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A Novel Method to Compare Lateralized Versus Non-Lateralized Specialization
Accounts of the Mechanism Underlying Theory of Mind
Haley J. Fallowfield
Honors Psychology Thesis
Department of Psychology
University of Western Ontario
London, Ontario, CANADA
April, 2012
Thesis Advisor: Adam S. Cohen, Ph.D.

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Abstract
Significant conflict exists within current Theory of Mind (ToM) literature regarding
whether the neural mechanism underlying ToM are represented bi-laterally or specifically in the
right hemisphere of the brain. The present study compares these hypotheses using a novel
method that borrows from methodologies used to assess functional lateralization in corpus
callosotomized patients. Following the presentation of true-belief and false-belief scenarios,
participants were required to make a forced-choice button press response in a violation of
expectation paradigm. Information regarding belief attribution was presented specifically to
either the right or left hemisphere of the brain, and reaction times were compared between trials
to determine whether presentation of stimuli to the right hemisphere resulted in a significant
reaction time advantage. No significant effects of hemisphere presentation were observed.
Bayesian analysis revealed a Bayes Factor of 21:1 in favour of the bi-lateral specialization
hypothesis. Results are discussed in terms of both bi-laterally specialized and non-specialized
neural models of ToM.

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A Novel Method to Compare Lateralized Versus Non-Lateralized Specialization Accounts
of the Mechanism Underlying Theory of Mind
Humans are equipped with a powerful inference mechanism that spontaneously imputes
mental states underlying the behaviours of others. This ability, often referred to as Theory of
Mind (ToM), is foundational to human cognition and social competence (Premack & Woodruff,
1978). A large body of evidence supports the universal (Avis & Harris, 1991; Callaghan et al.,
2005), automatic (Cohen & German, 2009; Kovács, Téglás, & Endress, 2010), and modular
(Mar, 2011; Saxe, Carey, & Kanwisher, 2004) nature of ToM in humans. Paleontologist Richard
Leakey concludes that the social interactions of upper primates are akin to a challenging game of
social chess in which "the pieces not only unpredictably change identity, [but] they occasionally
switch colours to become the enemy," (Leakey & Lewin, 1992, p. 191-293). Because the
reproductive success of higher primates hinges heavily upon social skills, possessing the ability
to not only understand but also predict the behaviours of others is highly adaptive.
Mindblindness, or the absence of a developed ToM, is evident in individuals diagnosed
with autism spectrum disorders (ASD) (Baron-Cohen, Leslie, & Frith, 1985; Senju, Southgate,
White, & Frith, 2009). Without the ability to make use of mentalistic explanations for the
behaviours of others, many individuals with ASD suffer from severe deficits in social
competence. To compensate, these individuals often rely upon inefficient and inflexible non-
mentalistic behavioural explanations that are unable to adequately reflect the complexity and
variability observed in human behaviour (Baron-Cohen, 1997; Leslie, 1999).
At present, there is a large amount of conflict in ToM literature regarding both the neural
system responsible for belief attribution as well as how neurodevelopmental changes within this
system are associated with age-related changes in ToM processing. While there is a large body of

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evidence indicating that both the left and right temoporo-parietal junction (lTPJ and rTPJ,
respectively) independently support ToM processing (Hampton, Bossaerts, & O'Doherty, 2008;
Saxe & Kanwisher, 2005; Young, Dodell-Feder, & Saxe, 2010), other evidence supports a
lateralized specialization account, wherein the rTPJ specifically supports the ability to infer
mental states in humans (Gweon, Dodell-Feder, Bedny, & Saxe, 2012; Perner, Aichhorn,
Kronbichler, Staffen, & Ladurner, 2006). Furthermore, recent evidence indicates that the
selectivity of the rTPJ for ToM processing increases throughout development, and that this
increase in selectivity is related to increased performance on tasks assessing ToM ability (Gweon
et al., 2012; Saxe, Whitfield-Gabrieli, Scholz, & Pelphrey, 2009).
Virtually all of the existing evidence regarding the neural representation of ToM in the
brain has been derived from research involving neuroimaging procedures. Current neuroimaging
technologies, while foundational in identifying patterns of neural activity associated with specific
functions, lack the spatial and temporal resolution necessary to adequately resolve this conflict.
Additionally, the ability to obtain evidence from young populations or populations of individuals
with ASD is extremely limited because of persistent reliance on neuroimaging techniques. In
order to understand both the normative and non-normative developmental trajectories of the
system underlying ToM processing, it is necessary to gain insight into the structural and
functional representation of this system in a developmental framework. As a result, the present
study aims to compare the bi-lateral specialization hypothesis and the right hemisphere
specialization hypothesis using a novel approach that borrows from techniques used to assess
functional lateralization in corpus callosotomized patients.

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Domain Specificity of Theory of Mind Mechanism
Many evolutionary theories purport that the neural mechanism underlying ToM in
humans evolved to cope with increasingly complex and cognitively demanding social
interactions (Baron-Cohen, 1997; Brüne & Brüne-Cohrs, 2006). Brain regions hypothesized to
be specifically involved in reasoning about beliefs include the medial prefrontal cortex (mPFC),
the precuneus (PC) and the TPJ bi-laterally. In 2004, Saxe and colleagues conducted a systematic
review of functional magnetic resonance imaging (fMRI) data from studies assessing the neural
representation of ToM. Functional magnetic resonance imaging techniques measure temporal
and spatial changes in the blood-oxygen level dependent (BOLD) response within various
tissues. Because increased functional activity in a particular brain region is associated with
increased metabolic demands, temporal and spatial patterns of change in the BOLD response can
be used as an indirect measure of patterns of neural activity in the brain. The authors surmised
that the mPFC, PC, and bi-lateral TPJ meet both specificity and generality criterion required of a
domain-specific system. That is, changes in activity were observed within these regions during
tasks that required belief attribution, but no such changes were observed during cognitively
similar tasks that did not involve belief attribution (specificity). Additionally, reliable changes in
activity were observed within these regions whenever belief attribution processes were engaged
(generality).
Critics of this domain-specific hypothesis, however, have identified a variety of concerns
with respect to the data reviewed by Saxe and colleagues (2004). In particular, to determine
whether a specific brain region met the aforementioned specificity criterion, the authors
compared regional patterns of activity during tasks involving belief attribution to those observed
during cognitively similar control tasks. A region met specificity criterion if changes in activity

