How one gambles if one must: Effects of differing return rates on multistage betting decisions

In the multistage betting game (MBG), a decision maker (DM) is provided with some capital x which he is required to bet over m (m > 1) mutually exclusive and collectively exhaustive alternatives, each of which occurs with probability p_i (p_i > 0, i = 1,…, m; Σ_{i = 1}^mp_i = 1). If y_i is bet on alternative i (y_i ≥ 0, Σ_{i = 1}^my_i = x) and alternative i obtains, the DM's capital for the next stage is y_ir_i, (r_i > 0). The MBG lasts until either the DM loses his capital or N stages elapse, whichever comes first. Each of six subjects participated in six sessions consisting of several hundred 3-alternative MBG stages. A within-subject design assigned negative expected value (EV) bets to the first three sessions and positive EV bets to three more sessions. Significant effects were found due to return rate, capital size, homogeneous runs of either wins or losses, and individual differences. Four maximization of expected utility and two minimization of risk models were presented and tested. A modified logarithmic utility model is proposed, which provides the best fit to the data. The implications of the results and directions for further research are briefly discussed.     

Perceived Success and Competence of the Opponent,or the Laboratory Dien Bien Phu1

The effect of information relevance and information availability on perceptual differences between Chinese and American nationals was investigated. Subjects participated in pairs as decision makers in a complex experimental environment. Participants' perceptions of success, failure, and competence levels for their own team (under conditions where judgments could be based on varying levels of relevant information) and for a supposed opposing team (under conditions where perceptions had to be inferred in the absence of information) were obtained. It was found that Americans and Chinese did not differ in ratings of their own team. Chinese, as opposed to Americans, perceived the opposing team as having more success, less failure, and more competence. The perceptual errors of the French and Viet Minh which led t o the defeat of the French at Dien Bien Phu were replicated in the laboratory for Americans and Chinese. Areas in which such potential cultural (oriental versus occidental) differences might be important are mentioned.     

Optional shift behavior as a function of age and dimensional dominance

An optional reversal-nonreversal shift task for which the relevant color or form cues were either dominant or nondominant was presented to 320 Ss, 6 through 20 years of age. Dominance, as defined in terms of relative cue similarity, was related to initial learning and shift behavior for kindergarten and third-grade Ss; but not for sixth-grade and college Ss. The speed of initial learning and percentage of reversal shifts was related to age when the nondominant dimension was relevant. There were no developmental differences when the dominant dimension was relevant.     

Some stages of information processing in a choice reaction-time task

Eight pigeons were tested for head nystagmus in a rotating drum with vertical black and white bars on the reside. When the birds viewed monocularly, they gave about four times as many responses to nasalward as to temporalward movement. However, no such asymmetry was observed in a discrimination paradigm. Six pigeons were taught binocularly to discriminate moving lines, which moved equally often to left and fight, from stationary fines. They were then tested monoculaxly, and the discrimination was controlled about equally by nasalward and temporalward movement.     

Second-order isomorphism of internal representations of familiar faces

Following a suggestion by Shepard and Chipman (1970), photographs and names of 15 well-known faces were used as stimuli in judgments of similarity. Ss ranked all pairs of stimuli in terms of facial similarity either from memory when presented with pairs of names, or from photographs. There was a highly significant positive correlation between these two types of judgment. A simple classificatory analysis of the 15 faces in terms of the physical features provided evidence that judgments based on the internal representation of the faces utilized pictorial information. These results extend the generality of Shepard and Chipman’s findings and confirm the usefulness of an approach to the problem of mental images based on the concept of second-order isomorphism.     

Changes in orienting and habituation in the rat following administration of chlorpromazine

Chlorpromazine (0.5-3.0 mg/kg) significantly reduced orienting to a novel auditory stimulus, but subsequent habituation after repeated presentations of the stimulus was not prevented nor significantly impaired. These results support the suggestion that the mechanisms underlying orienting and habituation are independent.     

Shifts in deprivation level: Different effects depending on amount of preshift training

Seventy-two male albino rats were trained to perform an instrumental running response, half at high deprivation and half at low. At Trials 23, 75, and 105 a third of the animals from each of the original groups were shifted to the opposite deprivation level. All shifts from high to low deprivation produced a significant decrease in performance; all shifts from low to high, a significant increase. After the early shift, performance was characterized by a residual effect of preshift deprivation level in which shifted groups gradually approached the new levels. After each of the later shifts, performance levels diverged sharply in what appeared to be both positive and negative contrast effects. The results were discussed in the framework of incentive motivation theory.     

The effect of Person on cardiac and motor responsivity to shock in dogs

Interaction between effect of social stimulus (Person) and a faradic shock on heart rate and motor response (leg flexion) in four dogs was observed and recorded. The trials during which the shock and petting were presented simultaneously showed a significant suppression of heart rate increase to shock when compared to the shock alone trials. The lack of this suppression effect in the motor response to the shock is discussed in relation to the concept of schizokinesis. The importance of controlling prior experience of subjects is also discussed.