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Understanding Differences in Neurotypical and Autism Spectrum
Special Interests Through Internet Forums
Chloe Jennifer Jordan and Catherine L. Caldwell-Harris
Abstract
Special interests are frequently developed by individuals with autism spectrum disorder, expressed as
an intense focus on specific topics. Neurotypical individuals also develop special interests, often in
the form of hobbies. Although past research has focused on special interests held by children with
autism spectrum disorder, little is known about their role in adulthood. The current study
investigated differences in the content, number, and specificity of the special interests held by adult
individuals with autism spectrum disorder and neurotypical individuals, using Internet discussion
forums as a data source. Quantitative analysis of forum posts revealed significant differences
between the diagnostic groups. Individuals with autism spectrum disorder reported having more
interests in systemizing domains, more specific interests, and a greater number of interests overall
than neurotypical individuals. Understanding special interests can lead to the development of
educational and therapeutic programs that facilitate the acquirement of other important social and
communication skills.
Key Words: autism spectrum disorder; Asperger syndrome; special interests; Internet discussion forums;
adults
Special Interests in Autism
Spectrum Disorder
Autism spectrum disorder (ASD) is characterized
by abnormalities in social communication, social
interaction, and repetitive behaviors (American
Psychiatric Association, 2000). ASD has also been
described as a ‘‘neurological variation,’’ which
includes different sensory perception, a need for
consistency, and atypical learning styles, language
expression, and social behavior (Autism Self
Advocacy Network, 2011). Among individuals
with high-functioning autism and Asperger syn-
drome, repetitive behaviors frequently manifest as
an intense focus on specific topics pursued with
intensity (Asperger, 1991; Attwood, 2003; Bodfish,
Symons, Parker, & Lewis, 2000). Interviews
revealed that these interests range from the atypical
(deep-fat fryers, toilet brushes), to those that are
unusual in the intensity of their circumscribed focus
(frogs, World War I biplanes, Star Wars), to topics
that overlap with the hobbies of typically develop-
ing children, such as trains, horses, swimming, role-
playing games, and sculpting (Winter-Messiers,
2007). Traditionally, special interests among those
with ASD were considered to be repetitive
behaviors; we propose that interests are qualita-
tively different from repetitive behaviors and
indeed lie on a continuum with the focused
interests of scientists, college professors, collectors,
hobbyists, and others.
Several terms have been used to describe the
interests developed by individuals with autism.
Restricted interests is a term used by the Diagnostic
and Statistical Manual of Mental Disorders (DSM-IV-
TR; American Psychiatric Association, 2000) to
describe one component of the repetitive behaviors
that occur in autism. Circumscribed interests refer to
interests focusing on an inclusive topic, such as
World War I biplanes (e.g., Attwood, 2003; Sasson,
Elison, Turner-Brown, Dichter, & Bodfish, 2011),
whereas obsessions describe the intense nature of
autism spectrum interests (e.g., Baron-Cohen &
Wheelwright, 1999). These latter terms have been
more frequently used to describe the interests of
low-functioning individuals. Following Winter-
Messiers (2007), Bashe and Kirby (2001), and the
Autism Self Advocacy Network (2011; ASAN), we
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C. J. Jordan and C. L. Caldwell-Harris 391
use the term special interests because it does not
prejudge the extent of topic restriction and it is also
the term most frequently used by ASD individuals
themselves on the discussion forums analyzed in the
current study. Similar terms have been used by other
prominent members of the autism community. For
example, Jackson (2002) coined the term speciality
subject in describing special interests, and Grandin
(2011) emphasizes the importance of finding a child’s
‘‘area of strength’’ (p. 16), which can be cultivated into
important skills that can even serve as the basis for a
career. Such terminology promotes a strength-based
understanding rather than the historically deficit-
focused framework. The ASAN (2011) describes
special interests as ‘‘narrow but deep,’’ resulting from
highly focused thought patterns. Individuals with
high-functioning autism and Asperger syndrome
posting on Internet discussion forums often describe
the intensity of their interests as ‘‘almost an addiction’’
and that they have the ability to ‘‘spend hours reading
and talking about them’’ to the extent that they ‘‘feel
in love when engaging in an obsession.’’
Past studies have focused on the role of special
interests in youth with autism (e.g., Baron-Cohen
& Wheelwright, 1999; Winter-Messiers, 2007).
Interests can develop as early as 2–3 years of age
and are usually manifested in efforts to collect
objects and information relevant to the interest
topic (Bashe & Kirby, 2001). Special interests are
primarily developed by individuals with high-
functioning autism or Asperger syndrome, with
over 99%–100% of individuals with Asperger
syndrome reporting one or more special interests
(Bashe & Kirby, 2001; Bodfish et al., 2000).
