Speed of Responding in ASDs: A Look at the First Seconds of Processing

Background: Minshew (2009) characterized slow processing speed as a hallmark of autism spectrum disorders (ASDs). However, slow processing in children with ASDs has been inconsistently demonstrated across a variety of tasks. For example, on some tasks, such as the embedded figures task, children with ASDs have quicker response times compared to typically developing (TD) children. Previous studies have primarily examined reaction times as responses to stimuli that remain visually present for extended periods of time, such as in working memory tasks. Less is known about the speed of responding in tasks when stimuli only remain in view for very short exposure times (e.g., 100 msec). Using free and cued recall tasks, the current study examines if speed of responding in children with ASDs is different from TD children after a presentation of visual stimuli for a very short duration in an iconic memory task. The results will provide clarification for whether observed differences in speed of responding begin extremely early in processing, or emerge after the initial input stages.

Objectives: To provide insight into children with ASD's information processing skills: Specifically to examine if children with ASDs have longer response times at the earliest stages of information processing.

Methods: Fourteen children with an ASD (M = 122.57 months; SD = 24.83 months) and fifteen TD children (M = 114.07 months; SD = 20.56 months) participated in the present study. Participants completed two tasks, each following a presentation of a circular array of eight letters for a brief, 100 msec period: 1) a free recall task where participants were asked to recall all the items they could remember; and 2) a cued recall task, where an arrow was also presented to cue which single item they were required to report. In the second task, the time between the presentation of the stimuli and the cue (interstimulus interval) was varied.

Results: For each participant reaction times were calculated from the end of the presentation of the stimuli to the start of the participant’s response, and response times were calculated from the start of the response to the end of the response. Data analysis is ongoing, and group differences are being evaluated for both correct and incorrect responses to examine possible speed-accuracy relations.

Conclusions: The results from this study will provide information about the first few seconds of information processing in children with ASDs compared to TD children. More specifically, if children with ASDs differ from TD children in their reaction and response times at this early stage of processing, it provides strong support for a general speed of processing deficit associated with ASDs. A finding of equivalent speed of responding would suggest that speed differences observed later in processing, such as in short term memory tasks, are due to downstream, higher level activities.