Hannes Schröter

Control Over Location-Based Response Activation in the Simon Task: Behavioral and Electrophysiological Evidence

In 4 Simon experiments the authors examined control over 2 routes of sensorimotor processing: response priming in the unconditional route and response selection via the conditional route. The Simon effect diminished as the frequency of noncorresponding trials increased. Location-based response priming was observed only when the stimulus followed a corresponding event but not after a noncorresponding trial. Therefore, the unconditional route appears to be suppressed whenever the task context indicates priming as potentially disadvantageous. Moreover, the task-irrelevant stimulus location was used for response selection as a function of correspondence probability. Although exact repetitions of stimulus-response sequences caused a marked speed-up of responses, this 3rd mechanism is independent of unconditional route suppression and frequency-based adjustments in the conditional route.

Testing the race model inequality: an algorithm and computer programs.

In divided-attention tasks, responses are faster when two target stimuli are presented, and thus one is redundant, than when only a single target stimulus is presented. Raab (1962) suggested an account of this redundanttargets effect in terms of a race model in which the response to redundant target stimuli is initiated by the faster of two separate target detection processes. Such models make a prediction about the probability distributions of reaction times that is often calledthe race model inequality, and it is often of interest to test this prediction. In this article, we describe a precise algorithm that can be used to test the race model inequality and present MATLAB routines and a Pascal program that implement this algorithm.

Automatic and controlled stimulus processing in conflict tasks: Superimposed diffusion processes and delta functions.

An elaborated diffusion process model (a Diffusion Model for Conflict Tasks, DMC) is introduced that combines conceptual features of standard diffusion models with the notion of controlled and automatic processes. DMC can account for a variety of distributional properties of reaction time (RT) in conflict tasks (e.g., Eriksen flanker, Simon, Stroop). Specifically, DMC is compatible with all observed shapes of delta functions, including negative-going delta functions that are particularly challenging for the class of standard diffusion models. Basically, DMC assumes that the activations of controlled and automatic processes superimpose to trigger a response. Monte Carlo simulations demonstrate that the unfolding of automatic activation in time largely determines the shape of delta functions. Furthermore, the predictions of DMC are consistent with other phenomena observed in conflict tasks such as error rate patterns. In addition, DMC was successfully fitted to experimental data of the standard Eriksen flanker and the Simon task. Thus, the present paper reconciles the prominent and successful class of diffusion models with the empirical finding of negative-going delta functions.

Electrophysiological evidence for response priming and conflict regulation in the auditory Simon task

The Simon effect refers to the finding that responses are faster when the task-irrelevant stimulus and response location correspond than when they do not. The present study examined the role of location-based response priming and its regulation by an ancillary monitoring mechanism (AMM) for the auditory Simon effect, manipulating response modality and analyzing event-related brain potentials (ERPs). An auditory Simon effect was obtained for responses with hand, foot, and eyes. Lateralized ERPs revealed a mix of location-based attentional and motor-related activations early on during information processing. The Simon effect in reaction time (RT) was absent or largely reduced when a non-corresponding rather than a corresponding trial preceded, indicating control over location-based response priming. Importantly, RT modulations as a function of the correspondence sequence were mirrored in the amplitude of a negative difference wave (N2c), in accord with the view that response priming is under control of an AMM. In conclusion, both behavioral and electrophysiological measures revealed effect patterns that are consistent with an information-processing model that assumes asynchronous transmission from two separate processing routes to the motor system and top-down control by an AMM over task-irrelevant response priming.

Effects of redundant auditory stimuli on reaction time.

Auditory redundancy gains were assessed in two experiments in which a simple reaction time task was used. In each trial, an auditory stimulus was presented to the left ear, to the right ear, or simultaneously to both ears. The physical difference between auditory stimuli presented to the two ears was systematically increased across experiments. No redundancy gains were observed when the stimuli were identical pure tones or pure tones of different frequencies (Experiment 1). A clear redundancy gain and evidence of coactivation were obtained, however, when one stimulus was a pure tone and the other was white noise (Experiment 2). Experiment 3 employed a two-alternative forced choice localization task and provided evidence that dichotically presented pure tones of different frequencies are apparently integrated into a single percept, whereas a pure tone and white noise are not fused. The results extend previous findings of redundancy gains and coactivation with visual and bimodal stimuli to the auditory modality. Furthermore, at least within this modality, the results indicate that redundancy gains do not emerge when redundant stimuli are integrated into a single percept.

