The control of fixation duration in visual search

A study is reported how fixation durations are affected as observers voluntarily use information in the visual environment to direct saccades in search of a target. In experiments with direction-coded displays, search fixation durations for correct and incorrectly directed saccades were comparable during image-driven/bottom-up search. In contrast, for knowledge-driven search, the relationship depended on peripheral preview. With ample access to peripheral preview, search fixation durations preceding correct saccades were shorter than those preceding incorrectly directed saccades. However, they were longer when preview was constrained by a gaze-contingent moving window. Fixation control was modeled as sigmoid functions.     

An age-related deficit in prefrontal cortical function associated with refreshing information

Older adults are slower than young adults to think of an item they just saw, that is, to engage or execute (or both) the simple reflective operation of refreshing just-activated information. In addition, they derive less long-term memory benefit from refreshing information. Using functional magnetic resonance imaging (fMRI), we found that relative to young adults, older adults showed reduced refresh-related activity in an area of dorsolateral prefrontal cortex (left middle frontal gyrus, Brodmann's Area 9), but not in other refresh-related areas. This provides strong evidence that a frontal component of the circuit that subserves this basic cognitive process is especially vulnerable to aging. Such a refresh deficit could contribute to poorer performance of older than young adults on a wide range of cognitive tasks.     

Mapping is not sufficient for specifying position in visual space

The general view is that one knows where an object is located in visual space on the basis of which neurons it activates. But there is reason to believe that a radically different method of specifying position is needed, one which identifies the position using coordinates. Those who study motor systems assume such coordinates, but the question of how the sensory system could derive these values is given no attention.     

Longitudinal patterns of risk for depression in dementia caregivers: objective and subjective primary stress as predictors

The present study examined how patterns of risk for depression over 1 year in 188 dementia caregivers (consistently asymptomatic, n = 88; consistently symptomatic, n = 40; changing risk, n = 60) could be predicted by objective (behavior problems of the relative) and subjective (role captivity and overload) primary stress. Results reveal that all primary stressors differentiated caregivers who remained at low levels of symptomatology over the course of 1 year from those who were at risk for experiencing a depressive disorder. In addition, caregivers' subjective experience of role captivity predicted the chronicity of risk. Findings extend prior caregiving research on patterns of depressive symptomatology by highlighting the relationship between subjective primary stressors and stability and change in caregivers' mental health.     

Temporal relationships between eye fixations and manual reactions in visual search

Observers freely searched for, and manually responded to, the presence of a target in multistimulus displays. The stimuli were presented on a cinema screen such that each display subtended a large visual angle to encourage the use of eye movements. Times taken to initially fixate the target (T1Fs) were compared to manual response times (MRTs). The results of two experiments were qualitatively similar, despite different levels of difficulty between them. MRTs were a linear function of T1Fs, but only when fixations did not occur very early after the onset of the stimulus display. When fixations were made very soon after the onset of the display, T1Fs were independent of MRTs. The findings were described within the framework of a one-way synchronization model which was modified to accommodate attention effects in visual search. Finally, the methodology provides a novel means of quantifying the contributions of eye movements to manual acknowledgements in real-world vision-guided tasks.     

Current status of psychological research in organ transplantation

Research addressing the psychological concomitants of organ transplantation is reviewed. Specifically, cognitive, behavioral, and psychosocial correlates of kidney, heart, liver, and bone marrow transplantation in both children and adults are discussed. Despite several conceptual and methodological shortcomings of the psychologically-based research in this area, results seem to indicate that organ transplantation is associated with many psychological issues at pretransplantation, posttransplantation, and follow-up periods. Implications of these general findings for the advancing roles of the health psychologist in organ transplantation are discussed.     

Study of structural analysis: comparing differential diagnoses based on psychiatric evaluation, the MMPI, and structural analysis of the Hand Test and Rorschach.

Experimental investigation of Structural Analysis compared diagnoses of 30 psychiatric inpatients derived independently from psychiatric evaluations, MMPI analyses, and Structural Analysis interpretation of Hand Test and Rorschach data. Results yielded positive preliminary implications for the use of Structural Analysis in psychodiagnostics.     

Evidence against a short-term-store account of long-term recency effects

When subjects perform a distractor task before and after every item on a list, recall of the last itemis much higher than recall of items from the middle of the list. Koppenaal and Glanzer (1990) have shown that this long-term recency effect can be eliminated by using, after the last item, a distractor task different from that used elsewhere on the list. They interpreted this finding as evidence in favor of a short-term-store account of long-term recency effects. This account is challenged by the results reported here. Practice either on the task or on time-sharing between the task and list items had little impact on the recency effect. Also, substantial recency effects were found when a different distractor task occurred after every list position. Thus, it is not true that long-term recency effects are found only when subjects have an opportunity to adapt to the distractor task. Our results are not consistent with a short-term-store account of recency effects.     

Level and form of psychopathology and the structure of group therapy

Drawing upon concepts derived from ego psychological and object relations psychoanalytic theories of individual development and from a depth group psychology, the present empirical study, a naturalistic field investigation, explored hypothesized relationships between aspects of patients' psychological boundaries and structural features of inpatient therapy groups. More specifically, patients were assessed in terms of their level (i.e., psychotic vs. borderline organization) and form (i.e., anaclitic vs. introjective) of psychopathology. Their perceptions of themselves and of their therapy groups were measured following participation in two kinds of small group treatment designed to differ in terms of degree of internal structuring. Findings, generally supporting the hypotheses, showed the anaclitic borderline patients, in particular, to be most sensitive to structural variations and most adversely affected by an impersonal and highly structured treatment climate. Theoretical and practical implications of these findings were discussed.     

EFFECTS OF CALORIC LEVEL ON RUMINATING

A series of recent studies has shown that a number of dietary variables affect ruminative behavior in institutionalized retarded persons. This experiment extends an earlier study that examined the influence of the caloric level of the diet on the frequency of ruminating. Subjects consumed regular portions of food that varied between phases from normal to high caloric levels. The data show a clear but modest inverse relation between the caloric value of the diet and the rates of postmeal ruminating.