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.     

Trait anxiety,stress, and learning a test of Saltz's hypothesis

Behavioral predictions from Saltz's, Spence's, and Spielberger's interpretations of trait anxiety were tested in a complex verbal learning task. Fifty-three high-anxious and 52 low-anxious male college students were randomly distributed to test conditions of failure-stress, pain-stress, or neutral instructions. The learning data revealed that high-anxious-failure and low-anxious-pain Ss were disrupted and supported Saltz's hypothesis; self-reported anxiety (A-State scale, STAI) was observed only in high-anxious-failure Ss and supported Spielberger's theory of the arousal of state anxiety as a function of trait anxiety. However, the contradiction between self-reported anxiety and learning behavior in low-anxious-pain Ss indicated that the verbal report of these Ss was an inaccurate or insensitive index of arousal.     

Potassium gymnemate and the sweet and bitter taste provoked electrically

The sweetness or bitterness of taste solutions of saccharin and quinine may be blocked, while the sweetness or bitterness evoked by electrical stimulation of the tongue by cathodal polarization is unchanged. Electrical taste stimulation apparently bypasses the most peripheral process by which taste solutions elicit sweet and bitter and thus acts directly on the receptor and/or its afferent nerve terminals.     

Bilateral apparent haptic movement

When Os are permitted to manipulate the interstimulus onset interval (ISOI) to obtain optimal apparent movement between two ipsilateral vibrotactile stimuli, a consistent quantitative relation between ISOI and stimulus duration appears. The present report describes conditions for movement between contralaterally-placed stimuli, and shows that whereas movement is qualitatively incomplete, the aforementioned relation is still evident. The results are discussed in the light of recent work in both visual apparent movement and complex patterns of stimulation on the skin.     

Induction of a principle

Two experiments are reported in which student subjects attempted to discover a principle obtaining among pairs of numbers and letters. In the first experiment, subjects were more successful when they were free to select whatever number-letter pairs they wished than if they were restricted in whole or in part to pairs specified by the experimenter. In the second experiment, subjects who did discover the principle were compared to those who did not. Successful subjects were shown to be slightly more systematic in their approach to the task, to work at a faster pace, to write down more positive instances, and to have a much stronger tendency to vary only one variable of the task at a time.

Wason (1960) reported a study in which subjects tried to discover a principle applying to instances each of which consisted of three numbers. He discovered that subjects mostly showed enumerative rather than eliminative induction, i.e. they made little use of instances that would have enabled them to eliminate wrong hypotheses. Wetherick (1962) found that by modifying Wason's procedure in certain ways, enumerative behaviour was reduced and the subject's chance of discovering the principle was increased. Elimination of hypotheses remained infrequent.

In the Wason study, the subject was free to write down, for each instance, any three numbers he wished, i.e. his choice of instances was not restricted in any way. This may account in part for the behaviour Wason observed. In the first experiment to be reported here, the subject is restricted, in various degrees, in his choice of instances, to determine whether the principle is discovered more (or less) readily under such restriction.     

Decision Theory and Vocational Counseling: Important Concepts and Questions

Ignorance of specifics of career decision-making processes has prevented development and use of more effective vocational counseling procedures. Simply giving clients vocational information and assuming rational use of it is criticized. Contemporary decision theories suggest several relevant variables. Two variables, subjective probabilities (individual's self-estimates of success) and utilities (desirabilities held for outcomes or alternatives), are discussed in relation to presenting clients with objective probability information concerning future plans. Some relevant research is reviewed and two questions are discussed: (1) How do different methods of presenting information influence subjective probabilities? (2) How are utilities influenced by objective probability data?