14
8081 Part1 Wk 3 Assignment
Student’s Name
Institution Affiliation
Date
8081 Part1 Wk 3 Assignment
Introduction
Home Life and Family
Amanda is a girl, she was born in Nigeria. She is the firstborn in the family. She has no siblings. Her family was very excited when she was born. Since the day she was born, the parents have become child-centric and don’t want to be away from the child for long. The support network is strong. The parents understand the biology of bonding. The bonding between mother and child develops due to the production of the hormone oxytocin. During pregnancy, the level of oxytocin rises. When the mother and the child touch, the level of oxytocin rises which makes the mothers want to be close with the child almost all of the time. ( Craig, 2021).
Amanda lives with her two parents but most of the time she spends with her mother when the father is at work. The father doesn’t get much time with the child because most of the time he finds her asleep. The father's involvement in the first stages of the child is increased. The father would take off from work just to spend time with the child. In the first stages of child development, fatherhood and motherhood are as deep. The more the father spends time with the baby, the more the and becomes strong. There are times when the mother goes to work and the father is left to take care of the baby. The mother usually takes primary care of the child. When Amanda cries, the mother is the first to take her. The mother is more vigilant in taking care of the baby than the father. ( Nabuzoka, & Empson, 2009).
Amanda is very noisy and likes to scream. To distract her, the caregiver has to use something noisy. The curiosity of Amanda is stimulated by the parents to enhance the coordination of the hands and the eyes. From a period of 6 weeks to three months, Amanda starts making vowel sounds and becomes more social, and will enjoy seeing faces and smiles when touched. The type of parenting for this period is attachment parenting. Amanda is the dearest of the parents. The parents of the child become child-centric and they both want to spend some time with the baby. The support network of the baby is very strong. The father's involvement at the early stages of the child's development is being increased. The father is connecting with the baby through touch. Most of the time off work will be spent with the baby. The hygiene of the infant is more emphasized by the person taking care of the baby. The baby will be cleaned regularly. Sickness hygiene of the baby will be observed where the mother will be careful to keep the environment around the baby clean from any germs that may cause sickness.
During this stage, Amanda learns to bond and trust her primary caregiver who is her mother, she seems to have mastered the sound of her mother, every time her mother talks she loos in the direction. There are times when she is crying and she hears her mother talk she pauses her cry. This is unlike ...
1. 14
8081 Part1 Wk 3 Assignment
Student’s Name
Institution Affiliation
Date
8081 Part1 Wk 3 Assignment
Introduction
Home Life and Family
Amanda is a girl, she was born in Nigeria. She is the firstborn
in the family. She has no siblings. Her family was very excited
when she was born. Since the day she was born, the parents
have become child-centric and don’t want to be away from the
child for long. The support network is strong. The parents
understand the biology of bonding. The bonding between
mother and child develops due to the production of the hormone
oxytocin. During pregnancy, the level of oxytocin rises. When
the mother and the child touch, the level of oxytocin rises which
makes the mothers want to be close with the child almost all of
the time. ( Craig, 2021).
Amanda lives with her two parents but most of the time she
spends with her mother when the father is at work. The father
doesn’t get much time with the child because most of the time
2. he finds her asleep. The father's involvement in the first stages
of the child is increased. The father would take off from work
just to spend time with the child. In the first stages of child
development, fatherhood and motherhood are as deep. The more
the father spends time with the baby, the more the and becomes
strong. There are times when the mother goes to work and the
father is left to take care of the baby. The mother usually takes
primary care of the child. When Amanda cries, the mother is the
first to take her. The mother is more vigilant in taking care of
the baby than the father. ( Nabuzoka, & Empson, 2009).
Amanda is very noisy and likes to scream. To distract her, the
caregiver has to use something noisy. The curiosity of Amanda
is stimulated by the parents to enhance the coordination of the
hands and the eyes. From a period of 6 weeks to three months,
Amanda starts making vowel sounds and becomes more social,
and will enjoy seeing faces and smiles when touched. The type
of parenting for this period is attachment parenting. Amanda is
the dearest of the parents. The parents of the child become
child-centric and they both want to spend some time with the
baby. The support network of the baby is very strong. The
father's involvement at the early stages of the child's
development is being increased. The father is connecting with
the baby through touch. Most of the time off work will be spent
with the baby. The hygiene of the infant is more emphasized by
the person taking care of the baby. The baby will be cleaned
regularly. Sickness hygiene of the baby will be observed where
the mother will be careful to keep the environment around the
baby clean from any germs that may cause sickness.
During this stage, Amanda learns to bond and trust her primary
caregiver who is her mother, she seems to have mastered the
sound of her mother, every time her mother talks she loos in the
direction. There are times when she is crying and she hears her
mother talk she pauses her cry. This is unlike with her father.
She enjoys playing with her mother, listening to music, and
simple games. ( Whitehead, 2009).
The parental experience of Amanda’s parents has been
3. fascinating, they have enjoyed it every step of the way. The
parents like to tickle the child and watch her smile. At the age
of three months, Amanda had learned to respond to her parent's
smile. She had learned to track objects with her eyes. In the
fourth month, Amanda had earned to manipulate the
environment around her and use various tools, her parents had
bought her a cuter princess doll that produced sounds when
squeezed. She learns to make certain sounds as she plays with
her favorite toy. Her favorite game that she enjoys playing with
her parents is peekaboo.
When Amanda was 12 months old .she seems to understand
some of the common words that her parents used often. She
often uses the same words to refer to different things. as time
goes by she learns new words.
Community and Culture
The child lives in Nigeria, Africa. The common language that is
spoken is the area where Amanda was born and lives in Hausa.
Hausa is a language that is spoken in the Northern side of
Nigeria. Other languages are spoken in the community where
Amanda libs sis Yoruba and Igbo. Her mother seems to be very
dedicated to helping the child learns to speak. Amanda’s mother
is dedicated to helping her child thrive despite the development
challenges. Her parents invest a considerable amount of time
and effort in helping their child in her developmental stages.t
home, Amanda’s parents usually speak English and they have
been interacting with her using English since she was born.
However, there are times that they use some words in mothering
but it is often rare. The home language that is often used in
Amanda’s home is Hausa. This is the language that the parents
use to communicate while at home. When they are interacting
with the child, they like shifting to English.
The family experiences and receives a lot of social support from
the community. It is the tradition that young mothers be visited
often and be helped with different chores. The child interacts
with different people speaking different languages. The
language that is spoken by most people is the Hausa language.
4. People usually interact with the child with the Hausa language.
The parents of the child strongly believe in learning the English
language. they believe that English is the official language and
learning English will give the chod an added advantage. English
is the dominant language in Nigeria. It is the language that is
used by the government, the schools, and the community. The
parents of the child do not want their child to be in a dilemma
of not understanding the English language. they want their child
to be bilingual. By being bilingual, Amanda would understand
and be able to express herself in two languages, English and
Hausa. The parents believe that by their child learning to speak
English, she will be more creative and will also have an easier
tie when trying to learn the languages. The opportunities that
are available for language literacy for Amanda is that her
parents are engaged and committed through encouraging
conversations to assist their child to learn the languages. (
Kümmerling-Meibauer, 2011).
