Based on social identity theory (Tajfel, 1978), it is expected that black sheep effect occurs only in cases where ingroup members are compared with outgroup individuals. In study 1, 112 female student nurses were divided into two groups, and evaluated both outgroup and ingroup individuals (outgroup-ingroup condition), or ingroup members only (ingroup-only condition). Black sheep effect was found only in the outgroup-ingroup condition. Ingroup members in the condition were evaluated more extremely than those in the ingroup-only condition, and there was no significant difference between the evaluations of outgroup individuals in the outgroup-ingroup condition and ingroup members in the ingroup-only condition. The results confirmed the ingroup-outgroup comparison prediction. In study 2, in addition to rating four individuals, desirable or undesirable and ingroup or outgroup, 86 female student nurses were asked to indicate the importance of their own social identity. Mack sheep effect was observed, with perception of ingroup homogeneity strengthening ingroup identification, thereby facilitating black sheep effect. These findings support Turners self categorization theory (1982) as an explanation of the mechanism for black sheep effect.
The purpose of this paper is to clarify whether chronic scopolamine injection of two different doses have different effects on temporal discrimination behaviors and whether a central cholinergic blockade alters memory of stimulus duration. After performances were stabilized in peak interval (PI) 20 s training with saline injection, rats were injected scopolamine hydrobromide 0.5 or 0.15mg/kg (n=9 or 10, respectively) intraperitoneally 15 min before training for 15 days. In 0.5mg/kg group, (a) values of discrimination index (DI) consistently decreased, (b) response rates during ITI increased, and (c) peak times were shortened with the scopolamine treatments. The second effect was attenuated as trainings with scopolamine were progressed. In 0.15mg/kg group, there was no notable effect. Against our expectation, we could not have any evidence that scopolamine changed the time value stored in memory. We consider these results that the sensitivity of temporal discrimination was attenuated with scopolamine. These results were discussed in relation to the central cholinergic systems, especially the prefrontal cortex.
To investigate the possible difference between first-order (luminance defined) and second-order (contrast defined) motion processing, performance of visual search was examined for both types of motion by measuring the search time. The target was a patch that was drifting in a pre-determined direction, and the distractors were other patches that were drifting in the opposite direction. We found that the search could be performed in parallel for first-order motion, as expected from earlier studies, but not for second-order motion. For second-order motion, the search time increased as the number of distractors increased, with slopes of more than 400ms per item. These results indicate distinct processing schemes for first- and second-order motion. First-order motion should be processed through low-level filtering mechanisms that are spread over the visual field for parallel operation, as discussed in earlier studies. On the other hand, the present results suggest that the spatial distribution, detection scheme, or the later grouping operation is different for second-order motion, so that the search requires focal attention.
Effects of stereotypic beliefs were examined in a group problem solving context, featuring full-fledged, face-to-face interaction. Based on formal analysis of group aggregation processes, it was hypothesized that positive and negative impacts of stereotypic beliefs on task performance in problem solving were larger on the group level than on the individual level. In the present study, data from five-person groups working on a series of problem-solving tasks were used to test the hypothesis. Results indicated that stereotypic beliefs indeed exerted “emergent influence” as hypothesized on task performance in the group problem solving. The finding illustrates the importance of socially-shared aspects of stereotypic beliefs, providing a case for the need for “truly social” social-cognition research.
In Experiment 1, eight pigeons were trained to discriminate between two positive and negative human faces in a go/no-go discrimination procedure. Complete transfer was shown to the morphed images composed of the positive faces and of the negative faces, regardless of morphed proportions. Responding to the faces composed of one positive and one negative face increased as a function of proportion of the positive face. In Experiment 2, four pigeons were trained to discriminate two sets of morphed images created from pairs of four original faces designated as A, B, C, and D in each set. The morphed images composed of 50% of each of the paired original faces; AB, AC, AD, BC, BD, and CD in a set. The birds were then tested with the stimuli including the 50% morphed images used for training, the original faces, and the prototypes created by averaging all the four original faces in each of the two sets. The most pronounced discrimination, even slightly better than to the stimuli used for training, occurred to the prototypes: a finding supporting the abstraction of the central tendency as a prototype.
This study deals with the disappearance of the half-occluded region that is the monocular region made by occlusion. The disappearance of the half-occluded region was suggested by the data shown in Shimojo and Nakayama's (1990) Experiment 1. In this article, to investigate the disappearance of the half-occluded region, three experiments were conducted. Following effects were found: (a) depth in stereopsis was seen while the half-occluded region was disappearing, (b) the disappearance of the half-occluded region was due to interocular suppression, i.e., binocular rivalry. Finally, the author discussed what mechanism sets off binocular rivalry and how binocular rivalry is escaped in the half-occluded region.
Renewal of conditioned fear by changing contexts after extinction was explored in an experiment with rats' lick suppression preparation. After repeated pairing of a tone with an electric shock in one chamber (Context A), conditioned fear to the tone was extinguished in the other chamber (Context B) on the water licking baseline. Return to the original chamber renewed the conditioned fear (ABA renewal effect). It was also found that shifting to Context B after both conditioning and extinction in Context A resulted in a brief recovery of the conditioned fear (AAB renewal effect). Implications for relapse of phobia after behavioral therapeutic treatments, such as flooding and systematic desensitization, were discussed.
When faced with the unknown or ambiguous, human beings tend to unconsciously consult others for guidance; they took to facial expressions or listen to vocal tones of others. Utilization of others as information sources, social referencing has been paid a lot of attention in developmental psychology, and its origin and development have been actively investigated and discussed. Nevertheless, there appear to be few integrated or comprehensive views on the developmental meanings and processes of social referencing in infancy. This paper reviews and evaluates various theoretical and empirical studies on early social referencing, and attempts to integrate them. Specifically, we first define social referencing and describe experimental paradigms to study infant social referencing. We next discuss its developmental function of effective learning facilitation and its requisites, such as understanding affect specificity and referential quality of information. We then consider some important problems in ontogeny of social referencing, in relation to theory of mind, attachment, and so on. And finally, we point out some unanswered questions and propose a new perspective for social referencing in daily situations.