However, special interests have also been reported
among low-functioning individuals with autism
(Bartak & Rutter, 1976), as well as individuals
with pervasive developmental disorders (PDDs)
other than Asperger syndrome or high-functioning
autism, including PDD not otherwise specified
(PDD-NOS; Sturm, Fernell, & Gillberg, 2004)
and Rett syndrome (Mazzocco et al., 1998). The
intensity associated with special interests has led
some researchers to suggest that such interests may
serve as precursors to the remarkable skills dis-
played by individuals with savant syndrome (e.g.,
Heaton & Wallace, 2004).
Special interests often reflect the heightened
and exceptional abilities that are unique to ASD,
such as systemizing, which is the drive to analyze,
explore, and construct a system (Baron-Cohen,
Richler, Bisarya, Gurunathan, & Wheelwright,
2003). Systemizable domains, which are character-
ized as predictable and amenable to rule-extraction
and outcome prediction, are heavily represented in
the special interests of children with autism, such as
those that involve mechanical, technical, and
factual details (e.g., Attwood, 2003; Baron-Cohen
& Wheelwright, 1999). Perceptual features of an
object, such as high spatial frequency, may also
dispose that object to becoming the focus of a
special interest (DeLoache, Simcock, & Macari,
2007), an observation that is consistent with the
finding that individuals with ASD have heightened
attention to detail (Frith, 2003).
The emergence of special interests has also
been explained as a result of social deficits and
lack of salience attributed to social information
(Carruthers, 1996; Sasson, Turner-Brown, Holtzclaw,
Lam, & Bodfish, 2008). Sasson and colleagues (2008)
found that children with ASD demonstrated circum-
scribed attention while viewing a visual array,
manifested as decreased exploration, decreased gaze
time at social objects such as faces, and increased gaze
time at objects that are frequently the subject of ASD
special interests (‘‘high-autism-interest’’ stimuli) such
as trains, vehicles, and electronics. The exploration
of a visual array of nonsocial objects by individuals
with ASD correlated with the severity of social
impairment, suggesting that a relationship between
social ability and special interests exists.
Little research currently exists on special
interests in adulthood. Among adults with Asperger
syndrome, special interests may focus on specific
concepts, such as computers, media, and art, and
most adults hold interests in more than one area
(Bashe & Kirby, 2001). DeLoache and colleagues
(2007) suggested that the development of adult
interests may depend on the degree of social
acceptability that is experienced for childhood
interests. Consistent with this suggestion, Winter-
Messiers (2007) observed that individuals with
ASD are often hesitant to discuss a special interest,
out of fear of peer ridicule or rejection. If an interest
is socially acceptable, as is often the case for high-
functioning individuals, parents, caregivers, and
peers can provide support, thus effectively shaping
children’s interests in socially approved directions.
Neurotypical Special Interests
Following Attwood (1998), we use the term
neurotypical to refer to individuals who do not have
ASD. Neurotypical (NT) children also develop
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392 Understanding Special Interests
intense interests, which emerge primarily between
1–2 years of age and last 22 months on average
(DeLoache, Simcock, & Macari, 2007). Special
interests in NT children are less frequent than in
children with ASD. In the study by DeLoache and
colleagues (2007), about 30% of typically develop-
ing children exhibited an intense interest, whereas
over 90% of individuals with ASD develop special
interests (Attwood, 2003).
Although systemizing is the drive to analyze
and construct systems, empathizing refers to the
motivation to understand other peoples’ mental
states and the ability to predict an individual’s
behavior and respond appropriately based on that
understanding (Baron-Cohen & Wheelwright,
2004). The special interests of NT children tend
to focus on domains that are most accessible via
empathizing, such as interests in people, imagina-
tive play, and the social environment more broadly
(Attwood, 2003; DeLoache et al., 2007). Consis-
tent with the ‘‘extreme male brain’’ hypothesis of
autism (Baron-Cohen, 1999), the interests of NT
boys are more similar to those of children with
ASD than to NT girls’ interests. Among NT
children, boys more frequently hold interests in
systemizable domains such as vehicles, trains, and
machines, whereas girls reported more interests in
pretend play, imagination, dress-up, and other
stereotypically female topics that are more amena-
ble to empathizing (DeLoache et al., 2007). Boys
were also twice as likely as girls to develop an
‘‘extremely intense interest’’ (DeLoache et al.,
2007).
Importance of Understanding
Special Interests
Special interests are often sources of enthusiasm
and pride for individuals with ASD (Winter-
Messiers, 2007) and serve to reduce stress and
anxiety (Attwood, 2003). The expertise attained in
areas of special interest can lead to employment
(Attwood, 2003; Grandin & Duffy, 2008). Al-
though preoccupation with special interests can be
a burden on parents, Winter-Messiers (2007)
reported that deficits in communication and social
interaction were reduced when children with ASD
engaged in discussion about their interest (Winter-
Messiers, 2007).
