Spatial Compatibility Effects Research Articles

Differential dynamics of spatial and non-spatial stimulus-response compatibility effects: A dual task LRP study

Choice reaction times are shorter when stimulus and response features are compatible rather than incompatible. Recent studies revealed that spatial compatibility effects in Simon tasks are strongly attenuated when there is temporal overlap with a different high-priority task. In contrast, non-spatial variants of the Simon task appear to be unaffected by task overlap. The present study used the lateralized readiness potential (LRP) within a dual task design to elucidate the dynamics underlying these differential effects for a color and a spatial variant of the Simon task. In the color version there was no sign of early response priming by irrelevant stimulus features in the LRP. The color compatibility effect was independent of task overlap and reflected in the LRP onset latency. In contrast, in the spatial version, priming by irrelevant stimulus location showed up and was mirrored by early LRP activation. Response priming and the corresponding Simon effect, however, were present only in case of little temporal overlap with the primary task. The absence of spatial compatibility effects at strong temporal overlap suggests that response conflicts due to stimulus-related priming depend on the availability of processing resources.

Individual Differences in Subconscious Motor Control Predicted by GABA Concentration in SMA

Subliminal visual stimuli affect motor planning, but the size of such effects differs greatly between individuals. Here, we investigated whether such variation may be related to neurochemical differences between people. Cortical responsiveness is expected to be lower under the influence of more of the main inhibitory neurotransmitter, GABA. Thus, we hypothesized that, if an individual has more GABA in the supplementary motor area (SMA)--a region previously associated with automatic motor control--this would result in smaller subliminal effects. We measured the reversed masked prime--or negative compatibility--effect, and found that it correlated strongly with GABA concentration, measured with magnetic resonance spectroscopy. This occurred specifically in the SMA region, and not in other regions from which spectroscopy measurements were taken. We replicated these results in an independent cohort: more GABA in the SMA region is reliably associated with smaller effect size. These findings suggest that, across individuals, the responsiveness of subconscious motor mechanisms is related to GABA concentration in the SMA.

Parallel patterns of spatial compatibility and spatial congruence…as long as you don't look too closely

The effects of spatial compatibility and spatial congruence have both been explained in terms of a dual-route model under which spatial information about the stimulus, regardless of task relevance, is directly passed from perception to action. Recently, however, some alternatives to the dual-route model of the Simon Effect have been proposed (or re-introduced) as viable explanations. The present experiment compared the magnitudes of the effects of spatial compatibility and spatial congruence across a range of tasks that varied in their dimensional overlap. The results exhibited a remarkable parallel between the two phenomena when viewed only in terms of the interaction between stimulus set and response set. This could be taken as new evidence for a common origin. However, when the entire pattern of results was examined, a large difference between compatibility and congruence were also seen, which implies that there is at least one important difference between the two phenomena.

Processing time shifts affects the execution of motor responses

We explore whether time shifts in text comprehension are represented spatially. Participants read sentences involving past or future events and made sensibility judgment responses in one of two ways: (1) moving toward or away from their body and (2) pressing the toward or away buttons without moving. Previous work suggests that spatial compatibility effects should be observed, where the future is mapped onto responses away from the body, and the past is mapped onto responses toward the body. These effects were observed, but only when participants were moving to make their responses, and only for larger time shifts (e.g., a month).

Three-dimensional spatial stimulus–response (S–R) compatibility for visual signals with hand and foot controls

This study investigated the performance of 24 participants in eight different three-dimensional spatial stimulus–response (S–R) mapping conditions. The stimulus visual signals were positioned at the corners of an imaginary cube, and responses were made by hands and feet. There was a significant interaction of visual signal position and response device position which demonstrated the existence of a strong spatial S–R compatibility effect in the task. Relatively faster reaction times and lower error percentages were obtained for the compatible S–R conditions. The spatial compatibility effect in the up–down dimension was the strongest, and the effect in the left–right dimension was stronger than the effect in the front–rear dimension. The findings of this study could be translated into practical and useful ergonomics recommendations for designing visual displays and control devices in three-dimensional space for improving overall human–machine system performance.

