Brief Report: Preliminary Evaluation of the Theory of Mind
Inventory and its Relationship to Measures of Social Skills
Matthew D. Lerner•Tiffany L. Hutchins•
Patricia A. Prelock
Published online: 14 July 2010
? Springer Science+Business Media, LLC 2010
parent-report measure of Theory of Mind (ToM), formerly
called the Perception of Children’s Theory of Mind Mea-
sure (Hutchins et al., J Autism Dev Disord 38:143–155,
2008), renamed the Theory of Mind Inventory (ToMI), for
use with parents of children with autism spectrum disorder
(ASD). This study examines the responses of parents of
adolescents with ASDs and explores the relationship of
parental responses on the ToMI to measures of autistic
symptoms and social skills. Descriptive statistics were
compared to previous samples; correlations and regressions
were conducted to examine the ToMI’s criterion-related
validity with social skills and ASD symptoms. Results
support use of the ToMI with adolescent samples and its
relationship to social impairments in ASDs.
This study presents updated information on a
Social skills ? Scale evaluation ? Psychometrics ?
Autism spectrum disorder ? Theory of Mind ?
Theory of Mind (ToM), or an individual’s ability to take
another’s perspective, is considered a central domain of
impairment among those with autism spectrum disorder
(ASD; Baron-Cohen 2001). In 2008, Hutchins et al.
reported on the development and psychometric evaluation
of a novel measure of child perspective-taking: the Per-
ceptions of Children’s Theory of Mind Measure—Experi-
mental version (PCToMM-E). The PCToMM-E is a
parent-informant measure of ToM, consisting of 33 state-
ments designed to tap a wide range of social-cognitive
understanding and skill sets that are believed to be sub-
sumed under (or strongly related to) the construct of ToM.
All statements (e.g., ‘‘My child understands that when
people frown, they feel differently than when they smile’’)
are accompanied by a 20-unit continuum anchored by
‘‘strongly disagree’’ to ‘‘strongly agree’’. Parents are asked
to indicate the degree to which they agree with each
statement by making a vertical hash mark at the appro-
priate point along the continuum. Each item is scored by
ruler with higher values reflecting greater degrees of the
Theory of Mind (ToM) is a broad and multifaceted
construct (Astington and Baird 2005; Hutchins et al. 2008),
physical versus mental perspectives, and making inferences
about thoughts and emotions (Baron-Cohen 2001; Repa-
choli and Slaughter 2003). Crucially, ToM is related to
social functioning and autistic symptoms (Frith et al.
1994). As Hutchins et al. (2008) described, the PCToMM-
E included (but was not limited to) items which were face
valid indicators of false belief understanding, the notion
that seeing leads to knowing, first and second order beliefs,
the appearance-reality distinction, the mental-physical
distinction, the understanding of speech acts, the under-
standing of a variety of mental state terms, and the causes
and consequences of mental states. In short, the PCToMM-
E was designed to be a content valid index of ToM.
To evaluatethe psychometric
PCToMM-E, Hutchins et al. (2008) performed several tests
M. D. Lerner (&)
Department of Psychology, University of Virginia, 102 Gilmer
Hall, P.O. Box 400400, Charlottesville, VA 22904-4400, USA
T. L. Hutchins ? P. A. Prelock
Department of Communication Sciences, University of Vermont,
Burlington, VT, USA
J Autism Dev Disord (2011) 41:512–517
of reliability and validity using a sample of parents of
typically-developing children and children with ASD. The
measure performed well and established strong test–retest
reliability for short and long lags as well as convergent
validity with scores on a measure of receptive vocabulary
and on a ToM task battery. It also performed well among
two contrasting group comparisons of construct validity,
distinguishing typically developing children from age-
matched children with ASD, and distinguishing younger
from older typically developing children.
Besides the encouraging evidence surrounding its reli-
ability and validity, measurement features found in the
PCToMM-E have been described as advantageous for sev-
eral reasons (see Peterson et al. 2009; Wellman and Liu
2004). First, it is used to gain estimates of ToM in typical
(ages 2–12) and ASD samples (ages 2–12) across verbal
abilities. It does not suffer from ceiling effects (see, e.g.,
Steele et al. 2003) even when mentalizing is relatively good.
Because it is an informant measure, it is not complicated by
child performance factors (e.g., memory, linguistic, atten-
tional, motivational factors) and can be used as a repeated
measurebecauseitdoesnotsuffer fromtest-practice effects.
Further, using interval scores generates continuous variable
amenable to more statistically powerful analyses.
A recent revision of the PCToMM-E (now referred to as
the Theory of Mind Inventory or ToMI) was similar except
that it consists of 48 statements believed to more adequately
tap advanced components of ToM, such as understanding
sarcasm, irony, and counter-factual reasoning (Steele et al.
of improvement in Cronbach’s alpha. In addition, authors
clarified the instructions to reduce error in responding (e.g.,
respondents sometimes circled anchors or indicated a
response with an ‘X’ as opposed to a vertical hash mark, so
correct and incorrect examples were provided).
