Defeasible inferences in Autistic Spectrum Disorders - An EEG study

Although a lot of experimental work has been done in the psychology of
reasoning, little is known about the reasoning capacities of patients with ASD.
This study will therefore investigate the reasoning capacities of ASD patients
and focus on defeasible inferences. These are inferences that can be cancelled
when there is enough evidence to do so. We will look at implicatures and
suppression of conditional inferences:

1) Although ASD patients have difficulties with reasoning about other people*s
belief, we found in a behavioral task that ASD participants are more
sophisticated pragmatic reasoners than we thought, in the sense that they were
capable in drawing implicatures. However, reaction times showed the task was
harder to process for the ASD participants than the control group. Because
reaction times are a coarse measure of information processing and sensitive to
strategies that people are applying, the current study will further explore the
processing of implicatures in autism by means of EEG.

2) We found that ASD patients have specific problemswith integrating an
exception in a reasoning task. However, they have no problems with integrating
new information in general. To get more insight into how the autistic brain
deals with suppression of conditional inferences, the current study will
further investigate the suppression effect by means of EEG

The primary objective of this study is to investigate defeasible inference in
ASD in order to obtain more insight into the reasoning capacities of ASD
patients. This study is part of the NWO-project Reasoning and the brain.

Brain activity will be registered by using ERPs. After electrode application,
participants will be seated in a sound-attenuating booth and they will be
presented sentences at a computer screen. Participants will be told that EEG
recording occurs as they read the sentences, and that during recording they
should avoid all movements, including eye movements and blinks. After reading
the sentences, participants have to judge whether a statement was correct by
pressing a button

In this study, between-subject comparisons will be made.

For participation participants have to visit the F.C. Donders Centre onetime
and the experiment will take around 4-5 hours (including breaks and
preparation).

EEG is a noninvasive method to record brain activation and there are no known
risks.