Adjusting foraging strategies: a comparison of rural and urban common mynas (<Emphasis Type="Italic">Acridotheres tristis</Emphasis>)

Establishment in urbanized environments is associated with changes in physiology, behaviour, and problem-solving. We compared the speed of learning in urban and rural female common mynas, Acridotheres tristis, using a standard visual discrimination task followed by a reversal learning phase. We also examined how quickly each bird progressed through different stages of learning, including sampling and acquisition within both initial and reversal learning, and persistence following reversal. Based on their reliance on very different food resources, we expected urban mynas to learn and reversal learn more quickly but to sample new contingencies for proportionately longer before learning them. When quantified from first presentation to criterion achievement, urban mynas took more 20-trial blocks to learn the initial discrimination, as well as the reversed contingency, than rural mynas. More detailed analyses at the level of stage revealed that this was because urban mynas explored the novel cue-outcome contingencies for longer, and despite transitioning faster through subsequent acquisition, remained overall slower than rural females. Our findings draw attention to fine adjustments in learning strategies in response to urbanization and caution against interpreting the speed to learn a task as a reflection of cognitive ability.     

Comparison of social time-out and activity time-out procedures in suppressing ethanol self-administration in alcoholics

The experiments compared the potencies of three different contingent time-out procedures for suppressing drinking in alcoholics, and also compared two different experimental methodologies for conducting such studies. In a residential research ward setting fourteen volunteer chronic alcoholics were given daily access to 17 alcoholic drinks provided that a minimum of 40 min elapsed between receiving successive drinks. Each drink contained 1 oz 95-proof ethanol in orange juice. During the baseline condition subjects were free to drink with no behavioral restrictions. However during the time-out conditions, specific behavioral restrictions were imposed on the subjects for the 40-min period following receipt of each drink. The results showed that Social time-out suppressed drinking to 71 per cent of baseline conditions, while Activity time-out and the combined Social and Activity time-out suppressed intake to 36 and 24 per cent, respectively. The study also demonstrated that similar experimental results were obtained when subjects were continuously exposed to the experimental conditions for a number of consecutive days. or intermittently exposed to different conditions in a mixed order over successive days.     

About the Contributors

Biography

About the Contributors     

The ecology of eating: smaller portion sizes in France Than in the United States help explain the French paradox

Part of the "French paradox" can be explained by the fact that the French eat less than Americans. We document that French portion sizes are smaller in comparable restaurants, in the sizes of individual portions of foods (but not other items) in supermarkets, in portions specified in cookbooks, and in the prominence of "all you can eat" restaurants in dining guides. We also present data, from observations at McDonald's, that the French take longer to eat than Americans. Our results suggest that in the domain of eating, and more generally, more attention should be paid to ecological factors, even though their mechanism of operation is transparent, and hence less revealing of fundamental psychological processes. Ironically, although the French eat less than Americans, they seem to eat for a longer period of time, and hence have more food experience. The French can have their cake and eat it as well.     

Alcohol,Fear, and Woman Abuse

Although there is ample evidence that alcoholusage is associated with greater frequency, incidenceand severity of spouse battering, there is alsoconsiderable evidence which does not support a direct linkage. This research investigates aheretofore neglected area, the role of substance use ininducing fear in victims. As part of a larger study ofthe police response to battering, 419 female victims of male offenders participated in intensiveinterviews; the sample consisted of 69.9% Black and28.9% White women. All the women had been victims of atleast one occurrence of misdemeanor-level abuse, and many were in chronically abusive relationships.The women participating in this study were moderatelyeducated and relatively young, with a mean age of 30years old. Relationship status was bimodal with roughly equal numbers of married and cohabitingcouples; there were relatively few who were divorced orseparated from their assailants, or were ex-cohabitants.The male partners of women represented in this sample were extremely heavy drinkerscompared to a national sample. The quantity andfrequency of alcohol use was less predictive ofthreatening or physically battering behavior than wasmale drunkenness. Frequent drunkenness was highly correlated withboth threats and with battering. Similarly, victims'fear of their partners was much more strongly associatedwith how frequently they were drunk than with drinking itself.     

Blockade of NR2B-Containing NMDA Receptors Prevents BDNF Enhancement of Glutamatergic Transmission in Hippocampal Neurons

Application of brain-derived neurotrophic factor (BDNF) to hippocampal neurons has profound effects on glutamatergic synaptic transmission. Both pre- and postsynaptic actions have been identified that depend on the age and type of preparation. To understand the nature of this diversity, we have begun to examine the mechanisms of BDNF action in cultured dissociated embryonic hippocampal neurons. Whole-cell patch-clamp recording during iontophoretic application of glutamate revealed that BDNF doubled the amplitude of induced inward current. Coexposure to BDNF and the NMDA receptor antagonist AP-5 markedly reduced, but did not entirely prevent, the increase in current. Coexposure to BDNF and ifenprodil, an NR2B subunit antagonist, reproduced the response observed with AP-5, suggesting BDNF primarily enhanced activity of NR2B-containing NMDA receptors with a lesser effect on non-NMDA receptors. Protein kinase involvement was confirmed with the broad spectrum inhibitor staurosporine, which prevented the response to BDNF. PKCI19-31 and H-89, selective antagonists of PKC and PKA, had no effect on the response to BDNF, whereas autocamtide-2-related inhibitory peptide, an antagonist of CaM kinase II, reduced response magnitude by 60%. These results demonstrate the predominant role of a specific NMDA receptor subtype in BDNF modulation of hippocampal synaptic transmission.     

Imagery skill and preference in bilinguals

A number of studies have reported differences in the performance of bilinguals and monolinguals in verbal tasks. It has been suggested that one source of this difference is a greater tendency among bilinguals to use non-verbal ways of representing events, because of the potential for confusions between their two verbal codes. In the present study, bilingual and monolingual college students were compared on three dimensions of self-reported aspects of imagery—control, vividness and preference—as well as on a performance measure of spatial manipulation skill. When these tasks were preceded by a nominally verbal activity (prose comprehension), there were no group differences on the self-report or objective imagery measures. In contrast, when they were preceded by an imagery rating task, some evidence of a compensatory reliance on spatial codes among bilinguals was obtained. Implications of these task induction effects on both subjective and performance measures of a skill were discussed.     

Termination of psychoanalysis and September 11

In the United States, the last illusion of safety from problems in distant parts of the world was shattered on September 11, 2001. Psychoanalysts are in a unique position to both experience and examine how such a man-made social disaster becomes internalized and affects one's psychic reality by studying the effects of that day on patients already engaged in a psychoanalytic process. The author hypothesizes that in one such case, that of Mr. N, the termination phase was significantly affected. Furthermore, Mr. N's reaction to reading the analyst's clinical write-up further influenced the termination phase.