The few existing studies have focused on special
interests in children, and thus, little is known about
their role in adulthood. Understanding special
interests in adulthood is important in illuminating
the positive role that interests play in adult life. This
is especially important for those with ASD, because
the expertise attained in areas of special interest can
lead to unique skills and rewarding careers (Att-
wood, 2003; Grandin & Duffy, 2008; Jackson, 2002).
The current study will examine the content,
number, and specificity of special interests in adults,
as reported by both NT individuals and individuals
with ASD on public Internet discussion forums.
Discussion forums represent a novel source of
autobiographical data, as ASD participants on such
forums are able to weave a personal narrative
without requiring the resources of traditional
publishing facilities. Utilizing discussion forums for
data collection allows researchers to learn from
individuals with autism themselves, without the risk
of influencing participant responses. This may
provide a more enriched understanding of the
interests of individuals on the autism spectrum as
well as of the NT population, and it may aid in
promoting a strength-based view of special interests
and ASD more broadly.
Following Baron-Cohen and Wheelwright
(1999), we expect the interests held by individuals
with ASD will be primarily in systemizing domains,
such as machines and technology, information and
mechanical systems, and the sciences. In contrast,
NT interests are likely to lie in domains that
function as mechanisms for socializing and rely on
empathizing ability, such as interests in people,
sports, belief systems, history and culture, and the
creative arts. We also expect that adults with ASD
will report a larger number of interests on average
and have interests of higher specificity, as observed
in children by Bashe and Kirby (2001).
Methods
Data Collection
Special interests were collected from posts on
WrongPlanet.net, a popular online discussion
forum used by individuals with ASD. Created in
2004, WrongPlanet forums now have over 36,131
unique members who have collectively made, at
this writing, over 2,816,964 posts, indicating a large
and very active discussion board (Plank, 2010).
Special interests of NT individuals were collected
from a separate popular online general discussion
forum, GoLiveWire.com. LiveWire forums were
created in 2000 and now have over 237,340 active
members who have made several million discussion
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C. J. Jordan and C. L. Caldwell-Harris 393
posts (Jones, 2010). The ASD and NT discussion
forums were identified through a Google Internet
search using the criteria ‘‘Asperger autism discus-
sion forums’’ and ‘‘teen and college discussion
forums,’’ respectively. The WrongPlanet and Live-
Wire Web sites were selected because they were the
first and largest boards listed in the Google search
results. Sampled discussion forums were public and
did not require a subscription or personal account
to be viewed.
Collection criteria required that the post
include language about specific interests or obses-
sions. Relevant posts were identified using the Web
sites’ search query options with the criteria
‘‘interests,’’ ‘‘hobbies,’’ and ‘‘obsessions.’’ For exam-
ple, discussion threads returned by the WrongPla-
net search query included the titles ‘‘What is your
special interest?’’ and ‘‘Likes and hobbies.’’ Exam-
ples of discussion threads returned by the LiveWire
search query included ‘‘My current obsessions’’ and
‘‘What are your interests and hobbies?’’ Posts were
sampled from discussion topics that had been
created within 1 year of the date of data sampling.
If listed in a public user profile, the individual’s age,
diagnostic category, and gender were recorded to
ensure that the ASD and NT samples were
comparable. Although it was not possible to
determine whether individuals with ASD or other
disorders frequented the sampled NT discussion
board, the LiveWire Web site includes subforums
designed specifically for individuals with ASD and
those with other disorders or health issues, such as
a ‘‘Living with Disability’’ forum and a ‘‘Teen
Depression and Emotional Imbalance’’ forum; these
were excluded from data collection. Similarly, it
was not possible to verify the diagnoses reported by
individuals on the ASD discussion board; however,
recent research on Internet forum user profiles
indicates that most users accurately describe
themselves online (Back et al., 2010). Individuals
on the forums were unaware of our research at the
time of data collection.
Because no interaction occurred between
researchers and forum posters, this study was
deemed not to involve human subjects research
and was thus exempt from further review by the
Boston University Charles River Campus Institu-
tional Review Board. Clearly, caution must be
exercised to avoid violating individuals’ privacy,
and we followed the recommendations of Brownlow
and O’Dell (2006) and Seale, Ziebland, and
Charteris-Black (2006) by only analyzing public
forums and not referring to user names or other
identifying information.
Measures
Interest categories. Interests were coded into
18 categories derived from the Cambridge Univer-
sity Obsessions Questionnaire designed for people
with ASD (Baron-Cohen & Wheelwright, 1999).
