A review of the biological bases of ADHD: what have we learned from imaging studies?

Attention Deficit Hyperactivity Disorder (ADHD) is a common and impairing neuropsychiatric disorder with onset at preschool age. Although a significant amount of progress has been made investigating the neurobiology of this disorder, its precise etiology still remains unclear. Converging evidence from studies of the neuropharmacology, genetics, neuropsychology, and neuroimaging of ADHD imply the involvement of fronto-striatal circuitry in ADHD. However, while it does appear that poor inhibitory control and the deficits in fronto-striatal circuitry associated with it are central, there is evidence to suggest that more posterior cerebral areas are also implicated in this disorder. Anatomical studies suggest widespread reductions in volume throughout the cerebrum and cerebellum, while functional imaging studies suggest that affected individuals activate more diffuse areas than controls during the performance of cognitive tasks. The future impact of new MR imaging methodologies on the field is discussed.     

Disproportionate deficit in associative recognition relative to item recognition in global amnesia

In two experiments, we tested the hypothesis that medial temporal lobe (MTL) amnesic patients and, likewise, diencephalic (DNC) amnesic patients evidence a disproportionate deficit in memory for associations in comparison with memory for single items. In Experiment 1, we equated item recognition in amnesic and control participants and found that, under these conditions, associative recognition remained impaired both for MTL patients and for DNC patients. To rule out an alternative interpretation of the results of Experiment 1, in Experiment 2 we compared the performance of amnesic and control participants on a one-item recognition task and a two-item recognition task that required no memory for the association between members of word pairs. In the MTL group, when single-item recognition was equated to that of the controls, two-item nonassociative pair memory was equivalent as well. In the DNC group, nonassociative pair memory was impaired, but this impairment did not fully account for the impairment in associative memory. These findings indicate that memory for novel associations between items is disproportionately impaired in comparison with memory for single items in amnesia.     

Incidental learning of real-world regularities

The large literature on incidental learning relies almost exclusively on laboratory experiments. Whenever researchers have attempted to demonstrate incidental learning of real-world regularities, they have typically failed to show learning. For example, it is well established that people do not learn regularities in everyday objects, such as the left-right orientation of faces on coins, despite a very large exposure to them. In this report, we examine this apparent contradiction. We argue that most studies exploring real-life incidental learning use tests that are not as sensitive to low-confidence information as those traditionally used in laboratory tasks. Using more sensitive measures, we show that it is possible to learn regularities from British and Japanese cultural life as a direct result of exposure to these regularities. Further, confidence measures suggest that although the information may be acquired incidentally, it can be expressed with and without concomitant awareness of that knowledge.     

Asymmetric dependencies in perceiving identity and emotion: experiments with morphed faces.

We investigated whether an asymmetric relationship between the perception of identity and emotional expressions in faces (Schweinberger & Soukup, 1998) may be related to differences in the relative processing speed of identity and expression information. Stimulus faces were morphed across identity within a given emotional expression, or were morphed across emotion within a given identity. In Experiment 1, consistent classifications of these images were demonstrated across a wide range of morphing, with only a relatively narrow category boundary. At the same time, classification reaction times (RTs) reflected the increased perceptual difficulty of the morphed images. In Experiment 2, we investigated the effects of variations in the irrelevant dimension on judgments of faces with respect to a relevant dimension, using a Garner-type speeded classification task. RTs for expression classifications were strongly influenced by irrelevant identity information. In contrast, RTs for identity classifications were unaffected by irrelevant expression information, and this held even for stimuli in which identity was more difficult and slower to discriminate than expression. This suggests that differences in processing speed cannot account for the asymmetric relationship between identity and emotion perception. Theoretical accounts proposing independence of identity and emotion perception are discussed in the light of these findings.     

