Stress and Immunity: Age Enhances the Risks

A competent immune response is central to good health. There is good evidence that both aging and psychological stress can dysregulate immune function, resulting in changes in various aspects of the immune response that are large enough to have consequences for health. Older adults appear to show even greater immunological impairments associated with stress or depression than younger adults. Thus, the data suggest that aging interacts with stress and depression to enhance risks for morbidity and mortality among older adults.     

A Dissociation between Symbolic Number Knowledge and Analogue Magnitude Information

Semantic understanding of numbers and related concepts can be dissociated from rote knowledge of arithmetic facts. However, distinctions among different kinds of semantic representations related to numbers have not been fully explored. Working with numbers and arithmetic requires representing semantic information that is both analogue (e.g., the approximate magnitude of a number) and symbolic (e.g., what / means). In this article, the authors describe a patient (MC) who exhibits a dissociation between tasks that require symbolic number knowledge (e.g., knowledge of arithmetic symbols including numbers, knowledge of concepts related to numbers such as rounding) and tasks that require an analogue magnitude representation (e.g., comparing size or frequency). MC is impaired on a variety of tasks that require symbolic number knowledge, but her ability to represent and process analogue magnitude information is intact. Her deficit in symbolic number knowledge extends to a variety of concepts related to numbers (e.g., decimal points, Roman numerals, what a quartet is) but not to any other semantic categories that we have tested. These findings suggest that symbolic number knowledge is a functionally independent component of the number processing system, that it is category specific, and that it is anatomically and functionally distinct from magnitude representations.     

Time pressure and group performance: Exploring underlying processes in the Attentional Focus Model

The Attentional Focus Model (Karau & Kelly, 1992) predicts that time pressure should lead group members to focus on a restricted range of task-relevant cues and to adopt task completion as their major interaction objective. Although this prediction has been supported in several studies (e.g., Karau & Kelly, 1992; Kelly, Jackson, & Hutson-Comeaux, 1997; Kelly & Karau, 1999; Parks & Cowlin, 1995), the exact processes that underlie information restriction have not been specified. We propose that two processes are involved. Specifically, the restriction of information may occur because time pressure affects the way in which information is initially encoded or attended to before a group enters its decision-making phase, or because group members filter out what they judge to be less important information during group discussion and decision making. We assessed both of these processes within a decision-making experiment where time pressure was manipulated prior to learning information that would be used to perform a task. Recall of information learned prior to group discussion did not differ by time pressure condition, arguing against an encoding process. In contrast, interaction data demonstrated information restriction by group members, arguing for a filtering process. Thought listings collected 1 min into the group discussion in some groups also supported a filtering process, as did questionnaire data. Implications of these findings for the Attentional Focus Model and for effective group decision making are discussed.     

Behavior of depressed subjects in problem solving groups

This study investigated leadership selection in groups in relation to level of depression of group members. On the basis of MMPI-D and DACL scores 66 subjects were organized into groups of six to eight people consisting of all depressed, all nondepressed, or half depressed and half nondepressed subjects. Subjects performed a problem solving task alone and in groups and completed a questionnaire on leadership choice and group performance. Results indicate that nondepressed group members talked more frequently, were rated as more important contributors, and were selected as leaders more frequently than depressed members. In addition, mixed groups were perceived as more efficient and enjoyable by group members than the unmixed groups. There were no significant differences between depressed and nondepressed subjects on performance of the problem solving task whether working alone or in groups. Results were discussed in relation to other literature on the interpersonal behavior of depressed persons.     

The role of attention in the shift from orientation-dependent to orientation-invariant identification of disoriented objects

In two experiments, the naming of rotated line drawings of natural objects was examined after a training phase in which the objects were either attended or ignored. In the training phase of Experiment 1, subjects were presented with objects in a number of orientations over five repeated blocks of trials. In the center of each object, seven letters (Xs and Ts, colored red or blue) were presented in rapid succession. Half the subjects named aloud the rotated object and ignored the changing letter display (object-attend). The other half ignored the object and counted the number of red Ts, and then used this number to perform a simple multiplication (object-ignore). In the test phase, all subjects named the rotated objects. The results showed that in the first block of trials in the training phase, mean naming time in the object-attend condition increased the further an object was rotated from the upright. This effect of orientation for attended objects was much reduced in the later presentations of the test phase. In contrast, there was no such benefit of prior presentation observed for the naming of objects that had previously been ignored. Instead, a substantial orientation effect was shown for the naming of previously ignored objects, which was similar to the orientation effect observed for attended objects named in the first block. Similar results were found in Experiment 2, in which object-attend subjects in training covertly named the objects and then performed a letter count and multiplication task. In both experiments, performance on the letter count and multiplication task varied with the angle of the ignored object. The results suggest that full attentional resources must be allocated in order for orientation-invariant representations to be formed and used in the identification of rotated objects.     

Negative priming by rotated objects

Previous work has found that repeated exposure to ignored rotated objects is insufficient to allow the formation of orientation-invariant representations (Murray, 1995b). In this study, the negative priming paradigm was used to examine whether the identity of ignored rotated objects was encoded. Subjects were briefly presented with a prime followed by a probe display. One of the two overlapping drawings of objects in each display was selected for further processing, and the other was ignored. In one condition, the ignored objects were upright; in another, they were rotated 240°; and in a final condition, subjects repeatedly named the 240° objects prior to experiencing them as ignored objects in the priming task. Naming latency for the attended probe was slower when it was semantically related to the ignored prime in all conditions. The results suggest that unattended rotated objects are processed to a level of representation that is at least categorical.     

Adult language use and infant comprehension of English: Associations with encoding and generalization across cues at 20 months

Adult-provided language shapes event memory in children who are preverbal and in those who are able to discuss the past using language. The research conducted to date, however, has not yet established whether infant language comprehension abilities moderate the extent to which preverbal infants benefit from adult-provided supportive language. The present study was conducted to address this question by examining immediate imitation and 1-week delayed generalization across cues in 20-month-old infants as a function of (a) variability in adult-provided linguistic support at encoding and test, (b) infant language comprehension abilities, and (c) their interaction. The provision of supportive adult language at encoding and test was associated with delayed generalization across cues although supportive adult language at encoding did not influence performance at immediate imitation. Infant language comprehension abilities were associated with performance at immediate imitation and delayed generalization across cues. In addition, infant language comprehension abilities moderated the extent to which infants benefited from adult-provided supportive language at encoding and test. The findings contribute to the literature by demonstrating that adult language use and infant language comprehension are independently and differentially associated with immediate imitation and 1-week delayed generalization across cues but also serve to jointly structure event memory in the second year of life.