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were observed during belief attribution tasks but not during relevant control tasks. In order for
this process of assigning regional specificity to have been valid, the control tasks included in the
review must have been designed appropriately such that they invited processing within systems
that may have been recruited concurrently with the ToM system in the belief attribution task, but
did not invite processing within the system directly involved in belief attribution. Since the
publication of this review it has become evident that many control tasks previously thought to be
appropriate are either representationally different from belief attribution tasks or may
inadvertently invite belief attribution processes. Furthermore, subsequent data indicates that the
mPFC and PC may be involved in processing a variety of social information (Mar, 2011;
Sebastian et al., 2011), whereas only the TPJ meets the specificity criterion for domain-
specificity (Perner et al., 2006). Although there is a large amount of concurrence in the literature
regarding the role of the TPJ in ToM, there is conflicting evidence concerning the localization of
ToM processing in the brain. Some research evidence supports a domain-specific bi-lateral
representation, wherein both the lTPJ and rTPJ can independently support ToM, while others
evidence indicates a domain-specific lateralized representation, in which the rTPJ is selectively
responsible for mental state attribution.
Lateralization of Theory of Mind Mechanism in Adults
Domain-Specific Bi-Lateral Representation. Multiple sources of evidence have indicated
that both the lTPJ and rTPJ show similar patterns of activity during tasks involving belief
attribution. Hampton and colleagues (2007) used fMRI analysis to measure changes in the
BOLD response associated with mentalizing during a competitive interaction paradigm.
Participants in an fMRI scanner competed strategically with opponents outside of the scanner in
an “inspection” task for a monetary reward. Each participant was given a role (employee or

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employer) and received specific incentives based on the interaction of their own actions with the
actions of their opponent. For example, the employer could choose to either inspect or not
inspect the employee while the employee was supposed to be working. The employer received
100 cents if the employee was working and an inspection was not conducted, 25 cents if the
employee was absent and an inspection was conducted, and zero cents in any other scenario. The
incentives of the employee were similarly structured such that, when one player received a
reward, the other player did not. Thus, the employer and employee in this game had competing
objectives, making the ability to predict the likely actions of the competitor advantageous. The
authors found that most participants used an influence learning model during the interaction; that
is, participants tracked the opponent’s actions and incorporated knowledge of how their own
actions influenced the strategies employed by the opponent into their own subsequent strategies.
Significant activity was observed in the bi-lateral superior temporal sulcus (STS; a region
anatomically adjacent to the TPJ) when information regarding the opponent’s strategy was
updated based on personal influence.
Previously, the STS and the TPJ were considered interchangeably when describing the
neural mechanism of ToM because of their anatomical proximity and apparent similarities in
patterns of neural activity during belief attribution tasks. With advances in neuroimaging
techniques, it has become evident that the STS and TPJ are functionally distinct; the STS is
involved in processing of a plethora of social information, whereas activity in the TPJ is
associated specifically with belief attribution processes (Saxe, in press). Because of the close
proximity of the two regions in the brain, activity in the TPJ may have previously been
overlooked as activity specifically in the STS, even though both regions were likely recruited for
different processes (Saxe, in press). Regardless of the potential misinterpretation of results

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reported by Hampton et al. (2007), the observed bi-laterality of activity in the vicinity of the lTPJ
and rTPJ indicates that both regions may be necessary for predicting both the strategic
motivations and the future behaviours of opponents in competitive interactions via belief
attribution.
False-belief tasks have been widely used in ToM research, as these tasks require the
ability of the observer to infer an agent’s belief when the beliefs of the agent and observer are
incongruent. Because correctly inferring a false-belief involves the dissociation between an
individual’s belief(s) and the belief(s) of the observer, false-belief tasks effectively assess the
individual’s ability to conceive of mental states. In a typical false-belief task, participants
observe the following scenario: an agent interacts with an object and then places the object in a
specific concealed location (e.g. a box or a drawer). After concealing the object, the agent
becomes distracted or moves to a location that is not within viewing range of the object’s
location. During this time, the object is moved to a different concealed location, and is thus no
longer located where the agent originally placed it. When the agent returns, participants are
asked to indicate where the agent will first look for the object. The correct response is to indicate
the location at which the agent initially placed the object. False-photograph tasks are very
similar, and are often used as controls when employing false-belief tasks. In the false-photograph
task, the scenario is exactly the same as in the false-belief task, except a photograph is taken of
the initial object placement before the switch occurs. When the agent returns, participants in the
false-photograph task are asked to indicate where the object is located in the photograph.
In an effort to measure patterns of neural activity related specifically to belief attribution,
Saxe and Kanwisher (2005) compared fMRI data within subjects during presentation of stories
varying in the degree to which ToM processes were recruited. The authors compared changes in

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the BOLD response in adults during the presentation of a story requiring belief attribution (false-
belief) to BOLD response changes observed during four cognitively similar control stories (not
requiring belief attribution) containing information regarding false-photographs, desires,
inanimate descriptions, or physical descriptions. The authors found that activity in the bi-lateral
TPJ increased significantly from baseline during the presentation of false-belief stories, but did
not differ significantly from baseline during the presentation of control stories. These results
provide evidence that in adults, the bi-lateral TPJ is specifically recruited during tasks requiring
belief attribution.
Domain-Specific Right Hemisphere Lateralized Representation. While the evidence
provided by Hampton et al. (2007) and Saxe and Kanwisher (2005) are in support of the bi-
lateral representation hypothesis, there are inherent weaknesses to both studies that may have
masked lateralized patterns of activity associated with belief attribution. The main weakness of
both studies is the lack of appropriate control procedures. In the paradigm employed by Hampton
and colleagues (2007), no control task was assigned to disentangle activity patterns associated
with the multitude of cognitive processes being elicited during the competitive interaction.
Additionally, while Saxe and Kanwisher (2005) made use of control tasks, these tasks may have
unintentionally invited belief attribution. For example, many individuals attribute beliefs to non-
human or inanimate objects via anthropomorphisms; and, because beliefs are often attributed
spontaneously, control stories describing inanimate objects or physical descriptions of people
may still invite ToM processing. Additionally, the use of false-photograph tasks as cognitively
similar controls for false-belief tasks is problematic; while false-belief tasks involve inferring a
belief to an agent when the agent has a belief that is incongruent with the present reality, false-
photograph tasks require making reference to a true photograph that reflects a past reality

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regardless of the fact that the present reality and past reality are incongruent. The false-
photograph task, when observed more closely, is thus representationally very different from the
false-belief task.
To address concerns regarding the use of inappropriate controls in paradigms assessing
the neural mechanism underlying ToM processing, Perner and colleagues (2006) developed the
false-sign task. In the false-sign task, participants observe the following scenario: initially, a sign
is presented that correctly points in the direction of a location or landmark. The sign is then
changed such that it points in the wrong direction, and no longer represents the correct path to
the destination. Participants are then asked to indicate which path correctly represents the path to
the destination. The false-sign task, unlike the false-photograph task, requires participants to
make inferences about a false-representation that is incongruent with the present reality, and is
thus representationally equivalent to the false-belief task. The authors used fMRI analysis to
compare changes in the BOLD response associated with the following four vignettes in adults:
standard false-belief, false-sign, false-photograph, and temporal change. Concurrent with the
results reported by Saxe and Kanwisher (2005), Perner and colleagues (2006) found that both the
lTPJ and rTPJ showed significant changes in the BOLD response during the false-belief vignette,
but not during the false-photograph or temporal change vignettes. Interestingly, however, only
changes in activity within the rTPJ distinguished between the false-belief vignette and the false-
sign vignette. These results indicate that the rTPJ is selectively associated with belief attribution
during false-belief tasks in adults.
Individuals with ASD (regardless of whether they are classified as high-or low-
functioning) consistently fail typical false-belief tasks, and often perform worse on belief
attribution tasks than individuals diagnosed with other developmental disorders such as Down’s

