The action congruency effect on the feelings of agency

Previous studies suggest that the sense of agency (SoA), the feeling of control about one’s own actions and ensuing effects is also generated during action selection processes. We investigate whether the conflict at the action selection stage induced by a supraliminal stimulus, modulates an implicit measure of SoA, namely intentional binding. Furthermore, we were interested to investigate the influence of different types of stimulus-response compatibility on SoA. To this aim we compared the influence of an automatic imitation task and a stroop-like task on intentional binding. In both tasks participants performed congruent and incongruent fingers movements (key release) in response to an external stimulus. Their movements caused an effect and participants estimated the time between their action and the ensuing effect. We found a reduced intentional binding effect in incongruent compared to congruent conditions in both tasks. The results are discussed within the theoretical framework of the fluency of action.     

Simon congruency effects based on stimulus and response numerosity

Three choice reaction time experiments documented a Simon-type congruence effect involving the numbers of stimuli and responses. In Experiment 1 the stimulus consisted of one or two high- or low-pitch tones, and participants were required to respond with one or two taps of a response key depending on stimulus pitch. Responses were faster when the number of tones matched the required number of response taps than when these numbers mismatched. Experiment 2 showed that a weaker version of this effect can also be obtained using visual stimuli, and Experiment 3 showed that the analogous effect can even be obtained, albeit very weakly, with bimodal stimuli. There was also evidence that the number of stimuli affected the rate of emitting the two-tap response. These results indicate that stimulus numerosity is processed automatically to the level at which it can affect the selection and possibly the execution of a varying number of responses.     

Simon congruency effects based on stimulus and response numerosity

Three choice reaction time experiments documented a Simon-type congruence effect involving the numbers of stimuli and responses. In Experiment 1 the stimulus consisted of one or two high- or low-pitch tones, and participants were required to respond with one or two taps of a response key depending on stimulus pitch. Responses were faster when the number of tones matched the required number of response taps than when these numbers mismatched. Experiment 2 showed that a weaker version of this effect can also be obtained using visual stimuli, and Experiment 3 showed that the analogous effect can even be obtained, albeit very weakly, with bimodal stimuli. There was also evidence that the number of stimuli affected the rate of emitting the two-tap response. These results indicate that stimulus numerosity is processed automatically to the level at which it can affect the selection and possibly the execution of a varying number of responses.     

Automatic integration of non-perceptual action effect features: the case of the associative affective Simon effect

In the first phase of Experiment 1, participants were instructed to move a response key up or down in response to a go signal. One of both responses was consistently followed by an aversive stimulus, whereas the other response was never followed by the aversive stimulus. In a subsequent test phase, the same responses had to be emitted according to the grammatical category (noun or adjective) of positive and negative target words. Results showed that the level of affective correspondence between the task-irrelevant positive or negative connotation of the target and the motivational significance of the effect of the correct response influenced performance. The results of Experiment 2 replicated those of Experiment 1, using alternating target-response assignment. These findings point to the integration of affective action effect feature codes in the cognitive representation of actions.     

The functional role of attention for spatial coding in the Simon effect

Summary Two experiments investigated relative spatial coding in the Simon effect. It was hypothesized that relative spatial coding is carried out with reference to the position of the focus of visual attention. The spatial code for an imperative stimulus presented exactly at the position of focal attention should be neutral on the horizontal plane, and therefore no Simon effect should be observed. However, when the imperative stimulus is presented to the left or to the right of the current position of focal attention, the spatial code should not be neutral, thus producing a Simon effect. In both experiments, focal attention was manipulated either by a peripherally presented onset precue (Experiment 1) or by a centrally presented symbolic precue (Experiment 2). Results showed that the Simon effect was substantially reduced in both experiments when a valid precue preceded the imperative stimulus just in time to conclude refocusing of attention to the position of the imperative stimulus before it was presented. However, conditions with neutral precues yielded a normally sized Simon effect. In both experiments, the Simon effect decreased as the SOA grew when the precue was valid. At least for the Simon effect, the results can be interpreted as evidence that relative spatial coding is functionally related to the position of the focus of attention.     

