceptions. These findings support the concept of expressed emotion reflecting
internal states that direct questioning does not capture (Glesser et al, 1969). Findings
also emphasize the importance of including different methodology as a single method
approach may inflate findings (Bank et al, 1990).
Hypothesis 2: Are there genetic influences on measures of the parent-child
relationship?
For self-report measures, parents consistently rated themselves as treating twins very
similarly. Genetic effects were also evident for all self-report measures apart from
positive parental feelings. This is in line with previous research that has found that
when using self-report measures findings yield a greater genetic influence for parental
negativity, whilst positivity has a greater influence of the environment, (Fienberg et al
2001; Neiderhiser et al, 2004; Boivin et al, 2005; Taylor et al, 2004). These findings
are supportive of a child-effect model (Larson et al, 2008) and an evocative genotype-
environment correlation (Plomin et al, 1977) that emphasize the role of the child as an
active agent within the family system (O’Conner et al, 1998).
Findings indicate no heritability for the 5MSS measures. It is noteworthy that this
may be due to the small sample size of mothers who completed the 5MSS, which may
23. 23
have reduced the power to detect differences between MZ and DZ twins. To examine
this further a Fisher’s z-transformation was re-run with a sample size of 279 (the
number of mothers who completed the self-report questionnaires). After adjusting the
sample size, heritability was evident for the positive perceptions measure but not for
the negative perceptions measure. A re-run of the study with a larger sample size is
necessary to draw further conclusions from this finding. This finding does however
emphasize the necessity of bigger samples in future studies.
Despite non-significant genetic effects for the 5MSS measures, the consistent pattern
of larger correlations for MZ twins for all measures is noteworthy. This pattern
(which is evident in numerous twin studies) demonstrates that genetic factors exert
some influence on measures of the environment (Arsenealt et al, 2004; Taylor et al,
2004) supporting the concept of bi-directional characteristics of parent-child
relationships (Hooley, 2000; Plomin, 1977). However it is clear from the present
study, that when using expressed emotion as a measure of the non-shared
environment, genetics are not the whole etiological story. Therefore other
environmental factors influence children’s shaping of their environment. These may
include one twin suffering from an illness, or the parent identifying with one twin as
being more similar to them (Caspi et al, 2004).
An important finding within this study is that when using the 5MSS parents appear to
treat twins a lot more differently than when using a self-report measure of parenting.
Measuring parental differential treatment either from the parent’s perspective using
self-report data or from the child’s perspective has limitations. When children report
on parenting, genetic influence could accrue for two reasons. Findings of genetic
24. 24
influence may be a genuine reflection of parents responding to the child’s genetic
propensity. However child reports may be influenced by genetically influenced
characteristics that affect perceptions (even if these bear no relation to reality). Thus,
despite some associations between child reports and observational measures (Reiss et
al, 2007), child reports may still be confounded by genetic effects on perception.
However for parent reports, a genetic contribution will be seen only to the extent that
parents respond to genetic characteristics of the children. However direct questioning
shows inflated reports in which parents report treating twins similarly; a finding that
does not correlate with observational data (Reiss et al, 2007). Thus direct questioning
regarding parental differential treatment is likely to be influenced by social
desirability to report treating children ‘fairly’. This explains mother’s self-reports of
very similar treatment of twins in the present study. These findings are also likely to
be due to the format of the questionnaire used in which mothers answered questions
about twins simultaneously.
Therefore it is evident from the present study that the 5MSS offers a possible means
of overcoming these limitations. Expressed emotion is less likely to be confounded by
social desirability and more likely to offer an objective reflection of parental
differential treatment. The finding that parents actually treat twins differently
emphasizes the influence of the non-shared environment, which contributes to
individual differences between genetically identical twins. This has important
implications because a greater understanding of these environmental factors is
necessary to implement effective interventions that aim to improve parent-child
relationships. It is also clear from the present study how different methodology can
offer a nuanced perspective into parental differential treatment. Thus the 5MSS
25. 25
measure can not only contribute to an understanding of the nature of nurture, but also
offer a better means to investigating parental differential treatment. This is essential
due to evidence of its effects on child adjustment and behavior problems (Hastings et
al, 2006; Caspi et al, 2004).
Limitations and Future Research
Within the present study some methodological limitations should be noted. Firstly
findings were limited by the small sample size that reduced the power to detect
differences between correlations (Deater-Deckard et al, 2001). Furthermore estimates
of the nonshared environment are polluted by measurement error. However the robust
methodology used within this study when coding speech samples minimalizes these
effects. Additionally non-significant associations between positive perceptions within
the 5MSS and self-report measures of parenting may have been due to social
desirability; mothers speaking to a researcher on the phone may have naturally spoken
in a more positive manner. In future studies mothers should independently record the
5MSS to prevent researcher effects.
A further limitation of behavioral genetic research is the assumption that twin designs
can be generalized to singleton siblings. There is speculation that twins differ from
singleton siblings as a result of lighter birth weight (MacGillivary et al, 1988),
different brain development (Knickmeyer et al, 2011) and rates of language
acquisition (Wilson et al, 2005). However this limitation has been defended by twin-
singleton comparison studies which have found no noticeable differences in behavior
26. 26
problems or personality (Gjone & Novik, 1995; McGue et al, 2002, Robbers et al,
2011)
A final limitation is that parental differential treatment may have been the mother’s
response to a child’s behavior or temperament that was not genetically determined .A
greater understanding of what aspects of the environment shapes these early
differences is necessary. Despite this, the child-based twin design utilized within this
study, as opposed to the MZ-differences design employed in other studies examining
expressed emotion (Caspi et al, 2004), offers greater leverage to infer genetic
influence.
Future studies should use the 5MSS within a longitudinal child-based twin design to
examine the nature of nurture across the developmental trajectory. Furthermore
studies should examine associations with observational measures to determine
whether expressed emotion offers a novel perspective to what is perceived by
researchers.
