The effects of binge MDMA on acquisition and reversal learning in a radial-arm maze task

The current study used the partially-baited radial-arm maze paradigm to study the effects of a single-treatment high-dose exposure ('binge') to MDMA (± 3,4-methylenedioxymethaphemtamine or 'Ecstasy') on memory task acquisition. Sprague-Dawley rats were administered a binge dose (4 × 10 mg/kg) of MDMA and their ability to subsequently acquire the radial-arm maze task was compared against saline controls. The MDMA-treated rats were significantly slower to learn the task and made more reference memory errors than the controls. Working memory function was found to be relatively unimpaired. Following a reversal of task rules the MDMA-treated rats were again significantly slower to acquire the appropriate rule despite having eventually achieved a similar level of overall performance as control rats. However evidence of drug tolerance was found when all rats were challenged with an acute low dose of MDMA (1 × 4.0 mg/kg) because the binge MDMA rats were relatively less impaired. Therefore, although binge treated MDMA rats were able to achieve very accurate performance equivalent to the controls they took significantly longer to do this and were less able to adapt their behavior to a change in task rules. In addition the binge treated MDMA rats displayed tolerance to acute MDMA exposure. These findings are consistent with the possibility that human Ecstasy users may show deficits in acquiring information and may experience deficits in cognitive flexibility as well as developing tolerance to the drug with repeated exposure.     

Investigating joint attention mechanisms through spoken human-robot interaction

Referential gaze during situated language production and comprehension is tightly coupled with the unfolding speech stream ( [Griffin, 2001] , [Meyer et al., 1998] and [Tanenhaus et al., 1995] ). In a shared environment, utterance comprehension may further be facilitated when the listener can exploit the speaker’s focus of (visual) attention to anticipate, ground, and disambiguate spoken references. To investigate the dynamics of such gaze-following and its influence on utterance comprehension in a controlled manner, we use a human–robot interaction setting. Specifically, we hypothesize that referential gaze is interpreted as a cue to the speaker’s referential intentions which facilitates or disrupts reference resolution. Moreover, the use of a dynamic and yet extremely controlled gaze cue enables us to shed light on the simultaneous and incremental integration of the unfolding speech and gaze movement.We report evidence from two eye-tracking experiments in which participants saw videos of a robot looking at and describing objects in a scene. The results reveal a quantified benefit-disruption spectrum of gaze on utterance comprehension and, further, show that gaze is used, even during the initial movement phase, to restrict the spatial domain of potential referents. These findings more broadly suggest that people treat artificial agents similar to human agents and, thus, validate such a setting for further explorations of joint attention mechanisms.     

A cross-cultural study of reference point adaptation: Evidence from China,Korea, and the US

We examined reference point adaptation following gains or losses in security trading using participants from China, Korea, and the US. In both questionnaire studies and trading experiments with real money incentives, reference point adaptation was larger for Asians than for Americans. Subjects in all countries adapted their reference points more after a gain than after an equal-sized loss. When we introduced a forced sale intervention that is designed to close the mental account for a prior outcome, Americans showed greater adaptation toward the new price than their Asian counterparts. We offer possible explanations both for the cross-cultural similarities and the cross-cultural differences.     

Personality and prejudice: Extension to the HEXACO personality model

We modelled the associations between the HEXACO dimensions of personality, Social Dominance Orientation (SDO), Right‐Wing Authoritarianism (RWA) and prejudice towards dangerous, derogated and dissident groups (N = 454 undergraduates). Consistent with a Big‐Five model, low Openness to Experience predicted RWA and therefore dangerous and dissident group prejudice. As predicted, low Emotionality (and Openness) rather than Agreeableness predicted SDO and therefore derogated and dissident group prejudice. Comparison with meta‐analytic averages of Big‐Five data supported expected similarities and differences in the association of Big‐Five and HEXACO models of personality with ideology. Finally, Honesty‐Humility simultaneously predicted increases in RWA but decreases in SDO, and thus opposing effects on prejudice. These opposing effects have gone unidentified in research employing Big‐Five models of personality structure. Copyright © 2010 John Wiley & Sons, Ltd.     

Essentialist theory of ‘hybrids’: From animal kinds to ethnic categories and race

This article presents a theory of the perception of hybrids, resulting from cross‐breeding natural animals that pertain to different species and of children parented by couples with a mixed ethnic or racial background. The theory states that natural living beings, including humans, are perceived as possessing a deeply ingrained characteristic that is called ‘essence’ or ‘blood’ or ‘genes’ in everyday discourse and that uniquely determines their category membership. If, by whatever means, the genes or essences of two animals of different species are combined in a hybrid, the two incompatible essences collapse, leaving the hybrid in a state of non‐identity and non‐belonging. People despise this state and reject the hybrid (Study 1). This devaluation effect holds with cross‐kind hybrids and with hybrids that arise from genetically combining animals from incompatible habitats across three cultures: Austria, India and Japan (Study 2). In the social world, groups and ethnic or racial categories frequently are essentialized in an analogue way. When people with an essentialist mindset judge ethnically or racially mixed offspring, they perceive a collapse of ethnic or racial essence and, consequently, denigrate these children, as compared to children from ‘pure’ in‐group or out‐group parents (Study 3). The findings are discussed in terms of the widespread ‘yuck factor’ against genetically modified animals, in terms of the cultural concepts of monstrosity and of racism and prejudice.     