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syndrome (Leslie, 1999). Comparisons of patterns of neural activity between developmentally
normative populations and developmentally non-normative populations wherein a specific deficit
in ToM is evident may provide strong insight into the neural mechanism underlying ToM.
Lombardo, Chakrabarti, Bullmore, and Baron-Cohen (2011) were able to overcome the
many inherent difficulties associated with designing appropriate neuroimaging procedures for
use with ASD individuals. Using fMRI, changes in the BOLD response associated with task
performance were compared between adult males with ASD and intelligence-matched males
with no known developmental, cognitive, or social impairments. The tasks involved either
inferring beliefs to agents (mentalizing) or making physical judgments about agents (control).
The agents in this task were either the “Self” or a non-close “Other” (the British Queen). As
expected, among typical male participants, a significant increase in the BOLD response was
observed in the rTPJ during the mentalizing condition. Strikingly, however, no such increase in
activity was observed in the rTPJ of males with ASD, and whole-brain analyses revealed that the
rTPJ was the only region that responded atypically in ASD participants during the mentalizing
condition. It is thus possible that many of the social impairments associated with ASD result
from atypical patterns of activity within the rTPJ in response to information relevant to ToM.
These results also support the hypothesis that the rTPJ is selectively responsible for belief
attribution in adults.
Developmental Trajectory of ToM
Decades of research concerning the developmental trajectory of ToM centered on the
hypothesis that ToM is acquired in stages throughout childhood (Caron, 2009; Song, Onishi,
Baillargeon, & Fisher, 2008). Many of the step-wise theories of development are supported by
evidence from the performance of children on false-belief tasks. While many studies observed

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that children were able to attribute agency by around age two, these studies also found that
children routinely failed false-belief tasks until approximately age four. Until recently, however,
researchers employing false-belief tasks relied solely upon explicit response measures, which
place high demands on cognitive control processes that are severely underdeveloped in young
children. In false-belief tasks, for instance, children must inhibit the pre-potent tendency to
respond using information relative to their own personal beliefs in favour of responding using
information relative to the beliefs of the identified agent. It is well known that response
inhibition is limited in young children, and thus their observed poor performance on standard
false-belief tasks involving explicit response measures may, in actuality, result from limited
cognitive control abilities and not an absence of ToM.
Recent evidence from studies making use of implicit measures of belief attribution (eye
tracking and active helping) indicates that children may have the ability to attribute beliefs within
the first two years of life. For example, Surian, Caldi & Sperber, (2007) found that 13-month old
infants looked reliably longer when an agent chose the correct goal path to a preferred object
(following a habituation phase wherein the preferred object was always retrieved from an
alternative location) when the child but not the agent could see the object at the new location,
versus when both the child and agent could see the object at the new location. Because increased
looking time is associated with violation of expectation, these results indicate that when children
inferred that the agent could not see that the object had been moved to the new location, they
expected the agent to look for the object first at the old location, and were surprised when the
agent instead chose the correct path. Thus, by 13 months of age, children seem to be able to
impute mental states based on their perception of an agent’s visual perspective.
Lateralization Changes and ToM Competence. While the evidence provided by Surian, et

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al. (2007) indicates that children implicitly infer beliefs to agents within the first two years of
life, the evidence fails to explain why children are unable to explicitly attribute false-beliefs to
agents until around age four. In consideration of the evidence indicating the role of the rTPJ in
thinking about thoughts, it is possible that developmental changes in the specificity of the rTPJ
for processing information related to mental state attribution underlie these seemingly conflicting
observations. In 2009, Saxe, and colleagues used fMRI analysis to monitor changes in the BOLD
response in children between the ages of 6 and 11 during the presentation of aural stories
describing physical facts about objects (Physical), characters’ appearance and social
relationships (People), or mental states (Mental). The authors then identified three regions of
interest (ROI: regions in which reliable task-related differences in the BOLD response were
observed for a majority of subjects). The ROI included the mPFC, the PC, and the TPJ, bi-
laterally. They found that activity in the rTPJ was not significantly more selective for mental
state facts relative to other social facts than the mPFC, PC, or lTPJ. The authors then calculated a
Selectivity Score for each ROI by measuring the difference in BOLD response observed between
the Mental versus People conditions relative to the difference in response observed between the
Mental versus Physical conditions. According to the authors:
A low Selectivity Score…indicates that the response to the people sections was
approximately as high as the response to the Mental sections; a high Selectivity Score
indicates that the response to the People sections was approximately as low as the
response to the Physical sections (p. 1205).
They reported that the rTPJ was not significantly more selective for belief attribution than the
other identified ROI in children. They did note, however, that the rTPJ was the only region
identified as having a significant correlation between age and selectivity index. Although these

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results provide evidence of age-related changes in the selectivity of the rTPJ for processing
information related to beliefs, the authors fail to provide evidence of a link between the
hypothesized developmental changes in rTPJ selectivity and ToM competence.
In a follow-up fMRI study, Gweon and colleagues (2012) compared changes in the
BOLD response associated with the presentation of the same three categories of aural stories as
were used in the study by Saxe et al. (2009; Physical, People, and Mental) in adults and children
aged 5 to 12. Additionally, data was compared within subjects to performance on a ToM task
battery that was administered following completion of the fMRI portion of the study. The mPFC,
PC, and TPJ, bi-laterally were all identified as ROI in both adults and children, and a Selectivity
Score was calculated for each ROI within each participant. The selectivity of both the rTPJ and
PC was significantly higher in adults than in children. Upon comparison of the Selectivity Score
of each individual ROI with age, the authors found that the selectivity of both the lTPJ and rTPJ
was significantly correlated with age. Furthermore, comparisons between ROI selectivity and
performance on the ToM task battery revealed only one significant correlation: increased
selectivity of the rTPJ for mental state information was significantly correlated with increased
performance on the ToM task battery. Thus, developmental changes in the functional
lateralization of the TPJ may explain the observed age-related changes in performance on belief
attribution tasks.
Limitations of Previous Research
In consideration of the evidence reviewed thus far, it is important to note the utility of
neuroimaging procedures in identifying patterns of neural activity associated with ToM
processes. Strict reliance on neuroimaging techniques, however, may have negative implications
for ToM research. For example, in order to accurately identify regions associated with belief

