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.     

What Provides Justification for Cheating—Producing or Observing Counterfactuals?

When people can profit financially by lying, they do so to the extent to which they can justify their lies. One type of justification is the observation and production of desirable counterfactual information. Here, we disentangle observing and producing of desired counterfactuals and test whether the mere observation is sufficient or whether one actually needs to produce the information in order to justify lying. By employing a modified version of the Die‐Under‐Cup task, we ask participants to privately roll a die three times and to report the outcome of the first die roll (with higher values corresponding to higher payoffs). In all three conditions, participants produce (roll the die) and observe the first die roll, which is relevant for pay. We manipulate whether participants produce and observe versus only observe the second and third die roll outcomes, which are both irrelevant for pay. Results reveal that people lie to the same extent—when producing and observing the counterfactuals, and when merely observing them. It seems that merely observing counterfactual information is sufficient to allow people to use this information to justify their lies. We further test whether creativity and moral disengagement are associated with dishonesty and replicate the finding showing that unethical behavior increases with creativity. Copyright © 2017 John Wiley & Sons, Ltd.     

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.     

Serial reversal learning in bumblebees (Bombus impatiens)

Bumblebees are capable of rapidly learning discriminations, but flexibility in bumblebee learning is less well understood. We tested bumblebees (Bombus impatiens) on a serial reversal learning task. A serial reversal task requires learning of an initial discrimination between two differentially rewarded stimuli, followed by multiple reversals of the reward contingency between stimuli. A reduction in errors with repeated reversals in a serial reversal task is an indicator of behavioural flexibility. Bees were housed in a large indoor environment and tested during foraging flights. Testing free-flying bees allowed for large numbers of trials and reversals. All bees were trained to perform a simultaneous discrimination between two colours for a nectar reward, followed by nine reversals of this discrimination. Results showed that bumblebees reduced errors and improved their performance across successive reversals. A reduction in perseverative errors was the major cause of the improvement in performance. Bees showed a slight increase in error rate in their final trials, perhaps as a consequence of increasing proactive interference, but proactive interference may also have contributed to the overall improvement in performance across reversals. Bumblebees are thus capable of behavioural flexibility comparable to that of other animals and may use proactive interference as a mechanism of behavioural flexibility in varying environments.