Hyperactivity and Learning Deficits in Transgenic Mice Bearing a Human Mutant Thyroid Hormone β1 Receptor Gene

Resistance to thyroid hormone (RTH) is a human syndrome mapped to the thyroid receptor β (TRβ) gene on chromosome 3, representing a mutation of the ligandbinding domain of the TRβ gene. The syndrome is characterized by reduced tissue responsiveness to thyroid hormone and elevated serum levels of thyroid hormones. A common behavioral phenotype associated with RTH is attention deficit hyperactivity disorder (ADHD). To test the hypothesis that RTH produces attention deficits and/or hyperactivity, transgenic mice expressing a mutant TRβ gene were generated. The present experiment tested RTH transgenic mice from the PV kindred on behavioral tasks relevant to the primary features of ADHD: hyperactivity, sustained attention (vigilance), learning, and impulsivity. Male transgenic mice showed elevated locomotor activity in an open field compared to male wild-type littermate controls. Both male and female transgenic mice exhibited impaired learning of an autoshaping task, compared to wild-type controls. On a vigilance task in an operant chamber, there were no differences between transgenics and controls on the proportion of hits, response latency, or duration of stimulus tolerated. On an operant go/no-go task measuring sustained attention and impulsivity, there were no differences between controls and transgenics. These results indicate that transgenic mice bearing a mutant human TRβ gene demonstrate several behavioral characteristics of ADHD and may serve a valuable heuristic role in elucidating possible candidate genes in converging pathways for other causes of ADHD.     

Dual processes in reasoning?

Previous results have shown that the introduction of negatives into the sentences used in a deductive problem affected behavior in a systematic way which was independent of the logical structure of the problem. In the present investigation, the subjects were asked to justify their responses when reasoning about such sentences. In accordance with previous results, the responses were dominated by the terms in the sentences regardless of whether they were negated. However, the justifications did vary when negatives were introduced in accordance with the logical consequences of the responses. The interpretation of these justifications as causes of behavior seemed implausible. It was suggested that they were rationalizations, or that there was at least some form of dual processing between behavior and conscious thought.     

MATCHING BIAS IN THE SELECTION TASK

A previous study (Evans, 1972) found that subjects tend to match rather than alter named values when constructing verifying and falsifying cases of conditional rules. It was suggested that this tendency (‘matching bias’) might account for the responses normally observed in Wason's (1968, 1969) ‘selection task’. This suggestion was tested by giving subjects the selection task with conditional rules in which the presence and absence of negative components was systematically varied, to see whether subjects consistently attempted to verify the rules (Wason's theory) or whether they continued to choose the matching values despite the presence of negatives, which would reverse the logical meaning of such selections. Significant matching tendencies were observed on four independent measures, and the overall pattern, with matching bias cancelled out, gave no evidence for a verification bias, indicating instead that the logically correct values were most frequently chosen.     

Distraction and attitude change: A resolution

Previous studies have shown that distraction may either increase or decrease attitude change. The present experiment, designed to reconcile earlier findings, was based on the hypothesis that distraction should interfere with message reception but also increase yielding to the message. Distraction should thus increase attitude change to a simple message (one which is easily understood but not very convincing), but decrease attitude change to a complex message (one which is difficult to understand but convicing if understood). Subjects beard messages on two topics, sometimes while distracted by a tape recording of music and sometimes not. Message complexity was successfully manipulated for one of the topics. The results support a model of attitude change which considers the effects of independent variables on both reception and yielding.     

Apparent distance in a horizontal plane with tactile-kinesthetic stimuli

In the study of active tactile-kinesthetic space perception apparent distance has been found to vary as a function of the direction of the line segment in a horizontal plane. The present data indicate that the error is not consistently related to the same frame of reference as the visual illusion. Rather, with movement of the extended arm to determine the relative distances between pairs of points, radial distances are overestimated in relation to tangential ones, whether parallel or perpendicular to the medial plane. Interpretations are in terms of kinesthetic stimulus patterns and the structure of perceptual representation.     

Understanding attraction in formal mentoring relationships from an affective perspective

Despite the critical role affect can play in mentoring, a type of close relationships in the workplace, affect has not received much attention in existing mentoring research. Drawing upon Byrne's affect-centered model of attraction, we examined the relationships among mentors' moods during their interaction with protégés, mentors' liking of protégés, and mentoring support received by protégés. Moreover, we also examined the moderating effect of protégés' emotional intelligence (EI) on the relationship between mentors' moods and liking. Based on data collected from 237 ongoing formal mentoring dyads, we found that mentors' positive moods were positively related, and negative moods were negatively related, to mentoring support received through mentors' liking. Furthermore, protégés' EI only moderated the positive relationship between mentors' positive moods and liking such that the positive relationship was stronger for protégés low on EI. Theoretical and practical implications of the findings are discussed.     

Do incompatible arguments cause extensive processing in the evaluation of arguments? The role of congruence between argument compatibility and argument quality

Previous studies have demonstrated that arguments incompatible with prior beliefs are subjected to more extensive refutational processing, scrutinized longer, and judged to be weaker than arguments compatible with prior beliefs. However, this study suggests whether extensive processing is implemented when evaluating arguments is not decided by argument compatibility, but by congruence between two evaluating tendencies elicited by both argument compatibility and argument quality. Consistent with this perspective, the results of two experiments show that relative to congruent arguments, participants judged arguments eliciting incongruent evaluating tendencies as less extreme in strength, spent more time, and felt more hesitant generating strength judgments for them. The results also show that it is mainly incongruent arguments, not congruent arguments, whose strength ratings were more closely associated with the perceived personal importance of the issue, which intensified the tendency to evaluate arguments depending on argument compatibility. These results suggest that it is the incongruity between argument compatibility and argument quality, and not simply the argument compatibility, that plays a more important role in activating an extensive processing in the evaluation of arguments.     

The Sceptical Paradox and the Nature of the Self

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