This brief report provides a preliminary psychometric
evaluation of the ToMI when administered to a sample of
parents of adolescents with ASD. In lab-based evaluations,
ToM has been shown to remain impaired, and to develop
slowly and inconsistently over time among individuals
with ASDs (Hutchins et al. 2008; Peterson et al. 2005).
Because ToM competencies are highly variable in indi-
viduals with ASD and less strongly related to chronological
age than in typically developing samples (Hutchins and
Prelock 2008), we sought to explore the patterns of parent
reporting on the ToMI in adolescents with ASDs (see
Dissanayake and Macintosh 2003; Tager-Flusberg 2003;
Watson et al. 1999) relative to previous younger samples
using the PCToMM-E. As the previous literature clearly
demonstrates a link between ToM, social skills, and ASD
symptoms (Frith et al. 1994), we sought to examine the
concurrent criterion validity of the ToMI by exploring the
relationship between ToMI and parent-report of these
constructs on well-validated measures. Crucially, we
expected the social impairment component of ASD to be
the most important predictor of ToM deficits (Frith et al.
1994), and so we explored this possibility using the
Forty families of children with ASDs were successfully
recruited from community-based programs and workshops
in rural and suburban Virginia. All parents completed a
questionnaire for demographic information; a subset of
parents completed an additional question regarding whe-
ther their child was able to read at a fourth grade level,
while the remainder provided their child’s Individualized
Education Plan. Only families of children who had
received a previous diagnosis from a licensed diagnostic
professional (i.e., Developmental Pediatrician, Psychiatrist,
Clinical Psychologist) were invited to participate in these
workshops. To support the validity of the ASD diagnosis,
strict recommended cutoffs on the Social Communication
Questionnaire (SCQ; Rutter et al. 2005) and Social
Responsiveness Scale (SRS; Constantino and Gruber 2005)
were used to screen participants. We acknowledge that the
Autism Diagnostic Interview—Revised (ADI-R; Lord et al.
1994) and Autism Diagnostic Observation System (ADOS;
Lord et al. 1999) are considered the ‘‘gold standard’’
diagnostic tools for ASD populations in research. However,
high correlations between the SRS & ADI-R (Bishop and
Norbury 2002) and between the SCQ and ADOS (Corsello
et al. 2007), as well as the recommendation to use the SCQ
in combination with another instrument (Rutter et al.
2005), led us to conclude that an individual simultaneously
exceeding recommended cutoffs on both of these instru-
ments met sufficient diagnostic criteria.
Of those recruited, thirty youth [24 (80%) male, six
female; Mage= 14.17, SDage= 3.11] met these criteria.
Their parents (Mage= 46.58, SDage= 7.80; Mincome=
$69,000, SDincome= $28,450) included 24 (80%) mothers,
two (7%) fathers, one (3%) grandfather, and three (10%)
parents who did not identify their relationship to the child.
Of these, 27 (90%) endorsed the SCQ item that their child
‘‘is able to talk using short phrases or sentences’’ (verbal
ability) and 19 (63%) indicated that their child could read
at least at a fourth grade level (reading ability).
Social Communication Questionnaire (Rutter et al. 2005).
J Autism Dev Disord (2011) 41:512–517 513
interests that preoccupy him/her and might seem odd to other
people?’’) parent report measure of ASD symptoms designed
as a screening tool in research and clinical settings. The SCQ
diagnosis: communication, reciprocal social interaction, and
restricted/repetitive behaviors. The SCQ scores range from 0
to 40, with higher scores corresponding to higher levels of
ASD symptoms and a recommended clinical cut-off score of
15. The SCQ has been shown to be a reliable instrument for
sufficient sensitivity and specificity to be considered valid in
identifying individuals with ASDs above the age of eight
(Corsello et al. 2007).
Social Skills Rating System—Parent (SSRS-P; Gresham
and Elliot 1990). The SSRS-P is a parent informant mea-
sure consisting of 52 items (sample item: ‘‘Joins group
activities without being told to’’) tapping four domains:
Cooperation, Assertion, Responsibility, and Self-control.
The SSRS-P yields standard scores (M = 100, SD = 15)
with higher scores indicating more developed social skills.
The SSRS-P is currently the most extensively used parent-
report measure for assessing social skills in adolescents
with ASD (White et al. 2007); in a normative sample, the
SSRS-P demonstrated excellent internal consistency (Gre-
sham and Elliot 1990).
