Learning to ignore the mask in texture segmentation tasks

Although traditionally texture segmentation has been regarded as an automatic, preattentive process, participants confronted with texture segmentation in experimental settings (i.e., with brief presentation time and subsequent masking) are initially unable to perform the task. According to perceptual learning concepts, participants must learn to fine-tune their sensory channels before perception improves under restricted viewing conditions. The present article proposes an alternative perspective that emphasizes the role of the mask. Four experiments showed that the amount of observed learning depends on the structural and temporal homogeneity or heterogeneity of the mask. The authors suggest that learning consists of separating the task-relevant signal stemming from the texture from the task-irrelevant signal of the mask and of ignoring the mask.     

Expressive writing can increase working memory capacity

The effect of emotional disclosure through expressive writing on available working memory (WM) capacity was examined in 2 semester-long experiments. In the first study, 35 freshmen assigned to write about their thoughts and feelings about coming to college demonstrated larger working memory gains 7 weeks later compared with 36 writers assigned to a trivial topic. Increased use of cause and insight words was associated with greater WM improvements. In the second study, students (n = 34) who wrote about a negative personal experience enjoyed greater WM improvements and declines in intrusive thinking compared with students who wrote about a positive experience (n = 33) or a trivial topic (n = 34). The results are discussed in terms of a model grounded in cognitive and social psychological theory in which expressive writing reduces intrusive and avoidant thinking about a stressful experience, thus freeing WM resources.     

Phonologically related lexical repetition disorder: a case study

Errors of repetition in aphasia are most often nonword substitutions. Phonologically related lexical errors, or formal errors, are real-word substitutions that overlap with target words in sound. In the present research we present the case of an aphasic patient, MMB, who produced an unusually high rate of formal paraphasias in repetition. Six experiments were conducted to investigate the combination of impairments contributing to MMB's pattern of repetition and to test the predictions made by two theories of formal errors. MMB's formal errors in repetition were influenced by target frequency, but not by target length or imageability. Formal errors tended to be more frequent than their targets and showed greatest phonological overlap with targets at initial consonant. These findings provided partial support for Martin and Saffran's fully interactive spreading activation account of formal errors and did not support Blanken's phonological interactive encoding account. In Experiment 6, the effect on repetition of increasing auditory verbal short-term memory (AVSTM) demands was examined using a paired word repetition experiment. Under these conditions, MMB produced semantic paraphasias for the first time, providing strong support for the Martin-Saffran hypothesis that phonologically related, and semantic, lexical repetition disorders lie on a continuum of severity moderated by the degree of AVSTM impairment.     

Representation of visuotactile space in the split brain

Recent neurophysiological research in the monkey has revealed bimodal neuronal cells with both tactile receptive fields on the hand and visual receptive fields that follow the hands as they move, suggesting the existence of a bimodal map of visuotactile space. Using a cross-modal congruency task, we examined the representation of visuotactile space in normal people and in a split-brain patient (J.W.) as the right arm assumed different postures. The results showed that the congruency effects from distracting lights followed the hand around in space in normal people, but failed to do so in the split-brain patient when the hand crossed the midline. This suggests that cross-cortical connections are required to remap visual space to the current hand position when the hand crosses the midline.     

Flashbulb memories in social groups: a comparative test-retest study of the memory of French President Mitterrand's death in a French and a Belgian group

Flashbulb memories are vivid and long-lasting memories for the reception context of an important public event (Brown & Kulik, 1977). They are assumed to be triggered by emotional factors (i.e., intensity of emotional feeling, appraisal of the original event) and by social factors (i.e., social sharing of the news, following media debate about the event). The present study investigated the memory for the death of the former President of France F. Mitterrand in two social groups, i.e., French and Belgian people. This study tests whether the flashbulb memory attributes, the memory for the original event, and the impact of the emotional and social determinants of flashbulb memory differed across groups. The results indicated that the flashbulb memory for Mitterrand's death is affected by group provenance, as French people showed higher levels of recall for the flashbulb memory attributes and their determinants than Belgian people. Time impaired recollections in both groups, so that flashbulb memories appear prone to decay and share the same destiny as ordinary memories. The theoretical construct of concern--as the most basic antecedent of emotional experiences and its related appraisal (Frijda, 1994)--is discussed in order to explain the differences in memory of the two social groups.     

