Task switching and the measurement of “switch costs”

The measurement of “switch costs” is held to be of interest because, as is widely believed, they may reflect the control processes that are engaged when subjects switch between two (or more) competing tasks. [In task-switching experiments, the reaction time (RT) switch cost is typically measured as the difference in RT between switch and non-switch (repeat) trials.] In this report we focus on the RT switch costs that remain even after the subject has had some time to prepare for the shift of task, when the switch cost may be approximately asymptotic (so-called residual switch costs). Three experiments are presented. All three experiments used Stroop colour/word, and neutral stimuli. Participants performed the two tasks of word-reading and colour-naming in a regular, double alternation, using the “alternating runs” paradigm (R. D. Rogers & S. Monsell, 1995). The experiments were designed to test the hypothesis that RT switch costs depend on a form of proactive interference (PI) arising from the performance of a prior, competing task. A. Allport, E. A. Styles and S. Hsieh (1994) suggested that these PI effects resulted from “task-set inertia”, that is, the persisting activation-suppression of competing task-sets, or competing task-processing pathways. The results confirmed the existence of long-lasting PI from the competing task as a major contributor to switch costs. Non-switch trials, used as the baseline in the measurement of switch costs, were also shown to be strongly affected by similar PI effects. However, task-set inertia was not sufficient to account for these results. The results appeared inconsistent also with all other previous models of task switching. A new hypothesis to explain these between-task interference effects was developed, based on the stimulus-triggered retrieval of competing stimulus-response (S-R) associations, acquired (or strengthened) in earlier trials. Consistent with this retrieval hypothesis, switch costs were shown to depend primarily on the S-R characteristics of the preceding task (the task that was switched from) rather than the upcoming task. Further, the effects of the other, competing task were found to persist over many successive switching trials, affecting switch costs long after the stimulus overlap (and hence the principal S-R competition) between the current tasks had been removed. Switch costs were also found to be affected by recent, item-specific experience with a given stimulus, in either the same or the competing task. Finally, the results showed that switch costs were massively affected by the ratio of the number of prior trials, in response to the same stimuli, that had implemented either the currently intended or the competing S-R mappings. None of these effects are predicted by current models of residual switch costs, which appeal to the differences in control processes assumed to be engaged in switch versus non-switch trials. Received: 31 March 1999 / Accepted: 23 July 1999     

Is inhibition of return a reflexive effect?

The inhibition of return (IOR) phenomenon is routinely considered an effect of reflexive attention because the paradigm used to generate IOR employs peripheral cues that are uninformative as to where a target will appear. Because the cues are spatially unreliable it is thought that there is no reason for attention to be committed volitionally to them, and hence, the IOR effect is considered reflexive. What has been generally overlooked, however, is that the cues provide reliable temporal information as to when a target will occur. This predictive information is used by participants to prepare volitionally for when a target is likely to appear. We investigated whether the IOR effect is a product of the volitional application of attention to peripheral cues for the use of their temporal information. To test this idea we rendered the temporal information provided by peripheral cues unreliable. While this eliminated participants using the cues volitionally, it did not abolish the IOR phenomenon. These data demonstrate two new findings. First, the IOR effect is fundamentally a reflexive phenomenon. Second, when peripheral cues are not used volitionally, the IOR effect is attenuated. Together, the present findings indicate that the IOR effect can be modulated by volitional (top-down) processes but it is not the product of them. We argue that an intimate link between fronto-parietal regions and the superior colliculus provide a functional neural mechanism for this volitional effect to impact IOR.     

Developmental changes in the relationship between the infant's attention and emotion during early face-to-face communication: the 2-month transition

Weekly observations documented developmental changes in mother-infant face-to-face communication between birth and 3 months. Developmental trajectories for each dyad of the duration of infant facial expressions showed a change from the dominance of Simple Attention (without other emotion expressions) to active and emotionally positive forms of attention to the mother toward the end of the 2nd month. The results support an overlapping waves model, rather than a stage model, of developmental change. Sequential analysis found developmental changes from cycling between Gaze Elsewhere and Simple Attention to the Mother's Face in the early weeks to a complex sequence of transitions between Concentrated Attention, Smile, and Cooing Expression nested into sequences of positive communication during the 2nd and 3rd months.     