Section 2:Parental and Infancy
Amanda’s development aligned with the milestones of typically
developing children. The developmental milestones and
physicals were portrayed by Amanda in her physical stage as
she was growing. Her parents had a watchlist calendar that
included the developmental milestones to check if their children
were developing normally. Amanda did not need a more detailed
checkup because she was normal. Between 8-12 months,
Amanda was paying increasing attention to the speech, she was
able to easily respond to simple verbal requests. She
understands when he is told no. She was able to use simple
gestures such as shaking her head when saying “No”.She was
able to babble with inflection. At 12 months she was able to say
“Mama” and “Dada”.She also tried to imitate some of the words
that she heard often. Unlike when she was few months old when
she was friendly with strangers, at 12 months, she is anxious
and shy when she is held with strangers. She cries when she is
left with strangers and her parents leave. She had certain
preferences for toys and certain people. She repeats certain
5. sounds and gestures that are positively reinforced for attention.
The developmental alignments that did not align include that
she was not able to stand when supported, some of the gestures
took long to learn such as waving her hand. ( Meier, 2004).
The factors that supported language acquisition and
development for Amanda were the relationship that she had with
the family members. Amanda receives proper parenting from her
parents which reduces anxiety. The child felt more secure to
spend more time with her parents which facilitated mo faster
language acquisition and development. Amanda being a girl had
an added advantage. Girls are better at mastering speech and
being fluent as compared to boys. The other factor that
supported language acquisition and development for Amanda is
motivation from the parent. She also received a lot of support at
home. She had a lot of exposure from her parents which
contributed to he comprehension and acquisition. The family
speaks more than one language. The primary caregivers of the
child usually speak more often to the child hence stimulating
the child to speak. When the adults speak to the child they
increase the scope of language development and acquisition.
The domains overlapped with Amanda’s acquisition of language
by the parents of the child meeting the emotional cognitive and
social needs. The parents especially interacted with the child
often by talking t her, singing, playing games with her. The
mother of the child often read to the child. This helped
stimulate the language skills of the child. Reading is a key to
introducing the child to the language. Infants learn new sounds
daily. The physical domain was very important for the child's
language acquisition. The caregivers provide a lot of spoken
language. ( Meier, 2004).
The child’s environment that supports the connection between
the domains is the social environment which involves the
relationship of the child with the parents and the people in the
community. Language and social-emotional domains. Language
development is dependent on other developmental domains. The
environment of the child supports the language development
6. where the parents read and talk to the child even before they
could speak their first word. Infants can acknowledge when
somebody is conveying something for their advantage and along
these lines to understand data uniquely in contrast to when they
only observe it. At the point when grown-ups utilize the eye to
eye contact, call a child's name, and point for the child's
advantage, these signs lead children to perceive that somebody
is showing them something, and this mindfulness can influence
how and what they realize. ( Plural Publishingrporated. 2018).
Language acquisition was strongly impacted by physical and
social-emotional development. The child experienced
significant and obvious change none domain at a time. For
example, when the child was learning to walk, which is in the
physical domain, their ere no progress in language development.
During language development and acquisition of the child, other
domains experienced less change and were less prominent.
Cognitive development includes the intellectual development of
the child develops the ability to pay attention and to process
thought. The social and emotional domain is where the child
grows to understand and control their emotions. they understand
what others want and feel. The child in this domain also learns
to interact with others. Interacting with others helps in language
development and acquisition. The language and the literary
skills of the child develop at different stages. It starts with
creating sounds of speech to understanding the syntax of the
language where the child understands the grammar and can put
sentences together.
The family and cultural influences that impacted the child's
language acquisition was the input that the child received from
her environment. Culture affects the parenting style. From the
early stages of infancy, parents talk to their children differently
which affects their language development and acquisition.
Parents prepare children on how they interact with others.
Culture molds the behavior of the children and their thinking
patterns which affects their language development and
acquisition. ( Wang, 2014).
7. The caregiver of the child provided opportunities for language
acquisition and development by talking, reading, and sing to the
child even before she could speak her first words. The frequent
interaction with the child played a huge impact on language
development the language that the parents were using when they
were interacting with the child provided a great opportunity.
The interaction with the child creates an environment where the
child can learn and begin to talk. In the early stages of child
development, the child undergoes different changes in different
domains. The language exposure from parents and caregivers
provides an opportunity for the child to learn a language.
Caregivers who respond to their children through verbal
descriptions and questions make children more receptive to
language. The culture that influenced the child’s language
acquisition is her mother talking reading and singing to her. The
book that she often read was “The Very Hungry Caterpillar” She
also liked to watch “Sesame Street”.( Becker, & Deen, 2020).
Section 3: Amanda as a Toddler
Amanda at this stage is able to communicate with her parents.
When compared with other children in terms of language
development, Amanda’s life follows a general developmental
milestone. She cannot be termed as having delayed her language
development. By the time she was 12 months old, Amanda
would look for and find out and identify where sound is coming
from. She would respond to her name when called by her
parents and other people both relatives and neighbours. Often,
when a ‘goodbye’ is said to her, she would wave back. Her
parents and caregivers, told her to look at something, she
looked at the place pointed. Amanda began speaking with
intonation where she would raise and lower her voice as if she
is speaking in sentences. Another remarkable milestone was the
capacity of Amanda to take turns in speaking (Mary L. Gavin,
2019). Amanda would be spotted listening an paying attention
to hr parents and in return, she would babble.
Amanda just began to say da-da to imply dad and ma-mama for
8. mom. She then began to say words, singly and point at items
that she needed when they are out of reach (Mary L. Gavin,
2019). Amanda often would point at things while making
sounds.
Between the age of 1 and 2, Amanda denoted further language
development. She started to follow simple commands. The
sequence followed was that when an adut spoke and
demonstrated with gestures, Amanda understood and responded.
Later on, Amanda began to understand commands issues
through words alone (Supporting Language and Literacy Skills
from 12–24 Months, 2021). For instance, she would be sent to
bring her toy from a box, she would also say yes or no when
asked if she wanted something. Amanda advanced her language
acquisition such that she would be sent to get something from a
diferent room and she could easily name a few of her body
parts. She would touch and say head, eyes, ears, mouth, nose.
In addition, Amanda had her favorite songs (itsy bitsy spider)
and cartoon, when aired, Amanda would often point at them,
calling mom to get her to lok at them. she would again go to her
room and pick her favorite dress and bring it to her mom to
dress her. Due to her interaction with smartphones, Amanda
would disntinguish a locked phone from an unclocked one.
When she needed to use the phone, Amanda takes the phone to
her mother and says ‘open’ to mean unlock. Notably, Amanda
would play her favorite music in the phone and try to repeat the
words and the rhythm (Association, 2021).
Another rimportant observation that may be said to have
contributed to amandas language acquisition, was her unique
manner of asking question. Often, Amanda would bring things
to he rparents or caregivers and ask them to say what it is. For
instance, she would bring a book, a pen, or anything and show
her caregiver waiting to hear what name it would be given.
Amanda learnt to anme fruits through this strategy and her
inquisitive nature. Amanda’s parents also acquired some boks
that had pictorial illustration og common objects such as fruits,
utensils, clothes, toys etc. Amanda would read the book
9. together with the caregiver. She got opportunities to name the
objects and associating names with pictures (Rachel Cortese,
2021). This was facilitated through questioning by caregivers
who read the book by asking Amanda ‘what is this?.
Amanda as a toddler acquired her language further through
pretence. Amanda spent most of her time with her mother and at
other instances with her female caregiver. Hence, she would
imitate cooking and pretend to be making her favorite dish. She
would also mimic the role of a mother and pretend to be
cleaning and feeding her dolls. This way, Amanda learnt the
food vocabulary and child care vocabulary such as sorry, eat,
cry, laugh, smile, sick, hungry. Learning these words did not
occur instantly, ech week, Amanda would add a new word to her
vocabulary and it continued to get richer and richer.
