Reduction of intraspecies aggression in rats by positive reinforcement of incompatible behaviors

Fighting responses were elicited by response-independent shocks delivered to pairs of rats. Food pellets were presented following different non-fighting responses to shock: some pairs of rats received pellets dependent upon a specific non-fighting response to shock; others received pellets dependent upon any non-fighting response to shock; and control pairs never received pellets. The mean probability of an elicited aggressive response to shock was reduced to 0.2 by food reinforcement for a specific non-fighting response, and to 0.5 by food reinforcement for any kind of non-fighting response. These values contrasted with the 0.8 probability of elicited aggression when pairs of rats received no food reinforcement. Consistent findings were obtained when treatment conditions were changed for individual pairs of rats.     

The calibration of neutral density wedges

A method for calibrating neutral-density filters is described.     

Instructions,strategies, and pattern uncertainty in a visual discrimination task

A card-sorting task involved discrimination of patterns from the same equivalence set, patterns from different sets of the same size, and patterns from different sets of different sizes. Instructions, experimental conditions, and the number of different patterns to be sorted into two trays were varied in an attempt to change Ss’ strategies from whole-pattern processing to single-element processing. Instructions alone were ineffectual in preventing whole-pattern processing, and physical masks over most of the criterion stimuli (patterns used as guides in sorting) were only somewhat effective. Differences among tasks that were attributable to size of equivalence set were eliminated only by arranging the stimuli so that a whole-pattern strategy required a great deal more information processing, or so that such a strategy could not lead to the required discrimination. The results were interpreted as confirming the influence of the properties of sets of stimuli, as well as the strength of the tendency of human Ss to process and categorize patterns in their entirety. nt]mis|This research was supported in part by a University Research Council grant.     

Rate of response as a visual social stimulus

In Exp. 1, a high rate of responding (chain pulling) of a stimulus monkey was established as a visual positive discriminative stimulus for the operant behavior (bar pressing) of an observer monkey. The terminal performance of the observer under conditions in which a high rate of response of the stimulus monkey alternated in a variable temporal arrangement with a zero rate of response of the stimulus monkey (negative discriminative stimulus) was essentially the same as when nonbehavioral stimuli are correlated with the availability of reinforcement. By manipulating the schedule of reinforcement to change the rate of responding of the stimulus subject without changing its rate of reinforcement, Exp. 2 showed that the effective behavioral stimulus for the observer was the rate of chain pulling by the stimulus subject. A novel intermediate rate of responding by the stimulus monkey resulted in an intermediate rate (generalization) on the part of the observer during an extinction test. These experiments demonstrated that the rate of responding of one organism can function as a discriminative stimulus to control the rate of responding of another organism; and that the rate of responding is similar to other physical stimuli in terms of discrimination and generalization.     

An increment threshold law for stimuli of arbitrary statistics

We obtain a generalized increment threshold law that describes the relationship between the just detectable average signal increment and the noise when the threshold is stabilized, for the usual yes-no (nonorthogonal) signal format. The results are applicable to audition and vision, for arbitrary (discrete or continuous) signal and noise statistics, and arbitrary detection probabilities. The results are most useful when the noise and signal-plusnoise probability densities have the same form. Previous treatments of this problem have been restricted to Gaussian and Poisson signal and noise densities.     

Wundt's schema of sensory affect in the light of research on gustatory preferences

Summary According to Wundt's schema of sensory affect, increases of stimulus intensity above threshold are felt as increasingly pleasant up to a peak value beyond which pleasantness falls off through indifference to increasing unpleasantness. In psychophysical studies salty and sour taste solutions follow such a biphasic curve. Bitterness is mostly increasingly unpleasant, sweetness is mostly increasingly pleasant to a maximum with little fall off with stimulus intensity. Individual differences among adult subjects reveal some — e.g., sugar dislikers — bitter likers who depart from, or attenuate, these general trends. Studies of one- to three-day-old human neonates show rejection and negative affect for sour and bitter, but only acceptance and pleasant affect for sugar.Taste preferences of animals, albeit with expections in some species, show mostly increasing aversion for acid and quinine, biphasic preference curves for salt and sugar. When post-ingestive effects are eliminated, animals show only increasing preference for sugar as concentration increases again, a departure from the Wundtian schema. Stimulus intensity, however, is only one factor influencing hedonic value which may be drastically changed by satiety, physiological need, and learning.Preparation supported in part by NSF Grant BNS78-16533     

有关遗传和精神分裂症的文献评论(下)

四、区分社会和遗传影响的尝试研究 1.寄养研究 Leonard Heston用不同遗传体质而生长在同样条件下的被试,设计了一个研究。他比较了47名有精神分裂症母亲的“实验”对象,和有正常母亲的50名“控制”组对象。所有97名被试,从初生就和母亲隔离。半数实验被试和半数控制组对象出生后立刻被送到4     

Water deprivation associated with operant conditioning inhibits hypertensive disease in young spontaneously hypertensive rats

The development of high blood pressure in young spontaneously hypertensive rats (SHR) is inhibited by operant conditioning motivated by chronic water deprivation. The present study showed that the inhibition of hypertension was not due to the operant conditioning,per se, but was a result of chronic water deprivation (23.5 hr schedule) imposed on the rats from five through 12 weeks of age. Blood pressures were measured directly using a carotid artery cannula and light enflurane anesthesia. The behaviorally conditioned SHR and the water-deprived SHR controls had equal blood pressures and were significantly less hypertensive than untreated or enriched environment SHR groups. The antihypertensive action of water deprivation was not detected by weekly indirect blood pressure measurements made in the awake state. Nonetheless, the chronicity of the deprivation-induced inhibition of hypertension was confirmed by a lesser degree of left ventricular hypertrophy in the deprived SHR relative to the nondeprived SHR. Our behavioral results again demonstrated hyperreactivity in the SHR relative to the Wistar Kyoto (WKY). This behavioral hyperreactivity in the SHR may explain the exaggerated increase in drinking in the deprived SHR groups when returned toad lib conditions. The data of this study and our previous work suggest that arousal differences between SHR and WKY strains are more reliably differentiated by fixed interval schedules of reinforcement than by a fixed ratio schedule. Hyperarousal may precede hypertension in the SHR, but it is undetermined whether hypertension can be found in the absence of hyperarousal in these rats.