Conclusions
This study utilized expressed emotion as a measure of the non-shared environment to
examine the nature of nurture. Findings show that measures of expressed emotion
offer a novel insight into parent-child relationships that self-report measures do not
capture. Additionally findings demonstrate a much greater influence of the nonshared
environment when using the 5MSS and greater parental differential treatment. That
said, the consistent pattern of findings still emphasizes the role of children as active
27. 27
agents within the family. Thus this study demonstrates compelling findings of how
measures of expressed emotion offer a novel and compelling window through which
to examine the nature of nurture and parental differential treatment.
28. 28
References
Anderson, K. E., Lytton, H., & Romney, D. M. (1986). Mothers' interactions with
normal and conduct-disordered boys: Who affects whom?. Developmental
Psychology, 22(5), 604.
Asarnow, J. R., Tompson, M., Hamilton, E. B., Goldstein, M. J., & Guthrie, D.
(1994). Family-expressed emotion, childhood-onset depression, and childhood-
onset schizophrenia spectrum disorders: is expressed emotion a nonspecific
correlate of child psychopathology or a specific risk factor for
depression?.Journal of abnormal child psychology, 22(2), 129-146.
Asbury, K., Dunn, J. F., Pike, A., & Plomin, R. (2003). Nonshared environmental
influences on individual differences in early behavioral development: A
monozygotic twin differences study. Child Development, 74(3), 933-943.
Bank, L., Dishion, T., Skinner, M., & Patterson, G. R. (1990). Method variance in
structural equation modeling: Living with “glop.”. Depression and aggression
in family interaction, 247-279.
Barnes, J., Ram, B., Leach, P., Altmann, L., Sylva, K., Malmberg, L. E., ... & Team,
T. F. (2007). Factors associated with negative emotional expression: a study of
mothers of young infants. Journal of reproductive and infant psychology, 25(2),
122-138.
Boivin, M., Pérusse, D., Dionne, G., Saysset, V., Zoccolillo, M., Tarabulsy, G. M., ...
& Tremblay, R. E. (2005). The genetic‐ environmental etiology of parents'
perceptions and self‐ assessed behaviours toward their 5‐ month‐ old infants in
a large twin and singleton sample. Journal of Child Psychology and
Psychiatry,46(6), 612-630.
Bouchard, T. J., & McGue, M. (1990). Genetic and rearing environmental influences
on adult personality: An analysis of adopted twins reared apart.Journal of
Personality, 58(1), 263-292.
Brody, G. H., Stoneman, Z., & McCoy, J. K. (1992). Associations of maternal and
paternal direct and differential behavior with sibling relationships:
Contemporaneous and longitudinal analyses. Child development, 63(1), 82-92.
Brown, G. W., Birley, J. L., & Wing, J. K. (1972). Influence of family life on the
course of schizophrenic disorders: a replication. The British Journal of
Psychiatry.
Cartwright, K. L., Bitsakou, P., Daley, D., Gramzow, R. H., Psychogiou, L.,
Simonoff, E. & Sonuga-Barke, E. J. (2011). Disentangling child and family
influences on maternal expressed emotion toward children with attention-
deficit/hyperactivity disorder. Journal of the American Academy of Child &
Adolescent Psychiatry, 50(10), 1042-1053.
29. 29
Caspi, A., Moffitt, T. E., Morgan, J., Rutter, M., Taylor, A., Arseneault, L. & Polo-
Tomas, M. (2004). Maternal expressed emotion predicts children's antisocial
behavior problems: using monozygotic-twin differences to identify
environmental effects on behavioral development. Developmental
psychology,40(2), 149.
Daley, D., Sonuga‐ Barke, E. J. S., & Thompson, M. (2003). Assessing expressed
emotion in mothers of preschool AD/HD children: Psychometric properties of a
modified speech sample. British Journal of Clinical Psychology,42(1), 53-67.
Deary, I. J., Pattie, A., Wilson, V., & Whalley, L. J. (2005). The cognitive cost of
being a twin: two whole-population surveys. Twin Research and Human
Genetics, 8(04), 376-383.
Deater‐ Deckard, K. (2000). Parenting and child behavioral adjustment in early
childhood: A quantitative genetic approach to studying family processes. Child
development, 71(2), 468-484.
Deater‐ Deckard, K., Pike, A., Petrill, S. A., Cutting, A. L., Hughes, C., & O’Connor,
T. G. (2001). Nonshared environmental processes in social‐ emotional
development: an observational study of identical twin differences in the
preschool period. Developmental Science, 4(2), F1-F6.
DiLalla, L. F., & Bishop, E. G. (1996). Differential maternal treatment of infant
twins: Effects on infant behaviors. Behavior genetics, 26(6), 535-542.
Duncan, G. J., Boisjoly, J., & Harris, K. M. (2001). Sibling, peer, neighbour, and
schoolmate correlations as indicators of the importance of context for
adolescent development. Demography, 38(3), 437-447.
Dunn, J., & Plomin, R. (1986). Determinants of maternal behaviour towards 3‐ year‐
old siblings. British Journal of Developmental Psychology, 4(2), 127-137.
Elkins, I. J., McGue, M., & Iacono, W. G. (1997). Genetic and environmental
influences on parent–son relationships: Evidence for increasing genetic
influence during adolescence. Developmental psychology, 33(2), 351.
Feinberg, M. E., Neiderhiser, J. M., Simmens, S., Reiss, D., & Hetherington, E. M.
(2000). Sibling Comparison of Differential Parental Treatment in Adolescence:
Gender, Self‐ Esteem, and Emotionality as Mediators of the Parenting‐
Adjustment Association. Child development, 71(6), 1611-1628.
Feinberg, M., Neiderhiser, J., Howe, G., & Hetherington, E. M. (2001). Adolescent,
parent, and observer perceptions of parenting: Genetic and environmental
influences on shared and distinct perceptions. Child Development, 72(4), 1266-
1284.