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attribution it is necessary to have appropriate control tasks or there is a severe risk of
misinterpretation. While it was previously believed that false-photograph tasks were
representationally equivalent to false-belief tasks, further assessment indicated that there are
various aspects of false-photograph tasks that render them inadequate as controls for false belief
tasks. Additionally, the spatial resolution of fMRI in itself can be misleading. Evidence of the
impact of poor spatial resolution on the understanding of the ToM mechanism was described
previously when discussing the misconception of functional equivalence between the STS and
TPJ. Also, the TPJ is a relatively large region in the brain, so it is not surprising that there may
be functionally distinct regions of the TPJ that support processes other than ToM. Furthermore,
reliance on neuroimaging procedures introduces limitations in the study of both the normative
and the non-normative developmental trajectories of ToM, as it is not yet procedurally possible
to obtain data from very young children or from a majority of individuals with ASD.
Neuroimaging evidence supporting developmental changes in the functional lateralization of the
TPJ and associated changes in ToM competence were unable to provide data for children under
the age of five, and to date few studies have attempted to gather neuroimaging data from
individuals with ASD due to ethical and procedural issues. Finally, converging evidence from
different methodologies is necessary to provide versatility in proposed theories as well as to help
resolve the existing conflict within neuroimaging data.
Borrowing from Split-Brain Research
Research initiatives involving patients who have undergone surgical resection of the
corpus callosum provide powerful insight into the functional lateralization of specific processes.
Because these patients lack the main mechanism of inter-hemispheric communication, lateralized
presentation of stimuli can effectively determine which hemisphere(s) is/are responsible for

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processing specific types of information or for computing specific forms of behavioural outputs.
From these research initiatives, it has become evident that visual information is projected to
contralateral hemispheres of the brain; that is, information presented to the left visual field (LVF)
is processed in the right hemisphere of the brain and vice versa (Gazzaniga, 2000). Furthermore,
motor pathways are also arranged contralaterally such that the right motor cortex controls both
proximal and distal musculature on the left side of the body and the left motor cortex controls
both proximal and distal musculature on the right side of the body (Gazzaniga, 2000).
The present study borrows from the methodologies employed in research assessing
functional lateralization in corpus callosotomized patients and addresses the previously discussed
limitations in existing evidence regarding the neural mechanism underlying ToM. The objective
of the present study is to compare the domain specific bi-lateral representation hypothesis with
the domain specific right hemisphere lateralized representation hypothesis of the mechanism
underlying belief attribution. Participants will be presented with a series of images on a computer
that depict either a false-belief or a true-belief scenario in a violation of expectation paradigm.
Participants will then be required to focus on a cross-hair that will appear in the center of the
screen. A final image will be presented on either the left side of the screen (LVF) or the right
side of the screen (right visual field: RVF) showing the agent looking for the object in one of the
two possible locations. Participants will be asked to indicate via a forced choice button press
response whether the image depicts where they expected the agent to look for the object.
Interhemispheric communication, although extremely rapid, introduces a temporal lag in
information processing. If belief attribution processes are lateralized to the right hemisphere, a
reaction time advantage is expected on trials in which the final scene is presented to the right
hemisphere (left visual field) versus trials in which the final scene is presented to the left

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hemisphere (right visual field). If, however, both the lTPJ and rTPJ can independently support
belief attribution, no expected reaction time advantage is predicted.
Methods
Participants
Twenty-eight English-speaking undergraduate students (M = 18.6 years, SD = 0.92;
males = 11, females = 17) enrolled in an introductory Psychology course at the University of
Western Ontario (UWO) completed the study for a course credit. All participants had corrected
or normal-to-corrected vision and no known motor disorders. Participants were recruited through
the Psychology Research Participation Pool (see Appendix A), and completed all measures on
campus in a designated testing room after giving informed consent. All participants completed a
handedness inventory to rule out effects of hand preference on performance (see Appendix B).
Measures
Belief Attribution. Belief attribution vignettes were adapted from the widely used Sally-
Anne task developed by Baron-Cohen, Leslie, and Frith (1985). For adult participants, a total of
eight vignettes were constructed. Vignettes were then separated into two categories containing
four vignettes each based on belief attribution condition (true belief or false belief). Within each
category, vignettes varied based on the gender of the agent (male agent or female agent) as well
as object and agent start location (right side or left side of the frame). Each vignette consisted of
11 still frames (9.5 cm x 14 cm), and a final still frame with dimensions (9.5 cm x 7.0 cm).
Vignettes were developed using E-prime 2.0 experiment generator software (Psychology
Software Tools Inc., Pittsburgh, PA) and were presented on an integrated Tobii T120 eye-

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tracking monitor with a display resolution of 1280 x 1024 pixels (Psychology Software Tools
Inc., Pittsburgh, PA) on a white background.
Adult participants viewed a total of 36 randomly assigned vignettes, 18 of which were
randomly selected true belief vignettes and 18 of which were randomly selected false belief
vignettes. Both true and false belief vignettes began similarly, with the agent removing an object
from one of two possible concealed locations, interacting with the object, and then replacing the
object back in the concealed location from which it was removed. The agent was then observed
leaving the room. In true belief vignettes, the agent returned to the room and observed a
confederate remove the object from the concealed location, interact with the object, and then
place the object in the second concealed location (not the location in which the agent had
previously placed the object). In the false belief condition, the agent remained out of sight while
the confederate interacted with the object, and did not observe the confederate place the object in
the new location. Refer to Appendix C for an example of a true belief vignette and Appendix D
for an example of a false belief vignette as developed for adults. The final still frame presented
depicted the agent looking in one of the two possible locations, either the expected location (in
which the agent would logically search given their knowledge of the object's location) or in the
unexpected location. The final still frame was randomly selected for each vignette based on
expectedness value to minimize any effects of expectedness on task performance measures.
Following the presentation of the final still frame, participants were required to indicate whether
it depicted where they expected the agent to look for the object.
Hemifield Presentation. In order to assess the effect of hemifield presentation on
response reaction time, the experiment was further subdivided into two trial blocks based on
visual field presentation (right visual field or left visual field: RVF or LVF, respectively). It is

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important to note that visual field presentation and hand response were coordinated such that
participants responded with the right hand (RH) throughout the RVF trial block and with the left
hand (LH) throughout the LVF trial block. All participants completed both trial blocks in a
randomized order. Each block consisted of an instructional segment, 2 randomized practice
trials, and 16 randomized experimental trials (eight from each belief attribution condition)
wherein all stimuli were presented either left (LVF) or right (RVF) justified on the display
monitor.
An experimental trial involved the following sequence of events: (a) the first 11 still
frames of a vignette were presented for 1.5 s each; (b) a fixation point (crosshairs) appeared in
the center of the monitor; (c) after 1 s of visual fixation, the final searching still frame was
presented for 0.5 s to the left (LVF) or right (RVF) of the fixation point; (d) a response screen
prompted the participant to indicate whether the agent was searching in the expected location
(press “R” button on keyboard if expected and “Y” button on keyboard if unexpected); (e) an
inter-trial interval of 10 s was initiated. Participants were instructed to maintain visual fixation
on the crosshairs until it was no longer present on the screen to ensure lateralized visual
processing. Each experimental trial took approximately 30 s to complete. Practice trials were
similar to experimental trials, except that captions were included throughout the vignettes, and
still frames within a vignette were presented for 5 s each to better acquaint participants with the
underlying storyline. Practice trials took approximately 1 min to complete.
Eye Tracking. The Tobii T120 eye tracking monitor was used to monitor participants'
eye movements throughout the task and is capable of collecting data at a rate of 120 Hz, with an
average gaze position error of less than 0.5°. The presentation of the final image was gaze
contingent, such that participants were required to maintain visual fixation on the crosshairs for 1

