Ulrich Ansorge

A response-discrimination account of the Simon effect.

Simon effects might partly reflect stimulus-triggered response activation. According to the response-discrimination hypothesis, however, stimulus-triggered response activation shows up in Simon effects only when stimulus locations match the top-down selected spatial codes used to discriminate between alternative responses. Five experiments support this hypothesis. In Experiment 1, spatial codes of each response differed by horizontal and vertical axis position, yet one axis discriminated between alternative responses, whereas the other did not. Simon effects resulted for targets on discriminating axes only. In Experiment 2, both spatial axes discriminated between responses, and targets on both axes produced Simon effects. In Experiment 3, Simon effects resulted for a spatial choice-reaction task but not for a go/no-go task. Even in the go/no-go task, a Simon effect was restored when a two-choice reaction task preceded the go/no-go task (Experiment 4) or when participants initiated trials with responses spatially discriminated from the go response (Experiment 5).

Exploring trial-by-trial modulations of the Simon effect.

The present study investigates sequential modulations of the Simon effect. The Simon effect involves faster responses to spatially corresponding than to noncorresponding stimuli, even when stimulus position is irrelevant. Recently, the Simon effect has been shown to decrease or to disappear after noncorresponding predecessor trials. Possible explanations for these sequential modulations include (a) the gating of position-based response activation (conflict monitoring), (b) repetition or alternation effects, and (c) the interaction between feature integration (binding) processes and stimulus-response (S-R) correspondence. Three experiments tested different predictions of these models by comparing Simon effects after neutral trials with those after corresponding and noncorresponding trials, respectively, and by varying the stimulus-onset asynchrony (SOA) between and within experiments. Experiments 1 and 2 revealed large Simon effects after corresponding trials, intermediate Simon effects after neutral trials, and small (or no) Simon effects after noncorresponding trials. Moreover, some systematic effects of S-R repetitions and S-R alternations were observed. Finally, the sequential modulations were maximal at short SOAs and decreased with increasing SOA, but still occurred at an SOA of 6 seconds. The results seem to exclude repetition or alternation effects as the main cause of sequential modulations of the Simon effect, but both conflict monitoring and binding may contribute to these effects.

Intentions Determine the Effect of Invisible Metacontrast-Masked Primes: Evidence for Top-Down Contingencies in a Peripheral Cuing Task.

In 5 experiments, the authors tested whether the processing of nonconscious spatial stimulus information depends on a prior intention. This test was conducted with the metacontrast dissociation paradigm. Experiment 1 demonstrated that masked primes that could not be discriminated above chance level affected responses to the visible stimuli that masked them. Experiments 2 and 3 showed that this effect was abolished when the task instruction was changed in such a way that the primes ceased to be task relevant. Experiments 4 and 5 demonstrated that a primes effect depended on whether it was associated with the same response as the target or with an opposite response.

Direct parameter specification of an attention shift: evidence from perceptual latency priming

In the direct parameter specification (DPS) mode of sensorimotor control, response parameters can be specified by stimuli that are not consciously perceived [Psychological Research/Psychologische Forschung 52 (1990) 207]. DPS is contingent on the current intentions. The invisible stimuli can be processed for the purposes of sensorimotor control only if they match the actual intentions, for example, share task-relevant features. The present experiments explore whether attentional capture by masked abrupt-onset stimuli is mediated via DPS. Participants judged which of two visual targets appeared first. Masked primes preceded one of the targets. The primes were either similar to the targets or not, in shape, or in color. Target-like (task-relevant), but not distractor-like (task-irrelevant), primes facilitated perceptual latencies of targets trailing at their positions. Thus, the latency effects resulted from DPS of an attention shift, rather than from bottom-up capture or from top-down search for dynamic features.

Influences of visibility, intentions, and probability in a peripheral cuing task.

According to the concept of direct parameter specification, nonconsciously registered information can be processed to the extent that it matches currently active intentions of a person. This prediction was tested and confirmed in the current study. Masked visual information provided by peripheral cues led to reaction time (RT) effects only if the information specified one of the required responses (Experiments 1 and 3). Information delivered by the same masked cues that did not match the intentions was not used. However, the same information influenced RT if it was provided by visible cues (Experiments 2 and 3). The results suggest that the processing of nonconsciously registered information is flexible because it is susceptible to the changing intentions of a person. Yet, these processes are apparently restricted, as nonconsciously registered information cannot be used as easily for purposes not corresponding to the currently active intentions as better visible information.