Frye, A. A., & Garber, J. (2005). The relations among maternal depression, maternal
criticism, and adolescents’ externalizing and internalizing symptoms.Journal of
Abnormal Child Psychology, 33(1), 1-11.
30. 30
Gjone, H., & Nøvik, T. S. (1995). Parental ratings of behaviour problems: a twin and
general population comparison. Journal of Child Psychology and
Psychiatry, 36(7), 1213-1224.
Gottschalk, L. A., & Gleser, G. C. (1969). The measurement of psychological states
through the content analysis of verbal behavior. Univ of California Press.
Hastings, R. P., Daley, D., Burns, C., & Beck, A. (2006). Maternal distress and
expressed emotion: Cross-sectional and longitudinal relationships with behavior
problems of children with intellectual disabilities. Journal Information, 111(1).
Hetherington, E. M., & Clingempeel, W. G. (1992). Coping with marital transitions.
University of Chicago Press for the Society for Research in Child Development.
Hooley, J. M. (2007). Expressed emotion and relapse of psychopathology.Annu. Rev.
Clin. Psychol., 3, 329-352
Hooley, J. M., & Hiller, J. B. (2000). Personality and expressed emotion. Journal of
abnormal psychology, 109(1), 40.
Jaffee, S. R., Caspi, A., Moffitt, T. E., Polo-Tomas, M., Price, T. S., & Taylor, A.
(2004). The limits of child effects: evidence for genetically mediated child
effects on corporal punishment but not on physical
maltreatment. Developmental psychology, 40(6), 1047.
Johnson, W., Krueger, R. F., Bouchard, T. J., & McGue, M. (2002). The personalities
of twins: Just ordinary folks. Twin Research, 5(02), 125-131.
Kendler, K. S., & Baker, J. H. (2007). Genetic influences on measures of the
environment: a systematic review. Psychological medicine, 37(05), 615-626.
Kim‐ Cohen, J., Moffitt, T. E., Caspi, A., & Taylor, A. (2004). Genetic and
environmental processes in young children's resilience and vulnerability to
socioeconomic deprivation. Child development, 75(3), 651-668.
Knafo, A., & Plomin, R. (2006). Prosocial behavior from early to middle childhood:
genetic and environmental influences on stability and change.Developmental
psychology, 42(5), 771.
Knickmeyer, R. C., Kang, C., Woolson, S., Smith, J. K., Hamer, R. M., Lin, W., ... &
Gilmore, J. H. (2011). Twin-singleton differences in neonatal brain
structure. Twin Research and Human Genetics, 14(03), 268-276.
Larsson, H., Viding, E., Rijsdijk, F. V., & Plomin, R. (2008). Relationships between
parental negativity and childhood antisocial behavior over time: A bidirectional
effects model in a longitudinal genetically informative design.Journal of
abnormal child psychology, 36(5), 633-645.
MacGillivray, I., Thompson, B., & Campbell, D. M. (Eds.). (1988). Twinning and
twins. John Wiley & Sons.
31. 31
McCarty, C. A., & Weisz, J. R. (2002). Correlates of expressed emotion in mothers of
clinically‐ referred youth: an examination of the five‐ minute speech
sample. Journal of Child Psychology and Psychiatry, 43(6), 759-768.
McCarty, C. A., Lau, A. S., Valeri, S. M., & Weisz, J. R. (2004). Parent-child
interactions in relation to critical and emotionally overinvolved expressed
emotion (EE): Is EE a proxy for behavior?. Journal of abnormal child
psychology, 32(1), 83-93.
McGuffin, P., Riley, B., & Plomin, R. (2001). Toward behavioural
genomics.Science, 291(5507), 1232-1249.
Minnis, H., Reekie, J., Young, D., O’CONNOR, T. O. M., Ronald, A., Gray, A., &
Plomin, R. (2007). Genetic, environmental and gender influences on attachment
disorder behaviours. The British Journal of Psychiatry, 190(6), 490-495.
Moore, P. S., Whaley, S. E., & Sigman, M. (2004). Interactions between mothers and
children: impacts of maternal and child anxiety. Journal of Abnormal
Psychology, 113(3), 471.
Neiderhiser, J. M., Reiss, D., & Hetherington, E. M. (2007). The Nonshared
Environment in Adolescent Development (NEAD) project: A longitudinal
family study of twins and siblings from adolescence to young adulthood. Twin
Research and Human Genetics, 10(01), 74-83.
O'Connor, T. G., Neiderhiser, J. M., Reiss, D., Hetherington, E. M., & Plomin, R.
(1998). Genetic contributions to continuity, change, and co‐ occurrence of
antisocial and depressive symptoms in adolescence. Journal of Child
Psychology and Psychiatry, 39(3), 323-336.
Pedersen, N. L., Plomin, R., McClearn, G. E., & Friberg, L. (1988). Neuroticism,
extraversion, and related traits in adult twins reared apart and reared
together.Journal of personality and social psychology, 55(6), 950.
Peris, T. S., & Baker, B. L. (2000). Applications of the expressed emotion construct
to young children with externalizing behavior: Stability and prediction over
time. Journal of Child Psychology and Psychiatry, 41(4), 457-462.
Pike, A., McGuire, S., Hetherington, E. M., Reiss, D., & Plomin, R. (1996).Family
environment and adolescent depressive symptoms and antisocial behavior: a
multivariate genetic analysis (Vol. 32, No. 4, p. 590). American Psychological
Association.
Plomin, R. (1994). Genetics and experience: The interplay between nature and
nurture. Sage Publications, Inc.
Plomin, R., DeFries, J. C., & Loehlin, J. C. (1977). Genotype-environment interaction
and correlation in the analysis of human behavior. Psychological bulletin, 84(2),
309.
