Colony aggression in laboratory rats: A review and some recommendations

The behavioral response of established colonies of domesticated rats to the presence of an unfamiliar intruder of the same species represents one of the most effective procedures yet developed to study aggression in the laboratory. Here, the social, experiential, and environmental variables that influence attack severity are reviewed and several important methodological issues are discussed. Brief exposures of intruders to intact colonies may produce misleading results but long-term test sessions increase the likelihood that intruders will be either killed or severely injured. We describe a simple modification of the colony-intruder procedure whereby intruders can successfully defend themselves during long sessions and thus reduce serious injury. The modified procedure appears to conform more closely to what happens during aggressive encounters in free-living populations of wild rats.     

Play fighting and the development of agonistic behavior in male and female rats

Two longitudinal studies were conducted to quantify the social behaviors exhibited by both male and female Long-Evans rats from the immediate postweaning period until young adulthood. In Experiment 1, male sibling pairs engaged in a high level of play fighting during the early juvenile period but such activity declined to a level significantly lower than that of female and mixed-sex pairs after 54 days of age. In Experiment 2, social exchanges during maturation were examined during the presence and absence of the piloerection response in an effort to distinguish play fighting from agonistic interactions. In male pairs, piloerection was rarely seen before 55–75 days of age but thereafter occurred with increasing frequency especially among dominant males. Furthermore, subordinate males retreated from their dominant partners and remained in an escape chamber for a significant amount of time only during encounters involving the exhibition of piloerection. This finding suggests that piloerection can be useful in identifying play and aggressive interactions. In female and heterosexual pairs, piloerection was observed infrequently during social encounters occurring throughout maturation. In addition, when given the opportunity to escape, females were less likely to retreat from play activity if their partner was another female than a male.     

A normative set of 98 pairs of nonsensical pictures (droodles)

Our purpose in the present study is to provide a normative set of nonsensical pictures known as droodles and to demonstrate the role of semantic comprehension in facilitating recall of pictorial stimuli. The set consists of 98 pairs of droodles. Experiment 1 standardized these pictorial stimuli with respect to several variables, such as appropriateness of verbal labels, relationship between two droodles, and correct recall. Appropriateness of verbal labels was rated higher for pictures presented in pairs than for pictures presented singly. Experiment 2 used the standardized set of droodles in a recall experiment similar to those of Bower, Karlin, and Dueck (1975) and others. As we expected, semantic interpretation can strongly facilitate recall. Multiple regression analysis showed that several measures had significant power of explanation for recall performance. The full set of norms and pictures from this article may be downloaded from http://brm.psychonomic-journals.org/content/supplemental.     

Remembering Public,Political Events: A Cross‐Cultural and ‐Sectional Examination of Australian and Japanese Public Memories

We examined and compared the initiating conditions of flashbulb memory (FBM) confidence and event memory accuracy across two different, yet similar public, political events occurring in two different countries: Australia and Japan. To do so, we seized upon the occurrence of two politically important events: the resignation of the Japanese and Australian Prime Ministers in June 2010. In a series of mean and correlation analyses, we concluded that different factors may determine event memory accuracy and FBM confidence across cultures. In particular, the way different cultures emotionally appraise and rehearse the event, their attitude toward the political parties/their political involvement and self‐construal may have important implications for how individuals accurately remember the event and the confidence they hold for their memories of the context when learning of the event. We discuss avenues of future research to better understand the extent to which cultural differences drove these results. Copyright © 2015 John Wiley & Sons, Ltd.     

Lesson Plans and the Contingency of Classroom Interactions

In their examination of elementary science classrooms, Amerine and Bilmes (1988) found that following instructions requires students to understand the relationship between the projected outcome and the corresponding course of actions. One of the most important resources for instructions is the lesson plan, which prescribes the sequence of teaching. However, there is often a gap between what is planned and what actually happens in the classroom. This raises the question of how teachers come to terms with contingent variants and unexpected outcomes that real-time interactions occasion and how lesson plans are configured into these processes. This study examines a teacher education program that uses lesson plans as a central resource for teaching mathematics. The results suggest that classroom teachers use lesson plans as communicative resources to identify problems, specify assumptions about their teaching and act on the evolving contingency of classroom interaction. The interactional contingency is the locus of teaching practices, not an obstacle to the application of procedures in lesson plans.     