We reviewed the collected data to ensure the
categories included in the Obsessions Question-
naire encompassed all the interests reported on
the forums. If a sizable proportion (.5%) of the
reported interests did not fall into any of the
existing Obsessions Questionnaire categories, a new
category was agreed on by coders and was added to
the coding scheme. Interest categories of nature,
history and culture, and psychological disorders
were thus added to the coding scheme. The existing
category of plants was included under the broader
nature category. The categories of item attachment
and item collection were collapsed into a single
category because many individuals who reported
attachment to specific objects also reported col-
lecting the objects. Similarly, the categories of
creative arts and crafts were collapsed into the
overarching creative arts category. The category of
numerical systems was collapsed into the factual
information category, because interest in numerical
systems was often expressed as fascination with
statistical and trivial information, which can be
considered as interests in facts. The spinning
objects interest category was excluded because no
individuals expressed this type. The 18 special
interest categories in our study were defined as
shown in Table 1.
Four coders labeled each reported interest into
one of the 18 categories. Coders were volunteer
undergraduate students and were unaware of the
age, gender, and diagnostic category of the
individual who wrote the post. Interrater agreement
on the categories of special interests was 93%,
confirming the integrity of the coding criteria.
Google search frequency and total number
of interests. The Google search frequency (ex-
pressed as logarithm values) of each reported
special interest was recorded using Query Google
(Ma, 2007). Interests consisting of multiple-word
phrases were entered into Query Google surrounded
by quotation marks. Individuals’ described interests
were also modified when necessary to reflect the
nature of the actual interest; for example, an interest
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394 Understanding Special Interests
in House, the television show, was entered into
Query Google as ‘‘House TV’’ to ensure that a
frequency corresponding to the television show was
obtained. Google search frequencies were collected
to characterize special interests as either common/
general or infrequent/specific. A high Google search
frequency generally indicated an interest that was
common and broad, such as ‘‘movies,’’ whereas a
low Google search frequency may indicate an
uncommon or specific interest, such as a specific
movie title. The total number of interests reported
by each individual was also recorded.
Participants (Forum Posters)
Of the NT individuals sampled (n5213), the
mean age was 24.1 years (range 514–41, SD 5
11.1). The male to female ratio was 14:25 (68 male,
121 female, 24 unreported). Of the individuals with
Table 1
Descriptions of the 18 Special Interest Categories
Category Description
Machines and
technology
Computers, radios, television, clocks, etc., or expresses interest in how things work,
not including watching or listening to movies, television, music, etc.
Information and
mechanical systems
Plumbing, light switches or electrical wiring, maps, city planning, subway maps
and/or schedules, businesses and organizations, etc., or an interest in creating
systems (such as languages or maps).
Sorting, categorizing,
and organizing
Making lists, lining objects up, arranging objects in certain orders or categories,
planning, or obsession with neatness or organization.
Belief systems Religions or mythologies, political systems, philosophies, alternative beliefs (such
as conspiracy theories), etc.
Sports and games Football, tennis, walking, biking, tennis, playing cards, chess, board games,
puzzles, video games, etc.
Factual information Reading or memorizing lists; reading encyclopedias, dictionaries, newspapers, etc.;
or memorizing statistics and trivial information.
Sensory Touching or feeling certain things, or mentions fascinations with texture, specific
sounds, lighting, colors, smells, etc.
Creative arts Movies, television shows, artwork, painting, playing an instrument, music, writing
and reading fiction, creating media (e.g., online films), performing arts, knitting,
sewing, carpentry, etc.
Sciences Astronomy, chemistry, biology, physics, engineering, mathematics, logic,
economics, psychology, meteorology, specific diseases or conditions, etc.
Animals Pets, wild or farm animals, insects, fish, birds, etc., also includes animal-related
activities (e.g., bird watching), but not mythical creatures.
Nature Plants, interacting with nature (e.g., hiking, gardening, exploring, etc.), and natural
phenomena (e.g., volcanoes, tsunamis, lightning, etc.).
Item attachment Focusing on a particular item or type of object, as well as certain words or phrases,
or expresses interest in acquiring collections of particular items (e.g., bottles,
keys, caps, stamps, rocks, etc.).
People A particular person, in types or groups of people, or in interacting with people,
including participation in online communities.
Vehicles Trains, airplanes, buses, boats, cars, etc.
Food and drink Consuming or creating a particular food or drink, cooking, baking, etc.
History and culture Existing languages, particular countries or civilizations, time periods or eras in
history, etc.
Psychological disorders Expresses interest in any psychological disorder.
Other Interests that did not fit within a specific category.
