Halos vs. stigmas: long-term effects of parent's death or divorce on college students' concepts of the family

College students from families of divorce, of death of a parent, and of intact families rated the meaning of six concepts of the family: mother, father, I myself, marriage, family, and divorce. The Semantic Differential was used to assess four dimensions of meaning of family concepts: evaluation, potency, activity, and general cultural favorability. Children of divorce rated father less favorably than did children of death of a parent or of intact families; however, children of divorce rated divorce more favorably than the remaining two groups. Also, children of divorce evaluated the family concepts that were rated here more negatively than, but equally as potent and active as, children of death of a parent and of intact families. Thus, several long-term stigmas attach to family among children of divorce, but no evidence was found of a halo effect for children of death of a parent.     

Inter-individual differences in the passive resistance of the human knee

The passive resistance of the knee to angular motion in the flexion-extension plane was investigated in groups of healthy males (n = 29) and females (n = 20). ‘Least square’ fitting procedures proved to be reliable for approximating the equilibrium angle of the knee and variables of the moment/angle diagrams. To assess the influence of the dimensions of the lower limb on the resistance of the knee, a multiple regression analysis was performed, using seven dimensional parameters of the lower limb. The results indicate that for males 35–77% (mean 58%) of the total variance is accounted for by the dimensional parameters. For females this range is 9–74% (mean 44%). Differences between males and females exist in all selected resistance variables. To decrease the influence of dimensional parameters, the slopes of the exponential curves relating moment and knee angle are expressed as percentages of the absolute moment values. When the values of these ‘relative slopes’ are used, differences between males and females become less in flexion and are absent when the knee is extended. These results indicate that male-female differences can partly be ascribed to differences in dimensions.     

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.