Nonconscious fear conditioning, visceral perception, and the development of gut feelings

When people are presented with backward-masked images of fear-relevant stimuli and only some of these images are paired consistently with electric shocks, they can predict the occurrence of shocks even though they do not consciously know which images they have seen. We postulated that they may use the perception of visceral cues from the conditional fear response to facilitate the prediction of shocks. In this study, ability to detect heartbeats was used to index sensitivity to visceral cues. The results showed that subjects who could detect their heartbeats performed better than chance in predicting whether or not they would receive a shock during the conditioning task. The findings support the notion that hunches, or "gut feelings," are based in part on the perception of visceral cues.     

Emotion knowledge as a predictor of social behavior and academic competence in children at risk

Following leads from differential emotions theory and empirical research, we evaluated an index of emotion knowledge as a long-term predictor of positive and negative social behavior and academic competence in a sample of children from economically disadvantaged families ( N = 72). The index of emotion knowledge represents the child's ability to recognize and label emotion expressions. We administered control and predictor measures when the children were 5 years old and obtained criterion data at age 9. After controlling for verbal ability and temperament, our index of emotion knowledge predicted aggregate indices of positive and negative social behavior and academic competence. Path analysis showed that emotion knowledge mediated the effect of verbal ability on academic competence. We argue that the ability to detect and label emotion cues facilitates positive social interactions and that a deficit in this ability contributes to behavioral and learning problems. Our findings have implications for primary prevention.     

Statistical properties of the rWG(J) index of agreement

L. R. James, R. G. Demaree, and G. Wolf (1984) introduced rWG(J) to estimate interrater agreement for a group. This index is calculated by comparing an observed group variance with an expected random variance. As researchers have gained experience using this index, several questions have arisen. What are the consequences of replacing values beyond the unit interval by 0? What is the dependence of rWG(J) on the group size? The authors' simulations show that a positive bias is caused by the truncation, but for large population values of rWG(J) it is negligible. Also, in this case, the group size has no effect on the expected value of rWG(J). For inference on rWG(J), researchers can exploit the availability of computers to simulate data from the hypothesized distribution and then compare the simulation results for rWG(J) with the actual values. In addition, it is shown how the bootstrap method can be used for comparing the indices of 2 groups.     

Target detection in scientific visualization

Three experiments were conducted to test participants' ability to detect targets in colored spatial displays using 7-level bipolar scales. Experiment 1 assessed the ability of participants to detect high or low targets using 12 scales whose poles either were directly opposed in color space or had a primary and an intermediate hue at each pole. Experiment 2 used 8 scales whose arms were orthogonal in color space. Experiment 3 examined the simultaneous detection of high and low targets. Although there are notable exceptions, scales that are close to or above the horizontal (red-green) axis in color space perform best. Of the scales with orthogonal arms, those that are oriented downward, toward the blues, in color space are least satisfactory. Scales that are asymmetrically effective are common, and applications requiring good detectability at both extremes must take this into account. The results are discussed in the context of the evolution of trichromatic color vision.     

Cross-cultural aspects of fears in African children and adolescents

The purpose of this study was to compare level and type of fears in Nigerian and Kenyan children using the Fear Survey Schedule for Children, Revised (FSSC-R; [Ollendick, T.H. (1983). Reliability and validity of the Revised Fear Survey Schedule for Children (FSSC-R). Behaviour Research and Therapy, 21, 685-692]). A total of 852 males and females between the ages of 8 and 17 were surveyed. Results indicated that Nigerian children reported significantly higher total fear than Kenyan children and that scores from both countries were higher than those found in the United States, Australia and China. This suggests that the cultures of Kenya and Nigeria may share a common variable that makes reporting of fears greater than that reported by children of other world cultures. In addition, Christian children in both countries reported higher levels of fear on several factors than Muslim children, indicating that Islamic beliefs may encourage children to report less fear or to deal with their fears better than Christian beliefs. Finally, children between the ages of 8 and 12 reported greater fear of the unknown than children between 13 and 17 years of age. Overall, these findings suggest that important cultural, religious and age differences exist for levels of childhood fears reported in Nigeria and Kenya.