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C. J. Jordan and C. L. Caldwell-Harris 395
ASD (n5211), the mean age was 25.5 years
(range 14–72, SD 59.5). Although NT and ASD
individuals ranged in age from teenagers to adults,
the number of teenagers in the sample was few in
number and did not significantly differ from young
adults in reported interest categories. The male to
female ratio was 1:1 (106 male, 105 female). Note
that posts were not selected for gender; rather, the
1:1 ratio reflects the average gender ratio of posters
on social networking Web sites, which is 47% male
and 53% female (Pingdom, 2009). Of the individ-
uals with ASD, 58% (n5123) reported having
been diagnosed with Asperger syndrome (AS),
whereas 24% (n551) judged themselves to have
AS although they had never received an official
diagnosis; 11% (n523) reported not being sure
whether they had an ASD, and 7% (n514)
reported being diagnosed with an ASD other than
Asperger syndrome.
Results
For each category of special interest, we compared
number of interests reported by ASD and NT
individuals. We also analyzed the total number of
interests reported by each individual, and the mean
log Google search frequency of each individual’s
reported interests.
The number of interests reported in each
category appear in Table 2, listed in order of how
strongly they differed between the ASD posters
compared to the NT posters. The Mann-Whitney U
test for independent samples revealed that 10 of the
17 interest categories differed significantly between
the groups. Two of these 10 interests that were more
frequently mentioned by NT individuals—sports
and games—were mentioned by 35% of NT in-
dividuals and by only 17% of ASD individuals.
Food and drink were mentioned as interests by
Table 2
Mean and Maximum Number of Interests Identified in Each Special Interest Category for NT Individuals and
Individuals with ASD
Category
Average no. of
interests per category
Maximum
no. mentioned Statistical comparison
Percentage with at
least one interest
ASD NT ASD NT
Mann-Whitney,
zstat
Signifi-
cance (p) ASD NT
Sciences 0.39 0.04 5 3 25.67 .001 20.4 2.8
Psychological disorders 0.13 0.00 2 0 25.39 .001 12.8 0
History and culture 0.36 0.06 7 3 25.22 .001 21.8 4.7
Belief systems 0.34 0.05 7 3 24.91 .001 17.1 2.8
Animals 0.15 0.01 3 1 24.69 .001 13.3 1.4
Sports and games 0.24 0.52 4 6 24.20 .001 17.5 35.2
Information and
mechanical systems 0.12 0.01 3 1 23.97 .001 9.5 0.9
Machines and technology 0.25 0.06 7 2 23.64 .001 16.6 5.6
Food and drink 0.05 0.12 4 2 22.90 .010 3.8 11.3
Vehicles 0.09 0.04 2 2 22.29 .050 8.5 3.3
People 0.21 0.25 5 4 21.47 n.s. 15.6 21.6
Sensory 0.03 0.02 1 2 21.01 n.s. 2.8 1.4
Creative arts 1.12 0.99 9 7 20.66 n.s. 54.5 51.6
Factual information 0.06 0.07 1 1 20.57 n.s. 5.7 7
Nature 0.08 0.07 3 2 20.54 n.s. 5.2 6.6
Item attachment 0.18 0.19 3 3 20.43 n.s. 14.2 16
Sorting, categorizing,
and organizing 0.02 0.03 1 2 20.33 n.s. 1.9 2.3
Note. Italicized categories are those for which the neurotypical (NT) posters mentioned significantly more
interests than the autism spectrum disorder (ASD) posters. n.s. 5not significant.
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396 Understanding Special Interests
11% of NT individuals but by only 4% of ASD
individuals. In contrast, ASD individuals men-
tioned more interests than did NT individuals in
the categories of sciences, history and culture,
belief systems, animals, information and mech-
anical systems, machines and technology, and
vehicles. The strongest difference (as indicated
by the size of zstatistic) was for sciences; 20% of
ASD individuals mentioned an interest in science
whereas only 3% of NT individuals did so. In the
psychological disorders category, individuals with
ASD reported having more interests than NT
individuals, however, this occurred because the
majority of interests in psychological disorders
were of autism spectrum disorders (24 of 28
interests), reported by individuals in the ASD
diagnostic categories.
Table 3 shows that the interests of NT
individuals had higher Google search frequencies
on average than the interests of individuals with
ASD. For example, one NT individual reported an
interest in the television show Sex and the City,
which produced a log Google search frequency of
8.1, representing the data point for that individ-
ual’s interest. An individual with Asperger syn-
drome reported an interest in the television show
Happy Tree Friends, corresponding to a log Google
search frequency of 7.5, indicating a markedly
more specific interest. Individuals with ASD also
reported having, on average approximately four
interests, whereas neurotypicals reported having,
on average, between two and three interests (see
Table 3).
Discussion
The aim of the current study was to determine how
the content, number, and specificity of the special
interests held by teenagers and adults with ASD
differed from NT teenagers and adults. Consistent
with previous studies on children with ASD (e.g.,
Bashe & Kirby, 2001), adults from the ASD forums
expressed a greater number of interests than NT
individuals.