32. 32
Plomin, R., DeFries, J. C., McClearn, G. E., & McGuff, N. F.(2001). Behavioral
genetics, 4.
Plomin, R., McClearn, G. E., Pedersen, N. L., Nesselroade, J. R., & Bergeman, C. S.
(1988). Genetic influence on childhood family environment perceived
retrospectively from the last half of the life span. Developmental
psychology,24(5), 738.
Ramchandani, P. G., Domoney, J., Sethna, V., Psychogiou, L., Vlachos, H., &
Murray, L. (2013). Do early father–infant interactions predict the onset of
externalising behaviours in young children? Findings from a longitudinal cohort
study. Journal of child psychology and psychiatry, 54(1), 56-64.
Reid, J. B., & Patterson, G. R. (1989). The development of antisocial behaviour
patterns in childhood and adolescence. European Journal of personality, 3(2),
107-119.
Rende, R. D., Slomkowski, C. L., Stocker, C., Fulker, D. W., & Plomin, R. (1992).
Genetic and environmental influences on maternal and sibling interaction in
middle childhood: A sibling adoption study. Developmental Psychology, 28(3),
484.
Rhee, S. H., & Waldman, I. D. (2002). Genetic and environmental influences on
antisocial behavior: a meta-analysis of twin and adoption studies. Psychological
bulletin, 128(3), 490.
Robbers, S. C., van Oort, F. V., Polderman, T. J., Bartels, M., Boomsma, D. I.,
Verhulst, F. C., ... & Huizink, A. C. (2011). Trajectories of CBCL attention
problems in childhood. European child & adolescent psychiatry, 20(8), 419-
427.
Rowe, D. C. (1981). Environmental and genetic influences on dimensions of
perceived parenting: A twin study. Developmental Psychology, 17(2), 203.
Scott, S., & Campbell, C. (2000). Expressed Emotion about children: reliability and
validity of a Camberwell Family Interview for Childhood (CFI‐
C).International Journal of Methods in Psychiatric Research, 9(1), 3-10.
Spotts, E. L., Neiderhiser, J. M., Towers, H., Hansson, K., Lichtenstein, P.,
Cederblad, M., ... & Reiss, D. (2004). Genetic and environmental influences on
marital relationships. Journal of Family Psychology, 18(1), 107.
Turkheimer, E., & Waldron, M. (2000). Nonshared environment: a theoretical,
methodological, and quantitative review. Psychological bulletin, 126(1), 78.
Vitaliano, P. P., Young, H. M., Russo, J., Romano, J., & Magana-Amato, A. (1993).
Does expressed emotion in spouses predict subsequent problems among care
recipients with Alzheimer's disease?. Journal of Gerontology,48(4), P202-P209.
34. 34
HOW TO FILL IN THIS BOOKLET
There are no right or wrong answers to any of the questions we ask. Every child
and every family is different, and this is a big part of what interests us.
Please be as honest as you can when answering our questions. Everything you
tell us will be kept strictly confidential.
Please try to answer all the questions you are asked. It is very important that the
booklets are completed as fully as possible.
We realise that many parents are very busy, so don’t feel that you have to answer
all our questions on the same day.
TEDS Research Centre
Dept. Box No. PO83, FreepostLON7567, London SE5 8AF
Appendix B: Self-Report Questionnaire of parenting
35. 35
Most of the questions in this booklet will ask you to tick a box next to the answer
that is most suitable. Some will also ask you to describe this answer in more
detail.
Please note: to be sure that we know who you are telling us about at each time,
we refer to your ‘OLDER’ and ‘YOUNGER’ twin – but of course, there may be only
a few minutes or hours between the children’s ages.
It would be helpful if you would write as clearly as possible, using a black or dark
blue pen.
Please indicate your answers with a cross
If you make a mistake, shade out and cross the appropriate box, e.g.
If you have any questions please don’t hesitate to email or call us on our
freephone number:
0800 317 029
teds-project@kcl.ac.uk
THANK YOU FOR YOUR TIME AND FOR YOUR HELP
WITH OUR RESEARCH
CONSENT FORM
Freephone0800 317029
Email: teds-project@kcl.ac.uk
36. 36
Please tick each box
1. I confirm that I have read and understand the information sheet for the above
study. I have had the opportunity to consider the information, ask questions
and had these answered satisfactorily.
2. I understand that my participation is voluntary and that I am free to withdraw
at any time without giving any reason, without my legal rights being affected.
3. I understand that unidentifiable data collected during the study may be
analysed by individuals from the TEDS team and other researchers. Access to
identifiable data is strictly controlled and used only by authorised TEDS staff,
where it is relevant to my taking part in this research. I give permission for
these individuals to have access to my data.
4. I agree to take part in the above study.
If you have any questionsat any time, pleasecontact the TEDS team on freephone
0800 317029, or email teds-project@kcl.ac.uk
Your name:
………………………..…………………………………………………….…..………………….………….
Relationship to the twin (e.g. mother, guardian etc):
…….……………….………….…………………….
Your address:
……………..……………………....…………………………….………..…..……………………...........
………………………………………………….……………………………………….……………….……….
……………………...
……………………………………………….……………………………….. Postcode:
…………………….………………..
Your telephone number:
…………..……………………………………………………………………………………..
Your email:
……………………...…………..…………………………………………………………………………………
SIGNATURE: ………………………………………………… Date: (day/month/year)
…..…/…..…/……..
It would be useful if we could have the contact details of a relative or friend
that we could contact should we be unable to reach you – for example, if
you move house.
First name: …………………………………………… Last name:
……………………………………………..
38. 38
3. What is your date of birth?
(dd/mm/yyyy)
4. What is your relationship to the twins?
Birth mother Natural father
Stepfather Stepmother
Other guardian (please describe)................................................................................
5. What is your marital status?
Single
unmarried
Married to parent
of twins Married to other
Single
separated
Cohabiting with
parent of twins
Cohabiting with
other
Single divorced Single widowed Other
6. What is your household income (per year, before tax)? This should include the
income for all of the adults in your household.