Object affordance and spatial-compatibility effects in Parkinson's disease

Movement in Parkinson's disease (PD) is strongly influenced by sensory stimuli. Here, we investigated two features of visual stimuli known to affect response times in healthy individuals; the spatial location of an object (the spatial effect) and its action-relevance (the ‘affordance’ effect). Poliakoff et al. (2007) found that while PD patients show normal spatial effects, they do not show an additional affordance effect. Here we investigated whether these effects are driven by facilitation or inhibition, and whether the affordance effect emerges over a longer time-course in PD. Participants (24 PD and 24 controls) viewed either a lateralised door handle (affordance condition), a lateralised abstract stimulus (spatial condition), or a centrally presented baseline stimulus (baseline condition), and responded to a colour change in the stimulus occurring after 0msec, 500msec or 1000msec. The colour change indicated whether to respond with the left or right hand, which were either spatially compatible or incompatible with the lateralised stimulus orientation in the affordance and spatial conditions. The baseline condition allowed us to assess whether compatibility effects were driven by facilitation of the compatible response or inhibition of the incompatible response. The results indicate that stimulus orientation elicited faster responses from the nearest hand. For controls, the affordance effect was stronger and driven by facilitation, whilst the spatial condition was driven by inhibition. In contrast, the affordance and spatial-compatibility effects did not differ between conditions in the PD group and both were driven by facilitation. This suggests that the PD group responded as if all stimuli were action-relevant, and may have implications for understanding the cueing of movement in PD.

Reversed effects of spatial compatibility in natural scenes

Effects of spatial stimulus-response compatibility are often attributed to automatic position-based activation of the response elicited by a stimulus. Three experiments examined this assumption in natural scenes. In Experiments 1 and 2, participants performed simulated driving, and a person appeared periodically on either side of the road. Participants were to turn toward a person calling a taxi and away from a person carelessly entering the street. The spatially incompatible response was faster than the compatible response, but neutral stimuli showed a typical benefit for spatially compatible responses. Placing the people further in the visual periphery eliminated the advantage for the incompatible response and showed an advantage for the compatible response. In Experiment 3, participants made left-right joystick responses to a vicious dog or puppy in a walking scenario. Instructions were to avoid the vicious dog and approach the puppy or vice versa. Results again showed an advantage for the spatially incompatible response. Thus, the typically observed advantage of spatially compatible responses was reversed for dangerous situations in natural scenes.

Task-defined associations are mode specific for selection of relevant dimension but mode independent for selection of location mapping

When compatible and incompatible mappings of a location-relevant task are mixed, or a location-relevant task is mixed with a task for which stimulus location is irrelevant, the benefit of the compatible mapping is eliminated for physical locations and enhanced for location words. Two experiments examined the influence of presenting the location information for the mixed conditions in different stimulus modes (physical location or word). Experiment 1 showed that the effects of mixing location-relevant and location-irrelevant tasks on the spatial compatibility and Simon effects are reduced when the location information is presented in different modes for the two tasks. Experiment 2 showed, in contrast, that the mode distinction had little influence on the effects of mixed compatible and incompatible mappings for location-relevant tasks: The compatibility effect was eliminated for physical locations and enhanced for words, as when there is no mode distinction. Thus, when location is relevant for one task and colour for the other, the task-defined associations of locations to responses are mode specific, but when location is relevant for both tasks, the associations are mode independent.