20. Lateralization
and
Theory
of
Mind
20
s before the image would appear. Since even small shifts from central fixation can have
significant effects of visual cue processing, a focal radius of 0.5 cm from the center of the
crosshairs was enforced, and response reaction time data was not collected on any trial wherein a
participant's gaze fell outside of the focal range at any point during the presentation of the
crosshairs. Furthermore, to ensure the stimulus was processed in the desired hemifield,
participants sat approximately 57 cm from the monitor, and the final still frame in each vignette
was oriented with the centermost edge 2 cm from the center of the fixation point to produce a
minimum visual angle from the point of central fixation to the stimulus of 2°.
Procedure
Each adult participant completed 32 experimental trials and 4 practice trials subdivided
into two blocks of 16 experimental and 2 practice trials. Participants were instructed to sit
approximately 57 cm from the monitor, and were trained on how to monitor their position using
a gaze feedback screen that was presented prior to calibration, as well as prior to the start of each
trial block. A five-point calibration was completed prior to task commencement, and was
repeated (if necessary) until optimal calibration criterion was achieved. Before each trial block,
participants completed a brief instructional exercise to practice focusing on the crosshairs during
lateralized stimulus presentation and responding correctly with the appropriate hand. Participants
were explicitly told which side of the screen subsequent images would appear on and which hand
to respond with. They were instructed to press the “R” key when the word “expected” appeared,
and to press the “Y” key when the word “unexpected” appeared. Each instructional exercise
consisted of six randomly assigned word presentations (three “expected” and three
“unexpected”). In each trial, participants observed the first 11 still frames from a randomly
selected vignette, following which they were asked to fixate on a crosshairs until the crosshairs

21. Lateralization
and
Theory
of
Mind
21
was no longer present on the screen. After 1 s of visual fixation on the crosshairs, the final image
for the vignette was presented. Following presentation of the final image, participants were asked
to press the “R” key on a keyboard with the index finger of the responding hand if the final
image depicted the agent searching for the object in the expected location, and the “Y” key on
the keyboard with the index finger of the responding hand if the final image depicted the agent
searching for the object in the unexpected location. Between trials, participants were instructed
to position the index finger of the responding hand over the “T” key, which was located centrally
to the two response keys. It was made clear to all participants that they were to answer as
quickly and accurately as possible on all trials. All response reaction time data was collected in
E-prime 2.0. Following completion of the experiment, participants completed the handedness
inventory to assess dexterity.
Results
A
significant
RT
advantage
on
trials
wherein
the
final
image
was
presented
to
the
LVF
was
predicted
to
support
the
right
hemisphere
lateralized
representation
hypothesis
of
the
mechanism
underlying
belief
attribution.
Mean
RTs
were
compared
with
a
three-­‐
factor
repeated
measures
analysis
of
variance
(ANOVA)
with
visual
field
presentation
(LVF,
RVF),
belief
condition
(true
belief,
false
belief),
and
expectedness
value
(expected,
unexpected)
as
within
subjects
factors
using
IBM
SPSS
Statistics
Software
(see
Table
1
for
descriptive
statistics).
Because
the
main
purpose
of
this
study
was
to
assess
two
competing
hypotheses,
Bayesian
analysis
was
conducted
to
compare
the
probability
that
the
bi-­‐lateral
specialization
hypothesis
is
favoured
over
the
right
hemisphere
lateralized
specialization
hypothesis.
The
computed
Bayes
Factor
“is
the
ratio
of
the
marginal
likelihoods
of
two
contrasted
hypotheses,”
(Gallistel,
2009,
p.
4).

22. Lateralization
and
Theory
of
Mind
22
Table
1
Sample
Size,
Mean
RT,
Standard
Deviation,
and
Standard
Error
for
Visual
Field,
Belief,
and
Expectedness
Factors
Factor
Description
N
M
SD
SE
Visual
Field
Left
18
1278.43
481.00
113.37
Right
18
1366.95
587.38
138.45
Belief
Value
True
18
1309.17
439.06
103.49
False
18
1361.51
504.25
118.85
Expectedness
Value
Expected
18
1248.70
428.97
101.11
Unexpected
18
1433.57
520.94
122.79

23. Lateralization
and
Theory
of
Mind
23
Seven
participants
were
excluded
from
analysis
because
of
lower
than
chance
performance
during
either
one
or
both
of
the
experimental
blocks.
Participants
were
also
excluded
from
analysis
if
no
data
was
available
for
any
one
of
the
experimental
conditions,
which
resulted
in
the
exclusion
of
an
additional
eight
participants.
A
total
of
18
participants
were
included
in
the
final
analysis
(M
=
18.6
years,
SD
=
0.92;
males
=
8,
females
=
10).
Reaction
times
were
not
included
in
the
average
calculation
for
trials
wherein
participants
responded
incorrectly
(16%
of
trials),
or
for
trials
during
which
the
contingent
eye
tracking
malfunctioned
and
the
image
depicting
the
agent
searching
in
one
of
the
two
possible
locations
was
not
automatically
presented
to
participants
(13%
of
trials).
Additionally,
RTs
were
not
included
in
the
average
calculation
if
they
fell
outside
of
3
SD
of
the
subject’s
mean
RT
across
all
trials
(4%
of
trials).
The
three-­‐factor
repeated
measures
ANOVA
(see
Table
2)
revealed
a
main
effect
of
expectedness
value,
F(1,17)
=
5.29,
p
=
.34,
ηp
2
=
.237,
characterized
by
a
significantly
faster
RT
on
trials
in
which
the
final
image
depicted
the
agent
searching
in
the
expected
location
(M
=
1248.70,
SD
=
428.97)
than
on
trials
in
which
the
agent
was
depicted
searching
in
the
unexpected
location
(M
=
1433.56,
SD
=
520.94).
There
was
no
significant
main
effect
of
belief
condition,
F
=
0.82,
p
=
.38,
ηp
2
=
.046,
nor
were
any
significant
interactions
observed.
Importantly,
participants
did
not
respond
significantly
faster
on
LVF
trials
(M
=
1278.43,
SD
=
481.00)
than
on
RVF
trials
(M
=
1366.95,
SD
=
587.38),
F(1,17)
=
0.21,
p
=
.65,
ηp
2
=
.012.
Bayesian
analysis
comparing
participants’
mean
RTs
between
LVF
and
RVF
trials
produced
an
odds
ratio
of
22:1
in
favour
of
the
bi-­‐lateral
representation
hypothesis.
All
participants
reported
being
right
handed,
and
as
such
no
further
analysis
regarding
the
effects
of
handedness
on
RT
was
required.