Qualitative observations of individuals with
Asperger syndrome have found that their interests
often reflect their cognitive strengths. Science,
machines and technology, and information and
mechanical systems have been identified as the
domains most amenable to systemizing (e.g., Baron-
Cohen & Wheelwright, 1999). Interests in these
systemizing domains are common among children
with ASD, whereas interests in people, culture, and
the arts are less frequent (Attwood, 2003; Winter-
Messiers, 2007). The special interests of NT
children in general also appear to reflect cognitive
strengths, focusing on domains that are most
accessible via empathizing, such as interests in
people (Attwood, 2003; DeLoache et al., 2007). In
the current study, adults with ASD reported having
more interests in sciences, history and culture,
animals, information and mechanical systems,
belief systems, machines and technology, and
psychological disorders. NT individuals reported
more interests in sports and games. Individuals with
ASD reported having more interests overall and
expressed interests with a lower average Google
search frequency than NT individuals.
Given the observation that NT individuals
have higher empathizing ability (Baron-Cohen &
Wheelwright, 2004), we expected interests col-
lected from the NT discussion forums to occur more
often in the sports and games, belief systems,
history and culture, people, and creative arts
categories, which may be more amenable to
empathizing than to systemizing. As predicted,
NT individuals expressed more interests in sports
and games compared to individuals with ASD.
Sports and games can serve as medium for social
bonding among NT individuals (e.g., Mueller,
Agamanolis, & Picard, 2003) and are thus
an interest category that relies on some empathiz-
ing ability. Individuals with ASD may be less
Table 3
Differences in Log Google Search Frequency and Total Number of Interests Between NT Individuals and Individuals
with ASD
Variable ASD M(SD)NTM(SD)t(422) g
2
Log Google Search Frequency 16.8 (2.6) 17.7 (1.9) 4.3* .04
Total Number of Interests 3.9 (4.2) 2.6 (2.1) 24.1* .04
Note. ASD 5autism spectrum disorder; NT 5neurotypical.
*p,.001.
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C. J. Jordan and C. L. Caldwell-Harris 397
motivated to pursue sports and games interests
because of reduced social motivation and decreased
empathizing ability relative to NT individuals.
Alternatively, it might be expected that sports
would be attractive to individuals with high-
systemizing ability and greater attention to detail
because of game rules and the associated team and
player statistics. However, sports and games inter-
ests are stereotypically treated as neurotypical and
socially normative—as Jackson (2002) writes,
‘‘When is an obsession not an obsession? When it
is about football’’—although such interests may
share a similar degree of intensity with those of
individuals with ASD.
Although NT individuals did report more
interests in sports and games than individuals with
ASD, our expectations regarding the other neuro-
typical interest categories were not confirmed.
Individuals with ASD reported more interests than
NT individuals in belief systems and history and
culture. Contrary to our predictions, this finding
has the potential to expand current understanding
of what constitutes a systemizable domain. For
example, the belief systems category, which includ-
ed philosophical and political systems, could be
amenable to systemizing because these types of
systems can be highly rule-governed. Furthermore,
belief systems may be particularly attractive to
individuals with high-systemizing ability because
of the cognitive drive to explore and construct
systems. Consistent with this notion, individuals
with ASD identifying as religious were more likely
to construct their own religious belief systems
compared to NT individuals (Caldwell-Harris,
Murphy, Velazquez, & McNamara, 2011). Interests
in history and culture may likewise be attractive to
individuals with heightened systemizing ability and
attention to detail due to a high level of detail in
these categories in the form of specific historical
events and dates.
We did not observe a difference in the number
of people interests between NT individuals and
those with ASD. This may be a result of a higher
desire to socialize among individuals with ASD who
participate in online communities, compared to the
general ASD population. Some individuals with
autism are reported to experience anxiety in face-
to-face conversations (e.g., Happe´, 1991; Mitchell,
2003). The use of online communication can
circumvent these anxieties and allow individuals
with autism to express themselves more comfort-
ably (Jordan, 2010). Wing and Gould (1979)
discuss subtypes of autism, one of which consists
of a group of individuals who desire social
interaction but who experience difficulty achieving
rewarding communication because of anxiety. The
individuals from the ASD forums may be in this
group, fulfilling a desire for social interaction online
and concurrently circumventing the anxiety of real-
life conversations. This explanation accounts for
interests in people in numbers comparable to the
NT group. The proposal that posters from the ASD
forums constitute a specific subgroup may be the
reason that we found no group differences in sorting
and categorizing, an interest domain very strongly
associated with the ASD cognitive and behavioral
profile. Future research could determine whether
sorting and categorizing are interests that are more
representative of lower-functioning ASD individu-
als, as suggested in Baron-Cohen’s (2009) discus-
sion about the nature of systematizing.