The role of selective attention in matching observed and executed actions

Substantial evidence suggests that observed actions can engage their corresponding motor representations within the observer. It is currently believed that this process of observation–execution matching occurs relatively automatically, without the need for top-down control. In this study we tested the susceptibility of the observation–execution matching process to selective attention. We used a Go/NoGo paradigm to investigate the phenomenon of ‘automatic imitation’, in which participants are faster to initiate a hand movement that is congruent with a concurrently observed action, relative to one that is incongruent. First, we replicated previous findings of automatic imitation, and excluded the possibility that spatial compatibility effects might explain these results (Experiment 1). We then presented participants with the same goal-directed actions while directing their attention to an imperative stimulus that spatially overlapped, but was distinct from, the observed actions (Experiment 2). Crucially, automatic imitation no longer occurred when participants directed their attention away from the displayed actions and towards the spatially overlapping stimulus. In a final experiment, we examined whether the automatic imitation of grasp persists when participants attend to an irrelevant feature of the observed action, such as whether it is performed by a left or right hand (Experiment 3). Here we found that automatic imitation is contingent on participants attending to the feature of the observed hand that was relevant to their responses. Together these findings demonstrate the importance of selective mechanisms in the filtering of task-irrelevant actions, and indicate a role for top-down control in limiting the motoric simulation of observed actions.

Does a tool eliminate spatial compatibility effects?

Responding to a stimulus is faster and more accurate when stimulus location and response location spatially correspond than when they do not correspond (stimulus–response compatibility). In five experiments this standard compatibility effect is examined when using a T-shaped lever as a tool. Handling the lever allowed distinguishing body-related action effects (e.g., the tactile feedback from the moving finger) from external action effects (e.g., reaching at the stimulus with the lever's end-point). Results showed that the spatial relationship between stimulus and the direction of the hand movement (S-R compatibility) as well as the relationship between the stimulus and the functional end-points of the tool (S-E compatibility) determine performance. More precisely, responses were fast and less error prone when both kinds of compatibility did correspond than when they did not correspond.

Automatic imitation of intransitive actions

Previous research has indicated a potential discontinuity between monkey and human ventral premotor-parietal mirror systems, namely that monkey mirror systems process only transitive (object-directed) actions, whereas human mirror systems may also process intransitive (non-object-directed) actions. The present study investigated this discontinuity by seeking evidence of automatic imitation of intransitive actions—hand opening and closing—in humans using a simple reaction time (RT), stimulus–response compatibility paradigm. Left–right and up–down spatial compatibility were controlled by ensuring that stimuli were presented and responses executed in orthogonal planes, and automatic imitation was isolated from simple and complex orthogonal spatial compatibility by varying the anatomical identity of the stimulus hand and response hemispace, respectively. In all conditions, action compatible responding was faster than action incompatible responding, and no effects of spatial compatibility were observed. This experiment therefore provides evidence of automatic imitation of intransitive actions, and support for the hypothesis that human and monkey mirror systems differ with respect to the processing of intransitive actions.

Your own actions influence how you perceive other people: A misattribution of action appraisals

The attribution of personal traits to other persons depends on the actions the observer performs at the same time (Bach & Tipper, 2007). Here, we show that the effect reflects a misattribution of appraisals of the observers’ own actions to the actions of others. We exploited spatial compatibility effects to manipulate how fluently—how fast and how accurately—participants identified two individuals performing sporty or academic actions. The traits attributed to each person in a subsequent rating task depended on the fluency of participants’ responses in a specific manner. An individual more fluently identified while performing the academic action appeared more academic and less sporty. An individual more fluently identified while performing the sporty action appeared sportier. Thus, social perception is—at least partially—embodied. The ease of our own responses can be misattributed to the actions of others, affecting which personal traits are attributed to them.

