Performance of blind and sighted humans on a tactile grating detection task

We compared the abilities of blind and sighted humans to distinguish grooved from smooth surfaces pressed against the stationary index fingertip. Ranging in age from 20 to 72 years, 37 blind and 47 sighted subjects participated in an automated two-alternative forced-choice tactile grating detection task. The tactile acuity of blind and sighted subjects declined with age at equivalent rates (0.011-mm threshold increase per year), but the blind subjects were able to perceive significantly thinner grooves than were their sighted peers (the average difference between blind and sighted subjects of the same age and gender was 0.267 mm). The blind Braille readers performed no better than the blind nonreaders, and the congenitally blind subjects performed equivalently to those with adult-onset blindness. The superior tactile acuity of blind persons may result from the involvement of normally visually responsive cerebrocortical areas in tactile processing, as shown by functional-imaging studies.     

The impact of emotional stress early in life on adult voluntary ethanol intake-results of maternal separation in rats

The combination of genetic and environmental factors determines the individual vulnerability for excessive ethanol intake, possibly leading to dependence. The environmental influences early in life represent examples of determinant factors for adult behaviour and can be protective as well as risk factors. Maternal separation is one model to examine the long-term consequences of early environmental experiences on neurochemistry and behaviour, including drug-taking behaviour in experimental animals. In the present review, findings from studies using repeated short and prolonged periods of maternal separation, with emphasis on effects on voluntary ethanol intake in rats with or without a genetic predisposition for high voluntary ethanol intake, are summarized. Despite some contradictory results, the general picture emerging shows that short periods of maternal separation during the postnatal period result in a lower adult voluntary ethanol intake in male rats. Prolonged periods of maternal separation were found to induce a high voluntary ethanol intake in male rats, including rats with a genetic predisposition for high ethanol intake. Results from the literature also show that changes were not just related to time of separation but were also related to the degree of handling. Interestingly, in terms of voluntary ethanol intake, female rats were generally not affected by postnatal maternal separation. The reasons for these sex differences need further investigation. In terms of neurobiological consequences of maternal separation, conclusive data are sparse and one of the future challenges will, therefore, be to identify and characterize underlying neurobiological mechanisms, especially in the individual animal.     

Social attitudes and education: Self-selection or socialization?

The aim of this study was to replicate earlier findings (Ekehammar et al., 1987) concerning the relationship between social attitudes and educational direction and field of study, by addressing further the causality issue. The sample comprised 256 Swedish adolescents from metropolitan Stockholm attending the two lowest grades in secondary school (modal age was 17 years). The main findings of the previous study were replicated, although the statistical power was weaker. Two higher-order attitude dimensions (labeled Political-economic conservatism and Social conservatism) discriminated between six groups, based on combinations of the two aspects of education. The main picture evidenced a socialization effect regarding Political-economic conservatism and a self-selection explanation for Social conservatism. Introducing intellectual ability as an independent variable in the causal model, affecting both educational direction and social attitudes, weakened the relationship, as compared to the previous study.     

Determinants of cumulative successive contrast in saltiness intensity judgments

When all stimuli elicit the same taste quality, solutions preceded by a high concentration level are judged to be significantly less intense than solutions preceded by a low concentration level. After repetitious stimulation with a different tasting stimulus, the intensity of the present stimulus is overestimated. This phenomenon is called “successive contrast.” In the present study, the cumulative effects of three identical stimuli on the saltiness ratings for a test stimulus are investigated. The preceding stimuli are manipulated with regard to taste quality, saltiness intensity, total taste intensity, and complexity. Whether the size of the cumulative contrast effect is associated with the degree of dissimilarity between preceding stimuli and test stimulus, or with the saltiness or total taste intensity of the preceding stimuli, is investigated. The size of the contrast effect depends on the type of preceding stimulus, its intensity, and the type of test stimulus. No association was found with judgments of the degree of dissimilarity between the preceding stimuli and the test stimulus. For nonsalty preceding stimuli, the contrast effects are independent of concentration level. When the preceding stimuli taste at least partly salty, the total intensity appears to determine the size of the contrast for an unmixed salty test stimulus.     

Women as cues for men's approach or distancing behavior: A study of interpersonal sexist discrimination

The purpose of this study was to investigate interpersonal sexist discrimination, operationally defined as distancing behavior. A heterogeneous sample of participants were approached at four train stations and completed two paper and pencil simulated seating measures, a sex role attitudes measure, and provided demographic information. It was predicted that in the neutral situations presented in the seating measures where there is a choice to sit either next to a man or a woman, men would more often choose to sit next to a man but women were not expected to make seating choices based on the gender of the person seated. Men's seating choices were found to be influenced by the gender of target persons whereas women's choices were not, but men either distanced from or approached women target persons. Self-reported sex role attitudes were found not to be related to distancing behavior.We gratefully acknowledge the assistance of Alyson Andrews, Nicholas Geraci, Scott Marino, Stacy Schiff, Robert Victoria, and Lisa Zamara, seniors at the University of Rhode Island, who served as investigators in this study and also assisted in the coding of data. Portions of this paper were presented at the national conference of the Association for Women in Psychology in Oakland, CA, on March 6, 1994.Requests for reprints may be sent to any of the authors at the University of Rhode Island, Department of Psychology, Kingston, RI 02881.     