By the age of two years and some months, Amanda had
developed really rich vocabulary. She began to name her body
parts and common objects. She also started to understand
commands issued as a sentence (Gallagher, 2013). For instance,
she understood phrases such as ‘take your tea’, ‘bring your
shoes’, ‘put the doll on the couch’, ‘lets go out and play’ amng
other things. She also started to make two-word phrases such as
‘give water’, ‘want mom’, ‘daddy go’. Slowly by slowly, she
increased the length of her sentences from two words to three or
four words. For instance, she would say ‘ I want water’, ‘bye
bye mom’, ‘I want to play’. In other words, Amanda started to
have conversations and be understood by adults.
At this stage, communicating with Amanda became one of the
most pleasurable and rewarding moments for the parents and
caregivers. It was evident that Amanda was absorbing new
information everyday through her own experiences and through
intercations with other children, her parents and through the
television (Gallagher, 2013). Family members were the most
commonly involved in cmmumicating with Amanda. It became
necessary that amanda’s parents initiated more interactive and
play like conversations so as to trigger Amanda to speak more
and more. There were scheduled periods for reading books,
10. singing, playing word games nd simply speaking with Amanda
(Rachel Cortese, 2021). These strategies are used to help
toddlers to build more amd more of their vocabularies. They
also teach listening skills and comprehension.
Amanda’s parents would often be found angaging Amanda
through talking to her about what she is doing, what she is
planning to do, what she thinks about something or simply
asking her about the day. The books bought for Amanda were
read repeatedly over and over again and parents would often
pretend to be reading so that Amanda reads the familiar words.
It was evident that Amanda was making huge steps in language
acquisition. she successfully followed two steps instructions
and increased her sentences. For instance, she would understand
pharces such as ‘ go outside and bring the ball to mom’, or ‘go
to the bedroom and bring me your sandles’. Amanda’s
vocabulary was more than 50 and near a hundred. By the time
Amanda was nearing 3 years of age, her vocabulary was more
than 200 (Rachel Cortese, 2021). She would string together upto
four words to form a sentence. Notably, Amanda would
understand more than she spoke. Some words would not come
out clearly, but she understood nearly all instructions. About 80
percent of Amanda’s language could be understood by her
parents and those who interacted with her in one way or another
(Rachel Cortese, 2021). Amanda by this time could use her
language feely as can be seen in the way she engaged in
question and answer sessions with her family and caregivers.
Amanda made an additional huge steps. She understood numbers
and culd count upto three objects. she also started to tell stories.
For instance, she would tell what she has done during the day.
She understood meaning of playing, sleeping, eating, going to
mention but a few. Amanda then developed huge interest in
learning her two names. She also developed interest in learning
the names of her parents and the new sibling who had just
joined the family. Although words are the predominant way
through which Amanda communicated, her parents did not
overlook the value of non-verbal communication. In orde to
11. increase amanda’s chances of learning to communicate. For
example, her mother would frown when Amanda made a mistake
and smile broadly when she did something right.
In summary, there are a few notable strategies that amanda’s
parents used to increase and expand amanda’s language
acquisition; they imitated her words and sounds so that she
could also imitate theirs, interpreted what she pointed by saying
words aloud, they expanded and recasted her already acquired
vocabulary, they often commented and described what they were
doing with Amanda, responded instantly to her, ensured tey
took turns when speaking with Amanda and labellled praises
(Rachel Cortese, 2021). These are just a few ways through
which Amanda’s parents helped expand Amanda’s vocabulary
and language acquisition.
12. References
ASHA. (n.d.). Activities to Encourage Speech and Language
Development. Retrieved from ASHA Organization: Activities to
Encourage Speech and Language Development
Association, A. S.-L.-H. (2021). Activities to Encourage Speech
and Language Development. Retrieved from Reading Rockets:
https://www.readingrockets.org/article/activities-encourage-
speech-and-language-development
Becker, M., & Deen, K. U. (2020). Language acquisition and
development: A generative introduction. MIT Press.
Craig, M. (2021). The young reader: A game plan for parents to
teach their little ones how to read and problem solve. Basil Sun
Publishing.
Gallagher, N. G.-N. (2013). More than baby talk: 10 ways to
promote the language and communication skills of infants and
toddlers. Chapel Hill: The University of North Carolina, FPG
Child Development Institute., 1-24. Retrieved from
https://fpg.unc.edu/sites/fpg.unc.edu/files/resource-
files/BabyTalk_WEB_2015.pdf
Kümmerling-Meibauer, B. (2011). Emergent literacy: Children's
books from 0 to 3. John Benjamins Publishing.
Mary L. Gavin, M. (2019, June). Communication and Your 2- to
3-Year-Old. Retrieved from Kids Health Organization:
https://kidshealth.org/en/parents/comm-2-to-3.html
Meier, D. R. (2004). The young child's memory for words:
Developing first and second language and literacy. Teachers
College Press.
Nabuzoka, D., & Empson, J. (2009). Culture and psychological
development. Macmillan International Higher Education.
Plural Publishingrporated. (2018). The role of the speech-
language pathologist in RtI: Implementing multiple tiers of
student support. Plural Publishing.
Rachel Cortese, M. C.-S. (2021). Helping Toddlers Expand
Language Skills. Retrieved from Child Mind Institute:
13. https://childmind.org/article/helping-toddlers-expand-their-
language-skills/
Rowland, C. (2013). Understanding child language acquisition.
Routledge.
Supporting Language and Literacy Skills from 12–24 Months.
(2021). Retrieved from Zero To Three Organization:
https://www.zerotothree.org/resources/1285-supporting-
language-and-literacy-skills-from-12-24-months
Wang, X. (2014). Understanding language and literacy
development: Diverse learners in the classroom. John Wiley &
Sons.
Whitehead, M. (2009). Supporting language and literacy
development in the early years. McGraw-Hill Education (UK).
8081MD3 Wk 5 Assignment “ Preschoolers “
Please refer to sections 1-3 to add and and complete sections 4-
5.
Section 4: Week 5: Preschoolers (about 3 to 5 years old) (4
pages)
· Write a 4 page continuation describing the preschool
developmental stage….. of your child.. remember to refer back
to section 1-3.
Just as this module is split into four distinct developmental
stages (prenatal and infancy, toddlers, preschoolers, and
kindergarteners), so too is Part 1 of your Assignment. As you
study the material in each week, consider how you will build
each developmental stage of your child’s language development
journey. You will complete the sections as follows:
Section 1: Week 3: Introducing Your Child: Home Life, Family,
Community, and Culture (4 pages)
14. Section 2: Week 3: Prenatal and Infancy (about age 1) (4 pages)
Section 3: Week 4: Toddlers (about 1 to 3 years old) (4 pages)
Section 4: Week 5: Preschoolers (about 3 to 5 years old) (4
pages)
Section 5: Week 6: Kindergarteners and Primary School-Age
Children (about 5 to 8 years old) (4 pages)
· Review the document titled A Language and Literacy
Development Journey Outline.
· Review the Kaltura instructions presented in the course
navigation menu. Take time to view the tutorials and consider
which might work best for your story and technical expertise.
· Think of a child you may know or a type of child to whom you
may feel drawn.
· Review the resource from the American Speech-Language-
Hearing Association (n.d.). Take your time reviewing the
milestones and suggested activities for each stage
The following resources and course text should be reviewed
before you participate in the Assignment:
https://www.asha.org/public/speech/development/chart/
https://childdevelopmentinfo.com/c hild-
development/language_development/
INFANT BEHAVIOR AND DEVELOPMENT 9, 1X3-150
(1986)
Prenatal Maternal Speech Influences
Newborns’ Perception of Speech Sounds*.
