Sol Z. Sun

Seeing the Forest and the Trees: Default Local Processing in Individuals with High Autistic Traits Does Not Come at the Expense of Global Attention

Atypical sensory perception is one of the most ubiquitous symptoms of autism, including a tendency towards a local-processing bias. We investigated whether local-processing biases were associated with global-processing impairments on a global/local attentional-scope paradigm in conjunction with a composite-face task. Behavioural results were related to individuals’ levels of autistic traits, specifically the Attention to Detail subscale of the Autism Quotient, and the Sensory Profile Questionnaire. Individuals showing high rates of Attention to Detail were more susceptible to global attentional-scope manipulations, suggesting that local-processing biases associated with Attention to Detail do not come at the cost of a global-processing deficit, but reflect a difference in default global versus local bias. This relationship operated at the attentional/perceptual level, but not response criterion.

Distinct cognitive mechanisms involved in the processing of single objects and object ensembles

Behavioral research has demonstrated that the shape and texture of single objects can be processed independently. Similarly, neuroimaging results have shown that an objects shape and texture are processed in distinct brain regions with shape in the lateral occipital area and texture in parahippocampal cortex. Meanwhile, objects are not always seen in isolation and are often grouped together as an ensemble. We recently showed that the processing of ensembles also involves parahippocampal cortex and that the shape and texture of ensemble elements are processed together within this region. These neural data suggest that the independence seen between shape and texture in single-object perception would not be observed in object-ensemble perception. Here we tested this prediction by examining whether observers could attend to the shape of ensemble elements while ignoring changes in an unattended texture feature and vice versa. Across six behavioral experiments, we replicated previous findings of independence between shape and texture in single-object perception. In contrast, we observed that changes in an unattended ensemble feature negatively impacted the processing of an attended ensemble feature only when ensemble features were attended globally. When they were attended locally, thereby making ensemble processing similar to single-object processing, interference was abolished. Overall, these findings confirm previous neuroimaging results and suggest that distinct cognitive mechanisms may be involved in single-object and object-ensemble perception. Additionally, they show that the scope of visual attention plays a critical role in determining which type of object processing (ensemble or single object) is engaged by the visual system.

Automatic Capture of Attention by Conceptually Generated Working Memory Templates

Many theories of attention propose that the contents of working memory (WM) can act as an attentional template, which biases processing in favor of perceptually similar inputs. While support has been found for this claim, it is unclear how attentional templates are generated when searching real-world environments. We hypothesized that in naturalistic settings, attentional templates are commonly generated from conceptual knowledge, an idea consistent with sensorimotor models of knowledge representation. Participants performed a visual search task in the delay period of a WM task, where the item in memory was either a colored disk or a word associated with a color concept (e.g., “Rose,” associated with red). During search, we manipulated whether a singleton distractor in the array matched the contents of WM. Overall, we found that search times were impaired in the presence of a memory-matching distractor. Furthermore, the degree of impairment did not differ based on the contents of WM. Put differently, regardless of whether participants were maintaining a perceptually colored disk identical to the singleton distractor, or whether they were simply maintaining a word associated with the color of the distractor, the magnitude of attentional capture was the same. Our results suggest that attentional templates can be generated from conceptual knowledge, in the physical absence of the visual feature.

Linking Anxiety and Insistence on Sameness in Autistic Children: The Role of Sensory Hypersensitivity.

Sensory hypersensitivity and insistence on sameness (I/S) are common, co-occurring features of autism, yet the relationship between them is poorly understood. This study assessed the impact of sensory hypersensitivity on the clinical symptoms of specific phobia, separation anxiety, social anxiety and I/S for autistic and typically developing (TD) children. Parents of 79 children completed questionnaires on their child’s difficulties related to sensory processing, I/S, and anxiety. Results demonstrated that sensory hypersensitivity mediated 67% of the relationship between symptoms of specific phobia and I/S and 57% of the relationship between separation anxiety and I/S. No relationship was observed between sensory hypersensitivity and social anxiety. These mediation effects of sensory hypersensitivity were found only in autistic children, not in TD children.