Less than £5,000 £5,000 to £9,999
£10,000 to £14,999 £15,000 to £19,999
£20,000 to £24,999 £25,000 to £29,999
£30,000 to £39,999 £40,000 to £49,999
£50,000 to £74,999 £75,000 to £100,000
More than £100,000
Prefer not to answer this
question
7. What is the highest level of qualifications that you have reached? Please select
the closest match from the list.
No qualifications
GCSEs or O levels with grades D – G, or CSEs with grades 2 - 5
39. 39
1 to 4 GCSEs or O levels with grades A - C (or CSEs with grade 1)
5+ GCSEs or O levels with grades A - C (or 5+ CSEs with grade 1)
1 A level pass (grades A - E)
2+ A level passes (grades A - E)
First degree (e.g. BA, BSc)
Higher degree (e.g. MA, PhD) or Postgraduate certificate or diploma (e.g. PGCE)
Other qualifications obtained outside the UK
Prefer not to answer this question
8. Which of the following best describes the type of work that you do? Please
select the closest match from the list.
Manager, director or senior official
Qualified scientist, engineering or IT professional
Teacher, lecturer, research or education professional
Qualified professional such as doctor, accountant, solicitor, architect or clergy
IT, science, engineering, electrical or laboratory technician
Nurse, midwife, paramedic, qualified therapist, social welfare
Armed forces, police or protective services
Artistic or literary, design or media, or professional sports occupation
Business or finance professional such as broker, estimator, estate agent
Administrator, secretary, PA, receptionist or clerical work
Agricultural or horticultural trades, such as farmer, gardener, groundsman
Trained construction or building trades (plasterer, bricklayer, carpenter, glazier,
electrician, plumber, etc)
Trained vehicle, craft or food trades (mechanic, tailor, florist, baker, chef, etc)
Leisure, sports or travel services
Childcare, classroom assistant, care assistant, dental or veterinary nurse
Hairdressing, housekeeping and other personal services
Sales assistant, cashier or check-out, trader, call centre or customer services
Driver or transport operator, machinist or vehicle fitter
40. 40
Security guard, attendant, school patrol, traffic warden
Postal worker, courier or messenger
Goods handling, porter, shelf filling, storage
Labourer, farm worker, factory worker or machine operator
Cleaning, laundering, refuse collection
Kitchen worker, bar staff, waiter or waitress
Unemployed or student
None of the above
Prefer not to answer this question
ABOUT THE PERSON YOU LIVE WITH
If you do not have a partner who lives with you, please go to page 9
1. First name: ………………………………………. Last name:
…………………………….………………..
2. What is their relationship to the twins?
Birth mother Natural father
Stepfather Stepmother
Other guardian (please
describe)................................................................................
3. Date of birth: (dd/mm/yyyy)
4. What is the highest level of qualifications that they have reached?
No qualifications
GCSEs or O levels with grades D – G, or CSEs with grades 2 - 5
1 to 4 GCSEs or O levels with grades A - C (or CSEs with grade 1)
5+ GCSEs or O levels with grades A - C (or 5+ CSEs with grade 1)
1 A level pass (grades A - E)
2+ A level passes (grades A - E)
41. 41
First degree (e.g. BA, BSc)
Higher degree (e.g. MA, PhD) or Postgraduate certificate or diploma (e.g. PGCE)
Other qualifications obtained outside the UK
Prefer not to answer this question
5. Which of the following best describes the type of work that they do? Please
select the closest match from the list.
Manager, director or senior official
Qualified scientist, engineering or IT professional
Teacher, lecturer, research or education professional
Qualified professional such as doctor, accountant, solicitor, architect or clergy
IT, science, engineering, electrical or laboratory technician
Nurse, midwife, paramedic, qualified therapist, social welfare
Armed forces, police or protective services
Artistic or literary, design or media, or professional sports occupation
Business or finance professional such as broker, estimator, estate agent
Administrator, secretary, PA, receptionist or clerical work
Agricultural or horticultural trades, such as farmer, gardener, groundsman
Trained construction or building trades (plasterer, bricklayer, carpenter, glazier,
electrician, plumber, etc)
Trained vehicle, craft or food trades (mechanic, tailor, florist, baker, chef, etc)
Leisure, sports or travel services
Childcare, classroom assistant, care assistant, dental or veterinary nurse
Hairdressing, housekeeping and other personal services
Sales assistant, cashier or check-out, trader, call centre or customer services
Driver or transport operator, machinist or vehicle fitter
Security guard, attendant, school patrol, traffic warden
Postal worker, courier or messenger
Goods handling, porter, shelf filling, storage
Labourer, farm worker, factory worker or machine operator
Cleaning, laundering, refuse collection
Kitchen worker, bar staff, waiter or waitress
Unemployed or student
None of the above
42. 42
Prefer not to answer this question
ARE YOUR TWINS IDENTICAL OR NON-IDENTICAL
(FRATERNAL)?
If your twins are one boy and one girl (opposite sex), then please go to page 11
1. Have you ever been told by a health professional (for example doctor, nurse,
consultant) that your twins are identical or non-identical?
YES, identical YES, non-identical NO
2. Do you think your twins are identical or non-identical?
Identical Non-identical
3. Are there differences in the shade of your twins’ hair?
Clear difference Only slight
difference
None
4. Are there differences in the texture of your twins’ hair (fine or coarse, straight
or curly etc)?
Clear difference Only slight
difference
None
5. Are there differences in the colour of your twins’ eyes?
Clear difference Only slight
difference
None
6. Are there differences in the shape of your twins’ ear lobes?
Clear difference Only slight
difference
None
7. Did the twins’ teeth begin to come through at about the same time?
Matching teeth on the same side came through within a few days of each other
Matching teeth on opposite sides came through within a few days of each other
The twins had different teeth come through within a few days of each other
The twins’ first teeth did not come through within a few days of each other
43. 43
The twins’ teeth have not come through yet
8. (a) Do you know your twins’ ABO blood group?