24. Lateralization
and
Theory
of
Mind
24
Table
2
Visual
Field
x
Belief
x
Expectedness
Repeated
Measures
Analysis
of
Variance
for
Response
Reaction
Time
Source
Df
F
ηp
2
p
(A)
Visual
Field
1
0.21
.012
.65
(B)
Belief
Value
1
0.82
.46
.38
(C)
Expectedness
Value
1
5.29
.24
.03
A
x
B
(interaction)
1
0.03
.002
.86
A
x
C
(interaction)
1
1.36
.074
.26
B
x
C
(interaction)
1
1.79
.95
.20
A
x
B
x
C
(interaction)
1
1.50
.081
.24
Error
(within
groups)
17

25. Lateralization
and
Theory
of
Mind
25
Discussion
Previous
neuroimaging
research
has
produced
conflicting
results
regarding
the
neural
mechanism
underlying
ToM.
While
the
TPJ
has
been
noted
by
various
sources
as
a
brain
region
specifically
designated
to
reasoning
about
beliefs,
the
hemispheric
distribution
of
belief
reasoning
is
of
burgeoning
interest
in
ToM
research.
While
some
evidence
indicates
that
both
the
lTPJ
and
rTPJ
are
independently
capable
of
supporting
belief
attribution
processes
(Hampton, Bossaerts, & O'Doherty, 2008; Saxe & Kanwisher,
2005; Young, Dodell-Feder, & Saxe, 2010) other
evidence
suggests
that
the
rTPJ
is
specifically
responsible
for
belief
attribution
(Gweon, Dodell-Feder, Bedny, & Saxe, 2012;
Perner, Aichhorn, Kronbichler, Staffen, & Ladurner, 2006).
A
small
number
of
studies
have
even
reported
that
the
lTPJ,
and
not
the
rTPJ,
is
the
control
center
for
belief
attribution
(van
der Meer, Groenwold, Nolen, Pijenborg, & Aleman, 2011).
The use of neuroimaging techniques to reconcile this conflict has various limitations.
When conducting neuroimaging research, neural activity is measured in discrete spatial units, or
voxels, which span one or more square centimetres of cortex. It is therefore not surprising that a
single voxel may contain multiple functionally distinct neural pathways. This lack of spatial
resolution hinders efforts to assign functional specificity to a particular region, as control tasks
may activate functionally distinct neural networks within the same voxel as experimental tasks.
Furthermore, because individual brains are anatomically and functionally different, the alignment
and normalization procedures conducted for group analyses can blur activation maps and lead to
false assumptions regarding common neural mechanisms for distinct processes. While cognizant
of the inherent limitations of neuroimaging techniques, few have endeavored to develop novel

26. Lateralization
and
Theory
of
Mind
26
tasks that can be easily and ethically used to provide converging evidence for theories regarding
neural organization in humans.
The
present
study
aimed
to
assess
two
competing
hypotheses
of
the
mechanism
underlying
belief
attribution:
the
domain-­‐specific
bi-­‐lateral
representation
hypothesis
and
the
domain-­‐specific
right
hemisphere
lateralized
representation
hypothesis.
Participants
completed
a
computerized
violation
of
expectation
task
requiring
the
attribution
of
both
true
and
false
beliefs
in
a
novel
paradigm
featuring
lateralized
presentation
of
ToM
relevant
stimuli.
A
significant
RT
advantage
for
trials
in
which
the
relevant
stimuli
were
presented
to
the
RVF
was
predicted
to
support
the
latter
hypothesis,
and
Bayesian
statistics
were
conducted
to
determine
the
odds
in
favour
of
or
against
the
former
hypothesis.
The
lack
of
an
observed
significant
effect
of
hemisphere
presentation
on
RT
indicates
that
right
hemisphere
is
not
specifically
responsible
for
belief
attribution.
Additionally,
Bayesian
analysis
revealed
that
the
bi-­‐lateral
representation
hypothesis
is
strongly
favoured
over
the
lateralized
representation
hypothesis.
Despite the shortcomings of neuroimaging techniques and the sizeable disagreement
regarding where, hemispherically, the belief computation center is located, many studies thus far
claim to support a domain-specific representation (Hampton, Bossaerts, & O'Doherty, 2008;
Saxe et al., 2004, Saxe & Kanwisher, 2005; Young, Dodell-Feder, & Saxe, 2010). While the
results of the present study can be explained in terms of a domain-specific bi-lateral
representation hypothesis, it is unclear whether the lTPJ and rTPJ independently support belief
attribution, or whether both are functionally dissimilar but necessary for this process. Also,
while the results of the present study support the hypothesis that beliefs are computed bi-
laterally, they do not provide evidence for or against domain-specificity. Many researchers have

27. Lateralization
and
Theory
of
Mind
27
expressed skepticism towards domain-specific ToM hypotheses, as "the roles of [brain regions
hypothesized to form the domain-specific ToM module] are not well understood because there is
no consensus about the cognitive requirements of ToM tasks," (Apperly, Samson, & Humphreys,
2005, p. 572). In consideration of evidence indicating that ToM may share a common neural
basis with a variety of cognitively similar processes, the present results are also explained in
terms of a domain-general bi-laterally distributed neural network.
Domain-­‐Specific
Mechanisms
Evidence for a Duplicate System. Perner and colleagues (2006) reported that while the
rTPJ and lTPJ showed similar levels of activation during false belief vignettes, the rTPJ showed
a more selective activity profile than the lTPJ: the lTPJ showed significant increases in neural
activity during false belief vignettes as well as false sign vignettes but not during false
photograph vignettes, whereas the rTPJ showed increased activity during false belief vignettes
only. The authors concluded that the lTPJ might be associated with a more broad range of tasks,
including basic mentalizing and processing perspective contrasts, whereas the rTPJ may be
specifically associated with belief attribution. It is possible, however, that a secondary process
engaged during both false belief vignettes and false sign vignettes is functionally represented in
the same anatomical region of the lTPJ as belief reasoning. The latter explanation is more
concurrent with the present findings, for if the rTPJ is more specifically attuned to belief
attribution than the lTPJ, it is likely that information processing would have occurred more
rapidly when relevant stimuli were presented to the right hemisphere versus the left hemisphere.
The idea that both the lTPJ and rTPJ can independently support belief attribution is
supported by the present findings as well as by studies showing similar profiles of activity in
both regions during tasks involving mentalizing but not during cognitively similar control tasks