Self-presentation and gender on MySpace

Within the cultural context of MySpace, this study explores the ways emerging adults experience social networking. Through focus group methodology, the role of virtual peer interaction in the development of personal, social, and gender identities was investigated. Findings suggest that college students utilize MySpace for identity exploration, engaging in social comparison and expressing idealized aspects of the selves they wish to become. The public nature of self and relationship displays introduce feedback mechanisms by which emerging adults can legitimize images as associated with the self. Also, male–female differences in self-presentation parallel, and possibly intensify, gender norms offline. Our study suggests that social networking sites provide valuable opportunities for emerging adults to realize possible selves; however, increased pressure for female sexual objectification and intensified social comparison may also negatively impact identity development. A balanced view, presenting both opportunities and drawbacks, should be encouraged in policies regarding youth participation in social networking sites.     

Measuring individualism and collectivism: The importance of considering differential components,reference groups,and measurement invariance

A new instrument of individualism and collectivism (I/C) was developed and three key issues in I/C measurement were addressed: differentiating components of I/C, understanding the impact of reference groups, and testing of measurement invariance. Three components of I/C were assessed in China and the U.S.: independence, competitiveness, and uniqueness for individualism; considering of one’s decisions on others, sharing of positive outcomes, and sharing of negative outcomes for collectivism. Collectivism was measured with respect to parents, friends, and general others. Results indicate that Chinese participants are less unique but more independent and competitive than their counterparts in the U.S. The expected cultural difference is found for parent collectivism across all three components and for sharing negative outcome with respect to all three reference groups. These results suggest that individualism is a multidimensional construct, whereas the dimensionality of collectivism appears to be a function of social distance. Measurement invariance was tested at configural, factor loading, and intercept levels for all components of I/C.     

Leadership and regressive group processes: A pilot study

Various perspectives on leadership within the psychoanalytic, organizational and socio‐biological literature are reviewed, with particular attention to research studies in these areas. Hypotheses are offered about what makes an effective leader: her ability to structure tasks well in order to avoid destructive regressions, to make constructive use of the omnipresent regressive energies in group life, and to redirect regressions when they occur. Systematic qualitative observations of three videotaped sessions each from N = 18 medical staff work groups at an urban medical center are discussed, as is the utility of a scale, the Leadership and Group Regressions Scale (LGRS), that attempts to operationalize the hypotheses. Analyzing the tapes qualitatively, it was noteworthy that at times (in N = 6 groups), the nominal leader of the group did not prove to be the actual, working leader. Quantitatively, a significant correlation was seen between leaders’ LGRS scores and the group’s satisfactory completion of their quantitative goals (p = 0.007) and ability to sustain the goals (p = 0.04), when the score of the person who met criteria for group leadership was used.     

Chinese working in groups: Effort dispensability versus normative influence

Chinese participants were found less likely to social loaf when working in groups than did North Americans. This result was attributed mainly to the collectivism and individualism characterizing Chinese and North Americans, respectively. However, this explanation does not address how Chinese people's social loafing tendency may vary across situations. If Chinese participants are concerned about their relations with coworkers, they should be more likely to conform to the performance level of their coworkers. This prediction is in opposition to effort dispensability, which is usually found among North Americans, whereby individuals adjust their effort in reverse to that of their coworkers. Consistent with our prediction, findings from three studies revealed that Chinese participants tended to conform to the performance level of their coworkers when their performance is made public ( vs kept anonymous) and when they have high ( vs low) relational concerns. These findings have implications for unpacking nuanced cultural influences on behaviours.     

Empirical metaphysics: the role of intuitions about possible cases in philosophy

Frank Jackson has argued that only if we have a priori knowledge of the extension-fixers for many of our terms can we vindicate the methodological practice of relying on intuitions to decide between philosophical theories. While there has been much discussion of Jackson’s claim that we have such knowledge, there has been comparatively little discussion of this most powerful argument for that claim. Here I defend an alternative explanation of our intuitions about possible cases, one that does not rely on a priori extension-fixers. This alternative explanation provides a vindication of our reliance on intuitions, while blocking Jackson’s abductive argument for a priori semantic knowledge. In brief, I argue that we should regard our armchair intuitions as providing an important, a priori source of evidence for hypotheses about the contents of our implicit referential policies with regard to our terms. But all such hypotheses have a potential falsifier that is only discoverable empirically. In other words, gold-standard evidence for such hypotheses is always empirical.