Utility maximization and melioration: Internalities in individual choice

How do people go about choosing between alternatives in relatively simple settings? This study explores some of the variables that past work suggests may be relevant. Volunteer subjects worked for money in six procedures in which the probability of a payment from either of two alternatives was 1.0, but the rate of pay (i.e. the speed with which a payment was delivered or the size of the payment) interacted with the subjects recent allocation of choices, which we define as the ‘internalities’. Because of the internalities, choosing the currently more profitable alternative did not maximize total earnings. Subjects were more likely to fail to maximize when the interaction between present pay and past choices was spread over longer sequences of choices, or when the reward variable was the speed, rather than the value, of each payment. Subjects often disregarded the internalities and were instead guided by the current yields of the two alternatives, which is a frequently observed tendency, called ‘melioration’, in experiments on choices by animals. The tendency toward melioration was only partially counteracted by explicit instructions on how to maximize earnings. We discuss a theoretical framework for melioration that postulates both motivational and cognitive sources.     

Measuring the prevalence of questionable research practices with incentives for truth telling

Cases of clear scientific misconduct have received significant media attention recently, but less flagrantly questionable research practices may be more prevalent and, ultimately, more damaging to the academic enterprise. Using an anonymous elicitation format supplemented by incentives for honest reporting, we surveyed over 2,000 psychologists about their involvement in questionable research practices. The impact of truth-telling incentives on self-admissions of questionable research practices was positive, and this impact was greater for practices that respondents judged to be less defensible. Combining three different estimation methods, we found that the percentage of respondents who have engaged in questionable practices was surprisingly high. This finding suggests that some questionable practices may constitute the prevailing research norm.     

Compound invariance implies prospect theory for simple prospects

Behavioral conditions such as compound invariance for risky choice and constant decreasing relative impatience for intertemporal choice have surprising implications for the underlying decision model. They imply a multiplicative separability of outcomes and either probability or time. Hence the underlying model must be prospect theory or discounted utility on the domain of prospects with one nonzero outcome. We indicate implications for richer domains with multiple outcomes, and with both risk and time involved.     

Psychological skills and mindfulness training effects on the psychological wellbeing of undergraduate music students: An exploratory study

This study explored the efficacy of psychological skills and mindfulness training intervention on the psychological wellbeing of undergraduate music students. Participants were undergraduate music students (n = 36) from the Department of Music at a South African university, 21 of whom were elected to take the psychological skills and mindfulness training intervention. Data on their self-reported psychological wellbeing, psychological skills, mindfulness and performance anxiety levels were collected pre-and post-intervention. The analysis applied non-parametric procedures to determine changes in students’ psychological wellbeing after the seven-week intervention programme. Findings suggest improvements in psychological wellbeing, psychological skills, mindfulness and performance anxiety with training. Psychological skills and mindfulness training may have benefits to the psychological wellbeing of music students.     

Changes in Behaviour and Body Weight Following a Single or Double Social Defeat in Rats

In a series of experiments, the consequences of a single and double social conflict on various behaviours and body weight in rats were studied. Animals were subjected to social defeat by placing them into the territory of an aggressive male conspecific for one hour, either once, or twice at the same time on two consecutive days. To assess the consequences of social defeat, three experiments were performed with independent groups of rats. In the first experiment, an open field test was performed two days after the last conflict. Locomotor activity was strongly reduced after social defeat. There were no differences between the single and double defeat group. To assess the effects of social defeat on subsequent social behaviour, a second experiment was performed in which experimental animals were confronted with an unfamiliar non-aggressive rat two days after a single or double conflict. Social defeat resulted in a reduction of social contact with the unfamiliar conspecific. There was no difference between the single and double conflict group. In the third experiment, the effects of social conflict on food intake, body weight and saccharine preference were measured. Food intake was not affected after a single conflict, but in the double conflict group food intake was decreased for several days. Body weight gain was decreased after both single and double social defeat. The decrease was stronger in the double conflict group. Water intake and saccharine preference were not significantly affected. This study revealed that social defeat in rats causes pronounced changes in various behaviours and body weight. Different aspects of behaviour are differentially affected by defeat with respect to the magnitude and time course of the changes induced. Moreover, different behavioural parameters are differentially sensitive to repetition of the stressor.