28. Lateralization
and
Theory
of
Mind
28
(Hampton, Bossaerts, & O'Doherty, 2008; Saxe & Kanwisher, 2005; Young et al., 2010). This
bi-lateral representation theory fails, however, to explain evidence indicating that abnormalities
in the functional profile of the rTPJ may underlie mindblindness in individuals diagnosed with
ASD (Lombardo et al., 2011) or evidence suggesting that increases in the selectivity of the rTPJ
for thinking about thoughts underlies age-related changes in ToM competence (Saxe et al., 2009;
Gweon et al., 2012). Additionally, a research endeavor assessing ToM ability in patients with
lTPJ lesions reported that the patients showed impaired performance on the false-belief task
(Apperly, Samson, Chiavarino, & Humphreys, 2004). Similar impairments in belief reasoning
were also observed in a study that employed transcranial magnetic stimulation (TMS) to disrupt
activity within the rTPJ (Young, Camprodon, Hauser, Pascual-Leone, & Saxe, 2010).
Unfortunately, no studies have yet assessed the effects of TMS administered to the lTPJ on the
ability to attribute beliefs to others.
These sources of evidence provide a theoretical stumbling block for a duplicate-system
hypothesis: if the lTPJ and rTPJ represent a duplicate system, and are both independently
capable of supporting belief attribution, then disruption of activity specifically within one region
should not have a significant effect on ToM competence. Despite the shortcomings of lesion
studies (heterogeneity of the lesion area, multiple functional networks affected) and studies
employing TMS to temporarily disrupt neural activity (lack of spatial accuracy and specificity of
functional region affected), a second explanation for the present results is suggested: the rTPJ
and lTPJ are functionally distinct but are both required for process of belief attribution.
Evidence for a Functional Dissociation. One possible functional distinction put forth by
Apperly and colleagues (2004) and supported by the aforementioned study by Perner et al.
(2006), suggests that the lTPJ is responsible for reasoning about perspective conflicts, whereas

29. Lateralization
and
Theory
of
Mind
29
the rTPJ is specifically involved in belief attribution. While this view may sufficiently explain
why no RT advantage was observed upon presentation of ToM-relevant information to one
hemisphere or the other during false belief vignettes, it does not explain the same observation
during true belief vignettes wherein the perspectives of the participant and agent were congruent.
Furthermore, no studies have directly assessed the role of the lTPJ in computing perspective
contrasts, and as such there is little support for this view.
An interesting possibility that has also received little direct attention is that the functional
distinction between the lTPJ and lTPJ relates to attributing beliefs to the self versus attributing
beliefs to others. For example, in a study assessing the neural correlates of the self-serving bias,
participants attributed negatively or positively valenced responsibility in various social situations
to either the self or a specified other (Seidel et al., 2010). The authors reported different
functional profiles between self- and other-attribution conditions. Self-attributions were
associated with increased activity in the rTPJ whereas increased activity in the lTPJ was
associated with attributing responsibility to a specified other. Furthermore, using positron
emission tomography (PET), Lou and colleagues (2004) observed a similar lateralized pattern of
activity during episodic retrieval of previous judgments about the self versus a best friend or a
distant other (the Danish Queen). Specifically, decreased self-reference was associated with
increased activity within the vicinity of the left lateral temporal cortex and decreased activity
within the right inferior parietal cortex. The belief attribution task employed in the present study
required participants to simultaneously reason about their own belief as well as the agent's belief
(true or false) regarding the object's location, and as such was not sensitive to any possible
lateralization differences in reasoning about self-beliefs versus reasoning about the beliefs of
others. Future research is necessary to evaluate the validity of this proposed functional

30. Lateralization
and
Theory
of
Mind
30
dissociation.
Domain-General Mechanism
Several studies have reported a high level of functional correspondence between ToM
and a variety of other cognitive processes. In a quantitative meta-analysis employing the
activation likelihood estimation (ALE) approach, Spreng, Mar, and Kim (2008) reported that the
number of shared clusters of activation between ToM, autobiographical memory, prospection,
and navigation far outweighed the number of unique clusters. Of particular interest in terms of
the present results, convergence in the rTPJ was found for all processes, and convergence was
observed in the lTPJ for all but navigation. Others have concurrently reported a strong
correlation in neural activity between belief reasoning and autobiographical memory (Gweon,
Young, and Saxe, 2011), characterized by bi-lateral activity within the TPJ. The present results
may thus also be explained in terms of a bi-laterally represented domain-general mechanism of
belief attribution.
Effect of Expectedness and Belief Value
Participants
responded
significantly
faster
on
congruent
trials
(the
agent
was
depicted
searching
in
the
expected
location)
than
on
incongruent
trials
(the
agent
was
depicted
searching
in
the
undexpected
location).
Sommer
and
colleagues
(2007)
reported
similar
results
when
they
employed
a
violation
of
expectation
paradigm
to
compare
the
neural
correlates
of
true
and
false
belief
reasoning.
The
authors
also
noted
that
there
was
no
significant
effect
of
belief
condition
on
RT,
which
concurs
with
the
results
reported
here.
Increased
response
competition
during
incongruent
belief
attribution
trials
likely
accounted
for
this
observation,
as
a
large
body
of
evidence
has
found
that
the
amount
of
attentional
control
(and
subsequently
the
rate
of
response)
required
to
respond

31. Lateralization
and
Theory
of
Mind
31
appropriately
increases
as
a
function
of
the
amount
of
cognitive
conflict
elicited
by
a
stimulus
(Davelaar
&
Stevens,
2009).
By
this
account,
it
seems
counter-­‐intuitive
that
no
RT
advantage
was
observed
for
true
belief
trials
over
false
belief
trials,
as
correctly
attributing
a
false
belief
involves
more
response
competition
that
correctly
attribution
a
false
belief.
As
discussed
shortly
in
study
limitations,
the
process
of
belief
attribution
may
have
temporally
preceded
the
process
of
selecting
the
appropriate
response
based
on
expectedness
value,
which
could
explain
why
no
effect
of
belief
condition
was
observed
on
RT.
Limitations
Central Bottleneck Effects. Uleman (1989) characterized the average RT of a single
automatic process as approximately 300 ms or less. In the present study, absolute RT for the task
fell between 500 and 2000 ms, which suggests that the task required multiple processes for
successful completion. Most notably, the task involved reading and verbal comprehension during
probe sentences as well as executive control to select appropriate motor responses, neither of
which is directly involved in the process of belief attribution. Furthermore, the task involved
rapid sequential determination of where the agent would logically search for the object given
his/her beliefs (true or false), as well as whether the agent was depicted in the final image as
searching for the object in the expected or unexpected location. It is thus possible that processing
during this task was subject to a bottleneck effect.
It has been noted that “despite the impressive complexity and processing power of the
human brain, it exhibits severe capacity limits in information processing…when we attempt to
preform two tasks at once, as such conditions will almost invariably lead to interference between
the tasks,” (Dux, Ivanoff, Asplund, & Marois, 2006, p. 1109). The authors noted that a central
bottleneck of information processing occurs via a neural network of frontal lobe areas; this