Contextual influences on the sequential congruency effect

The sequential congruency effect (SCE) refers to the reduction in the size of the congruency effect following incongruent, relative to congruent, trials. Prior evidence indicated that the SCE does not generalize across tasks or different conflict-producing feature dimensions. We present results from a Stroop task showing that when the local list context is such that all colors and words appear in the same proportion of congruent trials, the SCE is present, but when those same items vary in the proportions congruent, the SCE is absent. We suggest that if stimuli are sufficiently consistent in the informativeness of their dimensions for the responses, individuals will attempt to track such information and weight the dimensions accordingly. In this way, the SCE reflects sequential adjustments to the weights given to individual stimulus dimensions in an attempt to track this information.     

Religion and action control: Faith-specific modulation of the Simon effect but not Stop-Signal performance

Previous findings suggest that religion has a specific impact on attentional processes. Here we show that religion also affects action control. Experiment 1 compared Dutch Calvinists and Dutch atheists, matched for age, sex, intelligence, education, and cultural and socio-economic background, and Experiment 2 compared Italian Catholics with matched Italian seculars. As expected, Calvinists showed a smaller and Catholics a larger Simon effect than nonbelievers, while performance of the groups was comparable in the Stop-Signal task. This pattern suggests that religions emphasizing individualism or collectivism affects action control in specific ways, presumably by inducing chronic biases towards a more “exclusive” or “inclusive” style of decision-making. Interestingly, there was no evidence that religious practice affects inhibitory skills.     

Automatic spatial coding of perceived gaze direction is revealed by the Simon effect

In a typical Simon task, the (irrelevant) spatial position of the stimulus interferes with the processing of the salient characteristic (e.g., color). We used the Simon effect to investigate the automatic processing of gaze cues. We show that a simple drawing of schematic eyes automatically generates a spatially defined code of gaze direction. Although completely irrelevant to the task, direction of gaze influenced reaction times in a spatially selective two-choice discrimination based on eye color. Moreover, in one experiment employing an orthogonal manipulation of stimulus position and gaze direction, we found that coding of gaze direction is independent of stimulus spatial coding. Our finding of a “gazedirection Simon effect” is congruent with the hypothesis that gaze direction is coded by a specialized mechanism.     

The Simon effect and handedness: evidence for a dominant-hand attentional bias in spatial coding

In two experiments, the relation between handedness and the size of the Simon effect in each visual hemifield was investigated. Experiment 1 showed that the Simon effect was larger in the right visual hemifield in right-handers and in the left visual hemifield in left-handers, whereas ambidextrous individuals showed a symmetric Simon effect. In Experiment 2, participants performed the same Simon task as in Experiment 1, but with their hands crossed. The right- and left-handed groups showed a reversed pattern of results with respect to Experiment 1. We explained this phenomenon as a part of a more general account in which perception and action are embedded in a perception-for-action system. In this system, an attentional bias originating from the field of operation of the dominant hand would be at the basis of the relationship between the asymmetry of the Simon effect and handedness.     

Modes of spatial coding in the Simon task*

Many models of the Simon effect assume that categorical spatial representations underlie the phenomenon. The present study tested this assumption explicitly in two experiments, both of which involved eight possible spatial positions of imperative stimuli arranged horizontally on the screen. In Experiment 1, the eight stimulus locations were marked with eight square boxes that appeared at the same time during a trial. Results showed gradually increasing Simon effects from the central locations to the outer locations. In Experiment 2, the eight stimulus locations consisted of a combination of three frames of spatial reference (hemispace, hemifield, and position relative to the fixation), with each frame appearing in different timings. In contrast to Experiment 1, results showed an oscillating pattern of the Simon effect across the horizontal positions. These findings are discussed in terms of grouping factors involved in the Simon task. The locations seem to be coded as a single continuous dimension when all are visible at once as in Experiment 1, but they are represented as a combination of the lateral categories (“left” vs. “right”) with multiple frames of reference when the reference frames are presented successively as in Experiment 2.     