ANTHONY J. DECASPER AND MELANIE J. SPENCE
15. University of North Carolina at Greensboro
Pregnant women recited a particular speech passage aloud each
day during their
last 6 weeks of pregnancy. Their newborns were tested with an
operant-choice
procedure to determine whether the sounds of the recited
passage were more
reinforcing than the sounds of a novel passage. The previously
recited passage
was more reinforcing. The reinforcing value of the two passages
did not differ for
a matched group of control subjects. Thus, third-trimester
fetuses experience
their mothers’ speech sounds and that prenatal auditory
experience can in-
fluence postnatal auditory preferences.
prenatal sensory experience auditory perception newborn
perception
fetal experience prenatal learning speech perception moternol
voice
Human newborns do not act like passive and neutral listeners.
They prefer
their own mothers’ voices to those of other females, female
voices to male
voices, and intrauterine heartbeat sounds to male voices, but
they do not prefer
their fathers’ voices to those of other males (Brazelton, 1978;
DeCasper &
Fifer, 1980; DeCasper & Prescott, 1984; Fifer, 1980; Panneton
& DeCasper,
1984; Wolff, 1963). Why should newborns prefer some sounds
over others?
One hypothesis is that their auditory preferences are influenced
16. by prenatal ex-
perience with their mothers’ speech and heartbeats (DeCasper &
Prescott,
1984). Several considerations suggest this hypothesis is
plausible.
Third-trimester fetuses hear, or are behaviorally responsive to,
sound
(e.g., Bernard & Sontag, 1947; Birnholz & Benacerraf, 1983;
Grimwade,
Walker, Bartlett, Gordon, & Wood, 1971; Johansson,
Wedenberg, & Westin,
1964; Sontag & Wallace, 1935). Intrauterine recordings taken
near term indi-
cate that maternal speech and heartbeats are audible in utero
(Querleu &
Renard, 1981; Querleu, Renard, & Crepin, 1981; Walker,
Grimwade, &Wood,
1971). Nonmaternal speech, for example male speech, is less
audible because
of attenuation by maternal tissue and/or masking by intrauterine
sounds
(Querleu & Renard, 1981; Querleu et al., 1981).
* This research was supported by a Research Council Grant
from the University of North Carolina
at Greensboro and a generous equipment loan by Professor
Michael D. Zeiler. We wish to thank
the medical and administrative staff of Moses H. Cone Hospital,
Greensboro, NC and, especially,
the mothers and their infants for making this research possible.
Thanks also to G. Gottlieb, R.
Harter. R. Hunt, R. Panneton. K. Smith, and, especially, W.
Salinger for their helpful comments
on drafts of the manuscript. Portions of this paper were
presented at the Third Biennial Interna-
17. tional Conference on Infant Studies, March 1982. Austin, TX.
Correspondence and requests for reprints should be addressed to
Anthony J. DeCasper,
Department of Psychology, University of North Carolina at
Greensboro, Greensboro, NC 27412.
133
134 DECASPER AND SPENCE
The newborns’ preference for their own mothers’ voices
requires that
they had some prior experience with her voice, but there is no
evidence that the
necessary experience occurred after birth. Fifer (1980) failed to
find any relation
between maternal-voice preference and postnatal age, whether
the newborns
roomed with their mother or in a nursery, or whether they were
breast fed or
bottle fed. Since the maternal voice is audible in utero, and
since third-trimester
fetuses can hear, perhaps the necessary experience occurred
before birth. In
contrast, newborns show no preference for their own fathers’
voices, even if
they had explicit postnatal experience with his voice. Since
male voices are not
very audible in utero, perhaps the absence of a paternal -voice
preference indi-
cates the absence of prenatal experience with his voice
(DeCasper & Prescott,
1984). The correlations between the presence or absence of
18. specific-voice sounds
before birth, and the presence or absence of specific-voice
preferences after birth
suggest that prenatal auditory experiences influence the earliest
voice preferences.
Consider that complex auditory stimuli can function as positive
rein-
forcers, neutral stimuli, or negative reinforcers of newborn
behavior. Known
reinforcers include vocal-group singing, solo female singing,
prose spoken by a
female, synthetic speech sounds, and intrauterine heartbeat
sounds (Butter-
field & Cairns, 1974; Butterfield & Siperstein, 1972; DeCasper,
Butterfield, &
Cairns, 1976; DeCasper & Carstens, 1981; DeCasper &
Sigafoos, 1983). On
the other hand, male speech and instrumental music lack
reinforcing value,
while white noise and faster-than-normal heartbeat sounds are
aversive (Butter-
field & Siperstein, 1972; DeCasper & Prescott, 1984; Salk,
1962). The differen-
tial reinforcing effectiveness of these sounds seems to covary
more with their
similarity to sounds that were present in utero than with any
general acoustic
characteristic(s), which further suggests that prenatal auditory
experience in-
fluences postnatal auditory perception.
Finally, prenatal auditory experience has been shown to cause
postnatal
auditory preferences in a variety of infrahuman species (e.g.,
Gottlieb, 1981;
19. Vince, 1979; Vince, Armitage, Walser, & Reader, 1982).
The hypothesis implies that prenatal experience with maternal
speech
sounds causes some property of the sounds to be differentially
reinforcing
after birth. Speech sounds enable at least two kinds of
discriminations; some
speech cues allow discrimination of language-relevant sounds,
per se, or what
is said, and some allow discrimination of the speaker or source
of the speech
sounds (Bricker & Pruzansky, 1976; Studdert-Kennedy, 1982).
Thus, the pre-
natal experience hypothesis implies that newborns prefer their
own mothers’
voices, regardless of what she says, because of prenatal
experience with her
voice-specific cues. This implication, however, cannot be
directly tested for
obvious ethical and practical reasons. The hypothesis also
implies that new-
borns will prefer the acoustic properties of a particular speech
passage if their
mothers repeatedly recite that passage while they are pregnant.
We directly tested the latter implication in the following way.
First, preg-
nant women tape-recorded three separate prose passages. Then,
they recited
PRENATAL AUDITORY LEARNING 135
one of the passages, their target passage, aloud each day during
20. the last 6 weeks
of pregnancy. After birth their infants were observed in an
operant learning
task where recordings of the target passage and a novel passage,
one their
mothers had recorded but had not recited, were both available as
reinforcers.
Then their relative reinforcing effectiveness was evaluated. If
the prenatal ex-
perience with the target passage increases its reinforcing value
then: (a) the
acoustic properties of the target passage will be more
reinforcing than those of
a novel passage; (b) the differential reinforcing value of the
target passage
should be carried by its language-relevant cues and, thus,
should not require
the presence of the infant’s own mother’s voice cues; and (c)
the reinforcing
values of the target and novel passages should not differ for
control newborns
who had never been exposed to either passage.
METHOD
Prenatal Phase
Pregnant Subjects. Thirty-three healthy women approximately 7
Yz
months pregnant were recruited from childbirth preparation
classes after being
informed about the project. All were experiencing
uncomplicated pregnancies.
Prenatal Procedures. After becoming familiar with three short
children’s
21. stories they tape-recorded all three. Recordings were made in a
quiet room on an
Akai 4000 stereophonic tape recorder. The tapes would be used
as reinforcers
in a postnatal learning task. Each woman was then assigned one
of the stories
as her target story. Assignment was made after all three had
been recorded to
prevent them from biasing the recording of their target, for
example, by ex-
aggerated intonation.
The women were instructed to read their target story aloud “two
times
through each day when you feel that your baby (fetus) is awake”
and to “read
the story in a quiet place so that your voice is the only sound
that your baby
can hear.” They maintained a log of their daily recitations and
were occasion-
ally checked by the researchers.
