The visual perception of motion by observers with autism spectrum disorders: A review and synthesis

Traditionally, psychological research on autism spectrum disorder (ASD) has focused on social and cognitive abilities. Vision provides an important input channel to both of these processes, and, increasingly, researchers are investigating whether observers with ASD differ from typical observers in their visual percepts. Recently, significant controversies have arisen over whether observers with ASD differ from typical observers in their visual analyses of movement. Initial studies suggested that observers with ASD experience significant deficits in their visual sensitivity to coherent motion in random dot displays but not to point-light displays of human motion. More recent evidence suggests exactly the opposite: that observers with ASD do not differ from typical observers in their visual sensitivity to coherent motion in random dot displays, but do differ from typical observers in their visual sensitivity to human motion. This review examines these apparently conflicting results, notes gaps in previous findings, suggests a potentially unifying hypothesis, and identifies areas ripe for future research.     

Larger brain and white matter volumes in children with developmental language disorder

Developmental language disorder (DLD) is predominantly a language disorder, but children with DLD also manifest non-language impairments, and neuroanatomical abnormalities have been found in multiple areas of the brain, not all language-associated. We therefore performed a whole brain general segmentation analysis of all major brain regions on MRI scans of 24 DLD subjects (16M, 8F) and 30 controls (15M, 15F), ages 5.7 to 11.3 years. Children with DLD showed increased total brain volume, driven predominantly by a substantial increase in the volume of cerebral white matter. Cerebral cortex and caudate were relatively but not absolutely smaller in DLD. These findings are discussed in relation to issues of specificity vs. generality as they arise in debates about (1) modular vs. general processing deficits and connectionist modeling in DLD, (2) language-specific vs. pervasive, non-specific deficits in DLD and (3) specificity of the disorder vs. overlap with other disorders, notably autism.     

Phonemic effects in reading comprehension and text memory

Two experiments investigated the role of phonemic information in adult reading comprehension and replicated the visual tongue-twister effect in a new paradigm–a modified probe memory task. College students took longer to read sentences that repeated word initial consonants (tongue-twisters) than matched control sentences. Equally important, subjects also took longer to respond to probe words from tongue-twisters. Slower response times in both the sentence reading task and the probe memory task indicate that the tongue-twister effect is indeed phonemic in nature and that phonemic information is used in memory during comprehension.     

ON THE VALUE OF KNOWING ONE'S LIKES AND DISLIKES:

Abstract— On the basis of laboratory research indicating that accessible altitudes ease decision making we hypothesized that freshmen who enter college knowing their likes and dislikes regarding academically relevant issues may experience better health in this new life setting To test this hypothesis, we conducted a prospective study in which students completed self-report inventories of negative life events and mental and physical health at two points in time. The accessibility of attitudes toward academically relevant issues was assessed in the initial session Regression analyses revealed three-way interactions between attitude accessibility, stress (as indexed by the number of negative life events), and initial health status when initial health, the generally positive relation between stress and illness was buffered by the possession of accessible attitudes For students with relatively poor initial health, recovery Has generally greater among those experiencing less stress, especially as attitude accessibility increased.     

Is visual image segmentation a bottom-up or an interactive process?

Visualimage segmentation is the process by which the visual system groups features that are part of a single shape. Is image segmentation a bottom-up or an interactive process? In Experiments 1 and 2, we presented subjects with two overlapping shapes and asked them to determine whether two probed locations were on the same shape or on different shapes. The availability of top-down support was manipulated by presenting either upright or rotated letters. Subjects were fastest to respond when the shapes corresponded to familiar shapes—the upright letters. In Experiment 3, we used a variant of this segmentation task to rule out the possibility that subjects performed same/different judgments after segmentation and recognition of both letters. Finally, in Experiment 4,we ruled out the possibility that the advantage for upright letters was merely due to faster recognition of upright letters relative to rotated letters. The results suggested that the previous effects were not due to faster recognition of upright letters; stimulus familiarity influenced segmentation per se. The results are discussed in terms of an interactive model of visual image segmentation.     

Computer dialogue system (CDS): A system for capturing computer-mediated dialogue

In the process of studying human tutoring sessions as a basis for building an intelligent tutoring system, we developed a computer dialogue system (CDS) that allows two PC users to communicate with each other over a telephone line by typing at a computer keyboard. CDS records the content of dialogue on a disk in a specified, well-formatted way. It also makes available a way to mimic some of the characteristics of face-to-face dialogue such as repair. It was developed in the Smartcom III (Hayes Communication package) environment. Thus, it is fast, portable, and easy to use. In addition, to help us study the recorded dialogues, we have also written a numbering program to label each turn and each sentence within each turn. Although CDS was originally designed for the study of tutorial dialogues between students and teachers, it can be used to conduct and record dialogues of any kind.     

Perceptual interference and facilitation with auditory imagery

It has been claimed both that (1) imagery selectivelyinterferes with perception (because images can be confused with similar stimuli) and that (2) imagery selectivelyfacilitates perception (because images recruit attention for similar stimuli). However, the evidence for these claims can be accounted for without postulating either image-caused confusions or attentional set. Interference could be caused by general and modality-specific capacity demands of imaging, and facilitation, by image-caused eye fixations. The experiment reported here simultaneously tested these two apparently conflicting claims about the effect of imagery on perception in a way that rules out these alternative explanations. Subjects participated in a two-alternative forced-choice auditory signal detection task in which the target signal was either the same frequency as an auditory image or a different frequency. The possible effects of confusion and attention were separated by varying the temporal relationship between the image and the observation intervals, since an image can only be confused with a simultaneous signal. We found selective facilitation (lower thresholds) for signals of the same frequency as the image relative to signals of a different frequency, implying attention recruitment; we found no selective interference, implying the absence of confusion. These results also imply that frequency information is represented in images in a form that can interact with perceptual representations.