Elimination of the enhanced Simon effect for older adults in a three-choice situation: Ageing and the Simon effect in a go/no-go Simon task

In a Simon task, participants show better performance when the irrelevant stimulus location corresponds with the response location than when it does not, and this effect is typically greater for older adults than for younger adults. To study the effect of cognitive ageing in the Simon task, we compared young and old adults using two versions of the Simon task: (a) a standard visual Simon task, for which participants respond with left and right key-presses to the red and green colours of stimuli presented in left and right locations; (b) a go/no-go version of the Simon task, which was basically the same, except that the shape of the stimulus in one third of the trials indicates that no response is to be made. In both tasks, both age groups showed the Simon effect. The magnitude of the effect for the standard Simon task was greater for the older adults than for the younger adults. Nevertheless, the two groups showed an equivalent Simon effect in the go/no-go version of the Simon task. Reaction time distribution analyses revealed basically similar functions for both age groups: a decreasing pattern of the Simon effect in the standard task and an increasing pattern of the effect in the go/no-go version of the task. The results suggest that older adults find it more difficult to suppress an automatic activation of the corresponding response, though this automatic activation was reduced in situations where the response was frequently inhibited.     

Increased spatial salience in the social Simon task: A response-coding account of spatial compatibility effects

A spatial compatibility effect (SCE) is typically observed in forced two-choice tasks in which a spatially defined response (e.g., pressing a left vs. a right key) has to be executed to a nonspatial feature of a stimulus (e.g., discriminating red from green) that is additionally connoted by a spatial feature (e.g., the stimulus points to the left or the right). Responses are faster and more accurate when the response side and the spatial stimulus feature are compatible than when they are incompatible. Previous research has demonstrated that SCEs are diminished when stimuli from only one response category are responded to in individual go/no-go tasks, whereas SCEs reemerge when two participants work jointly on two complementary, individual go/no-go tasks in a joint go/no-go task setting. This social Simon effect has been considered evidence for shared task representations. We show that SCEs emerge in individual go/no-go tasks when the spatial dimension is made more salient, whereas SCEs are eliminated in joint go/no-go tasks when the spatial dimension is made less salient. These findings are consistent with an account of social Simon effects in terms of spatial response coding, whereas they are inconsistent with an account of shared task representations. The relevance of social factors for spatial response coding is discussed.     

Coding controlled and triggered cursor movements as action effects: influences on the auditory Simon effect for wheel-rotation responses

Four experiments investigated influences of irrelevant action effects on response selection in Simon tasks for which tone pitch was relevant and location irrelevant, and responses were clockwise- counterclockwise wheel rotations. When the wheel controlled left-right movement of a cursor in a direction opposite an instructed left-right hand-movement goal, the Simon effect was reduced. When the wheel was held at the bottom, this reduction was due to some participants coding responses relative to the cursor and others relative to the hands. However, when the wheel was held at the top, it was due to participants integrating cursor movements with hand movements as a single action concept. In contrast, a cursor triggered by the wheel movement showed little influence on the Simon effect, even when contiguity and contingency with the wheel movements were high. Experience with the controlled cursor in a prior trial block or between trials established a causal relation that enabled participants to code the triggered cursor as belonging to the action concept and thus reduce the Simon effect. Multiple factors determine the influence of an irrelevant action effect on performance.     