Story Materials. The stories were The King, the Mice, and the
Cheese
(Gurney & Gurney, 1965), the first 28 paragraphs of The Cat in
the Hat (Seuss,
1957), and a story we called The Dog in the Fog, which was the
last 28 para-
graphs of The Cut in rhe Hut with salient nouns changed. The
three stories
were about equally long, they contained 579, 611, and 642
words, respectively.
Each could be comfortably recited in about 3 min. Each was
also composed
from equal size vocabularies of 152, 142, and 154 words,
respectively. Salient,
22. high-frequency nouns common to at least two stories were
changed. For exam-
ple, cat and hat in The Cut became dog and fog in The Dog, and
cat and dog
from those stories became turtle and zebra in The King. The Cat
contained 46
unique words (i.e., words that appeared only in The Cat), which
accounted for
22% of the total word count; The Dog contained 57 unique
words, which ac-
counted for 22% of the total word count; and The King
contained 85 unique
136 DKASPER AND SPENCE
words, which accounted for 44% of the total word count. All
three stories con-
tained common high-frequency words. For example, a, all, and,
did, do, he, I,
in, like, not, now, of, said, that, the, to, with, and you occurred
at least three
times in each. The common high-frequency words accounted for
43% of The
Cat, 38% of the The Dog, and 36% of the The King. The
remaining words oc-
curred at least once in at least two of the stories. The stories
also differed in
prosodic qualities, such as patterns of syllabic beats. Thus, they
differed in the
acoustic properties of individual words as well as in prosody.
The Cat and The
Dog sounded more similar to each other than either did to The
King, but we
could readily identify the origin of short (several seconds)
23. segments from all
three.
Postnatal Phase
Experienced Newborns. Sixteen of the 33 fetal subjects
completed test-
ing as newborns. The 16 had been prenatally exposed to their
target story an
average of 67 times or for about 3.5 hours in all. They were
tested at an average
age of 55.8 hours (SD= 10). Each had to have had an
uncomplicated full-term
gestation and delivery, a birth weight between 3500-3900
grams, and APGAR
scores of 8, 9, or 10 at 1 and 5 min after birth. If a subject was
circumcised, he
was not tested until at least 12 hours afterward. Parents gave
informed consent
for the testing and were invited to observe.
Seventeen infants were not tested or did not complete a test
session: 5
because their mothers failed to return their logs, 4 because they
encountered
intrapartum or postpartum difficulties, 5 failed to meet state
criteria at the
time of testing or cried, and 3 subjects’ sessions were
unavoidably interrupted.
Apparatus. Sessions occurred in a quiet, dimly lit room adjacent
to the
nursery. The infants lay supine in their bassinets and wore
TDH-39 earphones,
which were suspended from a flexible rod. They sucked on a
regular feeding
24. nipple with the hole enlarged to 1 mm. Rubber tubing connected
the nipple to
a Statham P23AA pressure transducer that was connected to a
Grass poly-
graph and solid state programming and recording components.
Each infant
heard a tape recording of his/her target story and a tape
recording of a novel
story, one of the others their mother had recorded but not
recited. Both stories
were recorded by the same woman, and each was played on
separate channels
of the stereo recorder. The tape ran continuously, and sound
was electronically
gated to the earphones by the automated programming
equipment. Intensities
averaged 70 dB SPL at the earphones.
Testing Procedures. Sessions began about 2.5 hours after a
scheduled
feeding in order to maximize the chance of obtaining an awake,
alert, and
cooperative infant (Cairns & Butterfield, 1974). Each infant was
brought to a
quiet-alert state before testing could begin (Wolff, 1966) and
had to visually
fixate and follow an experimenter’s face when he/she spoke to
the infant. (If
PRENATAL AUDITORY LEARNING 137
the infant was not alert and did not fixate or follow, he/she was
returned to
the nursery, and another attempt was made after a later
25. feeding.)
The infant was then placed supine in the bassinet and the
earphones were
locked in place. One researcher, who could not be seen by the
infant and who
was blind to the exact experimental condition in effect, held the
nonnutritive
nipple loosely in the infant’s mouth. Another monitored the
equipment. The
infant was then allowed 2 min to adjust to the situation and had
to emit sucks
having negative pressures of at least 20-mm Hg, a pressure
normally exceeded
by healthy infants. (If the infant failed to suck adequately,
he/she was returned
to the nursery, and another attempt was made after a later
feeding.)
Testing began with 5 min of baseline sucking during which no
voices were
presented over the earphones. Unconstrained nonnutritive
sucking occurs as
groups or bursts of individual sucks separated by interburst
intervals of several
seconds. A sucking burst was defined as a series of individual
sucks separated
from one another by less than 2 s; when 2 s elapsed without a
suck the equip-
ment registered the end of the burst. Thus, interburst intervals
(IBIS) began 2 s
after the last suck of one burst and ended with the onset of the
the first suck of
the next burst. This criterion accurately captures the burst-pause
pattern of
newborns’ nonnutritive sucking (see Figure 1). IBIS tend to be
26. unimodally dis-
tributed for individual infants, and modal values vary between
infants. The
baseline was used to estimate the distribution and median value
of each infant’s
IBIS just before reinforcement began. Differential
reinforcement of IBIS began
after baseline had been established. (Hereafter, if the infant
stopped sucking
Figure 1. Polygraph record of a newborn’s nonnutritive sucking.
Wide horizontal
marks indicate the onset and offset of o sucking burst. The time
between the end
of one burst and the beginning of the next denotes on interburst
interval. Onset
of the narrow event mork denotes that the time criterion, t
seconds, has elapsed
since the end of the last burst. Vertical lines indicate time in
seconds.
138 DECASPER AND SPENCE
for two 1-min periods for any reason, he/she was returned to the
nursery and
not tested again.)
Reinforcement Contingencies. For eight randomly selected
infants, suck-
ing bursts that terminated IBIS equal to or greater than the
infants’ baseline
medians (t) produced the recording of a woman’s voice reciting
the target story.
Bursts terminating IBIS less than the baseline median were
27. reinforced with the
same woman’s recording of a novel story. Thus, only one of the
two stories
was presented binaurally with the first suck of a burst and
remained on until
the burst ended. Reinforcement contingencies were completely
controlled by
the solid-state equipment. Reinforcement contingencies were
reversed for the
other eight newborns, to control for the effects of any response
bias that might
arise from either of the contingencies or from changes in the
behavioral dis-
positions of the infants, for example, arousal or fatigue.
Differential reinforce-
ment lasted about 20 min.
The same differential reinforcement procedures were used in
earlier voice-
preference studies (DeCasper & Fifer, 1980; DeCasper &
Prescott, 1984). The
rationale is based on well established reinforcement procedures
that differenti-
ate the temporal properties of behavior: Differentially
reinforcing a range of
IBIS causes the shorter differentially reinforced IBIS to
increase in frequency
(see newborn studies by DeCasper & Fifer, 1980; DeCasper &
Sigafoos, 1983;
as well as animal studies by Anger, 1956; Catania, 1970;
DeCasper & Zeiler,
1977; Malott & Cumming, 1964).
Subject Controls. Twelve control newborns matched to a
prenatally ex-
perienced counterpart on sex, race, and median interburst
28. interval of baseline
were also tested. They met the same selection criteria and were
tested under ex-
actly the same conditions as their counterparts, but their
mothers had never
recited any of the three stories.
