Biomedical subjects

Mark Van Selst

Publications and source records attributed to Mark Van Selst.

4 recordsLinked to original sources

PubMed2005

Alcohol-induced impairment of behavioral control: differential effects on engaging vs. disengaging responses.

RATIONALE: Model-based assessments of behavioral control have been used to study the acute effects of alcohol on the ability to execute and inhibit behavioral responses. Response inhibition appears more vulnerable to the impairing effects of alcohol than response execution. Current information processing models have yet to account for this observation. OBJECTIVES: The present study used a reductionist approach to determine if the particular vulnerability of response inhibition to the effects of alcohol occurs at the level of the action (motor program). The study examined the effects of alcohol on the ability to execute and inhibit behavior in a context in which preliminary information signaled the likelihood that a response should be executed or suppressed. The engagement and disengagement of responses were directly compared under alcohol. METHODS: Adults (N = 24) performed a cued go/no-go task that required quick responses to go targets and suppression of responses to no-go targets. Response requirements were manipulated by varying the nature of the action required whereby half of the participants made key press responses (response engagement) and the other half released ongoing key presses (response disengagement). Performance was tested under three doses of alcohol: 0.00, 0.45, and 0.65 g/kg. RESULTS: Dose-dependent increases in commission errors were only observed with response engagement and not with response disengagement. Reaction times were faster for response engagement than response disengagement. CONCLUSIONS: Response disengagement affords some protection against alcohol-induced impairment of inhibition, indicating that not all aspects of motor processing requiring inhibition are equally impaired by alcohol.

Adult↗

PubMed2004

How does practice reduce dual-task interference: integration, automatization, or just stage-shortening?

The present study assessed three hypotheses of how practice reduces dual-task interference: Practice teaches participants to efficiently integrate performance of a task pair; practice promotes automatization of individual tasks, allowing the central bottleneck to be bypassed; practice leaves the bottleneck intact but shorter in duration. These hypotheses were tested in two transfer-of-training experiments. Participants received one of three training types (Task 1 only, or Task 2 only, or dual-task), followed by dual-task test sessions. Practice effects in Experiment 1 (Task 1: auditory-vocal; Task 2: visual-manual) were fully explained by the intact bottleneck hypothesis, without task integration or automatization. This hypothesis also accounted well for the majority of participants when the task order was reversed (Experiment 2). In this case, however, there were multiple indicators that several participants had succeeded in eliminating the bottleneck by automatizing one or both tasks. Neither experiment provided any evidence that practice promotes efficient task integration.

Automatism↗

PubMed2003

Vanishing dual-task interference after practice: has the bottleneck been eliminated or is it merely latent?

Practice can, in some cases, largely eliminate measured dual-task interference. Does this absence of interference indicate the absence of a processing bottleneck (defined as an inability to carry out certain stages in parallel)? The authors show that a bottleneck need not produce any observable interference, provided that there is no temporal overlap in the demand for bottleneck stages on the 2 tasks. Such a "latent" bottleneck is especially likely after practice, when central stages are short. The authors provide new evidence that a latent bottleneck occurred for a participant who produced no interference in M. Van Selst, E. Ruthruff, and J. C. Johnston (1999). These findings demonstrate that the absence of dual-task interference does not necessarily indicate the absence of a processing bottleneck.

Attention↗

PubMed2002

Constraints on information processing under alcohol in the context of response execution and response suppression.

This study tested the degree that alcohol restricts information processing on tasks requiring response execution and response suppression. A dual task required 12 participants to respond to 2 task stimuli (Tasks 1 and 2) presented in close succession. The task was performed before and after receiving 3 alcohol doses (placebo, 0.45 g/kg, and 0.65 g/kg) administered on separate days in a counterbalanced order. Alcohol increased task interference, as evidenced by increased time to respond to Task 2. Impairment was comparable regardless of whether Task 1 required a response to be executed or suppressed. The evidence supports a resource limitation account that argues that alcohol reduces capacity to process information required for execution and suppression of responses.

Acoustic Stimulation↗