Yes No
(b) If YES, what is their blood group?
Older twin A B AB O
Younger
twin A B AB O
9. As your twins have grown older, how has the likeness between them changed?
Remained the same Become less Become greater
10. If you look at a new photograph of your twins, can you tell them apart
(without looking at their clothes or using any other cues)?
YES, easily
YES, but it is hard sometimes
NO, I often confuse them in photographs
11. Do any of the following people ever mistake your twins for each other?
(a) Other parent of the twins
YES, often
YES, sometimes
Rarely or never
There is no other parent
(b) Older brothers or sisters
YES, often
YES, sometimes
Rarely or never
There are no older brothers or sisters
(c) Other relatives
YES, often
YES, sometimes
Rarely or never
(d) Babysitter/day carer
YES, often
YES, sometimes
Rarely or never
There is no babysitter/day carer
44. 44
(e) Parents’ close friends
YES, often
YES, sometimes
Rarely or never
(f) Parents’ casual friends
YES, often
YES, sometimes
Rarely or never
(g) People meeting the twins for the first time
YES, often
YES, sometimes
Rarely or never
12. If the twins are ever mistaken for one another, does this ever occur when
they are together?
YES, often
YES, sometimes
NO, almost never
They are not mistaken for one another
13. Would you say that your twins:
are as physically alike as “two peas in a pod” (virtually the same)
are as physically alike as brothers and sisters are
do not look very much alike at all
ABOUT YOUR CHILDREN
1. Relationships with you
Every parent experiences all sorts of positive and negative feelings towards their
children, and these can be different with different children. Here are some
examples of feelings parents might have. For each item, please tick a box to
show us how often you feel this way with each of your twins.
Definitely
untrue
Somewhat
untrue
Not really
true or
untrue
Somewhat
true
Definitely
true
1. Sometimes I feel very
impatient with him/her
Older twin
Younger twin
45. 45
Definitely
untrue
Somewhat
untrue
Not really
true or
untrue
Somewhat
true
Definitely
true
2. I usually feel quite happy
about my relationship with
him/her
Older twin
Younger twin
3. Sometimes I am amused
by him/her
Older twin
Younger twin
4. Sometimes I wish he/she
would go away for a few
minutes
Older twin
Younger twin
5. Sometimes he/she makes
me angry
Older twin
Younger twin
6. I usually feel close to
him/her
Older twin
Younger twin
7. Sometimes I am
frustrated by him/her
Older twin
Younger twin
Not at all A little Somewhat Very Extremely
8. How much do you enjoy spending
time alone with your child?
Older twin
Younger twin
9. How much do you think your
child enjoys spending time alone
with you?
Older twin
Younger twin
46. 46
Not at all A little Somewhat Very Extremely
10. How satisfied are you with the
amount of time you spend alone
with your child?
Older twin
Younger twin
11. How satisfied do you think your
child is with the amount of time you
spend alone with him/her?
Older twin
Younger twin
12. Is it easy to be affectionate
towards your child?
Older twin
Younger twin
13. How affectionate is your child
towards you?
Older twin
Younger twin
14. How much do you care about
what your child thinks about you?
Older twin
Younger twin
15. How much does your child care
about what you think of them?
Older twin
Younger twin
16. How much do you think of your
child?
Older twin
Younger twin
17. How much do you nag your
child about what he/she is doing
wrong?
Older twin
Younger twin
18. How much does your child nag
you about what you are doing
wrong?
Older twin
Younger twin
19. How much do you criticise your
child?
Older twin
Younger twin
47. 47
Not at all A little Somewhat Very Extremely
20. How much does your child
criticise you?
Older twin
Younger twin
21. How often does your child get
into disagreements with you?
Older twin
Younger twin
22. How much do you enjoy being
your child’s parent?
Older twin
Younger twin
Appendix C: Telephone interview script
Telephone Interview Schedule
48. 48
Check consent form has been received – if not, do not proceed.
Flip coin to determine child1 child2 order.
Record family ID, date of interview, and interviewer’s initials on recording device.
Introduction
Hello, is that ................................? It’s ........................... from the Twin Development Study-
TFaB, we had arranged to conductthe telephone interview today, is this still a
convenient time for youto do this? It willlikely take around 30-40 minutes. Are you
somewhere that youfeel comfortable to talk freely? It may not be possible, but are you
able to be somewhere youare not going to be overheard?
Just before I start, can I checka few details with you? Can I ask you to confirmyour
address? The contactnumber I’ve got for youis …………………………., is this still the best
one to contact youon? Can you also confirm yourdate of birth? And that of …………………..
and ………………….. On the questionnaire you completed, youindicated that ………………….
is the first born twin, is this correct?Okay,thank you.
The interview is made up of several sections- we will begin by thinking about significant
life events, then I will ask youspecifically about ............................ There willthen be few
questions about yourself before I willask youspecifically about ...................... . The final
part willbe about
........................... and .........................’s relationship. Does that sound ok, do you have any
questions at this stage?
If neededfor further warmup – To begin with, can youtell me a little bit about a day that
you spent as a family recently that you really enjoyed?
1. Five Minute Speech Sample (1)
Now,for the next couple of parts I’d like youto think about………………………………………….
This part will feel a little bit odd, but I’d like to hear yourthoughts and feelings about
……………………………, in your ownwords and withoutme interrupting withany questions
or comments. When I ask you to begin, I’d like you to speak for 5 minutes, telling me
what kind of a person ……………………………… is and how the twoof youget along
together.