Other Experimental Controls. The influence of mother-specific
voice
cues on the reinforcing effects of the target stories was
controlled by having
nine newborns reinforced with recordings made by their own
mother and seven
with recordings made by some other infant’s mother. Both
stories heard by an
infant were recorded by the same woman to insure that their
reinforcing value
could not be unequally influenced by the speaker’s voice
characteristics. The
acoustic properties of any one story could not systematically
influence the re-
inforcing value of the target because each of the three stories
had served as the
target at least four times. No particular combination of
target/novel pairings
could systematically influence the reinforcing vaiue of the
target because five
of the six possible target/novel pairings occurred at least twice.
Unpredictable
subject loss prevented precise counterbalancing of voices and
target/novel
pairings (see Table 1).
TA
53. .2
8
.0
6
.1
8
.3
1
.1
6
.1
4
.0
3
140 DECASPER AND SPENCE
Data Analysis. Interburst intervals were read off the polygraph
records.
Times between the event marks signalling the end of one burst
and the begin-
ning of the next burst were measured and rounded down to the
nearest whole
second (see Figure 1). Thus, the scorers (AJD and MJS), who
were highly prac-
ticed, did not have to make detailed judgments about IBI values
that might
54. bias the data. Interscorer reliability approached 100%.
Next, each subject’s IBIS from the baseline and reinforcement
phases
were converted to a proportion of their time criterion (t). For
example, if t =4
s then all 2-s IBIS had the value O.Sf, and if t = 6 s then 2-s
IBIS had the value of
0.331. Converted IBIS were grouped into bins that were 0.21 s
wide; Bin 1 con-
tained IBIS between O.Ot and 0.2t s, Bin 2 contained IBIS
between 0.2t and 0.4f
S . . , and Bin 10 contained IBIS between 1.81 and 2.0t s. Bin
11 contained all
&Is greater than 2.0f s. IBIS were assumed to be equally
distributed within a
bin. The conversion equates the relative size of IBIS across
subjects and allows
averaging over subjects.
RESULTS
Experienced Newborns
The hypothesis asserts that in utero exposure to the acoustic
properties of the
target story will make it more reinforcing than the novel story.
If so, the rela-
tive frequency of short IBIS should increase over baseline when
reinforced by
the target stories in the IBI<t condition and the relative
frequency of IBIS
slightly longer than the baseline median should increase when
reinforced by
target stories in the IBI > t condition.
55. Baseline IBI distributions were examined first in order to
determine
whether they differed between reinforcement contingencies.
They did not dif-
fer: A mixed ANOVA of the relative frequencies of baseline
IBIS, with Contin-
gencies (c t vs. > t) and Bin (l-10) as factors, indicated a
significant effect of
Bin, F(9, 126) = 13.3, p< X101. The effect merely confirms that
the IBIS were
unimodally distributed. Most important, there was no
Contingency effect,
F(1,14) p c 1 .O, and no Contingency x Bin interaction, F(9,
126) = 1.67, p > .lO.
The predictions of the hypothesis were first assessed by
examining the
differences between the relative frequencies of IBIS that
occurred during base-
line and those that occurred during reinforcement. Difference
scores were
entered into a mixed ANOVA with Contingencies (< t vs. > t)
and Bin (l-10)
as factors. There was no effect of Contingency, F( 1,14) < 1 .O,
and a signifi-
cant effect of Bin, F(9,126) = 5.48, p-c .025. Most important,
there was a sig-
nificant Contingency x Bin interaction, F(1,126) = 2.07, pc .05.
Planned tests
of simple effects confirmed that the interaction occurred
because with the
IBI < t contingency the relative frequency of short IBIS
increased over baseline
levels, while those of all other IBIS either decreased or did not
change. With
the IBI>t contingency the relative frequency of IBIS slightly
56. greater than f
seconds increased, while those of the others decreased or did
not change. Any
IBI between 0 and t seconds would have produced the target
story under the
PRENATAL AUDITORY LEARNING 141
IBI < t contingency, and any IBI L t seconds would have
produced it under the
IBI > t contingency. But only the relative frequencies of the
shorter IBIS rein-
forced by the targets sytematically increased.
The differential reinforcement effects are more clearly revealed
in the
analysis of IBIS between O.Ot and 0.4t (the shorter IBIS) and
those between 1 .Ot
and 1.4t (IBIS slightly longer than t seconds). Conditional
probabilities of
baseline and reinforced IBIS in these classes were obtained by
dividing the rela-
tive frequency of IBIS in each class by the relative frequency of
that class and
all longer IBIS (see Table 1). This is a sensitive measure of
temporally differ-
entiated responding because: (a) it adjusts the inherently
unequal opportunity
for infants to emit equal numbers of short and long IBIS in a
limited period of
time; (b) it measures the probability that an infant will emit a
particular class
of IBIS given the opportunity to do so (cf. Anger, 1956;
DeCasper & Fifer,
57. 1980); and (c) it renders the conditional probabili ties of IBIS
between O.Ot and
0.4[, and those between 1.01 and 1.41, arithmetically
independent of one
another. The dependent variables for the target story and for the
novel story
were their reinforcement ratios: (conditional probabilities of
IBIS during rein-
forcement) divided by (conditional probability of IBIS during
reinforcement)
plus (conditional probability of IBIS during baseline).
The average values of baseline conditional probabilities of
target-story
IBIS and novel-story IBIS did not differ, t(15) = 1.37, p> .lO.
However, their
reinforcement ratios differed as expected. A mixed ANOVA
with Contingency
(<t vs. > t) and Interval (O.Ot-0.4t vs. 1 .Ot-1.4t) as factors,
revealed no effect
of Contingency, F( 1,14) < 1 .O, and no effect of Interval, F(
1,14) = 1.59, p > .20,
but a significant Contingency x Interval interaction, F(l, 14) =
6.65, p< .025
(Figure 2). Target-story reinforcement ratios were larger than
novel-story rein-
forcement ratios, independent of the contingency and of the
interval. The fact
that 13 of the 16 infants had larger target ratios than novel
ratios (p = .Ol 1 by
the binomial test) and 13 of the 16 had target-story ratios
greater than .50 indi-
cates this result was typical. The individual-subject consistency
implies that
maternal voice cues were not necessary for producing the
differential rein-
58. forcement effect. Neither the target-story reinforcement ratios
nor the differ-
ence between the target ratios and novel ratios differed between
the 9 infants
who heard their own mothers’ voices and the 7 who heard
unfamiliar voices,
p-values of both f-tests > .lO.
Control Subjects
The following analysis of control-subject performances
parallels that of the
experienced subjects. The relative frequency distributions of
baseline IBIS did
not differ between reinforcement contingency conditions. A
mixed ANOVA
with Contingency (c t vs. > t) and Bin (l-10) as factors revealed
a marginal
effect of Bin, F(9,90) = 1.90, .lO<p> .05, but no effect of
Contingency,
F( 1,lO) < 1 .O, or of the Contingency x Bin interaction, F(9,90)
= 1.38, p> .lO.
The subsequent mixed ANOVA on the difference scores of IBIS
that occurred
142 DKASPER AND SPENCE
.60
IBI BIN Ct - sec1
Figure 2. Mean reinforcement ratios of the target (hatched bars)
and novel (open
bars) stories for Experienced infants in the 161 <f condition
(left side) and in the
59. 161 >t condition (right side). The means are based on a total of
400 baseline and
1040 reinforced interburst intervals.
during the baseline and reinforcement phases revealed no effect
of Contingency,
F(1) 10) < 1 .O, a significant effect of Bin, F(9,90) = 5.19, p<
.OOl, and a signifi-
cant Contingency x Bin interaction, F(9,90) = 3.48, p c .005.
