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Avoiding distractors is crucial for our daily lives. Load theory argues that high perceptual load facilitates distractor avoidance, while high cognitive load impedes distractor avoidance (see, Lavie, 2005). Difficulty in avoiding distractors is one of the key symptoms of Attention Deficit/Hyperactivity Disorder (ADHD; APA, 2013). In a series of experiments, we investigated visual attention during the viewing of complex scenes (featuring social and non-social objects), while manipulating Working Memory Load (WM) in a concurrent task. We also explored the relationship between these tasks and ADHD-like traits. Fixations during scene viewing were investigated with reference to objects of high and low saliency with social area (a person) also imbedded in the image. We tested the hypothesis that high WM load would lead to increased capture by the salient distractor. In contrast, attending to the social item might require more top-down resources and so be disrupted by WM load. The pattern of results suggests that during image viewing the social object was fixated to a greater degree than the other object (regardless of salience). While, there was a relationship between the degree of ADHD-like traits and performance on the memory task, WM load did not seem to affect scanning in scenes. Such findings suggest that top-down resources are not needed to attend to a social area in complex stimuli. [ABSTRACT FROM AUTHOR]

Background: Endophenotypes are intermediate variables in the hypothetical causal chain from observed behavior of a clinical disorder to its underlying genotype. Recent literature trends point to the potential etiological overlap between Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD). The present study aims to systematically compare these groups, by studying the potential endophenotypes of ASD (local-global processing; social cueing) and ADHD (Intra-Subject Variability (ISV)) in tandem. Methods: Three tasks, namely visual search, copying down and gaze cueing were administered to directly examine ASD- (ASD without co-morbid ADHD), ADHD and ASD+ (ASD with co-morbid ADHD) groups, in comparison to a typically developing (TD) group (N=100). Step-by-step process analysis and scan-path models were employed to analyze the oculomotor and behavioural data collected. Results: Results from the visual search task show that groups with ADHD symptoms (ADHD and ASD+) have increased intra-subject variability, whereas only the ASD- group showed signs of superior performance. Fixation durations during the copying down task can differentiate ASD- and ADHD groups on the strategies used. The gaze cueing task, shows the ASD+ group to use different strategies as compared to TD, and have slower and more variable saccadic RTs as compared to ADHD and ASD-. Conclusion: The present study gives evidence for a double dissociation between ADHD and ASD when no comorbid symptoms are present, on paradigms of local-global processing and social cueing. Oculomotor paradigms and analysis have successfully teased apart this interaction in the present study and can aid greatly in the quest for these endophenotypes. [ABSTRACT FROM AUTHOR]