CHANGE IN AFTERIMAGE AND SPIRAL AFTEREFFECT SERIALS DUE TO ANXIETY CAUSED BY SUBLIMINAL THREAT

Experiments with projected negative afterimages and with the aftereffects of a rotating spiral were performed serially (repeated stimulus presentation). In the middle of the sequences the experimental groups were subjected to subliminal threat by means of a metacontrast technique. The effects of threat on the latter part of the sequences were according to predictions and differed markedly from the results in control groups.     

Correlates and consequences of uncertainty in career aspirations: Gender differences among adolescents in England

Young people today face a great deal of uncertainty regarding their career opportunities, yet relatively little information is known about the correlates and consequences of uncertain aspirations. Drawing upon the Longitudinal Study of Young People in England (LSYPE) born in 1989/90, this study examined a pathway model investigating whether uncertain career aspirations and other associated variables mediate the link between socioeconomic status and prior achievement and later educational outcomes. Gender differences were also examined. Findings indicate that adolescents who had lower prior achievement and were from lower socioeconomic backgrounds were more likely to have uncertainty in their career aspirations. The hypothesized model was supported to some extent, indicating that uncertain career aspirations and other associated variables were significant mediators. Unexpectedly, adolescents with uncertain career aspirations had higher academic performance at age 16 and a greater likelihood of educational enrollment at age 18 compared to those with high, certain aspirations, when parental educational expectations, school motivation, perceived academic ability and useful career advice were taken into account, suggesting that these young people may benefit from an extended period of moratorium in their career choice.     

Prior entry and temporal attention: cueing affects order errors in RSVP

The law of prior entry states that attended objects come to consciousness more quickly than unattended ones. This has been well established in spatial cueing paradigms, where two task-relevant stimuli are presented near-simultaneously at two different locations. Here, we suggest that prior entry also plays a pivotal role in temporal attention paradigms, where stimuli appear at the same location but at distinct moments in time, in rapid serial presentation (RSVP). Specifically, we hypothesize that prior entry can explain temporal order reversals in reporting two targets from RSVP. In support of this, three experiments show that cueing attention toward either of the targets has a strong influence on order errors. We conclude that prior entry provides a viable explanation of the way in which relevant information is prioritized in RSVP.     

Shifting attention among working memory representations: testing cue type, awareness, and strategic control

It is well known that visual working memory (VWM) performance is modulated by attentional cues presented during encoding. Interestingly, retrospective cues presented after encoding, but prior to the test phase also improve performance. This improvement in performance is termed the retro-cue benefit. We investigated whether the retro-cue benefit is sensitive to cue type, whether participants were aware of their improvement in performance due to the retro-cue, and whether the effect was under strategic control. Experiment 1 compared the potential cueing benefits of abrupt onset retro-cues relying on bottom-up attention, number retro-cues relying on top-down attention, and arrow retro-cues, relying on a mixture of both. We found a significant retro-cue effect only for arrow retro-cues. In Experiment 2, we tested participants' awareness of their use of the informative retro-cue and found that they were aware of their improved performance. In Experiment 3, we asked whether participants have strategic control over the retro-cue. The retro-cue was difficult to ignore, suggesting that strategic control is low. The retro-cue effect appears to be within conscious awareness but not under full strategic control.     

Spatial mislocalization as a consequence of sequential coding of stimuli

In three experiments, we tested whether sequentially coding two visual stimuli can create a spatial misperception of a visual moving stimulus. In Experiment 1, we showed that a spatial misperception, the flash-lag effect, is accompanied by a similar temporal misperception of first perceiving the flash and only then a change of the moving stimulus, when in fact the two events were exactly simultaneous. In Experiment 2, we demonstrated that when the spatial misperception of a flash-lag effect is absent, the temporal misperception is also absent. In Experiment 3, we extended these findings and showed that if the stimulus conditions require coding first a flash and subsequently a nearby moving stimulus, a spatial flash-lag effect is found, with the position of the moving stimulus being misperceived as shifted in the direction of its motion, whereas this spatial misperception is reversed so that the moving stimulus is misperceived as shifted in a direction opposite to its motion when the conditions require coding first the moving stimulus and then the flash. Together, the results demonstrate that sequential coding of two stimuli can lead to a spatial misperception whose direction can be predicted from the order of coding the moving object versus the flash. We propose an attentional sequential-coding explanation for the flash-lag effect and discuss its explanatory power with respect to related illusions (e.g., the Fr?hlich effect) and other explanations.