Cortical dynamics of lateral inhibition: Visual persistence and ISI

Psychophysical studies show that increasing the interstimulus interval (ISI) between two stimuli decreases persistence of the first stimulus. While some researchers account for these results with interactions of transient and sustained inhibition, this paper describes an alternative explanation. In a neural-network model of boundary detection called the boundary contour system, persistence is the result of feedback-generated reverberations. Mechanisms to control these reverberations include lateral inhibition, which computer simulations show allows persistence in the network to qualitatively match the psychophysical data. Additional simulations predict that increasing the duration of the second stimulus should cause persistence to increase with ISI. The model links psychophysical data on visual persistence with computational requirements of spatial vision and properties of cells in visual cortex.     

Developmental trends in the interaction between auditory and linguistic processing

The developmental course of multidimensional speech processing was examined in 80 children between 3 and 6 years of age and in 60 adults between 20 and 86 years of age. Processing interactions were assessed with a speeded classification task (Garner, 1974a), which required the subjects to attend selectively to the voice dimension while ignoring the linguistic dimension, and vice versa. The children and adults exhibited both similarities and differences in the patterns of processing dependencies. For all ages, performance for each dimension was slower in the presence of variation in the irrelevant dimension; irrelevant variation in the voice dimension disrupted performance more than irrelevant variation in the linguistic dimension. Trends in the degree of interference, on the other hand, showed significant differences between dimensions as a function of age. Whereas the degree of interference for the voice-dimension-relevant did not show significant age-related change, the degree of interference for the word-dimension-relevant declined significantly with age in a linear as well as a quadratic manner. A major age-related change in the relation between dimensions was that word processing, relative to voice-gender processing, required significantly more time in the children than in the adults. Overall, the developmental course characterizing multidimensional speech processing evidenced more-pronounced change when the linguistic dimension, rather than the voice dimension, was relevant.     

Effects of Refutational Messages,Thought Provocation,and Decision Deadlines on Signing to Donate Organs1

Across three experiments college students were given refutational messages or other treatments encouraging signing drivers' licenses to donate bodily organs in case of accidental death. An attitudinal measure (willingness to sign) predicted observed signing behavior, but relatively weakly. A measure of behavioral expectation to sign or not to sign predicted more strongly. A discussion with family was encouraged, the impact of that discussion also predicted signing but less strongly so. In Study 1 groups given a refutational message signed at no greater rates than a group given a control message. In Study 2 a refutational message group and a group asked to think about donating for 2 min signed at higher rates than a true control group. In Study 3 groups asked to decide whether or not to sign by a certain date and time signed at a higher rate than a refutational message group as in earlier studies. These procedures are recommended for organ donation signing campaigns.     

A Laughing Matter? The Uses of Humor in Medical Interactions

Motivation and Emotion - As Coser (1962) demonstrated in her landmark hospital study, a humor is one of the great tools of reassurance on the hospital ward. After all, if something is ridiculous,...     

Relating covariation information to causal dimensions through principles of contrast and invariance

This paper examines the proposition that covariation information guides judgments about the dimensionality of attributions on the basis of causal principles of contrast and invariance, which are derived from Mill's methods of difference and agreement respectively. It is argued that the standard attribution categories specified in earlier research (e.g. person, occasion and stimulus) represent just one extreme of the attributional dimensions and require the principle of contrast, whereas additional attributional categories reflecting the opposite extreme of the dimensions (e.g. external, stable, general) require the principle of invariance. In three studies, subjects were given covariation information, and were asked to rate the properties of the likely cause along the dimensions of locus, stability, globality and control. In line with the predictions, consensus with others, consistency in time, distinctiveness between stimuli and contingency of one's actions showed the strongest effects on judgments of locus, stability, globality and control respectively. Similar results were obtained in a fourth study, where subjects had to judge the influence of eight causes with varying dimensional properties. Moreover, these judgments were rated somewhat higher given causes requiring the principle of invariance rather than the principle of contrast.