Individuals posting on the ASD forum also
displayed interests in creative arts at levels
comparable to individuals posting on NT forums,
contrary to our expectations. We anticipated that
interests in creative arts would be less attractive to
individuals with ASD because the arts are not
governed by clear rules that are amenable to
systemizing (Simonton, 2009). One explanation
for our finding that ASD and NT individuals
reported similar levels of interests in creative arts is
that the primary group difference in the creative
arts category lies in the specificity of the interest,
rather than the general content. For example, one
NT individual reported creative arts interests in
playing guitar, which has a log Google search
frequency of 8.3. An individual with ASD reported
creative arts interests in playing the mandolin,
which has a log Google search frequency of 6.8,
indicating it is a less common interest. In this
example, although the NT and ASD individuals’
interests were in the same category, the ASD
interest was less common than the NT interest.
The interests of individuals with ASD had
lower Google search frequencies than the interests
of NT individuals. A high Google search frequency
generally indicates a high frequency, common
interest, or a broad, nonspecific interest category.
Conversely, a low Google search frequency indi-
cates a less common interest or a more specific
interest. For example, a broad interest in ‘‘comput-
ers’’ corresponds to a log Google search frequency
of 8.4, whereas the specific interest in ‘‘G1
Heatseeker Transformers’’ corresponds to a log
INTELLECTUAL AND DEVELOPMENTAL DISABILITIES
2012, Vol. 50, No. 5, 391–402
’AAIDD
DOI: 10.1352/1934-9556-50.5.391
398 Understanding Special Interests
Google search frequency of 4.1. Our finding that
individuals with ASD have interests of a lower
Google search frequency, and thus may be more
specific, is consistent with previous research
suggesting that high specificity is a characteristic
of the special interests of children with autism
(Attwood, 2003; Sasson et al., 2011; Winter-
Messiers, 2007). The finding that ASD interests
had lower Google search frequencies than NT
interests could also suggest that individuals with
ASD may be choosing interests that are less
common or less popular than interests chosen by
NT individuals. This interpretation is consistent
with Bodfish’s (2009) suggestion that individuals
with ASD are less likely to use their interests as a
medium for socializing, because uncommon inter-
ests are less effective in initiating or sustaining
social interactions. One NT forum user wrote, ‘‘[My
interest is] theatre … you become close to the
people involved even if you had never met them
before; it’s good socially.’’ Recognizing the social
value of common interests, an individual with ASD
described modifying his interests to be more socially
normative: ‘‘[W]ithin the last two years I have
taken a new interest in cars … it helps me talk
more too because computers are too geeky and
socially unacceptable, but it’s cool to talk about
cars.’’ The latter quote also reflects the desire to
engage in meaningful social interactions, expressed
by many ASD forum members. Although some
interests, such as a type of instrument, may be more
common to specific cultures, many individuals with
ASD pride themselves on holding different, even
unusual interests. As Grandin (2011) writes, ‘‘every
person with autism is unique,’’ and while autism
holds many challenges for the diagnosed individual
and family, it also offers ‘‘great talents and unique
abilities’’ that should be nurtured and celebrated.
Use of Internet Forums in Research
The use of online forum posts as a medium for data
collection is an innovative technique that offers
both benefits and limitations. Large-scale commu-
nities of individuals with ASD congregate on
Internet discussion boards, where special interests
are a frequent conversation topic. Using these
discussion boards as a research resource allows access
to a large, ecologically valid data sample. Individuals
are prompted by their peers and are responding from
a familiar setting such as their own home, which may
facilitate more accurate and detailed assessments of
individuals’ interests because of a reduction in the
anxiety experienced in face-to-face interactions and
unfamiliar environments.
One limitation of collecting data from online
forums is that there is no way to verify that users on
the ASD forums are on the autism spectrum or that
users on the NT forums are indeed neurotypical.
However, prior work has fruitfully analyzed Web
sites created by parents of children with autism and
on chat groups for individuals with ASD without
verification of an autism diagnosis (see discussion in
Brownlow & O’Dell, 2006; Fleischmann, 2004,
2005). In our study, those who reported having
ASD showed significant differences on each variable
from NT individuals, and the observed differences
accorded with our hypotheses and with existing
literature on special interests. This is consistent with
the report of Back et al. (2010) that most users of
online forums accurately describe themselves.
