How specific are perceptual skills? A cross-cultural study of pattern reproduction.

Pattern reproduction tasks were presented in four different media to samples of urban Zambian and urban British schoolchildren. When the patterns were reproduced as wire models, the Zambian children excelled the British. When the patterns were reproduced by drawing, the British children excelled the Zambian. No reliable cross-cultural differences were found when the patterns were reproduced as plasticine models or as configurations of hand positions. Both cultural groups were equally adversely affected when required to perform the modelling tasks or the hand positions task blind-folded. The results are interpreted as suggesting that cross-cultural differences in performance of pattern reproduction tasks reflect different sets of highly specific perceptual skills rather than differences on broader cognitive variables such as practical intelligence, field-dependency or sensotypes.     

Can alcohol reduce tension?

The Tension Reduction Hypothesis of alcohol use is examined in the light of recent criticism. Contrary to the conclusions of Cappell and Herman (1972) it is argued that the hypothesis is supported by evidence from animal research in most cases where an appropriate paradigm has been employed.     

Roles of gonadotropins and releasing hormones in hypothalamic control of lordotic behavior in ovariectomized, estrogen-primed rats.

Intrahypothalamic effects of gonadotropins (luteinizing hormone and follicle-stimulating hormone), thyrotropin-releasing hormone (TRH), and luteinizing-hormone-releasing hormone (LRH) on lordotic behavior were evaluated in ovariectomized (OVX) rats maintained at different receptivity levels. Under conditions of low receptivity in which LRH has been shown to enchance mating behavior, medial preoptic area (MPOA) infusions of luteinizing hormone (LH) caused significant depressions in the lordotic response, whereas LH infusions into the arcuate ventromedial area (ARC-VM) had no sigificant effect. Follicle-stimulating hormone (FSH) infusions into either area did not alter the behavioral response. In the second experiment, in which OVX rats were primed with higher doses of estrone to maintain high ptrinfusion receptivity, MPOA or ARC-VM infusions of either LH or TRH were shown to depress lordotic behavior significantly, whereas neither LRH nor FSH was observed to inhibit the behavioral response. A third experiment evaluated the effects of LH, FSH, and TRH on LRH-facilitated mating behavior. Infusions of LRH into either the MPOA or the ARC-VM significantly enhanced mating behavior, whereas the addition of either TRH or LH to the LRH infusates abolished this response. The addition of FSH to LRH infusates neither enhanced nor depressed the behavioral response to MPOA or ARC-VM infusions of LRH. The antagonistic effects of LH and TRH on LRH-facilitated mating behavior were correlated with previous observations of antagonistic effects on hypothalamic unit activity and monoamine metabolism. The antagonistic interrelation between LRH and LH may represent a mechanism for the activation and coordination of sexual receptivity with ovulation.     

Thiamin deprivation in ventromedial hypothalamic hyperphagic rats: anorexia, specificity of food aversion, and a dietary consideration.

The anorexic consequence of thiamin deprivation was investigated in ventromedial hypothalamic (VMH) hyperphagic rats under either high-fat or low-fat thiamin-free diet conditions. The low-fat diet maintained feeding significantly longer in thiamin-deprived VMH rats than in intact rats, whereas the hig-fat diet sustained feeding in thiamin-deficient intact rats and accelerated anorexia onset in vitamin B1 deprived VMH rats. This effect was noted under both ad lib and pair-feeding conditions. Thiamin-deprived VMH rats subjected to weight control developed anorexia sooner than intact subjects regardless of the diet employed. The VMH rats fed a high-fat diet failed to resume feeding after thiamin readministration, which was interpreted as a permanent aversion to this diet. The relation between dietary intake and conditioned taste aversion is discussed with reference to the VMH and intact rat.     

Taste aversions to mother's milk: the age-related role of nursing in acquisition and expression of a learned association.