Auditory stimulus-response compatibility and control-display design

This study investigated spatial stimulus-response (S-R) compatibility effects for auditory signals, in order to suggest interface design recommendations. The auditory signals were presented in transverse and longitudinal orientations relative to the listener. The results showed that stimulus-response correspondence was the prime factor contributing to spatial compatibility and that there were spatial compatibility effects for both orientations. Relatively longer reaction times (RTs) and higher error percentages (EPs) were found for the longitudinal orientation than for the transverse one. The results suggest that the longitudinal orientation should not be used for getting attention and soliciting responses when using auditory signals. Transverse orientation signals produced quicker and more accurate responses. For faster reaction times, auditory signals should be positioned on the right hand side of right-handed operators. The length of warning time interval between an alerting visual message and the presentation of an auditory signal was shown to affect reaction time in the transverse stimulus orientation. To shorten reaction times, people should be given a greater than 1-s, and preferably a 3-s, forewarning period before being asked to make a response. For both orientations, reaction times varied with assigned hand posture, indicating that the layout of response keys on, for example, a control console should be compatible with the hand posture of the operators. Uncrossed hand posture should be assigned in the transverse orientation and the right and left hands should be used for the rear and front keys, respectively, in the longitudinal orientation. This study showed that in man–machine interface design, in addition to spatial S-R compatibility, hand position and an appropriate warning time should also be considered.

Spatial compatibility between stimulated eye and response location

It is assumed that the eye-of-origin information is restricted to the visual cortex. However, reactions to monocular stimuli are faster when the response location and the stimulated eye are ipsilateral (compatible trials) than when they are contralateral (incompatible trials). We investigated whether this spatial compatibility effect had the characteristics of the conventional visual Simon effect. We found that the size of the compatibility effect was constant throughout the reaction time distribution, and there were no electrophysiological signs of incorrect response activation. These results indicate that the spatial code derived from eye-of-origin information does not produce a transient activation of the spatially compatible response, but a more tonic influence on response selection. The results also show that monocular information can exert influence outside the visual cortex and that spatial codes can be produced in the absence of attention movements.

Affect and action: Towards an event-coding account

Viewing emotion from an evolutionary perspective, researchers have argued that simple responses to affective stimuli can be triggered without mediation of cognitive processes. Indeed, findings suggest that positively and negatively valenced stimuli trigger approach and avoidance movements automatically. However, affective stimulus–response compatibility phenomena share so many central characteristics with nonaffective stimulus–response compatibility phenomena that one may doubt whether the underlying mechanisms differ. We suggest an “affectively enriched” version of the theory of event coding (TEC) that is able to account for both affective and nonaffective compatibility, and that can account for the observation that both types of compatibility seem to be modulated by goals and intentions. Predictions from the model are tested in an experiment where participants carried out approach and avoidance responses to either the valence or the orientation of emotionally charged pictures. Under affective instruction the positive-approach/negative-avoid mapping yielded faster responses than the positive-avoid/negative-approach mapping, but no such effect was observed under spatial instruction. Conversely, spatial compatibility effects were obtained under spatial, but not under affective instruction. We conclude that affective and nonaffective compatibility effects reflect the same mechanism.

Spatial Compatibility Effects With Tool Use

We explored constraints in responding to spatially variable stimuli when hand movements are transformed into inverse movements of a tool. Generally, the spatial compatibility between stimuli and responses is a powerful determinant of performance. However, many tasks require the use of simple tools such as first-class levers that transform hand movements into inverted movements of a tool. What types of compatibility effects arise with such tools? Participants moved the tip of a pointer to the left or right according to the color of a stimulus. The pointer was manipulated either directly, so that a hand movement caused a pointer movement in the corresponding direction, or indirectly, so that the hand moved the pointer in the opposite direction. Responding was faster when the location of stimulus and the movement direction of the tool corresponded than when they did not correspond, independent of the movement direction of the hand. This occurred when stimulus location was task relevant (Experiment 1) as well as when it was task irrelevant (Experiment 2). Furthermore, responding was delayed when the hand and the relevant end of the tool moved in noncorresponding rather than corresponding directions. These results point to two distinct compatibility effects in tool use: one that relates to the transformation of stimuli into goals and one that relates to the transformation of goals into movements. Potential applications of this research include the prediction and possibly manipulation of unwanted "fulcrum effects" in laparoscopic surgery and other first-class lever movements.

Endogenous orienting modulates the Simon effect: critical factors in experimental design.