Spatial intention-response compatibility

In the current investigation the assumption that intentions and actions are represented in the same medium or code (common coding hypothesis of intention and action) was tested and confirmed [Q. J. Exp. Psychol. 52 (1999) 1; Eur. J. Cognit. Psychol. 9 (1997) 129]. In two experiments it is shown that the intention to produce a spatial consequence in the environment to an otherwise spatially neutral stimulus leads to a shorter response, if the responses and the intended consequences share relative positions compared to a situation where this is not the case. In two control experiments it is ruled out that this spatial intention-response compatibility effect is due to an intention-independent expectancy of the consequences of the correct responses.

Goal-driven attentional capture by invisible colors: Evidence from event-related potentials

We combined event-related brain potentials (ERPs) and behavioral measures to test whether subliminal visual stimuli can capture attention in a goal-dependent manner. Participants searched for visual targets defined by a specific color. Search displays served as metacontrast masks for preceding cue displays that contained one cue in the target color. Although this target-color cue was spatially uninformative, it produced behavioral spatial cuing effects and triggered an ERP correlate of attentional selection (i.e., the N2pc component). These results demonstrate that target-color cues captured attention, in spite of the fact that cue localization performance assessed in separate blocks was at chance level. We conclude that task-set contingent attentional capture is not restricted to supraliminal stimuli, but is also elicited by visual events that are not consciously perceived.

No conflict control in the absence of awareness

IntroductionIn the present study we tested whether control over the impact of potentially conflicting information depends on awareness of that conflicting information.Method and ResultsIn Experiment 1 participants performed a response-priming task, with either masked or unmasked primes. Prime awareness was assessed on a trial-by-trial basis. A typical conflict control pattern, with reduced priming effects following incongruent rather than congruent primes in the preceding trial was found. Yet, this pattern was obtained only when the prime information was visible and not when it was invisible. With invisible primes the effect did not occur, even when participants accidently judged the prime information correctly. Importantly, this confinement of the conflict adaptation effect to unmasked primes occurred despite identical prime processing times with and without masking−a variable that was confounded with prime awareness in previous studies. In Experiment 2, a similar data pattern was found for judgment times regarding the congruency of prime-target pairs.ConclusionAltogether, the results support the conclusion that awareness of visual primes is important for controlling conflict in visuo-motor processing.

A Body-Related Dot-Probe Task Reveals Distinct Attentional Patterns for Bulimia Nervosa and Anorexia Nervosa

We investigated body-related attentional biases in eating disorders by testing whether individuals with anorexia nervosa (AN, n = 19) and bulimia nervosa (BN, n = 18) differ from healthy controls (HC, n = 21) in their bias for attending to a photo of their own body (self-photo) relative to a photo of a matched control participants body (other photo). In a modified dot-probe task, self- and other photos served as cues on the left and the right of the screen. After 1 of 2 time intervals, 1 of the photos was singled out by a surrounding frame, and participants had to saccade toward it. Saccade latency was used as an index of covert attention to the cue photos. In the AN group, saccades were faster when the self-photo was the target than when the other photo was the target. In the BN group, there was a numerically opposite but nonsignificant pattern. Cues did not affect saccade latencies in healthy controls. The bias for self-photos correlated with body dissatisfaction in the AN group. This is the first evidence of an attentional bias for self-photos over other photos in the AN group and for fundamental attentional differences between AN and BN.

Controlling the Unconscious Attentional Task Sets Modulate Subliminal Semantic and Visuomotor Processes Differentially

Are unconscious processes susceptible to attentional influences? In two subliminal priming experiments, we investigated whether task sets differentially modulate the sensitivity of unconscious processing pathways. We developed a novel procedure for masked semantic priming of words (Experiment 1) and masked visuomotor priming of geometrical shapes (Experiment 2). Before presentation of the masked prime, participants performed an induction task in which they attended to either semantic or perceptual object features designed to activate a semantic or perceptual task set, respectively. Behavioral and electrophysiological effects showed that the induction tasks differentially modulated subliminal priming: Semantic priming, which involves access to conceptual meaning, was found after the semantic induction task but not after the perceptual induction task. Visuomotor priming was observed after the perceptual induction task but not after the semantic induction task. These results demonstrate that unconscious cognition is influenced by attentional control. Unconscious processes in perceptual and semantic processing streams are coordinated congruently with higher-level action goals.