The development of individuation in autism.

Abstract

Evidence suggests that people with autism use holistic information differently than typical adults. The current studies examine this possibility by investigating how core visual processes that contribute to holistic processing – individuation and element grouping – develop in participants with autism and typically developing (TD) participants matched for age, IQ and gender. Individuation refers to the ability to `see' up to 4 elements simultaneously; grouping these elements can change the number of elements that are rapidly apprehended. We examined these core processes using two well-established paradigms, rapid enumeration and multiple object tracking (MOT). In both tasks, a performance limit of about 4 elements in adulthood is thought to reflect individuation capacity. Participants with autism has a smaller individuation capacity than TD controls, regardless of whether they were enumerating static elements or tracking moving ones. To manipulate holistic information and individuation performance, we grouped the elements into a design or had elements move together. Participants with autism were affected to a similar degree as TD participants by the holistic information, whether the manipulation helped or hurt performance, consistent with evidence that some types of gestalt/grouping information are processed typically in autism. There was substantial development in autism from childhood to adolescence, but not from adolescence to adulthood, a pattern distinct from TD participants. These results provide important information about core visual processes in autism, as well as insight into the architecture of vision (e.g., individuation appears distinct from visual strengths in autism, such as visual search, despite similarities).

Multiple Object Tracking Reveals Object-Based Grouping Interference in Children with ASD

“…This finding is in line with the results by Evers et al (2014), who found group differences in grouping interference scores, but no overall group difference. However, the lack of an overall group difference contrasts with the findings of both Koldewyn et al (2013b) andO'Hearn et al (2013), who found overall diminished MOT performances for their ASD participant groups. Note that the presence or absence of an overall group difference in these four studies cannot be related to differences in the age of the samples or the type of group matching, but seems due to the particular type of MOT modifications used (or the particular participant samples).…”

“…Evers et al used two distinct trial conditions: one connection-based, grouped condition, where targets and distractors were connected with a single line, and one ungrouped, baseline condition, where targets and distractors were not paired. Although both participant groups suffered from connection-based grouping (in line with the 'grouping hurts' condition by O'Hearn et al 2013), the ASD group experienced significantly less grouping interference compared to the TD peers. These results were interpreted as indirect evidence for a reduced bias towards global processing in ASD, specifically through the influence of grouping on how attention automatically selects information.…”

Constraints on Multiple Object Tracking in Williams Syndrome: How Atypical Development Can Inform Theories of Visual Processing

“…A decrease in tracking capacity has been reported in other developmental disorders, including autism spectrum disorder (Koldewyn, Weigelt, Kanwisher, & Jiang, 2013;O'Hearn, Franconeri, Wright, Minshew, & Luna, 2013), Down syndrome (Brodeur et al, 2013), Turner syndrome (Beaton et al, 2010), 22q11.2 deletion syndrome (Cabaral, Beaton, Stoddard, & Simon, 2012), and amblyopia (Giaschi, Chapman, Meier, Narasimhan, & Regan, 2015). The MOT atypicalities across this range of developmental disorders, all with varying degrees of spatial impairment, suggests that the mechanism is particularly fragile and vulnerable to neurocognitive impairment (Atkinson & Braddick, 2012).…”

Individual Subitizing Range (ISR)

“…In addition, there is also variability in how much spatial arrangement affects the subitizing range in an individual (Figure 5(c)). Such differences raise interesting questions regarding the variability of subitizing and its relation to math abilities, spatial abilities, visuospatial working memory, or any of the different cognitive mechanisms (Ashkenazi et al, 2013;Green & Bavelier, 2003;O'Hearn et al, 2013) in the general population. The current method, allowing us to estimate an individual's subitizing range can go a long way in helping to find connections between individual differences in subitizing and individual differences in a variety of cognitive abilities.…”

“…Because the bilinear method is very sensitive to these variations, researchers often make several simplifying assumptions to "clean" the data. Such assumptions include limiting or restricting the slope of one or both lines to a predetermined range, enforcing positive slopes, enforcing continuity, truncating the data, or restricting the range over which the break points may vary (Logan & Zbrodoff, 2003;O'Hearn et al, 2015;O'Hearn, Franconeri, Wright, Minshew, & Luna, 2013;Starkey & McCandliss, 2014). Each of these a-priori assumptions bias the resulting calculation of subitizing range.…”