Erasing and blurring memories: The differential impact of interference on separate aspects of forgetting.

Interference disrupts information processing across many timescales, from immediate perception to memory over short and long durations. The widely held similarity assumption states that as similarity between interfering information and memory contents increases, so too does the degree of impairment. However, information is lost from memory in different ways. For instance, studied content might be erased in an all-or-nothing manner. Alternatively, information may be retained but the precision might be degraded or blurred. Here, we asked whether the similarity of interfering information to memory contents might differentially impact these 2 aspects of forgetting. Observers studied colored images of real-world objects, each followed by a stream of interfering objects. Across 4 experiments, we manipulated the similarity between the studied object and the interfering objects in circular color space. After interference, memory for object color was tested continuously on a color wheel, which in combination with mixture modeling, allowed for estimation of how erasing and blurring differentially contribute to forgetting. In contrast to the similarity assumption, we show that highly dissimilar interfering items caused the greatest increase in random guess responses, suggesting a greater frequency of memory erasure (Experiments 1–3). Moreover, we found that observers were generally able to resist interference from highly similar items, perhaps through surround suppression (Experiments 1 and 4). Finally, we report that interference from items of intermediate similarity tended to blur or decrease memory precision (Experiments 3 and 4). These results reveal that the nature of visual similarity can differentially alter how information is lost from memory.

A global attentional scope setting prioritizes faces for conscious detection

The scope of visual attention is known to affect conscious object perception, with recent studies showing that a global attentional scope boosts holistic face processing, relative to a local scope. Here we show that attentional scope settings can also modulate the availability of information for conscious visual awareness. In an initial experiment, we show that adopting a global attentional scope accelerates conscious detection of initially invisible faces, presented under continuous flash suppression (CFS). Furthermore, face detection time was not modulated by attentional scope in a nonrivalrous control condition, which emulated the experience of CFS without inducing binocular rivalry. In a follow-up experiment, we report an exact replication of the original effect, as well as data suggesting that this effect is specific to upright faces, and is abolished when using both inverted faces and images of houses in an otherwise identical task. Thus, attentional scope settings can modulate the availability of information to conscious awareness, fundamentally altering the contents of our subjective visual experience.

Individual differences in autistic traits predict visual binding abilities

A core symptom of autism spectrum disorder (ASD) is a deficit in binding sensory inputs into a unified representation. Past research suggests that these impairments extend from lower-level perceptual grouping to higher-level holistic face perception. Given that visuo-spatial attention plays a critical role in binding, we hypothesized that normally-distributed autistic traits in the healthy population would predict the degree to which attentional scope could be modified to influence holistic face perception. We directed participants to adopt either a global or local attentional scope using a Navon task. Participants viewed pairs of Navon letters (big letters composed of small letters) and made same/different judgments based on attention to the big (global scope) or small (local scope) letter. The effects of this manipulation were measured on the composite face task, a well-established measure of holistic face perception. Autistic traits and sensory processing styles were measured using the Autism Quotient (AQ) and Sensory Profile (SP), respectively. In the Navon task, we observed a global interference effect, that is, greater susceptibility to interference from global information, relative to local. Furthermore, individuals with higher SP scores showed weaker global interference effects. ASD has been associated with both abnormal sensory processing styles, as well as weaker global interference effects. Consistent with this idea, we found an interaction in that SP was more strongly associated with global interference in individuals with higher AQ scores. In the composite face task, we found that the attention-to-detail subscale of the AQ predicted differences in susceptibility to the composite face illusion between global and local conditions. Specifically, individuals high in autistic traits were less capable of adopting a global attentional setting, which led to weaker holistic face perception. These results shed light on how autistic traits and sensory processing styles converge to influence visual binding abilities. Meeting abstract presented at VSS 2015.