Another limitation is that we analyzed postings
of individuals who are on the high-functioning end
of the spectrum, although special interests occur in
both low- and high-functioning individuals with
autism (Bartak & Rutter, 1976). Our results are thus
primarily generalizable to individuals with good
social, verbal, and computer skills. More information
about the likely characteristics of individuals who
frequent WrongPlanet.net comes from a survey we
conducted following the reported forum analysis. We
recruited survey respondents from WrongPlanet.net
and obtained 70 individuals who self-reported an
ASD diagnosis, with 96% of them labeling them-
selves as having Asperger syndrome (Jordan &
Caldwell-Harris, 2011). These respondents had
higher scores than did our NT sample on the autism
quotient (Baron-Cohen, Wheelwright, Skinner,
Martin, & Clubley, 2001) and the systemizing
quotient (Baron-Cohen et al., 2003). The ASD
scores in that study were generally beyond the
suggested cutoff range for people with Asperger
syndrome. Although these are not the same
individuals as studied in the current forum analysis,
they were from the same discussion forum, and it is
thus plausible that that many of the individuals
whose posts we analyzed also had elevated autism
quotient and systemizing quotient scores.
Overall Clinical and
Research Implications
Understanding the nature and development of
special interests offers considerable therapeutic
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2012, Vol. 50, No. 5, 391–402
’AAIDD
DOI: 10.1352/1934-9556-50.5.391
C. J. Jordan and C. L. Caldwell-Harris 399
value. The importance of special interests for
individuals with ASD is illustrated in many posts
on the reviewed discussion forums; as one user
wrote, ‘‘[My interests] don’t control me; they define
me.’’ Special interest expertise can serve as
springboards for rewarding and successful careers
(Attwood, 2003; Grandin & Duffy, 2008; Robison,
2008). Individuals on the ASD discussion boards
often demonstrated the opportunities their special
interests provided them by writing posts such as,
‘‘I’m a singer, and I’m getting a scholarship for it’’
and ‘‘I am able to incorporate it [my interest] into
most of my activities. If things go well, I’d like to
turn pro.’’ Special interests can also serve as a basis
for companionship among individuals with ASD
who have interests in common (Attwood, 2003),
and the comparison of neurotypical and autism
spectrum interests may promote tolerance for
individual differences more broadly.
Our finding that the interests reported by adults
with ASD were more specific, more numerous, and
more frequently in systemizing domains than the
interests of NT individuals suggests that defining
characteristics of special interests in adulthood are
similar to those occurring in childhood. Special
interests offer manifold benefits for both individuals
with ASD and NT individuals. Unfortunately,
special interests are also frequently obsessive and
time-consuming (Attwood, 2003) and can alienate
an individual from peers (Frith, 1991). Families of
individuals with ASD often find obsessive special
interests difficult to accommodate (Mercier,
Mottron, & Belleville, 2000). Clinicians and family
members thus need to better understand the origin
and function of special interests. Although the
prevailing explanation for special interests has
focused on their function in reducing anxiety, our
findings in conjunction with observations reported
by Attwood (2003), Baron-Cohen and Wheelwright
(1999), and Winter-Messiers (2007) suggest differ-
ences in cognitive abilities, such as systemizing and
empathizing, may lead to the development of
interests of varying content and specificity. Family
members of individuals with ASD can benefit from
an explanation of special interests as existing on a
continuum that depends on individual cognitive
abilities, as this promotes a strength-based model of
interests rather than the prevailing deficit-focused
model (Winter-Messiers, 2007). Understanding
special interests may also help families in accepting
interests that appear to be obsessive.
In children, special interests may impede
development because of their time-consuming
nature (Attwood, 2003). By developing an under-
standing of adult interests, new methods of
treatment and education can be developed to
utilize special interests as channels for learning,
facilitating development in other areas such as
language and communication. For example, one
individual on the forums reported nine interests,
including an interest in urban planning, which was
categorized under the information and mechanical
systems category. His reported interests had an
average log Google search frequency of 18.3. This
individual’s interests were thus relatively specific
and were categorized in highly systemizable do-
mains. A tailored educational program for this
individual might introduce material related to his
interests that is similarly systemizable and specific,
then it can progressively introduce topics that are
closer toward the mid-range of the continuum,
helping the individual develop other desirable
skills. Special interests can additionally serve as
scaffolding for shaping social behaviors, as interests
shared between individuals can facilitate social
interactions and engagement in an interest can
be used as a reward (Attwood, 2003). The more
numerous interests found in individuals with ASD
may also provide more options for introducing
educational material, as there are several domains
with which to relate new material and broaden
individual achievements in a general education
curriculum. An understanding of special interests,
on both the neurotypical and autism spectrum,
can be used to encourage the development of
unique skills and abilities that will ultimately
improve an individual’s quality of life, by focusing
on cognitive strengths and celebrating individual
differences.
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Received 4/22/11, first decision 12/19/11, second
decision 4/19/2012, accepted 5/10/12.
Editor-in-Charge: Glenn T. Fujiura
Authors:
Catherine L. Caldwell-Harris (e-mail: charris@bu.
edu), Department of Psychology, Boston University,
64 Cummington St., Boston, MA 02215, USA; and
Chloe Jennifer Jordan, Boston University.
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402 Understanding Special Interests