The development of taste aversion learning to novel cues contained in mother's milk was examined in rat pups. Pups receiving distinctive mild by experimenter-delivered oral infusions followed by toxicosis formed an aversion to the dam's diet. Robust aversions were learned as early as Day 10 and were retained for at least 11 days. When the same distinctive milk was obtained directly from a foster mother through nursing, however, only weanling-age pups (over 20 days) formed an aversion. X-ray analysis of nipple location in the mouths of suckling pups suggested that pups between the ages of 10 and 21 days receive milk at a similar tongue locus. Flavored milk was then delivered at specific time intervals in controlled quantities through tongue cannulas implanted at loci corresponding to the nipple position shown by the X-rays. Cannulated preweanling pups that were attached to a nipple during milk delivery failed to associate the taste cue with illness, whereas both preweanlings off the nipple and weanlings on the nipple acquired aversions to the taste cue in the milk. The evidence obtained in these experiments suggests that pups of all ages are incapable of expressing a taste aversion in a nursing situation and that preweanling pups in particular are also dificient in acquiring aversions within a suckling context. The inability of preweanling pups to acquire taste aversions in a nursing situation appears to result from a failure to associate taste cues with illness rather than a failure to detect taste cues obtained from a nipple.     

Approach and withdrawal analysis of the effects of hypothalamic stimulation and lesions in rats.

In a paradigm in which rats would both initiate and terminate hypothalamic stimulation, "purely" rewarding lateral hypothalamic and "purely" aversive medial hypothalamic electrodes were identified. Subjects were then given a series of tests designed to assess the effects of brain stimulation on approach and withdrawal behaviors. Lateral hypothalamic stimulation facilitated approach behavior and suppressed withdrawal behaviors, whereas medial hypothalamic stimulation produced largely the opposite effects. No serious motor deficits due to stimulation were detected with either type of electrode. In a second experiment, the approach-withdrawal effects of bilateral lateral hypothalamic lesions were tested and found to suppress approach behaviors and facilitate withdrawal behaviors. Other neurological examinations revealed motor deficits, but these deficits do not account for the specific pattern of results observed on the approach-withdrawal tests. These approach-withdrawal phenomena are interpreted in terms of altering a natural balance between approach and withdrawl behavior facilitating systems in the lateral and medial hypothalamus, respectively.     

EVALUATION OF BIOFEEDBACK IN THE TREATMENT OF BORDERLINE ESSENTIAL HYPERTENSION1

Direct biofeedback of blood pressure was compared with frontal EMG biofeedback and with self-instructed relaxation for the treatment of essential hypertension in a controlled group outcome study. Patients were followed up for four months after the end of treatment. Generalization of treatment effects was assessed through pre- and posttreatment measurements of blood pressure under clinical conditions in a physician's office. There were no significant reductions in diastolic blood pressure. The systolic blood pressure (SBP) of the patients receiving blood pressure biofeedback decreased 8.1 mm mercury (p = 0.07) and the SBP of the patients in the relaxation condition decreased 9.5 mm mercury (p = 0.05). In the generalization measures, there were significant reductions in SBP for the relaxation group. The results are discussed in terms of the general lack of replicability within the area of biofeedback treatment of hypertension.     

Developmental patterns in the encoding and combination of logical connectives

A total of 224 subjects in grades 2, 4, 6, 8, high school, and college solved problems requiring comprehension of the logical connectives and, or, if-then, only if, and if and only if, as well as the terms is and is not. Half the subjects were required merely to encode the connectives; the other half were required to combine as well as encode them. Problems were presented in two replications (over two sessions) via two different content vehicles. Quantitative analyses revealed significant effects of task, age, session, and connective, with comprehension of different connectives developing at different rates. In general, comprehension of the conjunctive connective was easiest; comprehension of the conditional and biconditional connectives was most difficult. Qualitative analyses indicated just how the logical connectives were interpreted at each grade level, and also investigated individual differences within each grade level.