Ecological perception affords an explanation of object permanence

In this paper I aim to present an explanation of object permanence that is derived from an ecological account of perceptually based action. In understanding why children below a certain age do not search for occluded objects, one must first understand the process by which these children perform certain intentional actions on non-occluded items; and to do this one must understand the role affordances play in eliciting retrieval behaviour. My affordance-based explanation is contrasted with Shinskey and Munakata's graded representation account; and although I do not reject totally the role representations play in initiating intentional action I nevertheless maintain that only by incorporating direct perception into an account of object permanence can a fuller understanding of this phenomenon be achieved.     

Do older individuals have difficulty processing motion or excluding noise? Implications for safe driving

This study aimed to determine if difficulties extracting signal from noise explained poorer coherent motion thresholds in older individuals, particularly women. In four experimental conditions the contrast of the signal and noise dots used in a random dot kinematogram was manipulated. Coherence thresholds were highest when the signal dots were of a lower contrast than the noise dots and lowest when the signal dots were of a higher contrast than the noise dots. In all conditions the older group had higher coherence thresholds than the younger group, and women had higher thresholds than men. Significant correlations were found between coherence thresholds and self-reported driving difficulties in conditions in which the signal dots had to be extracted from noise only. The results indicate that older individuals have difficulties extracting signal from noise in cluttered visual environments. The implications for safe driving are discussed.     

Randomized Controlled Trial of Cognitive–Behavioral Group Therapy for Irritable Bowel Syndrome in a Medical Setting

Standard medical treatments have not been effective for irritable bowel syndrome (IBS) patients. Though individualized cognitive–behavior therapy is an empirically supported treatment option, cognitive–behavioral group therapy (CBGT) has yet to be established as an effective alternative in a randomized controlled trial. This study compared the efficacy of a 10-session CBGT with a home-based symptom monitoring with weekly telephone contact (SMTC) treatment for IBS, extending previous quasi-experimental research in this area. Twenty-eight refractory IBS patients, evaluated and referred by gastroenterologists using the Rome criteria, participated in the study. IBS symptoms, psychological functioning, and health-related quality of life were assessed pre- and posttreatment, and at 3-month follow-up. CBGT patients reported significantly more gastrointestinal (GI) symptom improvement than SMTC patients on posttreatment global measures and had significantly reduced daily diary pain scores at 3-month follow-up. Based on MANOVA, there was significant improvement in psychological distress and health-related quality of life for the CBGT patients in comparison to the SMTC patients. These improvements were also maintained at the 3-month follow-up. Reductions in GI symptoms, psychological distress, and improved health related quality of life may contribute to less behavioral avoidance, disability, and health care utilization in refractory IBS patients.     

Alcohol as social lubricant.

This study examines how consuming alcohol differentially affects the communicative behavior and perceptions of high and low social self‐esteem (SSE) women as they engage in a brief interaction with a flirtatious male. Alcohol myopia theory proposes that alcohol affects behavior when it blocks a person's normal inhibitions about enacting a behavior. It was predicted that low SSE women would be more inhibited when talking to a flirtatious male than would high SSE women and, therefore administration of a social self‐esteem measure and random assignment to an alcoholic or nonalcoholic beverage condition, participants (N=50) talked with an attractive, flirtatious male confederate. Low SSE women were less anxious and self‐disclosed more when drinking than when sober, whereas high SSE women were not significantly affected by alcohol consumption. The discussion highlights the complex and often contradictory effects of alcohol consumption on social interaction.     

Diversity and Community Can Coexist

We examine the (in)compatibility of diversity and sense of community by means of agent‐based models based on the well‐known Schelling model of residential segregation and Axelrod model of cultural dissemination. We find that diversity and highly clustered social networks, on the assumptions of social tie formation based on spatial proximity and homophily, are incompatible when agent features are immutable, and this holds even for multiple independent features. We include both mutable and immutable features into a model that integrates Schelling and Axelrod models, and we find that even for multiple independent features, diversity and highly clustered social networks can be incompatible on the assumptions of social tie formation based on spatial proximity and homophily. However, this incompatibility breaks down when cultural diversity can be sufficiently large, at which point diversity and clustering need not be negatively correlated. This implies that segregation based on immutable characteristics such as race can possibly be overcome by sufficient similarity on mutable characteristics based on culture, which are subject to a process of social influence, provided a sufficiently large “scope of cultural possibilities” exists.     

Orientation categories used in guidance of attention in visual search can differ in strength

We investigated orientation categories in the guidance of attention in visual search. In the first two experiments, participants had a limited amount of time to find a target line among distractors lines. We systematically varied the orientation of the target and the angular difference between the target and distractors. We find vertical, horizontal, and 45° targets require the least target/distractor angular difference to be found reliably and that the rate at which increases in target/distractor difference decrease search difficulty to be independent of target identity. Unexpectedly, even when the angular difference between the target and distractors was large, search performance was never optimal when the target orientation was 45°. A third experiment investigates this unexpected finding by correlating target/distractor difference and error rate with performance on tasks that measure a specific perceptual or cognitive ability. We find that the elevated error rate is correlated with performance on stimulus recognition and identification tasks, while the amount of target/distractor difference needed to detect the target reliably is correlated with performance on a stimulus reproduction task. We conclude that the target/distractor difference reveals the number of orientation categories in visual search, and, accordingly, that there are four such categories: two strong ones centred on 0° and 90° and two weak ones centred on 45° and 135°.     

Warnings reduce false memories for missing aspects of events

When people see movies with some parts missing, they falsely recognize many of the missing parts later. In two experiments, we examined the effect of warnings on people's false memories for these parts. In Experiment 1, warning subjects about false recognition before the movie (forewarnings) reduced false recognition, but warning them after the movie (postwarnings) reduced false recognition to a lesser extent. In Experiment 2, the effect of the warnings depended on the nature of the missing parts. Forewarnings were more effective than postwarnings in reducing false recognition of missing noncrucial parts, but forewarnings and postwarnings were similarly effective in reducing false recognition of crucial missing parts. We use the source monitoring framework to explain our results.