After you begin to speak, I prefer not to answer any questions until after the 5 minutes
are over,but I’ll tell you when yourtime is up. Do youhave any questions before we
begin? Okay great, whenever you’re ready
Appendix D: Five Minute Speech Sample Coding manual
49. 49
TFaB Five Minute Speech Sample Coding
Manual
(adapted from David Daley PFMSS coding manual)
Table of Contents
Coding Category Page
Global Codes:
Initial Statement 2 - 3
Warmth 4 - 5
Relationship 6
Emotional Over Involvement 7 - 8
FrequencyCodes:
Critical Comments 9
Positive Comments 10 – 11
Expressions of Change 12
50. 50
Initial Statement
The very first thought/utterance expressed by the parent which is
specifically about the child.
It is a global rating- rated as positive, neutral or negative.
Initial Statements which are notscored:
Statements that are not to do with the child.
“Oh, I don’t know what to say.”
“Five minutes, this is difficult.”
Positive initial statement:
A statement that expresses praise, approval, appreciation for the behaviour or
personality of the child.
“He’s a kind boy.”
A statement that indicates the parent and child have a good relationship.
“Charlotte and I get on really well.”
Neutral initial statement:
A statement which contains descriptive or factual information with little or no
tone.
“Sarah likes to draw.”
“Andrew is the older twin.”
A statement which is qualified by a condition
“He is a lovely boy except when he is tired.”
Statements of improvement
“He’s much better behaved now that he’s older.”
Statements in the past
“She was so cute when she younger.”
Statements which are both positive and negative are rated as neutral
“Libby is cute but very naughty.”
Negative initial statement:
A statement which describes the child’s personality or behaviour
unfavourably.
“David is a horrible boy.”
A statement which indicates an adverse relationship between parent and child
“ Elizabeth and I always get in to arguments.”
Warmth
The intensity of sentiment or feeling which parents express about their
child during the 5 minute speech sample.
It is a global rating- rated as high, moderate or low.
Consider tone of voice, spontaneity, concern or empathy.
51. 51
High Warmth
Tone of voice: Signs of enthusiasm when talking about child, positive
changes in tone when switching from neutral subjects to talking about child,
consider the respondents’ normal tone of voice and pitch as well as variations
in tone before making a rating.
Spontaneity: Expressions of affection, love, appreciation etc result in higher
ratings of warmth. Often parents elaborate on points they are making and in
doing so express positive feelings about their child
“She likes drawing, she’s always bringing me home pictures from play
school, in fact last week she drew me this picture of a castle, it was
very well drawn. I was very proud of her so I stuck it up in the kitchen
and I’ve been showing it to everyone who has called.”
Concern & empathy: Ability to demonstrate concern for their child as well as
demonstrate ability to see things from the child’s point of view or understand
what the child is going through.
“He really has difficulty concentrating, I mean it’s not really a problem
now but I do worry about how he is going to get on when he gets to
school next year.”
“I know he likes to watch Tellytubbies, but when I put the TV on he is
only able to watch for a few minutes before he is gone, playing with
another toy or looking out of the window, it must be terrible not being
able to sit still.”
Moderate Warmth
Tone of voice: Some evidence of change in pitch/tone when talking about
the child. The consistency of this would distinguish a high rating based on
tone.
Spontaneity: Some evidence of affection, love or appreciation of the child
but this is not expressed with enough intensity to warrant a high rating.
“He’s good at football, I think for his age, he’s got better co-ordination
than most children and is probably more athletic.”
Concern & empathy: Some evidence which demonstrates concern for their
child or sees things from their point of view
“She fights with most children she plays with, so they don’t usually stay
for very long, so she is quite lonely. I have tried to explain to her that
she has to be nice to other children otherwise they won’t want to play
with her.”
Low Warmth
Tone of voice: An absence of tone. Parent speaks about their child in a
monotonic voice with no voice modulation when talking about the child.
Spontaneity: Absence of spontaneity is where the respondent is more
matter of fact and just makes statements about the child
“She’s good at drawing.”
52. 52
(NB: these statements can still be rated as positive comments even though
they lack spontaneity.)
Empathy & concern: The parent talks about the child without any evidence
that they see things from the child’s point of view or understand what the child
is going through
“She grabs other toys from children, and then gets upset when they
won’t play with her, why does she do that when I tell her not to, it does
my head in.”
Caveats to coding warmth
1. Depression: Even if it is known that the parent is depressed, this
knowledge should be discounted when rating warmth.
2. Critical comments: The frequency of critical comments should not be
allowed to influence ratings of warmth
3. Stereotyped endearments: such as ‘love’ ‘poppet’ ‘pet’ may be used by
parents to describe their children and are not necessarily evidence of
warmth.
Relationship
The quality of the relationship and joint activities undertaken between
parent & child
It is a global rating- rated as positive, neutral or negative.
Consider parents’ reports of the relationship, parents’ reports that they
enjoy and value their time with their child.
Positive Relationship
A direct statement that the parent and child get along together is strong
evidence of a positive relationship. Unless this is contradicted elsewhere in
the speech sample, a positive rating would be made.
“Charlotte and I get on really well together.”
Parents’ report that they enjoy spending time with their child is indicative of a
positive relationship however it is not sufficient to just state that they spend
time together, they must indicate that enjoy/value the time.
“We often do some baking together during the week, we have such fun
mixing cake and making a mess.”
Neutral Relationship
If the relationship isn’t addressed as part of the speech sample as parents are
specifically asked to talk about the relationship they have with their child.
Unclear evidence- e.g. the parent makes a direct statement but includes a
qualifying/conditional term which weakens the positive relationship.
“We have an okay relationship.”
“We get on great together when her brother isn’t around.”
53. 53
The parent gives details of joint activities but does not indicate that they enjoy
or value them
“We go to the park all the time.”
Negative Relationship
Should be coded with caution!
Parent makes a direct statement about their relationship with the child which
is not contradicted elsewhere in the speech sample.
“We just don’t seem to get along. He ignores me.”
Emotional Over Involvement
Assessment of the level of emotional relationship between parent and
child.
