The impact of stimulus-specific practice and task instructions on response congruency effects between tasks

In task switching experiments participants have to respond to the same set of stimuli while task instructions vary (e.g., digit stimuli are assigned to left- or right-sided key presses by means of magnitude vs. parity classification). Response congruency effects denote worse performance for a stimulus, which is associated with different responses in the two tasks as compared to a stimulus, which is associated with the same response. Previous research suggests that such effects reflect direct links between stimuli and responses acquired in the course of experimental practice. In the current study we investigated the impact of stimulus-specific practice and task instruction by reversing the S–R mapping of one task (Experiment 1) or replacing one task with a new one (Experiment 2) in the second half of an experimental session. Consistent with the direct link account, S–R links practiced during the first half of the experiment largely determined congruency effects despite altered task instructions. Furthermore, the results suggest that previously practiced S–R links (a) can be relatively quickly overwritten by practicing a novel S–R mapping, and (b) are subject to passive decay when no longer in use.     

Immediate source-monitoring, self-focused attention and the positive symptoms of schizophrenia

Previous research suggests that tendencies to misattribute one's own thoughts to an external source, as assessed by an immediate source-monitoring test, are associated with auditory verbal hallucinations (AVHs). However, recent research suggests that such tendencies are associated instead with symptoms of thought interference. The main aim of the present study was to examine whether such tendencies are differentially associated with different types of thought interference, with AVHs, or with both. It has also been suggested that external misattributions are especially likely to occur with emotionally salient material and if the individual's focus is on the self. These suggestions were also tested. The positive psychotic symptoms of 57 individuals with a diagnosis of schizophrenia were assessed and they then completed the Self-Focus Sentence Completion blank. Immediately after completing each sentence they were asked to indicate to what extent the sentence was their own. The number of sentences that were not rated as completely their own served as their externalisation score. Externalisation scores correlated significantly with the severity of three symptoms: voices commenting, delusions of being controlled, and thought insertion. In a logistic regression analysis, all three of these symptoms were significantly and independently related to externalisation. Externalisation was not associated with either a negative or a neutral self-focus. Thus tendencies to misattribute one's own thoughts to an external source are associated with AVHs and some, but not all, symptoms of thought interference. The importance for externalisation of self-focused attention and of the emotional salience of the elicited thoughts was not supported.     

A Taxonomy of Equity Factors

A perplexing problem with Adams' (1963 ) equity theory has been the difficulty associated with operationalizing requisite components, perceived employee inputs, and outcomes. This study, involving 352 respondents, produced empirically derived, two-dimensional taxonomies of inputs and outcomes, laying the foundation for identification of key variables. Specifically, the study summarizes a typology of 9 distinct employee inputs perceived as controllable by individuals, including effort, education, attendance, and cooperativeness. Conversely, the study summarizes a typology of 14 distinct outcomes along a continuum of 4 dimensions, including personalized vs. generalized and economic vs. noneconomic characteristics. These typologies and incumbent regression analysis provide insight into the complexities associated with inputs and outcomes in the context of equity theory.     

The involvement of executive functions in prospective memory performance of adults

The present study examines the relationship between prospective memory performance and executive functioning. The four phases of the prospective memory process—intention formation, intention retention, reinstantiation of the intention, and intention execution—are assumed to require different amounts of executive processing, most of which is demanded in the phases of intention formation and intention execution. At present, though, it is still unclear whether, and to what extent, prefrontal executive systems are involved in different kinds of prospective memory tasks, as some findings suggest that prospective memory might rather rely on nonstrategic processes that are unlikely to depend on prefrontal executive systems. Therefore, this study focuses on the following questions: (1) to what degree does executive functioning predict prospective memory performance in different standard prospective memory tasks and, furthermore, are certain executive measures better predictors than others; (2) are age‐related effects in different prospective memory measures due to individual differences in executive functioning; and (3) do age‐related differences in prospective memory exist that are not explained by individual differences in executive functioning. In a sample of 80 adults (20‐80 years), we applied four instruments to measure prospective memory: a traditional single‐task paradigm, two more complex tasks—one time‐based and one event‐based—and a highly complex multi‐task paradigm. We further assessed a broadly defined construct of executive functioning using several standard neuropsychological tests. Results showed that executive functioning did not predict performance in the simple single‐task paradigm. However, executive functioning, but not age, predicted performance in the two more complex standard tests of prospective remembering, and both executive functioning and age predicted performance in the most complex paradigm. In sum, the obtained data underline the assumption that frontal/ executive functions are related to prospective memory performance across a range of prospective paradigms. It also seems clear that age differences in prospective memory performance partially depend on age‐related individual differences in frontal/executive functions.     

