Effects of acute simulated microgravity on nocturnal sleep, daytime vigilance, and psychomotor performance: comparison of horizontal and 6 degrees head-down bed rest

This study examined the effect of acute simulated microgravity on nocturnal sleep, daytime vigilance, and psychomotor performance. Each of 7 volunteers were maintained for 3 days of head-down and horizontal bed rest in a counter-balanced design. Assessment measures were polysomnographic recordings on the first night and performance on psychophysiological tasks on the second day involving subjective and objective vigilance, P300, simple reaction time tasks, and dual performance tasks. No clear difference in sleep structure was observed between the head-down and horizontal conditions, except for a slight decrease in Stage 4 for head-down. Both subjective and objective daytime vigilance, P300, and the simple RT task showed no statistical difference, although tracking performance on the dual task showed deterioration at 10:00 for the head-down condition. These results suggest that nocturnal sleep, daytime vigilance, and psychophysiological functions were not disturbed in head-down sleep conditions, although there was a mild deterioration of higher attentional function in the morning.     

Cast shadow can modulate the judged final position of a moving target

Observers tend to localize the final position of a suddenly vanished moving target farther along in the direction of the target motion (representational momentum). We report here that such localization errors are mediated by perceived motion rather than by retinal motion. By manipulating the cast shadow of a moving target, we induced illusory motion to a target stimulus while keeping the retinal motion constant. Participants indicated the vanishing point of the target by directing a mouse cursor. The resulting magnitude of localization errors was modulated on the basis of the induced direction of the target. Such systematic localization biases were not obtained in a control condition in which the motion paths of the ball and shadow were switched. Our results suggest that cues to object motion trajectory, such as cast shadows, are used for the localization task, supporting a view that a predictive mechanism is responsible for the production of localization errors.     

Status conferral in intergroup social dilemmas: behavioral antecedents and consequences of prestige and dominance

Bridging the literatures on social dilemmas, intergroup conflict, and social hierarchy, the authors systematically varied the intergroup context in which social dilemmas were embedded to investigate how costly contributions to public goods influence status conferral. They predicted that contribution behavior would have opposite effects on 2 forms of status-prestige and dominance-depending on its consequences for the self, in-group and out-group members. When the only way to benefit in-group members was by harming out-group members (Study 1), contributions increased prestige and decreased dominance, compared with free-riding. Adding the option of benefitting in-group members without harming out-group members (Study 2) decreased the prestige and increased the dominance of those who chose to benefit in-group members via intergroup competition. Finally, sharing resources with both in-group and out-group members decreased perceptions of both prestige and dominance, compared with sharing them with in-group members only (Study 3). Prestige and dominance differentially mediated the effects of contribution behavior on leader election, exclusion from the group, and choices of a group representative for an intergroup competition. Taken together, these findings show that the well-established relationship between contribution and status is moderated by both the intergroup context and the conceptualization of status.     

Group morality and intergroup relations: cross-cultural and experimental evidence

An observational, cross-cultural study and an experimental study assessed behaviors indicative of a moral code that condones, and even values, hostility toward outgroups. The cross-cultural study, which used data from the Standard Cross-Cultural Sample (Murdock & White, 1969), found that for preindustrial societies, as loyalty to the ingroup increased the tendency to value outgroup violence more than ingroup violence increased, as did the tendencies to engage in more external than internal warfare, and enjoy war. The experimental study found that relative to guilt-prone group members who were instructed to remain objective, guilt-prone group members who were instructed to be empathic with their ingroup were more competitive in an intergroup interaction. The findings from these studies suggest that group morality is associated with intergroup conflict.     

Do groups lie more than individuals? Honesty and deception as a function of strategic self-interest

An experiment tested whether groups lie more than individuals. Groups lied more than individuals when deception was guaranteed to maximize economic outcomes, but lied relatively less than individuals when honesty could be used strategically. These results suggest that groups are more strategic than individuals in that they will adopt whatever course of action best serves their economic interest.     

War and Peace: Possible Approaches to Reducing Intergroup Conflict

ABSTRACT— We discuss four potential ways to reduce conflict between groups: consideration of future consequences, independent leadership, outgroup empathy, and coordination. We review relevant empirical findings for each method and discuss how each can be used to promote intergroup cooperation.     

Interindividual–intergroup discontinuity in the prisoner’s dilemma game: How common fate,proximity, and similarity affect intergroup competition

In two experiments with the PDG we manipulated the Campbell (1958), or Wertheimer (1923), indices of entitativity (common fate, proximity, and similarity) to examine when a set of individuals interacts with another set of individuals in the competitive manner that is characteristic of group-on-group interactions. Experiment 1 found that interactions between two 3-person sets were more competitive when participants within each set shared (vs. did not share) common fate. In Experiment 2, the Wertheimer–Campbell indices were manipulated for one 3-person set only (targets). Participants in the other 3-person set were sequestered in separate rooms (observers). Observers as well as targets were more competitive when targets shared (vs. did not share) common fate. Path analyses in both experiments supported the idea that common fate increases competition via increased own-set entitativity and subsequent greed, and via increased other-set entitativity and subsequent fear. We found no consistent evidence for the possible roles of proximity and similarity.     

Introducing the GASP scale: a new measure of guilt and shame proneness

Although scholars agree that moral emotions are critical for deterring unethical and antisocial behavior, there is disagreement about how 2 prototypical moral emotions--guilt and shame--should be defined, differentiated, and measured. We addressed these issues by developing a new assessment--the Guilt and Shame Proneness scale (GASP)--that measures individual differences in the propensity to experience guilt and shame across a range of personal transgressions. The GASP contains 2 guilt subscales that assess negative behavior-evaluations and repair action tendencies following private transgressions and 2 shame subscales that assess negative self-evaluations (NSEs) and withdrawal action tendencies following publically exposed transgressions. Both guilt subscales were highly correlated with one another and negatively correlated with unethical decision making. Although both shame subscales were associated with relatively poor psychological functioning (e.g., neuroticism, personal distress, low self-esteem), they were only weakly correlated with one another, and their relationships with unethical decision making diverged. Whereas shame-NSE constrained unethical decision making, shame-withdraw did not. Our findings suggest that differentiating the tendency to make NSEs following publically exposed transgressions from the tendency to hide or withdraw from public view is critically important for understanding and measuring dispositional shame proneness. The GASP's ability to distinguish these 2 classes of responses represents an important advantage of the scale over existing assessments. Although further validation research is required, the present studies are promising in that they suggest the GASP has the potential to be an important measurement tool for detecting individuals susceptible to corruption and unethical behavior.     

The reversed Müller-Lyer illusion and figure-ground organization theory.

When the shaft is shortened and reaches neither of the vertices of the two pairs of wings, a reversed Müller-Lyer illusion is observed: a shaft between inward-pointing wings appears to be longer than a shaft between the outward-pointing wings. In this paper it is examined whether this illusion can be explained in terms of figure-ground organization. A circle was used as the focal area, instead of a shaft or a pair of dots, so that the figure-ground character could be seen more definitely in this focal area. The apparent size of the focal circle was measured under different conditions with three variables (enclosure, wings direction, and depth). The focal circle appeared to be largest in the condition where the circle should appear most readily as a hole, ie in the single, wings-in, space condition. The circle appeared to be smallest in the condition where the circle should appear most readily as a disc, ie in the separate, wings-out, object condition. This is consistent with an explanation of the usual, as well as the reversed, Müller-Lyer illusion in terms of figure-ground organization theory.