The role of marking when reward is delayed

Two-choice spatial discrimination by rats is enhanced if a salient stimulus marker occurs immediately after every choice response and again after a delay interval (Lieberman, McIntosh & Thomas, 1979). Three experiments further explore this effect. Experiment 1 found that the second marker is unnecessary. Experiment 2 found that a marker presented before a response is as effective as one presented after. Both effects could be explained in terms of markers focusing attention on subsequent cues. Experiment 3, however, found that markers after choice enhance learning even when no discriminative cues are present following the marker. Markers thus appear to initiate both a backward search through memory and attention to subsequent events; both processes help to identify events that might be related to the unexpected marking stimulus.     

Spatial metrics of integral and separable dimensions

Two experiments were conducted to investigate the relationship between dimensional integrality and the form of the combination rule or spatial metric used in a similarity judgment task. In Experiment 1, two groups of eight subjects judged the dissimilarity of all pairwise combinations of 12 rectangles differing in height and width (integral dimensions) or 12 circles differing in size and diameter orientation (separable dimensions). The dimensional organization and spatial metric of both sets of dimensions were determined. The results showed that differences in height and width contributed independently to judgments of the overall dissimilarity of rectangles and that these dimensions were combined using a Euclidean metric. In contrast, substantial interactions between circle size and diameter orientation were found. Combinations of these dimensions also appeared to violate the triangle inequality implying that no spatial metric was appropriate. In Experiment 2, parallelogram size and tilt were similarly analyzed. Although some degree of dimensional interaction was observed, it was found that on the average these dimensions were combined using a city-block metric. In a subsequent speeded classification task, orthogonal interference was observed, which suggested that size and tilt are integral dimensions. The implications of both experiments for the supposed association between the Euclidean metric and dimensional integrality are discussed.     

Selective attention to multidimensional auditory stimuli

Event-related brain potentials (ERPs) elicited by multidimensional auditory stimuli were recorded from the scalp in a selective-attention task. Subjects listened to tone pips varying orthogonally between two levels each of pitch, location, and duration and responded to longer duration target stimuli having specific values of pitch and location. The discriminability of the pitch and location attributes was varied between groups. By examining the ERPs to tones that shared pitch and/or locational cues with the designated target, we inferred interrelationships among the processing of these attributes. In all groups, stimuli that failed to match the target tone in an easily discriminable cue elicited only transitory ERP signs of selective processing. Tones sharing the "easy" but not the "hard" cue with the target elicited ERPs that indicated more extensive processing, but not as extensive as stimuli sharing both cues. In addition, reaction times and ERP latencies to the designated targets were not influenced by variations in the discriminability of pitch and location. This pattern of results is consistent with parallel, self-terminating models and holistic models of processing and contradicts models specifying either serial or exhaustive parallel processing of these dimensions. Both the parallel, self-terminating models and the holistic models provide a generalized mechanism for hierarchical stimulus selections that achieve an economy of processing, an underlying goal of classic, multiple-stage theories of selective attention.     

Children's strategies for controlling affective responses to aversive social experience

It was hypothesized that one mechanism of self-control that children develop is the strategic capacity to select the experiences they encounter. This hypothesis led to the prediction that children would deal with certain aversive social experiences by seeking out or taking advantage of opportunities for nurturant experiences. Young children were exposed to an aversive social experience in which they received less nurturance than a peer, a positive experience in which they received more nurturance, or a neutral experience in which nurturance was equal. Subsequently, an opportunity was provided for children to control the length of time they watched a highly nurturant television program. As predicted, boys experiencing an aversive social encounter increased the length of time they exposed themselves to the nurturant television show, and their level of reduced positive affect was related to how long they watched the nurturant content, further supporting the interpretation that they did so in response to their own affective state. Girls did not adopt the strategy of self-exposure to nurturant television but did appear to engage in self-distraction during the aversive social experience. Despite the apparent use of control strategies, there was no indication that these strategies were effective for the amelioration of reduced positive affect resulting from the aversive social experience. Discussion focuses on the sex differences observed in the adoption of strategic behavior and factors contributing to the ineffectiveness of the control strategies. A general model is proposed for personal and environmental factors requisite for the selection, employment, and effectiveness of strategies to control experiences and their affective consequences.     