However, none
of the follow-up tests of simple effects were statistically
reliable; the inter-
action seemed to result from unsystematic variation in the
difference scores of
the two contingency conditions in Bins 1-5.
Subsequent analysis of conditional probabilities confirmed that
the pre-
ceding interaction did not result from systematic effects of
target-story rein-
forcement. The baseline conditional probabilities of target and
novel stories
did not differ, t( 11) < 1 .O; neither did their reinforcement
ratios computed for
the intervals O.Ot-0.4t and 1 .Ot-1.41. The mixed ANOVA with
Contingency
and Interval as factors revealed no reliable effects whatever, p
values of all F
statistics > .10 (Figure 3).
A comparison of the reinforcement ratios of matched-subject
pairs re-
vealed that experienced newborns had larger target-story ratios
than their
matched naive counterparts, t(l1) =2.68, p< .05, but that their
novel-story
60. ratios did not differ, t(1 1)~ 1 .O.
DISCUSSION
Three implications of the prenatal-experience hypothesis were
confirmed: (1)
For experienced subjects the target story was more reinforcing
than the novel
PRENATAL AUDITORY LEARNING 143
IX
(0t - .4tmt-1.4t) (0t - .4tM-7.4t)
IBI BIN Ct-set)
Figure 3. Mean reinforcement rotios of the target (hatched bars)
and novel (open
bars) stories for Control infants in the I81 <t condition (left
side) and in the 181 >t
condition (right side). The means are based on 300 baseline and
800 reinforced in-
terburst intervals.
story when both were concurrently available (2) the greater
reinforcing value of
the target story was independent of who recited the story; and
(3) for matched-
control infants the target story was no more reinforcing than the
novel story.
The only experimental variable that can systematically account
for these find-
ings is whether the infants’ mothers had recited the target story
while pregnant.
61. Subject characteristics also seem unable to account for the
results; the differen-
tial-reinforcement effect did not occur within the matched-
control group, and
the differential-reinforcing value of the target story differed
between matched
subjects, but the reinforcing effect of the novel story did not.
The results also
cannot be attributed to individual-subject and subgroup
differences in baseline
patterns of responding. The most reasonable conclusion is that
the target stories
were the more effective reinforcers, that is, were preferred,
because the infants
had heard them before birth. The conclusion is consistent with
earlier, inde-
pendent evidence that hearing becomes functional during the
third trimester
and that maternal speech attains audible in utero levels during
this time. Thus,
the study provides the first direct evidence that prenatal
auditory experience
with a particular maternally generated speech stimulus
influences the rein-
forcing value of that stimulus after birth.
The conclusion implies that the fetuses had learned and
remembered some-
thing about the acoustic cues which specified their particular
target passage
(e.g., prosodic cues such as syllabic beat, the voice-onset-time
of consonants,
the harmonic structure of sustained vowel sounds, and/or the
temporal order
of these sounds). Recall also that newborns prefer their
mothers’ voices over
62. 144 DECASPER AND SPENCE
that of another female, when both speak the same novel material
(DeCasper &
Fifer, 1980; Fifer, 1980). The present results add to the
evidence indicating
that the maternal-voice preference also originated in utero. If
so, then fetuses
also register some specific information about their mothers’
voices (e.g., spectra
of nasals and vowels, glottal frequency and spectrum, and/or the
temporal
characteristics of pitch, intensity, and formants) (Bricker &
Pruzansky, 1976).
The specific acoustic cues that register in utero and which
influence subsequent
perception of speech and voice sounds are not known at present.
However,
whether language-relevant cues or voice-specific cues play an
active role in
newborns’ perception has now been shown to depend upon: (a)
which class of
cues are differentially available, (b) the infants’ prenatal
experience with the
cues, and (c) the circumstances attending postnatal perception
(e.g., behavioral
contingencies, infant state, or the presence or absence of other
sounds).
The present study suggests noninvasive, ethically acceptable
methods to
further study the effects of prenatal auditory stimulation on
postnatal auditory
63. function and development, especially the development of speech
perception.
Such research might also benefit clinical treatment of the
perinate, for exam-
ple, by aiding in the diagnosis of fetal condition and by
providing information
for designing environments of preterm infants.
Some Post Hoc Considerations
Learning is generally and most satisfactorily inferred from a
change in perfor-
mance rather than from absolute measures of performance.
However, change
scores-the difference scores and reinforcement ratios used in
this study-are
almost always inversely related to prelearning performance, the
baseline proba-
bilities of responding (cf. Glass & Stanley, 1970, p. 182). The
present discussion
focuses on the extent to which the preceding inferences about
differential-
reinforcement effects were influenced by the relation between
baseline levels of
performance and the difference scores and reinforcement ratios.
The issue is
salient here because the hypothesis asserts that reinforcement
would differen-
tially affect specific IBIS whose baseline probabilities varied
considerably.
The abscissa of Figure 4 shows the mean conditional
probabilities of base-
line IBIS for each of the eight subconditions represented in
Table 1. The mean
baseline conditional probabilities of IBIS between O.Ot and 0.4t
64. (subconditions
l-4 in Figure 4) are lower than the mean baseline conditional
probabilities of
IBIS between 1 .Ot and 1.4t (subconditions 5-8). They differ
simply because
baseline IBIS between O.Ot and 0.4t come from the left of a
unimodal distribu-
tion and IBIS between 1 .Ot and 1.4t come from near the median
of the distribu-
tion. The primary means of experimentally controlling for the
influence of
these baseline differences was to counterbalance the reinforcers
associated
with the IBI < t and IBI > I contingencies: As Figure 4 suggests ,
and as reported
earlier, when the values of baseline probabilities are pooled
over IBI < f and the
IBI > I contingencies (1 with 6; 2 with 5; 3 with 8; 4 with 7) the
average baseline
probabilities do not differ.
.25
I-
z .20
I
ti
5 .15
z”
iii
a
65. $ .lO
IX
PRENATAL AUDITORY LEARNING 145
.05 .l 0 .15 .20 .25 .30
Ti CP BASELINE
Flgure 4. Mean conditional probability that subjects in the eight
subconditions
would emit IBIS between O.Ot-0.41 and betweenl.Ot-1.41
during reinforcement OS
a function of the mean conditional probability that they would
do so during base-
line. Open circles refer to Experienced subjects reinforced by
the target story
with IBI < t (2) and with lBl> t (5). Filled circles refer to
Experienced subiects re-
inforced by the novel story with IBI <t (4) and with IBI >t (7);
to Control subjects
reinforced by the target story with IBI < t (3) and with 181 > f
(8): and to Control
subjects reinforced by the novel story with IBI < t (1) and with
181 > t (6). The solid
line represents the regression equation (.07+.3B [baseline
probability]) for the
six control subconditions (filled circles) and the dashed lines
represent the 95%
confidence interval around the regression line.
Figure 4 also shows the empirical relation between the mean
baseline pro-
babilities and the mean probabilities occurring with
66. reinforcement for each
subcondition. The solid line represents the regression equation
relating the
baseline and reinforcement probabilities for the six
subconditions in which no
differential-reinforcer effect was expected (filled symbols), r=
.89, p< .02. For
these six subconditions the probability of responding during
reinforcement is
almost completely determined by the prior baseline probability.
Their rein-
forcement probabilities do not increase over baseline
probabilities, but instead
become increasingly smaller than baseline as the baseline
probability increases.
Figure 5 shows that when reinforcement ratio (a change score)
is substituted
for reinforcement probability (the absolute score), the strong
linear relation
between baseline performance and reinforced performance is
preserved, but
for statistical and mathematical reasons, the correlation is
negative, r= - .93,
p< .Ol.