Buying cars online: the adoption of the web for high‐involvement,high‐cost purchases

This research explores the adoption of the Web throughout the buying process within high‐value, high‐involvement product categories (the car sector). Diffusion of innovations (Rogers, 1983) and innovation resistance Ram and Sheth (1989) theories are utilised and found to be useful. The research is exploratory, based on eight qualitative, semi‐structured individual interviews with potential car buyers. Findings indicate that there is resistance to adopting online car purchase overall, but relative advantage is recognised at the early, information seeking stages. Consumers use the Web to improve the balance of power between themselves and car salespeople. Innovation resistance during later stages, result from the need for personal experience of the product prior to purchase, ie test driving, as well as the uncertainty regarding after‐sales support. Further resistance comes from a reluctance to give up the social aspects of car buying and a perceived inability to negotiate with websites. It is suggested that organisations operating in these markets should focus Web activities on information provision, or opt for a hybrid strategy using both online and offline channels. Copyright © 2002 Henry Stewart Publications.     

The locus of semantic priming effects in person recognition

Semantic priming in person recognition has been studied extensively. In a typical experiment, participants are asked to make a familiarity decision to target items that have been immediately preceded by related or unrelated primes. Facilitation is usually observed from related primes, and this priming is equivalent across stimulus domains (i.e., faces and names prime one another equally). Structural models of face recognition (e.g., IAC: Burton, Bruce, & Johnston, 1990) accommodate these effects by proposing a level of person identity nodes (PINs) at which recognition routes converge, and which allow access to a common pool of semantics. We present three experiments that examine semantic priming for different decisions. Priming for a semantic decision (e.g., British/American?) shows exactly the same pattern that is normally observed for a familiarity decision. The pattern is equivalent for name and face recognition. However, no semantic priming is observed when participants are asked to make a sex decision. These results constrain future models of face processing and are discussed with reference to current theories of semantic priming.     

Adjustments to recent and frequent conflict reflect two distinguishable mechanisms

In conflict paradigms such as the Eriksen flanker task, interference has been found to be reduced under conditions of recent and/or frequent cognitive conflict. Using a modified flanker task, we investigated the interplay of conflict recency and conflict frequency by comparing the interference reductions following conflict trials under conditions in which conflict was either frequent or infrequent overall, while controlling for stimulus and response feature repetitions to rule out nonattentional accounts. The reduction of flanker interference after a conflict trial was attenuated when overall conflict was frequent. This result is consistent with models assuming that processing adjustments occur gradually in response to conflict strength, such as the connectionist model of Botvinick, Braver, Barch, Carter, and Cohen (2001), in which both recency and frequency modulations are brought about by the same mechanism. By decomposing response times into initiation times and movement times, we revealed that frequent conflict delayed response initiation but sped up movement. Moreover, whereas frequent conflict reduced interference in both components, interference reduction after individual conflict trials was confined to movement times. Taken together, these results suggest that different mechanisms underlie the two kinds of modulation.     

The Nature and Predictors of Undercontrolled and Internalizing Problem Trajectories Across Early Childhood

Using growth curve modeling, trajectories of undercontrolled (oppositional, irritable, inattentive and overactive behaviors) and internalizing (worried, sad and fearful) problems from 18 months to 4.5 years were studied in a population based sample of 921 Norwegian children. At the population level, undercontrolled problems decreased and internalizing problems increased with increasing age. Child temperament and family factors present at 18 months predicted 43% of the stability and 20% of the linear changes in undercontrolled problems and 30% of the stability and 7% of the linear changes in internalizing problems. Persisting effects of child and family factors from 18 month were found on the two problem dimensions over and above the impact of changes in the same risk factors. Lower initial level of partner support and higher initial level of child emotionality predicted higher slope of undercontrolled problems and higher initial level of family stress predicted higher slope for internalizing problems. As expected, time to time change (t1 to t2 and t2 to t3) in risk factors predicted time to time change in problem scores as well. The study shows the significance of early emerging internalizing and undercontrolled problems, the need to consider their pathways separately from very young ages, lasting effects of early experiences, and the importance of a dynamic approach to the analysis of risk.     

Hiding and finding: The relationship between visual concealment and visual search

As an initial step toward developing a theory of visual concealment, we assessed whether people would use factors known to influence visual search difficulty when the degree of concealment of objects among distractors was varied. In Experiment 1, participants arranged search objects (shapes, emotional faces, and graphemes) to create displays in which the targets were in plain sight but were either easy or hard to find. Analyses of easy and hard displays created during Experiment 1 revealed that the participants reliably used factors known to influence search difficulty (e.g., eccentricity, target—distractor similarity, presence/absence of a feature) to vary the difficulty of search across displays. In Experiment 2, a new participant group searched for the targets in the displays created by the participants in Experiment 1. Results indicated that search was more difficult in the hard than in the easy condition. In Experiments 3 and 4, participants used presence versus absence of a feature to vary search difficulty with several novel stimulus sets. Taken together, the results reveal a close link between the factors that govern concealment and the factors known to influence search difficulty, suggesting that a visual search theory can be extended to form the basis of a theory of visual concealment.