Responses are faster when the side of stimulus and response correspond than when they do not correspond, even if stimulus location is irrelevant to the task at hand: the correspondence, spatial compatibility effect, or Simon effect. Generally, it is assumed that an automatically generated spatial code is responsible for this effect, but the precise mechanism underlying the formation of this code is still under dispute. Two major alternatives have been proposed: the referential-coding account, which can be subdivided into a static version and an attention-centered version, and the attention-shift account. These accounts hold clear-cut predictions for attentional cuing experiments. The former would assume a Simon effect irrespective of attentional cuing in its static version, whereas the attention-centered version of the referential-coding account and the attention-shift account would predict a decreased Simon effect on validly as opposed to invalidly cued trials. However, results from previous studies are equivocal to the effects of attentional cuing on the Simon effect. We argue here that attentional cueing reliably modulates the Simon effect if some crucial experimental conditions, mostly relevant for optimizing attentional allocation, are met. Furthermore, we propose that the Simon effect may be better understood within the perspective of supra-modal spatial attention, thereby providing an explanation for observed discrepancies in the literature.

Short article: Control over speeded actions: A common processing locus for micro- and macro-trade-offs?

Cognitive control processes associated with long- and short-term adjustments of human behaviour have attracted much interest recently. It is still unclear, however, whether the mechanisms underlying these adjustments share a common locus within the chain of stimulus-response processing. In order to address this issue, the present study employed a speed-accuracy instruction producing a macro-trade-off, whereas micro-trade-off was studied by means of posterror slowing in reaction time (RT). Participants performed a spatially compatible or incompatible four-stimuli-to-two-response alternative choice RT task. Reliable variations in micro-and macro-trade-off as well as effects of spatial compatibility were found in RT and error rate. Most importantly, posterror slowing was larger when instruction stressed accuracy rather than speed, an effect being independent of spatial compatibility. Because the influence of speed-accuracy instruction and posterror slowing on performance was strongest for response alternations, together present findings suggest that the mechanisms underlying micro- and macro-trade-offs have one common locus at the level of motor processing. Additional influences of macro-trade-off on premotoric processing are likely.

Spatial correspondence between onsets and offsets of stimuli and responses

The Simon effect denotes faster responses when the task-irrelevant stimulus position corresponds to response position than when it does not. A common explanation is that a spatial stimulus code is formed automatically and activates a spatially corresponding response code. Previous research on stimulus–response (S–R) compatibility has focused on the ability to initiate movements to stimulus onsets. The present study investigates spatial-compatibility effects (i.e., the Simon effect) in the ability to initiate and to terminate actions both to stimulus onsets and to stimulus offsets. There were four major results. Firstly, offset stimuli produced normal Simon effects suggesting that stimulus offsets can automatically produce spatial codes. Secondly, onset stimuli produced larger Simon effects than offset stimuli, which is consistent with the attention-shift account of spatial coding. Thirdly, Simon effects were also observed in action termination. Fourthly, Simon effects in action initiation and in action termination were of similar size.

Imitative response tendencies following observation of intransitive actions.

Clear and unequivocal evidence shows that observation of object affordances or transitive actions facilitates the activation of a compatible response. By contrast, the evidence showing response facilitation following observation of intransitive actions is less conclusive because automatic imitation and spatial compatibility have been confounded. Three experiments tested whether observation of a finger movement (i.e., an intransitive action) in a choice reaction-time task facilitates the corresponding finger movement response because of imitation, a common spatial code, or some combination of both factors. The priming effects of a spatial and an imitative stimulus were tested in combination (Experiment 1), in opposition (Experiment 2), and independently (Experiment 3). Contrary to previous findings, the evidence revealed significant contributions from both automatic imitation and spatial compatibility, but the priming effects from an automatic tendency to imitate declined significantly across a block of trials whereas the effects of spatial compatibility remained constant or increased slightly. These differential effects suggest that priming associated with automatic imitation is mediated by a different regime than priming associated with spatial compatibility.