Alcohol consumption, drinking patterns, and alcohol problems among managerial versus non-managerial women and men

In the present study, we examined alcohol consumption and alcohol problems between managerial and nonmanagerial men and women. We also examined alcohol problems as a function of drinking context (i.e., when they drink and with whom they drink) for each of these four groups. Survey data and data from company records were collected from a large sample of blue and white collar employees (n = 2279). Participants completed a detailed questionnaire aimed at assessing many work-related attitudes, general mental and physical health-related perceptions, motivations for alcohol use, alcohol consumption indices, and alcohol problems. We found that several of the demographic variables differentially predicted alcohol consumption and problems for the four groups. In addition, drinking alone and immediately after work were associated with alcohol problems for women managers at a significantly higher rate than for the other groups of employees. These results support the assertion that more complex models are needed to understand the linkages between work and alcohol use. The research reported in this paper was supported by Grant AA 10690-02, National Institute of Alcohol Abuse and Alcoholism, National Institutes of Health.     

HYPERFEMININITY AND INFLUENCE

Murnen and Byrne (1991) have defined hyperfemininity as an exaggerated adherence to a feminine gender role as it relates to heterosexual relationships. Hyperfeminine women believe their success is determined by maintaining a romantic relationship with a man, and that their sexuality can be used to maintain this relationship. Extrapolating from theory concerning gender and status, including expectation states theory, it was hypothesized that a woman's expression of hyperfeminine attitudes would lead male college student participants to agree with her in response to a persuasive speech because it would indicate her compliance with women's subordinate status. It was found that men (but not women) who listened to a very hyperfeminine (high) speaker agreed with her more than did men who heard a mildly hyperfeminine (low) speaker, despite the fact that the high hyperfeminine speaker was judged less competent and knowledgeable. Implications of the results, including the idea that the sexual objectification of women perpetuates women's subordinate status, were discussed.     

The Interactive Role of Negative Affectivity and Job Characteristics: Are High-NA Employees Destined to Be Unhappy at Work?1

The present study examined whether employees high in negative affectivity (NA) are destined to be unhappy at work. Managerial employees provided information regarding perceptions of job characteristics, negative affectivity (NA), job satisfaction, and intentions to turnover. Using hierarchical regression, our findings suggest that employees who reported being high NA were more reactive to the environmental cues of perceived job scope. Specifically, NA interacted with job scope such that individuals high in NA who perceived their jobs as being higher (lower) in scope reported more (less) job satisfaction than did individuals low in NA. Implications for organizations and future research directions are discussed.     

When days are numbered: calendar structure and the development of calendar processing in English and Chinese.

Unlike English, Chinese uses a numerical system for naming months and days. This study explored whether this difference in naming affects the development of simple calendar calculation. Eight- and 10-year-old children as well as undergraduates in China and the United States were asked to name the day or month that comes a specified time before or after a given day or month. In each age group Chinese speakers primarily used calculation based on calendar names to solve these tasks, while English speakers primarily resorted to reciting the names. The magnitude of these differences was substantial; on difficult tasks Chinese fourth graders performed at speeds comparable to those of English-speaking adults. Implications for models of how linguistic structure affects cognition are discussed.     

Mitigating Burnout Among High-NA Employees in Health Care: What Can Organizations Do?

The purpose of this study was to examine the extent to which factors in the nursing environment have differential effects on burnout levels among nurses high and low in negative affectivity (NA). Specifically, this field study examined the moderating relationships among role ambiguity, role conflict, and collective efficacy on the NA–burnout relationship among nurses in a hospital setting. Findings suggest that perceived role conflict exacerbates while perceptions of collective efficacy reduce specific dimensions of burnout for nurses high in NA. These results offer some evidence regarding which environmental characteristics may mitigate burnout for high-NA nurses.     

Iterated Belief Revision, Reliability, and Inductive Amnesia

Belief revision theory concerns methods for reformulating an agent's epistemic state when the agent's beliefs are refuted by new information. The usual guiding principle in the design of such methods is to preserve as much of the agent's epistemic state as possible when the state is revised. Learning theoretic research focuses, instead, on a learning method's reliability or ability to converge to true, informative beliefs over a wide range of possible environments. This paper bridges the two perspectives by assessing the reliability of several proposed belief revision operators. Stringent conceptions of minimal change are shown to occasion a limitation called inductive amnesia: they can predict the future only if they cannot remember the past. Avoidance of inductive amnesia can therefore function as a plausible and hitherto unrecognized constraint on the design of belief revision operators.