List of Contributors

Authors Index

List of Contributors     

Separate and shared sources of dual-task cost in stimulus identification and response selection

There is often strong interference if a second target stimulus (T2) is presented before processing of a prior target stimulus (T1) is complete. In the "Psychological Refractory Period" (PRP) paradigm, responses are speeded and interference manifests as increased response time for T2. In the "Attentional Blink" (AB) paradigm, stimuli are masked and responses unspeeded; interference manifests as reduced T2 accuracy. While different causes have usually been considered for PRP and AB phenomena, recent evidence has supported a unified account based on a single, shared restriction on concurrent processing. Here we show that a full assessment of separate and shared resource limitations requires direct comparison of hybrid PRP/AB trials with corresponding pure PRP and AB cases. Randomizing trial types in such a comparison also brings substantial benefit in addressing possible changes in task preparation or readiness. The data from two such experiments--combining speeded auditory (SA) and unspeeded visual (UV) task events--provide clear evidence for both separate and shared resource limitations. Often interference is strongest for T1 and T2 events of the same type, reflecting predominantly different limitations in SA and UV processing. With modest increases in demand, however, interference between different event types can also be made arbitrarily large, reflecting arbitrarily important shared limitations. For even such simple tasks as these, T--T2 interference reflects a combination of relatively local and relatively global sources.     

Dual-task attention deficits in dysphoric mood

The attentional functioning of nondysphoric, mildly dysphoric, and moderately to severely dysphoric college students was tested using the attentional blink (AB) paradigm. These groups performed equally well at reporting a single target appearing in a rapidly presented stream of stimuli. All groups showed an AB, with report sensitivity for a 2nd target being reduced when the 2 targets were presented less than 0.5 s apart. Nondysphoric and mildly dysphoric participants showed the same size ABs, but the ABs for moderately to severely dysphoric participants were larger and longer. As predicted, the results showed that moderately to severely dysphoric individuals have attentional impairments. These impairments, however, were evident only in the more demanding dual-task condition.     

Working and long-term memory deficits in schizophrenia: is there a common prefrontal mechanism?

This study tested the hypothesis that dorsolateral prefrontal cortex deficits contribute to both working memory and long-term memory disturbances in schizophrenia. It also examined whether such deficits were more severe for verbal than nonverbal stimuli. Functional magnetic resonance imaging was used to assess cortical activation during performance of verbal and nonverbal versions of a working memory task and both encoding and recognition tasks in 38 individuals with schizophrenia and 48 healthy controls. Performance of both working memory and long-term memory tasks revealed disturbed dorsolateral prefrontal cortex activation in schizophrenia, although medial temporal deficits were also present. Some evidence was found for more severe cognitive and functional deficits with verbal than nonverbal stimuli, although these results were mixed.     

Clinical features of major depressive disorder in adolescents and their relatives: impact on familial aggregation, implications for phenotype definition, and specificity of transmission

Three questions were addressed using family study data from a community sample: (a) Which clinical features of major depressive disorder (MDD) in adolescents are associated with elevated rates of MDD in relatives? (b) Which features of MDD in relatives distinguish family members of depressed adolescents from relatives of adolescents without mood disorders (NMD)? and (c) Do depressed adolescents with particular features have higher proportions of depressed relatives with the same features? Participants included 268 MDD adolescents, 401 NMD adolescents, and their 2,202 first-degree relatives. Rates of MDD were highest among relatives of depressed adolescents with recurrent episodes and greater impairment. Depression severity best distinguished the relatives of depressed adolescents from relatives of controls. Specific clinical features did not aggregate in families.     

An evaluation of contingency strength and response suppression

Typically, functional analyses of severe problem behavior have been conducted in two ways: (a) The target response is reinforced immediately after it occurs, or (b) the target response is reinforced on some schedule thought to mimic a naturally occurring schedule. We evaluated the effects of contingency strength in reducing levels of problem behavior with 2 participants who had been diagnosed with developmental disabilities. Results showed that under a neutral contingency, one in which the probability of reinforcement for aggression was equal to the probability of reinforcement for the nonoccurrence of aggression, rates of aggression were suppressed to low levels for both participants.     

Commitment to organizational change: extension of a three-component model

Three studies were conducted to test the application of a three-component model of workplace commitment (J. P. Meyer & N. J. Allen, 1991: J. P. Meyer & L. Herscovitch, 2001) in the context of employee commitment to organizational change. Study 1, conducted with 224 university students, provided preliminary evidence for the validity of newly developed Affective, Continuance, and Normative Commitment to Change Scales. Studies 2 and 3, conducted with hospital nurses (N = 157 and 108, respectively), provided further support for the validity of the three Commitment to Change Scales, and demonstrated that (a) commitment to a change is a better predictor of behavioral support for a change than is organizational commitment, (b) affective and normative commitment to a change are associated with higher levels of support than is continuance commitment, and (c) the components of commitment combine to predict behavior.     

Retaking ability tests in a selection setting: implications for practice effects,training performance,and turnover

This field study investigated the effect of retaking identical selection tests on subsequent test scores of 4,726 candidates for law enforcement positions. For both cognitive ability and oral communication ability selection tests, candidates produced significant score increases between the 1st and 2nd and the 2nd and 3rd test administrations. Furthermore, the repeat testing relationships with posthire training performance and turnover were examined in a sample of 1,515 candidates eventually selected into the organization. As predicted from persistence and continuance commitment rationales, the number of tests necessary to gain entry into the organization was positively associated with training performance and negatively associated with turnover probability.     

Temperamental differences between healthy,asthmatic, and allergic children before onset of illness: a longitudinal prospective study of asthma development

The authors investigated the link between children's temperament and the development of asthma and allergies. Prospective longitudinal data on children at the ages of 3-5 months, 3-5 years, and 7-9 years were collected. At age 7-9 years, analyses were performed on data for 3 groups of children (n = 42): those with asthma (no allergies), those with allergies (no asthma), and those with neither asthma nor allergies (the control group). Data for children who developed asthma or allergies prior to age 7-9 years were not analyzed. Differences were found in the premorbid period between the control group and the children who later developed asthma or allergies as well as between the asthma and allergy groups. After onset of illness, no temperamental differences were observed between the 3 groups. The study shows the importance of longitudinal design for asthma research.     

Work-group characteristics and performance in collectivistic and individualistic cultures

The authors conducted a cross-cultural longitudinal investigation of the effects of culture (individualism-collectivism dichotomy) on group characteristics (functional heterogeneity, preference for teamwork, group potency, outcome expectation) and on performance of 83 work groups performing 2 decision-making tasks over a 15-week period. The individualists (U.S. students) reported higher levels of functional heterogeneity and group potency and attained higher levels of group performance than did the collectivists (Korean students). In addition, culture and time interacted to influence ratings of group potency and outcome expectation. The difference in ratings of group potency between individualists and collectivists increased over time. Outcome expectation was greater among the collectivists in Time 1 and among the individualists in Time 2. The authors discuss implications for future cross-cultural group research and international management.