Object-location binding across a saccade: A retinotopic spatial congruency bias

Despite frequent eye movements that rapidly shift the locations of objects on our retinas, our visual system creates a stable perception of the world. To do this, it must convert eye-centered (retinotopic) input to world-centered (spatiotopic) percepts. Moreover, for successful behavior we must also incorporate information about object features/identities during this updating – a fundamental challenge that remains to be understood. Here we adapted a recent behavioral paradigm, the “spatial congruency bias,” to investigate object-location binding across an eye movement. In two initial baseline experiments, we showed that the spatial congruency bias was present for both gabor and face stimuli in addition to the object stimuli used in the original paradigm. Then, across three main experiments, we found the bias was preserved across an eye movement, but only in retinotopic coordinates: Subjects were more likely to perceive two stimuli as having the same features/identity when they were presented in the same retinotopic location. Strikingly, there was no evidence of location binding in the more ecologically relevant spatiotopic (world-centered) coordinates; the reference frame did not update to spatiotopic even at longer post-saccade delays, nor did it transition to spatiotopic with more complex stimuli (gabors, shapes, and faces all showed a retinotopic congruency bias). Our results suggest that object-location binding may be tied to retinotopic coordinates, and that it may need to be re-established following each eye movement rather than being automatically updated to spatiotopic coordinates.     

No effect of synesthetic congruency on temporal ventriloquism

A sound presented in temporal proximity to a light can alter the perceived temporal occurrence of that light (temporal ventriloquism). Recent studies have suggested that pitch-size synesthetic congruency (i.e., a natural association between the relative pitch of a sound and the relative size of a visual stimulus) might affect this phenomenon. To reexamine this, participants made temporal order judgements about small- and large-sized visual stimuli while high- or low-pitched tones were presented before the first and after the second light. We replicated a previous study showing that, at large sound-light intervals, sensitivity for visual temporal order was better for synesthetically congruent than for incongruent pairs. However, this congruency effect could not be attributed to temporal ventriloquism, since it disappeared at short sound-light intervals, if compared with a synchronous audiovisual baseline condition that excluded response biases. In addition, synesthetic congruency did not affect temporal ventriloquism even if participants were made explicitly aware of congruency before testing. Our results thus challenge the view that synesthetic congruency affects temporal ventriloquism.     

Attention precuing and Simon effects: A test of the attention-coding account of the Simon effect

Simon effects refer to the finding that choice-response latencies to a nonspatial aspect of a stimulus vary depending on the spatial correspondence between the stimulus position and the position of the correct response alternative. Recently, researchers have proposed an attention-coding account of Simon effects whereby the (irrelevant) stimulus spatial code involved in the generation of the effect is formed in the process of attentional orienting to the stimulus. This account predicts that if attentional orienting is unnecessary at stimulus onset, as when the stimulus appears at an attended location, Simon effects will not be observed. This prediction was tested by measurement of Simon effects in an attention-precuing task in which the stimulus was presented at attended and unattended locations. Significant Simon effects were observed independently of the focus of attention. This result was obtained over a large range of precue-target SOAs, and did not depend on whether central or peripheral precues were used to direct attention or on whether the relevant target dimension was color or form. Significant Simon effects were not observed when the precue-target SOA was 50 ms, irrespective of the other precue and task conditions. The data do not support the prediction of the attention-coding account and thus question the generality of the account in its current form. It is suggested that spatial and temporal uncertainties are important factors that influence the pattern of results, and that these factors must be incorporated into attention-coding models of the Simon effect.     

A Simon effect in pigeons

Pigeons pecked left versus right keys contingent upon the color presented at 1 of those locations. Spatial-response latencies were shorter when the color appeared at the same location as the required response than at the opposite location. This Simon effect occurred when the stimulus on the alternative key was constant, varied from trial to trial, or changed when the color cue appeared and when the reinforcement probability for correct responses was the same on corresponding as on noncorresponding trials. Humans performing the same task by touching the keys also showed the Simon effect. These findings demonstrate that for pigeons, too, a relevant symbolic cue activates a spatial code that produces faster responses at the location corresponding with the activated code.