Autism spectrum disorders (ASDs) are primarily defined by problems with social
interaction and communication, but they are also associated with a complex cognitive
profile. One area of difficulty for children and adults with ASD is problem-solving, or
the process of identifying a solution to a puzzle or question where the answer is hidden.
This can be seen on the Twenty Questions Task (TQT), a commonly-used measure of
verbal problem-solving and executive functioning. Children with autism are
consistently less efficient than typically-developing children in their questioning on the
task: for instance, rather than ask a general, category-based question (e.g. “Is it a living
thing?”) they may ask about single items (“Is it the dog?”) or very restricted groupings
(“Is it something you wear on your feet?”). This has previously been interpreted as an
example of a concept formation deficit in autism, deriving from underlying difficulties
with complex and integrative information processing. However, success in problemsolving
relies on a number of cognitive and linguistic processes that may be impaired in
ASD. This thesis attempts to identify which of these may better explain autistic
problem-solving performance, using the TQT as a specific example.
The first experiment presented here examines the role of executive functioning
difficulties in this profile. The performance of 22 children with ASD and 21 age- and
IQ-matched typically-developing (TD) children was compared on a version of the TQT
adapted to assess planning skills prior to problem-solving and selective attention during
the task. Compared to controls, ASD participants were less efficient in their planning of
questions, although not all ASD participants had difficulty constructing a plan. No
specific effects of selective attention were evident.
The second and third experiments explore the importance of atypical language
development to this profile, using the example of deafness. Experiment 2 compares the
performance of deaf (n = 9) and hearing (n = 27) adults on the TQT, replicating prior
evidence of less efficient problem-solving in deaf graduate students. Experiment 3
contrasts TQT performance in 13 deaf schoolchildren with the ASD and TD data
acquired in experiment 1. Like ASD children, deaf children were less efficient in their
questioning than TD participants, even when controlling for cognitive ability
differences. Both autism and deafness are associated with delays in early language development,
whereas Asperger Syndrome (AS) is not. To test whether language delay explains
autistic problem-solving difficulties, experiment 4 compares TQT performance in 15
children with autism, 15 AS children and 15 age- and IQ- matched typically-developing
controls. Participants with autism asked less efficient questions than both AS and TD
participants, between whom no differences were observed. This suggests that the
problem-solving profile in autism may be better explained as a consequence of atypical
language development, rather than other aspects of information processing or executive
dysfunction