Test of a Level of Aspiration model of group decision making: Non-obvious group preference reversal due to an irrelevant alternative

We conducted two experiments that investigated a non-obvious prediction of a Level of Aspiration (LOA) model of group decision making. In both experiments, groups chose among three alternatives, A, B, and C, with C always being least preferred by all of the group members. In each experiment, by manipulating the nature of alternative C, we created two conditions differing in whether only A or only B was acceptable to all members. In support of the LOA model, groups tended to choose the alternative acceptable to all members, even when (Experiment 2) a majority of members most preferred a different alternative. Implications of the results for the LOA model are discussed in the context of social choice theory.     

Japanese children's development of false belief understanding

Two studies were conducted to examine the Japanese children's false belief understanding. Study 1, a small-scale meta-analysis that included 21 Japanese false belief studies yielding 60 data points, revealed that the Japanese children's false belief understanding develops with age (effect size = 2.48 in odds ratio for 1 year), the Japanese children's performance exceeds the chance level at the age of 64 months, and question type (think vs look-for) produced no statistically significant difference. An experiment (Study 2) employing a change-of-locations task was conducted to confirm these findings, manipulating question type as a within-participant factor. Participants were 43 Japanese kindergartners (24 boys and 19 girls; 3 yr. 4 mo. to 6 yr. 1 mo.). The results showed that Japanese children's false belief performance developed with age. Their performance level exceeded the chance level at the age of 5 years, and question type did not affect their performance.     

Attending inside or outside: A Japanese–US comparison of spontaneous memory of group information

A recent review of empirical evidence disconfirmed the widely‐held view that North Americans are less collectivistic than East Asians. However, previous research has proposed that the motivations underlying group behaviours differ across cultures: North Americans are more strongly motivated to acquire and maintain higher in‐group status relative to outgroups, whereas East Asians tend to emphasize maintenance of reciprocal relationships within in‐groups. We tested this hypothesis by examining the pattern of attentional allocation in group situations using a memory task. As predicted, compared to Japanese, memory performance among Americans was biased towards intergroup status difference over intragroup relationship information.     

Contrast Effects and Approval Voting: An Illustration of a Systematic Violation of the Independence of Irrelevant Alternatives Condition

In approval voting, voters indicate all alternatives acceptable to them, instead of indicating their most preferred alternative. This study sought to examine the hypothesis that, under certain conditions, approval voting systematically violates a rationality condition of social choice: the independence of irrelevant alternatives condition. Given a well-known psychological phenomenon, the contrast effect, it was hypothesized that sets of acceptable alternatives might be changed as a result of changes in unacceptable alternatives. This hypothesis was tested in a sample of undergraduates who were presented with fictional profiles of juvenile delinquents and then were asked whether they should be granted parole. The outcomes of approval voting changed merely as the result of a change in an alternative least preferred by all voters.     

Effects of group decision rules on decisions involving continuous alternatives: The unanimity rule and extreme decisions in mock civil juries

Two experiments examined the effects of majority and unanimity decision rules on group decisions involving continuous alternatives. Each experiment used mock civil juries to test three hypotheses related to the claim that when the distribution of group members’ initial preferences is skewed, the group’s decision will be influenced more by the presence of outlier members under unanimity rule than under majority rule. Experiment 1 tested the hypotheses using a punitive damages case and positively skewed preference distributions. Experiment 2 tested the hypotheses using a compensatory damages case and manipulating the skewness of preference distributions in a 2 (group decision rule) × 2 (valence of skewness) factorial design. In both experiments, the extreme (outlier) member’s individual preference was significantly correlated with the group decision only under unanimity rule. A simple thought experiment based on the experimental results is suggested regarding the implications of using unanimity or majority rule for making decisions in civil juries.     

Mutual liking and meta‐perception accuracy

The present study investigated the underlying mechanism yielding a positive correlation between dyad members' mutual liking and meta‐accuracy (i.e., dyad members who like each other tend to be accurate in judging how their partner sees them). Two pilot studies were first conducted to confirm the presence of the positive correlation. The main study was conducted to test several possible explanations for the observed positive correlation. In the main study, each participant took part in a series of brief interactions with an unacquainted opposite‐sex partner three times. In each interaction, participants rated their liking for the partner, evaluated their impression of the partner on 15 items, and finally inferred the partner's impression of them on the same 15 items. The meta‐accuracy was operationally defined as the correlation between the partner's impression and the participant's inference. Neither of the two types of unilateral liking (i.e., participant's liking for the partner nor the partner's liking for the participant) predicted meta‐accuracy. However, when both members found the partner likeable (i.e., mutual liking was present), the within‐dyad average meta‐accuracy tended to be high. The implications of these results for meta‐perception research are discussed on the basis of Brunswik's lens model framework. Copyright © 2008 John Wiley & Sons, Ltd.     

Connectivity perception of partly occluded gratings in 4-month-old infants

Four groups of eight 4-month-old infants were each habituated to one of four displays consisting of a grating of either low (0.4 cycle deg(-1) or high (1.2 cycles deg(-1) spatial frequency, whose central portion was covered up with a horizontal occluder which was either narrow (1.33 deg) or broad (4.17 deg). Posthabituation displays consisted of a complete grating of the same frequency as the habituated grating, along with a separate grating whose central portion was replaced with a black gap of the same height as the occluder in the habituation displays. All the infants, except those who were habituated to the high frequency with the broad occluder, looked longer at the separate grating than the complete grating display during posthabituation trials. Previously, we found that infants under 1 month of age perceive the grating continuation only when the occluder height is less than about 0.5 cycle of the grating; our present results show that this figure increases to about 1.6 cycles of the grating frequency in the case of 4-month-old infants. These findings indicate that those developmental changes depend on both the sufficiency of visual information available and the efficiency of the perceptual ability of infants for grasping spatial relationships.     

Should information be redundantly distributed among group members? Effective use of group memory in collaborative problem solving

This study examined the relation between the redundancy in task assignment and group performance. It was predicted that assigning items to group members too redundantly would undermine group problem‐solving performance. To test this prediction, dyads and triads engaged in a problem‐solving task. A logic puzzle solvable with seven clues was employed as the task. Participants were asked to memorize the clues before engaging in group problem solving. In the shared condition, all seven clues were assigned to each group member. In the unshared condition, a portion of the seven clues was assigned to each member. Unshared triads whose members were assigned the smallest number of clues were most likely to return the correct solution. This result suggests that less redundant item assignment led to successful problem solving via information pooling among group members. Copyright © 2005 John Wiley & Sons, Ltd.