Social Responsiveness Scale (SRS; Constantino and
Gruber 2005). The SRS is a parent-informant measure
consisting of 65 items (sample item: ‘‘takes things too lit-
erally and doesn’t get the real meaning of a conversation’’)
tapping five subscales: Social Awareness, Social Cognition,
Social Communication, Social Motivation, and Autistic
Mannerisms. The SRS yields T-scores (M = 50, SD = 10),
with higher scores corresponding to a higher degrees of
social impairment. Good internal consistency and validity is
reported for ASD populations (Constantino et al. 2003).
Data Analytic Plan
The mean and range on the ToMI were compared to the
PCToMM-E values reported by Hutchins et al. (2008) with
the expectation that scores would be comparable. Likewise,
differences in ToMI scores between those with high and
low reported verbal and reading ability were compared.
Next, correlations between variables were explored.
Finally, as we expected that SRS would best account for
the variance in ToMI after controlling for SCQ and SSRS-
P, a hierarchical multiple regression model was specified,
with SCQ on Step 1, SSRS-P on Step 2, and SRS on Step 3.
Table 1 demonstrates that, on average, parents reported
their adolescent children with ASDs to have a similar mean
level of ToM ability as found in younger ASD samples, but
that variability in ToM was considerably greater than was
found in those samples. Parents also reported their children
to be approximately one standard deviation below popu-
lation means of typically-developing children on social
skills (MSSRS-P= 100, SDSSRS-P= 15).
One-way ANOVAs indicated a significant difference in
ToMI scores between children with high and low verbal
(Mhigh= 12.11, SDhigh= 3.00; Mlow= 3.49, SDlow=
2.54), F(1, 29) = 22.73 (p\0.001) and reading (Mhigh
= 12.67, SDhigh= 3.19; Mlow= 8.77, SDlow= 3.98),
F(1, 29) = 8.71 (p\0.006) abilities. ToMI scores dem-
onstrated excellent internal consistency (a = 0.98).
Table 2 demonstrates that ToMI scores were positively
correlated with parent report of social skills and negatively
correlated with autistic symptoms and autism-related social
impairment. Autism-related social impairment was posi-
tively correlated with autistic symptoms.
As each of the primary measures yielded significant
correlations with the ToMI, correlations with the subscales
were explored and these data are represented in Table 3.
Table 1 Descriptive statistics
Variables MeanSD Range
Social Communication Questionnaire (SCQ) 23.275.08 15.00 31.00
Social Skills Rating System—Parent (SSRS-P)76.0715.31 48.00113.00
Social Responsiveness Scale (SRS) 89.5011.46 68.00115.00
n = 30
aPC-ToMM-E values reported from Hutchins et al. (2008)
514J Autism Dev Disord (2011) 41:512–517
On the SCQ, only the reciprocal social interaction subscale
was significantly correlated with ToMI scores, indicating
that this factor alone accounted for the relationship
between SCQ and ToMI. All SSRS-P and SRS subscales
were significantly correlated with ToMI scores. We
examined the difference in these correlations using Stei-
ger’s (1980) recommended t-test (one-tailed). There was no
t(27)\0.79, p[0.20) or SRS (all t(27)\1.71, p[0.05)
subscale coefficients when correlated with ToMI scores.
This indicates that no single subscale accounted for a sig-
nificantly greater proportion than any other in explaining
the relationship between ToMI and either SSRS-P or SRS.
Table 4 demonstrates results of the hierarchical multiple
regression model. After controlling for parent-reported
autistic symptoms, both higher parent-reported social skills
and fewer autistic symptoms significantly predicted ToMI
scores. Effect sizes were large. After controlling for parent-
reported social skills and autistic symptoms, parent-report
autism-related social impairments negatively predicted
ToMI scores and explained a significant additional portion
of its variance. Effect size was medium to large.