The relative contribution of trait and social influences to the links among perceived social support, affect, and self-esteem

Although perceived support is influenced by both the personality traits of support recipients as well as various social factors, it is unknown to what extent these two types of influences account for perceived support's link to mental health. We investigated these relations using multivariate generalizability analyses. In three samples, both the trait and social influence components of perceived support were related to favorable affect and to self-esteem. The magnitude of the correlations between perceived support and mental health was similar for both the trait and social influence components. Similar findings were obtained for social conflict, although the links between conflict and mental health varied somewhat depending upon the level of analysis. These findings suggest that social support theories and interventions should include both trait and social mechanisms to explain and modify perceived support and mental health.     

The Impact of Personality and Religion on Attitudes toward Alcohol among 16–18 Year Olds in Northern Ireland

Background: Previous research demonstrates a negative relationship between attitude toward alcohol and religiosity. However, what is less apparent is if this relationship may, at least in part, be a function of individual differences in personality, as previous research has demonstrated a relationship between certain measures of personality and both attitude toward alcohol and attitude toward religiosity. The aim of the present study was to explore the impact of personality and the relative efficacy of different markers of religiosity in predicting attitude toward alcohol among a sample of 16–18 year olds in Northern Ireland. Method: The Francis Scale of Attitude toward Alcohol (Francis, 1992c. Drug and Alcohol Dependence, 31, 45–50) was administered alongside the Abbreviated Revised Eysenck Personality Questionnaire (Francis, Brown, & Philipchalk, 1992. Personality and Individual Differences, 13(4), 443–449), the Francis Scale of Attitude toward Christianity (Francis & Stubbs, 1987. Personality and Individual Differences, 8, 741–743) and measures of frequency of personal prayer and church attendance among a sample of 243 16- to 18-year-old sixth-form students in Northern Ireland. Results and conclusion: The data demonstrate that a more prohibitive attitude toward alcohol was correlated with lower psychoticism scores (tendermindedness) and a more positive attitude toward Christianity. Multiple-regression analyses confirm the importance of attitude toward religion in predicting individual differences in attitude toward alcohol.     

Internal consistency reliability of the Francis Scale of Attitude toward Alcohol among adolescents in Northern Ireland

The Francis Scale of Attitude toward Alcohol was completed by 324 adolescents (M= 17.1 yr., SD=3.6) in Northern Ireland to examine reliability of the measure among this age group. These data support its internal consistency (.89) and suggest that the Francis Scale of Attitude toward Alcohol is psychometrically appropriate for use among this age group.     

Accounting for belief bias in a mental model framework: comment on Klauer, Musch, and Naumer (2000)

K. C. Klauer, J. Musch, and B. Naumer (2000; see record 2000-02818-008) presented a general multinomial model of belief bias effects in syllogistic reasoning. They claimed to map a particular mental model account of belief bias (J. V. Oakhill, P. N. Johnson-Laird, & A. Garnham, 1989; see record 1989-38845-001)) onto this model and to show empirically that it is incorrect. The authors argue that this mental model account does not map onto the multinomial model and that it can account for the data presented by Klauer et al. (Experiments 1-4). The authors further argue that additional data Klauer et al. presented in support of a new model of their own (Experiments 5-8) are explained by this mental model account. The mental model account is, therefore, refuted neither by Klauer et al.'s theoretical analysis nor by any of the results they presented. Furthermore, the account can accommodate more recent findings on belief bias in a more satisfactory way than can alternative models that have been proposed.     

Constraints on view combination: effects of self-occlusion and differences among familiar and novel views

The use of multiple familiar views of objects to facilitate recognition of novel views has been addressed in a number of behavioral studies, but the results have not been conclusive. The present study was a comprehensive examination of view combination for different types of novel views (internal or external to the studied views) and different objects (amoeboid objects and objects composed of geons; objects with and without self-occlusion across rotation). The authors found that the advantage gained from the study of 2 views was more than the generalization from each of the studied views presented alone. This facilitation occurred only for internal views but not external views. In addition, the benefits from the study of 2 views diminished when (a) the studied views did not share the same visible features and when (b) the studied views were separated by a small angular difference.