Relational Learning in Pigeons?

Two experiments investigated whether discrimination learning and transposition by pigeons were facilitated by the opportunity to compare rectangles differing in luminance or stars differing in number of vertices. In Experiment 1, one group was trained with stimuli from the same dimension appearing simultaneously on each trial, but for a second group such stimuli appeared on separate trials. The opportunity to compare stimuli from the same dimension on a single trial facilitated the learning of the luminance discrimination but not of the stars discrimination. Such comparison also resulted in greater luminance but not greater stars transposition. Using a different training procedure, Experiment 2 confirmed that the opportunity for comparison facilitated a luminance discrimination. The results for the star discrimination are entirely consistent with 'absolute' theories of discrimination learning; but the results for the luminance discrimination suggest some kind of 'relational' learning. Given the difference between the star and luminance discriminations, a low-level, sensory theory of relational learning seems most consistent with the data.     

The evolutionary basis of risky adolescent behavior: implications for science, policy, and practice

This article proposes an evolutionary model of risky behavior in adolescence and contrasts it with the prevailing developmental psychopathology model. The evolutionary model contends that understanding the evolutionary functions of adolescence is critical to explaining why adolescents engage in risky behavior and that successful intervention depends on working with, instead of against, adolescent goals and motivations. The current article articulates 5 key evolutionary insights into risky adolescent behavior: (a) The adolescent transition is an inflection point in development of social status and reproductive trajectories; (b) interventions need to address the adaptive functions of risky and aggressive behaviors like bullying; (c) risky adolescent behavior adaptively calibrates over development to match both harsh and unpredictable environmental conditions; (d) understanding evolved sex differences is critical for understanding the psychology of risky behavior; and (e) mismatches between current and past environments can dysregulate adolescent behavior, as demonstrated by age-segregated social groupings. The evolutionary model has broad implications for designing interventions for high-risk youth and suggests new directions for research that have not been forthcoming from other perspectives.     

Restoration of the orienting response to a light by a change in its predictive accuracy

In three experiments the orienting response (OR) to a light was reduced by presenting rats with a serial conditioning schedule in which the light was always followed by a tone, and the tone was intermittently paired with food. The original strength of the OR was then restored by changing the nature of the serial conditioning: the light was followed either by the tone and food, or by nothing. Experiments 1 and 2 demonstrated that this change resulted in an increase in the OR relative to control groups, which continued to receive the original training. Experiment 3 revealed a similar effect using a within-subjects design. A further finding from the first two experiments was that the recovery of the OR was accompanied by an enhancement in the conditionability of the light. Overall, the results suggest that the accuracy with which the light signals the events that immediately follow it is an important determinant of the strength of the OR it elicits.     

Ideational fluency in Parkinson's disease.

Recent research on Parkinson's disease (PD) suggests that executive functions are impaired but that visuospatial functions may be spared. This dissociation has been attributed to dysfunction in ascending dopaminergic pathways affecting the prefrontal cortex. We investigated these ideas in a sample of intellectually intact patients with idiopathic, optimally treated PD (N = 20) and in spouse controls (N = 15); the groups were divided into young (age < 60) and old subgroups, each comparable on education, vocabulary level, and Mini-Mental State scores. Six tasks were selected from a set of factor-referenced cognitive tests to measure three abilities: (1) ideational fluency (ability to generate ideas), (2) flexibility of use (ability to shift mental set), and (3) spatial orientation (ability to perceive spatial patterns). PD patients were impaired only on the ideational fluency factor (p = .01). An age-related deficit was seen on the spatial factor (p < .05) with a trend on the flexibility factor (.05 < p < .10). No interactions were significant. The findings suggest that when age and verbal intelligence are controlled, PD patients show no deficit on purely spatial tasks; in contrast, patients seem less able to generate ideas though capable of shifting from one idea to another.     

Hemodynamic characteristics of young men at risk for hypertension at rest and during laboratory stressors.

Examined hemodynamic activity--at rest, during mental arithmetic, and during hand cold pressor--in young men varying in risk for hypertension. Classification into low-risk (n = 72), moderate-risk (n = 20), and high-risk (n = 13) groups was based on resting systolic blood pressure (SBP) and parental history of essential hypertension (PH). Dependent variables were SBP, diastolic BP (DBP), heart rate, and rate-pressure product (RPP). Progressively greater hemodynamic activity was seen across risk groups at rest and during the tasks. Risk groups differed significantly in SBP, DBP, and RPP at baseline (ps less than .003) and in size of response to mental arithmetic (ps less than .05) but not to cold pressor. These relationships were either absent or weaker when using either risk factor alone to form risk groups. These findings suggest that hemodynamic reactivity to mental stress is predicted better by a combination of resting SBP and PH than by either risk factor alone and that physiological reactivity may be an important accompaniment of increased risk for hypertension.     

THE EFFICACY OF WOMEN'S RESISTANCE STRATEGIES IN RAPE SITUATIONS

The effectiveness of women's resistance strategies for reducing the severity of sexual abuse and physical injury during sexual assaults was analyzed in a variety of assault circumstances. Data were obtained from police reports and court testimonies of 274 women (96% White, 4% Black) who either were raped or avoided rape by subsequently incarcerated violent stranger rapists. Statistical analyses showed that particular resistance strategies were effective in specific situations. Women who fought back forcefully were more likely to avoid rape than women who did not fight back, regardles of whether a waepon was present. Forceful fighting resistance was related to increased physical injury when a weapon was present, but most physical injury was caused by nonlethal weapons. Women who screamed or fled when confronted with weapons experienced less severe sexual abuse. Increased physical injury was associated with pleading, crying, or reasoning indoors. Women who used drugs or alcohol experienced more severe sexual abuse and physical injury.     

Semantic, episodic, and autobiographical memory in a postmeningitic amnesic patient

This study is concerned with the semantic and episodic memory performance of a highly intelligent and intellectually unimpaired patient, K.J., who became amnesic following meningitis. Although densely amnesic he showed unimpaired performance on tests of vocabulary and verbal fluency, while both speed and accuracy on semantic category judgment and sentence verification tests are unimpaired. It is concluded that semantic memory performance may be intact despite dense amnesia. However, this does not necessarily imply separate semantic and episodic memory systems. K.J. showed an impaired capacity for registering new material in semantic memory, and apparently normal autobiographical memory for events occurring well before his illness. The simplest interpretation of our results would therefore appear to be in terms of the sparing of old and overlearned memories rather than the specific preservation of semantic memory.