32. Lateralization
and
Theory
of
Mind
32
amodal stage of information processing during dual-tasks leads to increasing RT to the second
task as the temporal disparity between the two tasks decreases. This effect has been observed in a
study assessing the effects of cognitive load on implicit theory of mind processing (Schneider,
Lam, Bayliss, & Dux, 2012). Eye movements associated with implicit belief processing were
reported to be absent among participants in a dual-task (high cognitive load) condition, wherein
they were required to perform a separate task concurrently with either a true or false belief task.
These results suggest that belief processing is a capacity-limited operation that draws on
executive processing resources. Thus, the presently employed task may not have been sensitive
to differences in RT specifically related to the process of belief attribution due to the effects of
dual-task interference.
Time-Course of Anticipating Behaviour. While the results reported here suggest that
belief attribution processes are represented bi-laterally in the brain, the experimental design
employed may have failed to garner a measure of the rate at which ToM relevant information is
processed. A large body of evidence indicates that ToM is rapidly and automatically imputed
(Cohen & German, 2009; Kovács et al., 2010). Ferguson and Breheny (2011) measured
anticipatory eye movements in adults in a visual world paradigm to gain a better understanding
of the time-course of ToM inference during language processing. Participants listened to stories
consisting of two sentences; the first sentence contained contextual information regarding an
agent’s willingness for others to know about his or her preferences (open or secret), and the
second sentence described the agent completing a contextually appropriate action. Following the
cessation of the first sentence, a display featuring four images (the agent, the open referent, the
secret referent, and a distracter) was presented to participants. The second sentence was played
following the presentation of the display. Participants’ anticipatory eye movements were

33. Lateralization
and
Theory
of
Mind
33
monitored to see at what point during the second sentence individuals made predictions
regarding the agent’s actions in the context of the agent’s previously described intentional stance.
Analysis of the probabilities of gazes to the open and secret referents as a function of time
revealed that participants anticipated towards the appropriate referent well before the
disambiguating target word (explicitly identifying the correct referent) was auditorily mentioned.
Thus, healthy adults appear to be capable of rapidly predicting the behaviours of others through
belief reasoning.
In relation to the methods employed presently, participants likely formed expectations
regarding where the agent would most likely search for the hidden object prior to the lateralized
presentation of the response-eliciting stimulus. As noted by Cohen and German (2009), assessing
belief attribution processes offline “inevitably measures the extent to which any encoded belief
information might have been maintained in the cognitive system, rather than whether or not it
was ever encoded, (p. 361). This problem may be circumvented in the present study by
incorporating online assessments of belief reasoning in real time, such as those employed in the
previously discussed study conducted by Ferguson and Breheny (2011).
Suggestions for Future Research
It is important to note that the paradigm developed in this study provides indirect
evidence regarding functional lateralization only. That being said, the relatively cost effective
and simple design of the employed paradigm may help to provide exciting insight into the
representation of belief attribution processes in populations of individuals who would otherwise
be excluded from analysis due to ethical or procedural constraints. Employing the present
paradigm to assess differences in lateralization between normative and non-normative
populations (such as those with ASD) may provide valuable insight into the neural substrates

34. Lateralization
and
Theory
of
Mind
34
underlying ToM impairments. For example, evidence indicates that individuals with ASD show
abnormal functional profiles in the rTPJ during belief attribution tasks (Lombardo et al., 2011),
and thus neural activity may be less bi-laterally represented in these individuals. Also, as this
task is suitable for use with young children, it may be useful in assessing whether changes in
lateralization occur throughout development. Understanding how the neural representation of
ToM differs between normative, non-normative, and developmentally immature individuals may
be helpful in informing both pharmacological and behavioural therapies for clinical populations
as well as educational strategies to facilitate optimal development among normative populations.
As noted previously, a large body of research has thus far focused on the role of the rTPJ
as the belief control center, and little attention has been given to the specific role of the lTPJ in
belief reasoning. This paradigm may be useful in disambiguation the contributions of the lTPJ
and rTPJ to ToM. For example, a paradigm could be developed comparing response RT
associated with trials in which participants attributed beliefs to the self versus a specific other to
determine whether the lTPJ is specifically responsible for reasoning about self-beliefs and the
rTPJ is specifically responsible for reasoning about other-beliefs.
Conclusion
The right-hemisphere lateralization hypothesis is not supported, as presenting ToM-
relevant information specifically to the LVF did not result in a significant RT advantage over
presenting the same information specifically to the RVF. The bi-lateral specialization hypothesis
is favoured over the alternative with a Bayes factor of 22. Concurrent functional frameworks
include both domain-specific and domain-general theories of the neural organization underlying
belief attribution.

35. Lateralization
and
Theory
of
Mind
35
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Appendix A
Study description as observed by participants in UWO’s Psychology Research Participation Pool
Research Participants Needed
How do people reason and solve problems? In this study, participants first watch videos or
view a series of pictures of people interacting with other people and with objects and then
answer questions based on the information provided. The study takes 60 minutes and you
will receive 1 credit for your participation.
If you are interested, please contact Dr. Adam Cohen for more information.
acohen42@uwo.ca

41. Lateralization
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Appendix B
Handedness Inventory
Please
indicate
your
hand
preferences
in
the
following
activities
by
putting
a
check
in
the
appropriate
column.
If
in
any
case
you
are
really
indifferent,
put
a
check
in
both
columns.
Some
of
the
activities
listed
below
require
the
use
of
both
hands.
In
these
cases,
the
part
of
the
task,
or
object,
for
which
hand
preference
is
wanted
is
indicated
in
parentheses.
Please
try
and
answer
all
of
the
questions,
and
only
leave
a
blank
if
you
have
no
experience
at
all
with
the
object
or
task.
1.
Writing
Left
Right
2.
Throwing
a
ball
Left
Right
3.
Holding
a
racquet
Left
Right
4.
Lighting
a
match
Left
Right
5.
Cutting
with
scissors
Left
Right
6.
Threading
a
needle
Left
Right
7.
Sweeping
with
a
broom
(top
hand)
Left
Right
8.
Shoveling
Left
Right
9.
Dealing
cards
Left
Right
10.
Hammering
Left
Right
11.
Holding
a
toothbrush
Left
Right
12.
Unscrewing
a
lid
Left
Right

42. Lateralization
and
Theory
of
Mind
42
Appendix C
Sample of True Belief Vignette for Adult Participants
1 6 11
2 7 12
3 8 13
4 9
5 10

43. Lateralization
and
Theory
of
Mind
43
Appendix D
Sample of False Belief Vignette for Adult Participants
1 6 11
2 7 12
3 8 13
4 9
5 10