Splitting attention across the two visual fields in visual short-term memory

Humans have the ability to attentionally select the most relevant visual information from their extrapersonal world and to retain it in a temporary buffer, known as visual short-term memory (VSTM). Research suggests that at least two non-contiguous items can be selected simultaneously when they are distributed across the two visual hemifields. In two experiments, we show that attention can also be split between the left and right sides of internal representations held in VSTM. Participants were asked to remember several colors, while cues presented during the delay instructed them to orient their attention to a subset of memorized colors. Experiment 1 revealed that orienting attention to one or two colors strengthened equally participants' memory for those colors, but only when they were from separate hemifields. Experiment 2 showed that in the absence of attentional cues the distribution of the items in the visual field per se had no effect on memory. These findings strongly suggest the existence of independent attentional resources in the two hemifields for selecting and/or consolidating information in VSTM.     

Flexible visual processing of spatial relationships

Visual processing breaks the world into parts and objects, allowing us not only to examine the pieces individually, but also to perceive the relationships among them. There is work exploring how we perceive spatial relationships within structures with existing representations, such as faces, common objects, or prototypical scenes. But strikingly, there is little work on the perceptual mechanisms that allow us to flexibly represent arbitrary spatial relationships, e.g., between objects in a novel room, or the elements within a map, graph or diagram. We describe two classes of mechanism that might allow such judgments. In the simultaneous class, both objects are selected concurrently. In contrast, we propose a sequential class, where objects are selected individually over time. We argue that this latter mechanism is more plausible even though it violates our intuitions. We demonstrate that shifts of selection do occur during spatial relationship judgments that feel simultaneous, by tracking selection with an electrophysiological correlate. We speculate that static structure across space may be encoded as a dynamic sequence across time. Flexible visual spatial relationship processing may serve as a case study of more general visual relation processing beyond space, to other dimensions such as size or numerosity.     

A COMPARISON OF DIFFERENTIAL REINFORCEMENT AND NONCONTINGENT REINFORCEMENT TO TREAT FOOD SELECTIVITY IN A CHILD WITH AUTISM

We compared differential reinforcement plus escape extinction to noncontingent reinforcement plus escape extinction to treat food selectivity exhibited by a young child with autism. The interventions were equally effective for increasing bite acceptance and decreasing problem behaviors. However, a social validity measure suggested that noncontingent reinforcement was preferred by the child's caregiver.     

THE EFFECTS OF MATCHED STIMULATION AND RESPONSE INTERRUPTION AND REDIRECTION ON VOCAL STEREOTYPY

Stereotypy has been classified as repetitive behavior that does not serve any apparent function. Two procedures that have been found to reduce rates of vocal stereotypy effectively are response interruption and redirection (RIRD) and noncontingent access to matched stimulation (MS). The purpose of the current study was to evaluate the effects of RIRD alone, MS alone, and MS combined with RIRD. One participant's results suggested similar suppressive effects on vocal stereotypy across treatment conditions. For the second participant, a slightly greater suppression of stereotypy was associated with MS + RIRD. In addition, both participants emitted a greater frequency of appropriate vocalizations in conditions with RIRD. Data suggest that the addition of MS might facilitate the implementation of RIRD in applied settings.     

characters and clues: factors affecting children's extension of knowledge through integration of separate episodes

Children build up knowledge about the world and also remember individual episodes. How individual episodes during which children learn new things become integrated with one another to form general knowledge is only beginning to be explored. Integration between separate episodes is called on in educational contexts and in everyday life as a major means of extending knowledge and organizing information. Bauer and San Souci (2010) provided an initial demonstration that 6-year-olds extend their knowledge by integrating between separate but related episodes; the episodes shared a high level of surface similarity. Experiments 1A and 1B of the current research were tests of integration under low and high levels of surface similarity, respectively. In Experiment 1A, when surface similarity of the episodes was low, 6-year-olds integrated between passages of text, yet their performance was not as robust as observed previously. In Experiment 1B, when surface similarity of the episodes was high, a replication of Bauer and San Souci's results was observed. In Experiment 2, we tested whether a "hint" to consult the information learned in the passages improved performance even when surface level similarity was low. The hint had a strong facilitating effect. Possible mechanisms of integration between separate yet related episodes are discussed.     

Temperamental surgency and emotion regulation as predictors of childhood social competence

The primary aims of the current study were to longitudinally examine the direct relationship between children's temperamental surgency and social behaviors as well as the moderating role of children's emotion regulation. A total of 90 4.5-year-old children participated in a laboratory visit where children's temperamental surgency was rated by experimenters and children's emotion regulation abilities were assessed. The summer before entry into first grade, children's social behaviors with unfamiliar peers were observed in the laboratory and mothers completed a questionnaire about children's social behaviors. Supporting our hypotheses, results revealed that children high in temperamental surgency developed more negative peer behaviors, whereas children low in temperamental surgency were more likely to develop behavioral wariness with peers. Emotion regulatory behaviors were found to moderate the relation between temperamental surgency and aggression, where high-surgent children who showed high levels of social support seeking were less likely to be rated by their mothers as high in aggression. Furthermore, results revealed that low-surgent children who showed high levels of distraction/self-soothing were more likely to show behavioral wariness around unfamiliar peers, whereas high-surgent children who used more distraction/self-soothing behaviors were rated by their mothers as lower in social competence.     

SUPPRESSIVE AND FACILITATIVE EFFECTS OF SHOCK INTENSITY AND INTERRESPONSE TIMES FOLLOWED BY SHOCK

Although response‐dependent shock often suppresses responding, response facilitation can occur. In two experiments, we examined the suppressive and facilitative effects of shock by manipulating shock intensity and the interresponse times that produced shock. Rats' lever presses were reinforced on a variable‐interval 40‐s schedule of food presentation. Shock followed either long or short interresponse times. Shock intensity was raised from 0.05 mA to 0.4 mA or 0.8 mA. Overall, shock contingent on long interresponse times punished long interresponse times and increased response rates. Shock contingent on short interresponse times punished short interresponse times and decreased response rates. In Experiment 1, raising the range of interresponse times that produced shock enhanced these effects. In Experiment 2, the effects of shock intensity depended on the interresponse times that produced shock. When long interresponse times produced shock, low intensities increased response rates. High intensities decreased response rates. When short interresponse times produced shock, high shock intensities punished short interresponse times and decreased response rates more than low intensities. The results may explain why punishment procedures occasionally facilitate responding and establish parameters for future studies of punishment.