Are spatial responses to visuospatial stimuli and spoken responses to auditory letters ideomotor-compatible tasks? Examination of set-size effects on dual-task interference

Previous studies have paired a visual-manual Task 1 with an auditory-vocal Task 2 to evaluate whether the psychological refractory period (PRP) effect is eliminated with two ideomotor-compatible tasks (for which stimuli resemble the response feedback). The present study varied the number of stimulus-response alternatives for Task 1 in three experiments to determine whether set-size and PRP effects were absent, as would be expected if the tasks bypass limited-capacity response-selection processes. In Experiments 1 and 2, the visual-manual task was used as Task 1, with lever-movement and keypress responses, respectively. In Experiment 3, the auditory-vocal task was used as Task 1 and the visual-manual task as Task 2. A significant lengthening of reaction time for 4 vs. 2 alternatives was found for the visual-manual Task 1 and the Task 2 PRP effect in Experiments 1 and 2, suggesting that the visual-manual task is not ideomotor compatible. Neither effect of set size was significant for the auditory-vocal Task 1 in Experiment 3, but there was still a Task 2 PRP effect. Our results imply that neither version of the visual-manual task is ideomotor compatible; other considerations suggest that the auditory-vocal task may also still require response selection.     

Validation of scales from the Deployment Risk and Resilience Inventory in a sample of Operation Iraqi Freedom veterans

The Deployment Risk and Resilience Inventory (DRRI) is a suite of scales that can be used to assess deployment-related factors implicated in the health and well-being of military veterans. Although initial evidence for the reliability and validity of DRRI scales based on Gulf War veteran samples is encouraging, evidence with respect to a more contemporary cohort of Operation Iraqi Freedom (OIF) veterans is not available. Therefore, the primary goal of the present study was to validate scales from the DRRI in a large sample of OIF army personnel diversified in occupational and demographic characteristics. In general, results supported the use of these DRRI scales in this population. Internal consistency reliability estimates were quite strong. Additionally, support was obtained for criterion-related validity, as demonstrated by associations with mental and physical health measures, and discriminative validity, as demonstrated by differences between key military subgroups.     

Is the psychological refractory period effect for ideomotor compatible tasks eliminated by speed-stress instructions?

It has been argued that the psychological refractory period (PRP) effect is eliminated with two ideomotor compatible tasks when instructions stress fast and simultaneous responding. Three experiments were conducted to test this hypothesis. In all experiments, Task 1 required spatially compatible manual responses (left or right) to the direction of an arrow, and Task 2 required saying the name of the auditory letter A or B. In Experiments 1 and 3, the manual responses were keypresses made with the left and right hands, whereas in Experiment 2 they were left-right toggle-switch movements made with the dominant hand. Instructions that stressed response speed reduced reaction time and increased error rate compared to standard instructions to respond fast and accurately, but did not eliminate the PRP effect on Task 2 reaction time. These results imply that, even when response speed is emphasized, ideomotor compatible tasks do not bypass response selection.     

The effect of causal knowledge on judgments of the likelihood of unknown features

People frequently infer unknown aspects of an entity based on their knowledge about that entity. The current study reports a novel phenomenon, an inductive bias people have in making such inferences. Upon learning that one symptom causes another in a person, both undergraduate students (Experiment 1) and clinicians (Experiment 2) judged that an unknown feature associated with the cause-symptom was more likely to be present in that person than an unknown feature associated with the effect-symptom. Thus, these findings suggest a specific mechanism in which causal explanations influence one’s representation of and inferences about an entity. Implications for clinical reasoning and associative models of conceptual knowledge are discussed.     