It is a global rating- rated as high, moderate or low.
Consider self-sacrificing/over protective behaviour and lack of
objectivity.
It is important to rate EOI conservatively.
High emotionalover involvement
Evidence that the parent has sacrificed themselves in an extreme or unusual
manner for their child and that they do not enjoy such sacrifices.
“I was frightened to leave Sarah with a babysitter, so I gave up my
evening classes. I do really miss them but I had no choice.”
“He is so destructive, breaks all of his toys, I never have any money for
myself, it all goes on replacing his toys.”
Evidence that the parent always thinks their child is right, and always defends
their child’s behaviour.
“He fights with his sister but she always winds him up.”
Moderate emotionalover involvement
Some evidence that the parent has sacrificed themselves but not in an
extreme or unusual manner for their child and some indication that they do not
enjoy such sacrifices.
“I do worry sometimes when I leave her with my parents, as she can be
quite unpredictable. Sometimes I cancel going out if she’s been difficult
rather than leave her with my Mum and Dad.”
Evidence that the parent usually thinks their child is right and usually defends
their child’s behaviour.
“He fights with his sister, I’m sure she is usually the one who starts it
all.”
Low emotionalover involvement
No evidence of EOI or inconclusive evidence.
54. 54
Caveats to coding emotionalover involvement
1. When rating EOI based on overprotective behaviour, the concern must
be associated with leaving the child in someone else’s care and
concerned with the child’s wellbeing (ie they will come to harm or be
upset) and not a concern about the child’s behaviour in their absence
(ie concern that they’d have a tantrum, cause damage or be too much
for someone else to manage).
Critical Comments
Negative comments about the child’s behaviour and/or personality.
Compared unfavourably/negatively to co-twin
Code qualified & unqualified comments separately
Frequency count.
Scored on the basis of tone and critical phrases.
Critical phrases: Frequency of statements that criticise, find fault with the
child, use descriptive words which indicate a negative trait of the child and
typically said in a negative tone.
“Libby is a selfish girl.” (unqualified)
“Sarah is sometimes a nightmare to put to bed at night.” (qualified)
“Andrew is much more lazy than his brother.” (comparison to co-twin)
Tone: It is possible to score on the basis of tone, even if the content of the
statement doesn’t contain critical content. To do this, establish a baseline
level of tone for the respondent so that you are able to notice possible
fluctuations in tone which, depending on their direction, will denote positive or
critical comments.
Guidelines for scoringstrings of comments
Statements about related or similar behaviours are scored as one critical
comment.
“She’s destructive, she destroys her toys, my plants, everything.”
As these all relate to the child’s destruction, one critical comment is scored.
Statements about unrelated behaviours are coded as separate critical
comments
“Sarah’s a bad tempered girl, always grumpy and disobedient.”
‘Bad tempered’ and ‘disobedient’ are two unrelated behaviours so scored as 2
critical comments.
Caveats to coding criticalcomments
1. Do not code stereotyped descriptions unless accompanied by a
negative tone.
“She is such a monkey.” “He’s a scamp.”
55. 55
2. Critical comments must be the opinion of the respondent e.g.
“Elizabeth is argumentative” but not “Elizabeth’s teacher says she is
argumentative.”
3. Only code comments in the present or recent past. Anything that
refers to past phases if, if at all, only coded under ‘expressions of
change.’
Positive Comments
Statements of praise, approval or appreciation.
Compared favourably/positively to co-twin
Code qualified & unqualified comments separately
Frequency count.
Scored on the basis of tone and positive phrases.
Positive phrases: Frequency of statements that praise, or indicate
appreciation or approval for the child, use descriptive words which indicate a
positive trait of the child and typically said in a positive tone. Qualified positive
phrases are those which are accompanied by a word or phrase which ‘takes
the shine off’ the complement- e.g ‘sometimes kind.’
“David is a very thoughtful boy.” (unqualified)
“When she’s in the right mood Charlotte has a great sense of humour.”
(qualified)
“Libby is more intelligent than her sister.” (comparison to co-twin)
Some parents with poorer vocabulary may choose to talk around these issues
rather than use specific descriptive words- these descriptive phrases can also
be coded as positive phrases.
“She’s always making things out of old pieces of paper and boxes, she
can turn an old box into anything.”
Tone: It is possible to score on the basis of tone, even if the content of the
statement doesn’t contain positive content. To do this, establish a baseline
level of tone for the respondent so that you are able to notice possible
fluctuations in tone which, depending on their direction, will denote positive or
critical comments. Rate conservatively, if in doubt do not rate a positive
comment.
Guidelines for scoringstrings of comments
Statements about related or similar behaviours are scored as one critical
comment.
“She’s very musical, she plays the recorder very well and sings.”
As these all relate to the child’s musical ability, one positive comment is
scored.
Statements about unrelated behaviours are coded as separate positive
comments
“He’s a bright boy, and he’s very good at sport.”
56. 56
‘Bright’ and ‘sporty’ are two unrelated behaviours so scored as 2 positive
comments.
Caveats to coding positive comments
1. Do not code comments coined in the negative- “he’s a great kid, not.”
2. Only code comments on the present or recent past. Anything that
refers to past phases if, if at all, only coded under ‘expressions of
change.’
Expressions of Change
Any evidence of change or stability in the parent-child relationship –
namely closeness, conflict and autonomy.
It is a global rating- rated as high-stable, increasing, decreasing, low-
stable or no code.
Closeness
“We’ve always spent loads of time together.” (High-stable)
“She used to be difficult, but recently we have a strong relationship.”
(Increasing)
Conflict
“We have had more arguments since she started school.” (Increasing)
“He used to be jealous of the time I gave his to baby brother, but not so
much now.” (Decreasing)
Autonomy
“He relies on me for everything and always has done.” (low-stable)
“She now likes to choose her own clothes to wear.” (increasing)
