饥饿对认知与社会行为的影响及其机制

从心理学视角综述了饥饿对个体认知与社会行为的广泛影响。饥饿会损害一般认知功能, 潜在导致决策与认知偏差, 并引发道德判断标准降低、社会态度改变以及攻击行为增加等现象。在以往研究的基础上, 总结出饥饿影响认知与社会行为内在机制的三种假说：自我损耗说、认知激活说以及协调机制说。最后, 指出当前研究存在着饥饿主观感受差异、测量方法不够准确等问题, 未来研究需要提高饥饿的测量效度, 从生理、心理、社会等多个层面对饥饿影响的机制进行深入探讨。     

The effect of hunger on water intake in rats

Although reciprocal inhibition between eating and drinking has been postulated, the commonly observed reduction of water intake by hungry rats may not be due to any direct inhibitory mechanism. In one experiment rats deprived of food for 24 hr. and then injected with 2 ml. of NaCl drank the same as rats that had received food ad lib. In the second experiment a stomach load of 10 ml. of water 3 hr. before the salt injection was designed to abolish any water deficit that might have occurred during food deprivation had there been inhibition of drinking by hunger. Here again rats deprived of food did not drink less than undeprived animals. In fact the hungry rats drank slightly but significantly more. This phenomenon may be related to the observation confirmed here that during food deprivation rats excrete about twice as much rather dilute urine as during ad lib food intake. This seems to indicate that though in general food deprived rats drink less than normal they actually drink more than they need. Schedule induced polydipsia also occurs during food deprivation and this too makes it unlikely that water-intake is actually inhibited during hunger.     

The GABAergic effect of low doses of lorazepam on social behavior

The aim of this work was to test the antiaggressive effects of lorazepam and to determine whether these effects were mediated by benzodiazepine receptors. In a first experiment, male mice were injected with lorazepam in a range of low doses (0.05, 0.1, 0.2, and 0.6 mg/kg) or saline solution. In a second experiment, 1 mg/kg of Ro 15‐1788, a benzodiazepine receptor antagonist, and a saline solution were injected before the behavioral test. Results showed that 0.6 mg/kg of lorazepam was the only dose that decreased the total duration of threat (P < .01) and social investigation (P < .05) and that 1 mg/kg of Ro 15‐1788 had no effects. In the third experiment, animals received two injections: 0.6 mg/kg of lorazepam plus 1 mg/kg of Ro 15‐1788, 0.6 mg/kg of lorazepam plus saline solution, or saline solution plus saline solution. Those treated with lorazepam and saline solution spent less time digging (P < .001), threatening (P < .001), and attacking (P < .05) and more time avoiding the opponent (P < .01) or being immobile (P < .001) than the controls. Ro 15‐1788 was successful in completely antagonizing the behavior modulated by lorazepam. Aggr. Behav. 28:248–256, 2002. © 2002 Wiley‐Liss, Inc.     

The effect of insulin-induced hypoglycemia on NaCl hunger in the adrenalectomized rat

Rats that have developed a polydipsia for a saccharinglucose solution (S-G) are less likely after ADX to drink quantities of NaCl which are necessary for adequate body maintenance. Their appetite for the S-G interferes with the more regulatory NaCl appetite. It was hypothesized, then, that a need-related, S-G polydipsia established via insulin administration prior to ADX would result in an even greater dysfunction after ADX when S-G and NaCl were available as drinking fluids. And,a fortiori, rats with simultaneous adrenal insufficiency (via ADX) and an insulin-induced hypoglycemia would be so maximally responsive to S-G that they would be maximally resistant to NaCl regulation. Anda fortiori, rats with simultaneous adrenal insufficiency (via ADX) and an insulin-induced hypoglycemia would show maximum inertia to reverse a preoperatively-established S-G preference to a NaCl preference. The results were mixed. Preference for NaCl was equal in all ADX animals regardless of experimental condition. However, while ADX rats with a previous need-related S-G polydipsia sustain considerably long periods of weight loss (indicating poor adaptation), the insulin-injected, ADX rats manifest markedly more adaptive weight gains. The results are discussed in light of hierarchies and cross-linkages in behavioral and physiochemical homeostasis.     

Directional scanning effect and strength of reading habit in picture naming and recall

The present research examined directional scanning effects (DSE) as a function of reading habit strength among right handers. A picture array naming and recall task was administered to three groups of child readers--unidirectional right-to-left readers of Arabic, unidirectional left-to-right readers of Kannada, and bidirectional readers of Urdu and English--and one group of Urdu illiterate adults. The results showed a right-to-left DSE in the Arabic and Urdu readers. In the latter group the strength of the scanning effect decreased with greater schooling in English. No R-L effect was observed in the Kannada readers or in the Urdu illiterates. These results extend prior research in documenting an "invasion" of culturally acquired reading scan habits onto a nonlinguistic domain. It is suggested that directional scanning effects be controlled or else directly examined in future laterality research involving nonlinguistic stimuli.     

Transfer from discrimination under hunger to discrimination under thirst: The role of expectancy and habit

The experimental group (Group HA-TA) received food (F) and water (W) rewarded trials in an alternating sequence under hunger in Phase 1 and under thirst in Phase 2. Group HA-TA ran faster on F than on W trials in Phase 1, and faster on W than on F trials in Phase 2. Early in Phase 2 the difference between speeds on W and F trials was larger for Group HA-TA than for a group which received no runway training in Phase 1 (Group HO-TA), but later in Phase 2 this difference was larger for Group HO-TA than for Group HA-TA. Also in Phase 2 the difference between speeds on W and F trials was larger for Group HA-TA than for a group which received a random sequence of F and W trials under hunger in Phase 1, and smaller for Group HA-TA than for a group which received alternating F and W trials under thirst in both phases. To interpret these results it was assumed that for Group HA-TA the expectancies of reward formed in Phase 1 facilitated development of alternation performance in Phase 2, but that the S-R associative connections formed in Phase 1 inhibited ultimate development of alternation performance in Phase 2.