Transfer of orthogonal stimulus-response mappings to an orthogonal Simon task

When up-down stimulus locations are mapped to left-right keypresses, an overall advantage for the up-right/down-left mapping is often obtained that varies as a function of response eccentricity. This orthogonal stimulus-response compatibility (SRC) effect also occurs when stimulus location is irrelevant, a phenomenon called the orthogonal Simon effect, and has been attributed to correspondence of stimulus and response code polarities. The Simon effect for horizontal stimulus-response (S-R) arrangements has been shown to be affected by short-term S-R associations established through the mapping used for a prior SRC task in which stimulus location was relevant. We examined whether such associations also transfer between orthogonal SRC and Simon tasks and whether correspondence of code polarities continues to contribute to performance in the Simon task. In Experiment 1, the orthogonal Simon effect was larger after practising with an up-right/down-left mapping of visual stimuli to responses than with the alternative mapping, for which the orthogonal Simon effect tended to reverse. Experiment 2 showed similar results when practice was with high (up) and low (down) pitch tones, though the influence of practice mapping was not as large as that in Experiment 1, implying that the short-term S-R associations acquired in practice are at least in part not modality specific. In Experiment 3, response eccentricity and practice mapping were shown to have separate influences on the orthogonal Simon effect, as expected if both code polarity and acquired S-R associations contribute to performance.     

Reducing and restoring stimulus-response compatibility effects by decreasing the discriminability of location words

In two experiments, we compared level of activation and temporal overlap accounts of compatibility effects in the Simon task by reducing the discriminability of spatial and non-spatial features of a target location word. Participants made keypress responses to the non-spatial or spatial feature of centrally presented location words. The discriminability of the spatial feature of the word (Experiment 1), or of both the spatial and non-spatial feature (Experiment 2), was manipulated. When the spatial feature of the word was task-irrelevant, lowering the discriminability of this feature reduced the compatibility effect. The compatibility effect was restored when the discriminability of both the task-relevant and task-irrelevant features were reduced together. Results provide further evidence for the temporal overlap account of compatibility effects. Furthermore, compatibility effects when the spatial information was task-relevant and those when the spatial information was task-irrelevant were moderately correlated with each other, suggesting a common underlying mechanism in both versions.     

Influence of mapping complexity on negative priming for incompatible spatial mappings

For tasks with an incompatible stimulus-response mapping, whether the compatible response must be inhibited paradigm for four-choice tasks with three different incompatible spatial mappings. For a mapping that did not follow a simple rule, reaction time was lengthened when the corresponding response on the preceding trial became the required response on the current trial, as compared with when it did not, showing a negative priming effect. However, for mappings that followed a simple rule, negative priming was not evident. The present study extends this research to a more complex mapping. On the basis of a two-process model adopted from the negative priming literature, we hypothesized that high mapping complexity should also diminish the negative priming effect for incompatible mappings, because the balance of cognitive resources is allocated to identification of the correct response. Two experiments are reported in which mappings of different complexity were used in six-choice spatial tasks. Analyses of reaction times showed that negative priming diminished with increased mapping complexity, apparently due to increased dominance of response identification processes, rather than inhibition of the corresponding response.     

Empirical evaluation and justification of methodologies in psychological science.

The purpose of this article is to describe a relatively new movement in the history and philosophy of science, naturalism, a form of pragmatism emphasizing that methodological principles are empirical statements. Thus, methodological principles must be evaluated and justified on the same basis as other empirical statements. On this view, methodological statements may be less secure than the specific scientific theories to which they give rise. The authors examined the feasibility of a naturalistic approach to methodology using logical and historical analysis and by contrasting theories that predict new facts versus theories that explain already known facts. They provide examples of how differences over methodological issues in psychology and in science generally may be resolved using a naturalistic, or empirical, approach.     

Enhancement of the Simon effect by response precuing.

When stimuli are presented to the left or right of fixation, and stimulus location is irrelevant, responses are faster if the stimulus location coincides with the location of the assigned response. This phenomenon is called the Simon effect. The present study examined the influence on the Simon effect of attentional precues that signaled the likely stimulus location and intentional precues that signaled the likely response. Experiment 1 was a close procedural replication of an experiment by Verfaellie, Bowers, and Heilman (1988); consistent with their findings, the Simon effect was enhanced by the intentional precue and unaffected by the attentional precue. Experiments 2 and 3 demonstrated the importance of the intentional precue with simpler procedures that involved only intentional and attentional precues, respectively. Finally, the intentional precuing enhancement of the Simon effect was obtained when two stimuli were assigned to each response, regardless of whether the hands were uncrossed (experiment 4) or crossed (experiment 5). Overall, the results indicate that response precuing enhances the Simon effect and favor response-selection accounts over those that attribute the effect to stimulus identification.