Unbalanced triangle in the social dilemma of trust: Internet studies of real‐time,real money social exchange between China,Japan, and Taiwan

Using a dyadic game theory paradigm, three experiments on the social dilemma of trust were conducted over the Internet in real time, involving real money. It was predicted and found that in‐group favouritism in trusting behaviour was contingent on historical relationships between societies. In the China–Japan experiment, mainland Chinese but not Japanese trusted and made fair allocations to in‐group members more than out‐group members, and out‐group trust was best predicted by positive stereotypes of the out‐group for Chinese and identity for Japanese. In the China–Taiwan experiment, Taiwanese but not Mainland Chinese trusted in‐group members more than out‐group members, and in‐group trust for Taiwanese was best predicted by perceptions of current realistic threats. In the Taiwan–Japan experiment, there were slight in‐group favouring tendencies in trust, and positive stereotypes of the out‐group were the best predictors of out‐group trust. Japanese were unique in not displaying in‐group favouring behaviour at all, whereas both Chinese and Taiwanese were context specific in their in‐group favouritism. Stereotypes, social identities, perceptions of realistic threat, and historical anger made significant contributions to predicting trusting behaviour, but overall these survey measures only accounted for small and inconsistent amounts of variance across the three experiments.     

Conscientiousness mediates the relation between perceived parental socialisation and self-rated health

The pathways between parenting behaviours, personality and physical health have all been separately studied. Prior research has paid little attention to the indirect effects of personality in the path between parenting behaviours and better health. The purpose of this study was to explore the mediational effects of conscientiousness on the relationships between parental socialisation of responsibility and self-rated health, and to examine potential age differences in this mediational pathway. In total, 736 female and 749 male members across Japan participated in this study. They were divided into three groups by age category: younger-, middle-aged and older-aged. Conscientiousness and health were concurrently rated, while parental socialisation of responsibility was retrospectively assessed. Our analyses revealed that parental socialisation of responsibility is positively associated with conscientiousness and self-rated health, that conscientiousness is positively associated with self-rated health, and that conscientiousness fully mediated the effect of parental socialisation of responsibility on self-rated health. The mediational links were consistent across younger, middle-aged and older-aged cohorts. Our findings suggest that greater parental socialisation of responsibility relates to higher conscientiousness, and consequently healthier adults. These findings imply that parental behaviours could be a plausible target for intervention to foster the development of conscientiousness and better health.     

Short-term memory for event duration: Modality specificity and goal dependency

Time perception is involved in various cognitive functions. This study investigated the characteristics of short-term memory for event duration by examining how the length of the retention period affects inter- and intramodal duration judgment. On each trial, a sample stimulus was followed by a comparison stimulus, after a variable delay period (0.5?C5?s). The sample and comparison stimuli were presented in the visual or auditory modality. The participants determined whether the comparison stimulus was longer or shorter than the sample stimulus. The distortion pattern of subjective duration during the delay period depended on the sensory modality of the comparison stimulus but was not affected by that of the sample stimulus. When the comparison stimulus was visually presented, the retained duration of the sample stimulus was shortened as the delay period increased. Contrarily, when the comparison stimulus was presented in the auditory modality, the delay period had little to no effect on the retained duration. Furthermore, whenever the participants did not know the sensory modality of the comparison stimulus beforehand, the effect of the delay period disappeared. These results suggest that the memory process for event duration is specific to sensory modality and that its performance is determined depending on the sensory modality in which the retained duration will be used subsequently.     

Retrieval-induced forgetting in rats

“Retrieval-induced forgetting” in rats was evaluated using a modified spontaneous object recognition test. The test consisted of a sample phase, retrieval or interference phase, and a test phase with 60-min delay period inserted between the phases. Rats were randomly assigned to one of three groups (control, retrieval and interference) and allowed to explore the field in which two different objects (A, B) were placed in the sample phase. In the retrieval phase, two identical objects (B, B), which were the same as one of the objects presented in the sample phase, were placed again. In the interference phase, two identical objects (C, C), which were novel for animals, were placed. In the test phase, two different objects (A, D), one of which was identical to that presented in sample phase (familiar object) and the other was novel, were placed and the time spent exploring each object was analyzed. While the exploration of the novel object was significantly longer than that of the familiar object in rats subjected to the interference phase, rats subjected to the retrieval phase could not discriminate between the familiar and the novel objects at the test phase. These results demonstrate the “retrieval-induced forgetting” phenomenon in a spontaneous object recognition test in rats.     

Influence of gender membership on sequential decisions of face attractiveness

Responses in a current trial are biased by the stimulus and response in the preceding trial. In a mixed-category sequence, the sequential dependency is weaker when the stimuli of the current and preceding trials fall under different categories. In the present study, we investigated the influence of the gender membership of faces on the sequential dependency. Forty-eight pictures of male and female faces were presented successively. Participants rated the attractiveness, roundness, or intelligence of each face on a 7-point scale. The sequential effect was robustly observed, irrespective of the property to be judged. However, between-gender sequential dependency was weaker than within-gender dependency only in the attractiveness judgment. These findings suggest that the gender of faces serves as a cue for forming category representations when face attractiveness is of interest, and hence that the formation of categories in sequential decisions is an adaptive process that depends on the property to be judged.