Motor Limitation in Dual-Task Processing Under Ballistic Movement Conditions

The standard bottleneck model of the psychological refractory period (PRP) assumes that the selection of the second response is postponed until the first response has been selected. Accordingly, dual-task interference is attributed to a single central-processing bottleneck involving decision and response selection, but not the execution of the response itself. In order to critically examine the assumption that response execution is not part of this bottleneck, we systematically manipulated the temporal demand for executing the first response in a classical PRP paradigm. Contrary to the assumption of the standard bottleneck model, this manipulation affected the reaction time for Task 2. Specifically, reaction time for Task 2 increased with execution time for Task 1. This carryover effect from Task 1 to Task 2 provides evidence for the notion that response execution can be part of the processing bottleneck.

Duration perception of visual and auditory oddball stimuli: Does judgment task modulate the temporal oddball effect?

The duration of rare stimuli (oddballs) presented within a stream of homogenous standards tends to be overestimated. This temporal oddball effect (OE) has been attributed to perceptual processes. The OE is usually assessed with a comparative judgment task. It has been argued, however, that this task is prone to decision biases. The present experiments employed comparative and equality judgments, since it has been suggested that equality judgments are less vulnerable to such biases. Experiments 1a and 1b used visual stimuli, and Experiment 2 auditory stimuli. The results provide no strong evidence for decision biases influencing the OE. In addition, computational modeling clearly suggests that the equality judgment is not particularly suited to distinguish between perceptual and decisional effects. Taken together, the pattern of the present results is most consistent with a perceptual origin of the OE.

Error reactivity in self-paced performance: Highly-accurate individuals exhibit largest post-error slowing:

Reaction time is typically increased following an erroneous response. This post-error slowing is traditionally explained by a strategic adjustment of response threshold towards more conservative behaviour. A recently proposed orienting account provides an alternative explanation for post-error slowing. According to this account, committing an error evokes an orienting response (OR), which inhibits information processing in the subsequent trial, resulting in slow and inaccurate performance. We tested a straightforward prediction of the orienting account in the context of self-paced performance, adopting an individual-differences approach: Post-error slowing should be larger the less frequent an error is. To this end, participants were classified into three groups differing in overall performance accuracy. Larger post-error slowing and stronger post-error accuracy decrease were observed for the high-accuracy group than for the two other groups. Practice pronounced the post-error accuracy decline, especially for the high-accuracy group. The results are consistent with the orienting account of post-error slowing but are problematic for accounts based on strategic evaluation mechanisms.

Asking sensitive questions: a statistical power analysis of randomized response models.

This article derives the power curves for a Wald test that can be applied to randomized response models when small prevalence rates must be assessed (e.g., detecting doping behavior among elite athletes). These curves enable the assessment of the statistical power that is associated with each model (e.g., Warners model, crosswise model, unrelated question model, forced-choice models, item count model, cheater detection model). This power analysis can help in choosing the optimal model and sample size and in setting model parameters in survey studies. The general framework can be applied to all existing randomized response model versions. The Appendix of this article contains worked-out numerical examples to demonstrate the power analysis for each specific model.

Motor programming of rapid finger sequences: Inferences from movement‐related brain potentials

The present study investigated the predictions of two prominent models (Klapp, 1995, 2003; Rosenbaum, Inhoff, & Gordon, 1984) of programming of response sequences with the help of behavioral data, the foreperiod Contingent Negative Variation (CNV) and the Lateralized Readiness Potential (LRP). Participants performed one-key and three-key responses with their left or right hand in a precuing task. Sequence length was manipulated across blocks and precues provided either no information, partial information about hand or start finger, or full information about the response. A sequence length effect was indicated by reaction time when the precue provided partial or full information. The LRP data suggested that the duration of motor processes increases with sequence length. Foreperiod LRP and CNV revealed that participants preprogram only the first element of the sequence and prepare multiple responses if the precue provides only partial information. We discuss the implications of current findings for the two models.