We explored parent ratings on the ToMI using a sample of
ASD adolescents. We found that ToMI scores were similar
to those found for the experimental version of the measure
Table 2 Correlation matrix showing relationships between overall scores for each measure
1. Theory of Mind Inventory (ToMI)–-0.55**0.61***-0.75***
2. Social Communication Questionnaire (SCQ)–-0.03 0.23
3. Social Skills Rating System—Parent (SSRS-P)–-0.64***
4. Social Responsiveness Scale (SRS)–
*p\0.05; **p\0.01; ***p\0.001
Table 3 Correlation matrix between ToMI and the subscales of each
Theory of Mind Inventory (ToMI)
Pearson’s rp-value (2-tailed)
aSocial Communication Questionnaire
bSocial Skills Rating System
cSocial Responsiveness Scale
Table 4 Hierarchical multiple regression model predicting ToMI scores
VariableModel 1 B
Model 2 B
Constant21.19***9.25** 26.77***[15.25, 27.13]
Social Communication Questionnaire (SCQ)-0.43**-0.41***-0.34***[- 0.67, -0.18]
Social Skills Rating System—Parent (SSRS-P)0.15***0.08* [0.09, 0.21]
Social Responsiveness Scale (SRS)
-0.15**[- 0.24, -0.06]
*p\0.05; **p\0.01; ***p\0.001
J Autism Dev Disord (2011) 41:512–517 515
(i.e., PCToMM-E) which was validated on a younger
sample of children with ASD. ToMI scores also discrimi-
nated effectively between those with high and low verbal
ability. We also explored the relationship of ToMI scores
to parent-reported autistic symptoms, social skills, and
autism-related social impairments. We found that ToMI
scores were positively correlated with social skills, and
negatively correlated with ASD symptoms and autism-
related social impairments. We also found that these cor-
relations were equivalently explained by each of the sub-
scales in the social skills domain, and by each of the
subscales in the autism-related social impairment domain,
but were only accounted for by reciprocal social interaction
(e.g., ‘‘does she/he have any particular friends or best
friends?’’) in the ASD symptom domain. Finally, we
expected that autism-related social impairments would best
account for the variance in ToMI scores after controlling
for autistic symptoms and social skills. Our results sup-
ported this prediction.
These findings extend the use of the ToMI as a valuable
parent-report measure of ToM. First, they repeat the find-
ing that ToM remains impaired at comparable levels
among adolescents with ASDs and is related to verbal and
communication ability (Frith et al. 1994), and that vari-
ability in ToM may increase over time (Peterson et al.
2005); no ceiling effects were observed. Second, results
support the external validity of the ToMI, demonstrating its
valid use in a rural and suburban sample of community-
recruited adolescents with ASDs. Third, findings support
the relationship of ToM to ASD (Frith et al. 1994; Tager-
Flusberg 2003), social skills (Dissanayake and Macintosh
2003), and particularly the social impairments character-
istic of ASDs (Baron-Cohen 2001), supporting the con-
current criterion validity of the measure. In addition, results
support parents as reliable and accurate sources of infor-
mation about their children’s ToM.
Several important limitations to the findings are note-
worthy. First, while strict procedures were used to ensure
the ASD diagnosis of adolescent participants, gold-stan-
dard research measures (ADOS, ADI-R) were not used to
confirm diagnoses. Thus, this sample may be considered to
only represent a sample ‘‘at-risk’’ for ASDs. Second, the
sample was fairly small, drawn only from a rural and
suburban sample, and not compared to a normative control.
Larger, more geographically diverse samples compared
with normative peer data will be crucial to future efforts to
explore the validity and utility of the ToMI, and such
efforts are currently underway. Third, ToM scores were not
assessed using existing experimental batteries for adoles-
cents with ASDs or standard tests of verbal and adaptive
functioning (e.g., language; Astington and Baird 2005), so
more conclusive criterion validity could not be achieved.
Current research efforts are also underway to explore these
relationships and examine convergent validity of the ToMI.
Fourth, measures were only administered at a single time
point, so stability over time could not be assessed. Addi-
tional analyses of data using a normative control, and
examining criterion-related validity and test-retest reli-
ability are the subject of further research.
Future research will expand upon these promising
findings regarding the use of the ToMI with diverse pop-
ulations and its relationship to related measures. In par-
ticular, the ToMI should be administered to a broad
normative sample of parents of children with ASDs across
the lifespan as well as typically developing children to
establish standardized scores. Additionally, ToMI scores
should be compared to scores on measures of other theo-
retically related constructs to continue to explore its con-
current criterion validity. Finally, the ToMI should be used
as an outcome measure in interventions designed to
improve ToM in individuals with ASDs.
This study supports the importance of the ToMI as a
valid parent-report measure of ToM among parents of
adolescents with ASDs. This is an important step in the
advancement of ToM research in this population, that does
not suffer from floor or ceiling effects and represents a
helpful, easy-to-use alternative to existing ToM paradigms.
These paradigms require the scheduling of child visits and
yield (often ordinal) scores that may not evidence sufficient
variability to be sensitive to development and individual
differences in ToM. In a related vein, this study supports
the notion that parents are sensitive to the relationship of
mentalizing ability to social functioning in their children
with ASDs. In summary, we propose the continued and
expanded use of the ToMI in research settings to advance
its potential for clinical application.
of time and resources by the Commonwealth Autism Services, par-
ticularly Dottie Narodny, Didi Zaryczny, and John Toscano, who
helped us to collect much of these data. We also thank Amori Mikami
for her support of this project and the primary research assistant,
Nancy Chae, for the hours she contributed. Most importantly, we
thank the participating families, who volunteered a considerable
amount of time to contributing their responses to these surveys and
without whom this study would not be possible. The sponsor of the
study (Commonwealth Autism Services) had no role in study design,
data interpretation, or writing of the report.
The authors acknowledge the generous support
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