Hierarchical factor solution of coding and planning processes: Any new insights?

Hierarchical factor solution was used in the present paper in order to examine if two coding processes, simultaneous and successive, would load on a general 2nd level factor. It was further used to test if the coding processes and a factor representing planful behavior will not share the same general factor, revealing their relative independence as expected from a theoretical model of cognitive functions. Results supported the grouping of the coding tasks within a general factor, as well as the emergence of two general factors, one each for coding and planning. Further correlational evidence supported the relative independence of these two kinds of cognitive processes. These findings were discussed in the context of a general factor of intelligence.     

Aerobic conditioning and stress reduction: Participation or conditioning?

The efficiency of an aerobic conditioning program (jogging) is compared to cognitive therapy (stress inoculation) and a waiting list control in modifying self-reported chronic stress. The participants were community residents; 48 were females and 25 were males. Treatment sessions were conducted over a 10-week period with subjects meeting in small groups for 1$\text{1}\text{2}$ hours per week. The State/Trait Inventories, a Tension Thermometer and a submaximal bicycle ergometer test were administered pre, post and follow-up. Repeated measures, multivariate analysis of variance indicated that both treatments were effective in reducing stress compared to the waiting list control and that these changes were maintained at 3-month follow-up. Multivariate analysis indicated that participants with higher initial levels of aerobic fitness did not report less stress, while participants who obtained higher levels of fitness during the conditioning program fared no better in reducing stress than their counterparts who obtained lower levels of aerobic fitness. These findings are of interest because they suggest that the psychosocial components of the fitness program were active ingredients of treatment rathee than the effects of improved cardiovascular functioning.     

Preprogramming vs. on-line control in simple movement sequences

In the present experiment the acceleration traces produced during a repetitive arm extension/flexion movement were measured in addition to the RT required to initiate such a movement. The speed at which this task was completed as well as the number of extension/flexion segments were varied to allow for either preprogramming or on-line control. Evidence from the acceleration traces and the RT data suggested that the movements completed as quickly as possible were preprogrammed; whereas, those completed more slowly were controlled on-line. Furthermore, the topologies of the power spectral density functions from the acceleration traces of each type of movement displayed characteristics typical of these forms of control.     

Rural mental health in America

Mental health services are in short supply in rural America. This article describes both the mental health service needs in rural areas and the barriers to improving the availability, accessibility, and acceptability of rural mental health services. Federal programs in rural mental health care in the Departments of Health and Human Services, Agriculture, and Education are described, as well as selected congressional initiatives. The role of the federal Office of Rural Health Policy is emphasized, and policy recommendations for improving rural mental health care delivery are presented.     

Social relationships and vulnerability to becoming homeless among poor families.

This study compares social relationships of 677 mothers in families requesting shelter with those of 495 mothers in housed families, randomly selected from the public assistance caseload in New York City. As hypothesized, women seeking shelter had experienced higher levels of a variety of childhood and adult events indicative of disruptions in social relationships. Contrary to our hypothesis, they were more likely than were housed mothers to have had recent contact with parents, other relatives, and friends, although they felt less able to draw on these resources for help with their current housing needs. More than three fourths of families seeking shelter had already stayed with members of their social network in the past year. The data suggest that they had used up potential sources of support before turning to public shelter.     

Homelessness and dual diagnosis.

People who are dually diagnosed with severe mental illness and substance use disorders constitute 10%-20% of homeless persons. They are a heterogeneous and extremely vulnerable subgroup with complex, poorly understood needs. In this article recent research on the epidemiology, subject characteristics, and service needs of the dually diagnosed homeless population is reviewed. Also, the range of evolving approaches to providing social services, housing, and mental health and substance-abuse treatments; the relevant system issues and legal issues; and problems with current research, as well as future research directions, are discussed. The importance of the distinction between providing appropriate living environments and mental health treatments emerges throughout.