146 DECASPER AND SPENCE
Since the means of the subcondition baselines were not equal
these, corre-
lations raise an important question. Might the reinforcement
probabilities and
reinforcement ratios that resulted when Experienced newborns
were reinforced
with their target story be determined simply by their baseline
67. probabilities?
That is, do the differences in the subgroups’ terminal
performances, as mea-
sured by reinforcement probabilities or difference scores and
reinforcement
ratios, reflect differential reinforcement effects or just the fact
that the sub-
groups began with different baseline probabilities?
Figure 4 shows that the mean baseline probabilities of the two
conditions
where Experienced subjects were reinforced with their target
story (open sym-
bols) fall within the range of baseline probabilities entailed in
the correlation.
Significantly, however, the mean probabilities that occur with
reinforcement
by the target story are both above their baseline levels and
above the 95% con-
fidence interval of the regression line @C .0006). Similarly,
both reinforcement
ratios are well above SO and also above the 95% confidence
interval of the
regression line of Figure 5. Thus, the possibility that the
reinforcement proba-
bilities and reinforcement ratios occurring when Experienced
subjects were
reinforced with their target story were determined by or could
be predicted by
.70
0
2 .60
a
68. L
r” .50
Y
i5
P .40 I
iii
a
.05 30 15 30 .2 5 .30
iCP BASELINE
Figure 3. Reinforcement ratio as o function of baseline
conditional probobility for
the eight subconditions described in Figure 4. The regression
equotion is (.57- .63
[baseline probobility]) for the control subconditions and the
doshed lines repre-
sent the 95% confidence interval.
PRENATAL AUDITORY LEARNING 147
their baseline probabilities can be rejected. The favored
alternative hypothesis,
of course, is that prenatal experience increased the reinforcing
effectiveness of
their target stories: The effect of prenatal experience with the
reinforcer was to
increase the conditional probability of reinforced responding by
69. 40% over the
level predicted by baseline in the IBI c f condition and by 76%
in the IBI > t
condition. Reinforcement ratios were increased by 20% and 26%
over the
levels predicted by baseline performance.
It may still be argued, however, that the preceding analysis was
based on
subgroup means and that the pattern of individual-subject
baseline probabili-
ties within the subgroups was biased toward producing
difference scores and
reinforcement ratios that supported the prenatal hypothesis.
That is, if the
baseline probability of each Experienced subject reinforced with
the target
story had been the same as the baseline of a control subject,
then their rein-
forcement probabilities and reinforcement ratios might not
differ.
The following analyses addressed this possibility by comparing
selected
groups of subjects after matching individual infants on baseline
probabilities.
Subject matching was accomplished by applying the following
three rules: (1)
baseline probabilities had to be within f .02 of each other; (2) if
possible, the
subjects were to have the same reinforcement contingency; and
(3) if more
than one match was possible, pairs were matched so as to
minimize the differ-
ence between conditional probabilities that occurred with
reinforcement. No
70. other factors were considered.
In the first comparison, 10 of the 16 baseline probabilities
produced by
Experienced infants in the conditions where they were
reinforced with the tar-
get story were matched to the baseline probabilities of 10 of the
16 Experienced
subjects in the conditions where they were reinforced with the
novel story. The
10 baseline pairs were: (.06/.06), (.06/.06), (.09/.09), (.lO/.lO),
(.12/.12),
(.14/.13), (.16/.17), (.17/.17), (.23/.24), and (.26/.26). The mean
baseline
probability for each group was .14. The mean probability
occurring with rein-
forcement by the target story (.20) was greater than that
occurring with rein-
forcement by the novel story (.15), t((9)=2.61, pc.01 (l -tail I
test) T=4.5,
p < .025 (Wilcoxen test). the mean probability of responding
with target-story
reinforcement was greater than the baseline mean, f(9) =2.99,
p< .005; T=3,
p < .Ol, but the mean probability of responding with novel-story
reinforcement
did not differ from baseline, t(9) = .58; T= 22.5. In addition, the
mean occur-
ring with target-story reinforcement was well above the 95%
confidence inter-
val of Figure 4, but the mean occurring with novel-story
reinforcement was
well within the interval. The reinforcement ratio of the target
story was well
above the 95% confidence interval of Figure 5, but the
reinforcement ratio for
71. the ,novel-story was within the interval.
Six infants from each reinforcement condition could not be
matched.
The mean of the unmatched baselines for the target-story
condition was .12;
the mean occurring with reinforcement was .18. For the novel -
story infants
148 * DECASPER AND SPENCE
these means were .22 and .17, respectively. The reinforcement
mean and rein-
forcement ratio occurring with target-story reinforcement were
above the 95%
confidence intervals of Figures 4 and 5, but the analogous
measures resulting
from reinforcement with the novel story were well within the
confidence inter-
vals.
Next, baselines of Experienced subjects who were reinforced
with the tar-
get story were matched to baselines of Control subjects
reinforced with the target
story. Nine pairs could be formed: (.03/.04), (.06/.06), (.06/.06),
(.09/.08),
(.lO/.lO), (.14/.13), (.16/.16), (.26/.26), and (.29/.31). The
baseline mean of
each group was .13. The mean reinforcement probability for the
Experienced
subjects (.19) was greater than that of Control infants (.lO), r(8)
= 2.58,p< .Ol;
T= 1, p < .005. The Experienced subjects’ reinforcement
72. probabilities were
larger than baseline probabilities, t (8) = 2.94, p< .005; T= 0, pc
.005, but the
Control subjects’ were not, f(8) = 1.19, p> .lO; T= 15. Here,
too, the Experi-
enced subject’s mean reinforcement probability and
reinforcement ratio were
both well above the 95% confidence intervals of Figures 4 and
5. The reinforce-
ment probability of the Control group was within the interval of
Figure 4.
Their reinforcement ratio, however, fell below the 95%
confidence interval of
Figure 5, even though the members of the group had exactly the
same baseline
probabilities as their Experienced counterparts.
Seven Experienced subjects’ and three Control subjects’
baselines could
not be matched. The baseline means of these subjects are .13
and .40, respec-
tively. Their respective means occurring with reinforcement by
the target story
were .19 and .20. The reinforcement mean and reinforcement
ratio of the Ex-
perienced subjects both lay well above the 95 % confidence
intervals of Figures
4 and 5. Analogous scores for Control subjects were within the
intervals.
Finally, Experienced subjects reinforced with the novel story
were matched
to Control subjects who were also reinforced with the novel
story. The nine
pairs of baseline probabilities were: (.06/.06), (.09/.09),
(.lO/.lO), (.12/.12),
73. (.13/.13), (.19/.20), (.19/.19), (.24/.24), and (.33/.32). The mean
for each
group was .16. Neither the between-group difference nor the
changes from
baseline were statistically reliable (all t values < 1 .O; all T
values > 16). All re-
inforcement means and reinforcement ratios fell within the
confidence intervals
of Figures 4 and 5. Seven Experienced infants and three Control
infants could
not be matched. Their respective baseline means were .19 and
.16, and their
respective reinforcement means were .18 and .13. All
reinforcement means and
reinforcement ratios were within the confidence intervals of
Figures 4 and 5.
After equating the baseline probability of IBIS of individual
infants in
specific conditions, the only consistent finding was that the
target story was the
more effective reinforcer for Experienced infants. In sum, the
results of this
study cannot be accounted for by differences in the baseline
values of subcon-
ditions or individual subjects. The previous conclusion can be
retained: The
postnatal reinforcing value of a speech passage is increased by
prenatal experi-
ence with the passage.
PRENATAL AUDITORY LEARNING 149
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