Potential Gender Difference In Attentional Filtering In Girls Relative to Boys with Higher Functioning Autism

Background:

The ratio of males to females diagnosed with an Autism Spectrum Disorder (ASD) is 4:1. For this reason ASD research has primarily focused on males. Recent work suggests that higher functioning individuals with ASD in comparison to typically developing controls may have superior fluid intelligence, or the ability to reason quickly and to think abstractly (Dawson et al., 2007). However, due to the small sample size of females in the study (N = 5), these results cannot be generalized to females with ASD. Hayashi et al. (2007) found that boys with higher functioning ASD (N = 10) outperformed the TD group, whereas girls with higher functioning ASD (N = 7) showed equivalent performance to the TD girls. These data suggest that girls relative to boys with higher functioning ASD may have lower fluid intelligence.

In TD adults, fluid intelligence has been found to strongly correlate with visual working memory (VWM), or the ability to actively maintain visual information in a readily accessible state (Colom et al., 2005; Fukuda et al., 2010; Engle et al., 1999). Further, VWM in TD adults has also been found to correlate strongly with attentional filtering, or the ability to ignore salient stimuli while restricting attention to goal-relevant stimuli.

These typically developing adult findings in combination with the fluid intelligence ASD findings, suggest that girls with higher functioning ASD in comparison to boys with ASD may have lower fluid intelligence, VWM, and attentional filtering abilities.

Objectives:

The objective of the current study was to examine whether there are gender differences in the higher functioning ASD population with respect to fluid intelligence, VWM, and attentional filtering.

Methods:

Adolescents with higher functioning ASD (male = 15; female 9), ranging in age from 11.6-17.9 years (M = 14.62), participated in the study. We employed Fukuda and Vogel’s (2009) attentional filtering paradigm. In this task, participants are instructed to remember the colors of target stimuli (i.e., squares) over a brief delay. Then they are presented with one test stimulus and must respond yes or no depending on whether or not the test stimuli matches the color of the target stimuli presented in that same location. In three conditions, there are only targets present (set size 2, 4, 6). In a fourth condition, there are two target stimuli in addition to four distracting stimuli (i.e., colored rectangles). This measures how well participants filter out contingent distractors in the environment.

Results:

Based on our preliminary data, females with higher functioning ASD compared to boys with higher functioning ASD did not significantly differ in terms of fluid intelligence or working memory capacity. However, girls relative to boys with higher functioning ASD showed significantly worse attentional filtering, even after controlling for age and composite IQ, F(1, 22) = 5.86, p = 0.03.

Conclusions:

These preliminary data suggest that there may indeed be gender differences in the ASD cognitive profile, specifically in attentional filtering.