The role of instructions,practice, and stimulus-hand correspondence on the Simon effect

Numerous studies of two-choice reaction tasks, including auditory and visual Simon tasks (i.e., tasks in which stimulus location is irrelevant) and visual compatibility tasks, have found that only spatial stimulus-response (S-R) correspondence affected S-R compatibility. Their results provided no indication that stimulus-hand correspondence was a significant factor. However, Wascher et al. (2001) suggested that hand coding plays a role in visual and auditory Simon tasks when the instructions are in terms of the finger/hand used for responding. The present experiments examined whether instructing subjects in terms of response locations or fingers/hands influenced the Simon effect for visual and auditory tasks. In Experiments 1-3, only spatial S-R correspondence contributed significantly to the Simon effect, even when the instructions were in terms of the fingers/hands. However, in Experiment 4, which used auditory stimuli and finger/hand instructions, the contribution of stimulus-hand correspondence increased with practice.     

Auditory stimulus-response compatibility: Is there a contribution of stimulus-hand correspondence?

 Simon, Hinrichs, and Craft found that when subjects responded to a tone in the left or right ear with a left or right keypress, both ear-response-location correspondence and ear-hand correspondence affected reaction time. This outcome is in contrast to results obtained for auditory and visual Simon tasks (i.e., tasks in which stimulus location is irrelevant) as well as results obtained in visual stimulus-response (S-R) compatibility studies, which show only an effect of spatial S-R correspondence. Experiment 1 was a replication of Simon et al.'s experiment in which spatial mapping and hand placement (uncrossed, crossed) were varied. The results were inconsistent with those of Simon et al., showing no ear-hand compatibility effect. Experiment 2 was a second replication with an additional condition examined in which the stimuli were visual locations. The results showed no contribution of stimulus-hand correspondence for either auditory or visual stimuli. Experiment 3 was a replication of another experiment by Simon et al. in which tone pitch was relevant and tone location irrelevant. Like Simon et al.'s data, our results showed no indication that stimulus-hand correspondence is a significant factor. Overall, our results imply that regardless of whether tone location is relevant or irrelevant, ear-response-location correspondence is the only factor that contributes to S-R compatibility in auditory two-choice reaction tasks. Received: 15 March 1999 / Accepted: 8 June 1999     

The role of attention for the Simon effect

Summary It has been claimed that spatial attention plays a decisive role in the effect of irrelevant spatial stimulus-response correspondence (i. e., the Simon effect), especially the way the attentional focus is moved onto the stimulus (lateral shifting rather than zooming). This attentional-movement hypothesis is contrasted with a referential-coding hypothesis, according to which spatial stimulus coding depends on the availability of frames or objects of reference rather than on certain attentional movements. In six experiments, reference objects were made available to aid spatial coding, which either appeared simultaneously with the stimulus (Experiments 1–3), or were continuously visible (Experiments 4–6). In contrast to previous experiments and to the attentional predictions, the Simon effect occurred even though the stimuli were precued by large frames surrounding both possible stimulus positions (Experiment 1), even when the reference object's salience was markedly reduced (Experiment 2), or when the precueing frames were made more informative (Experiment 3). Furthermore, it was found that the Simon effect is not reduced by spatial correspondence between an uninformative spatial precue and the stimulus (Experiment 4), and it does not depend on the location of spatial precues appearing to the left or right of both possible stimulus locations (Experiment 5). This was true even when the precue was made task-relevant in order to ensure attentional focusing (Experiment 6). In sum, it is shown that the Simon effect does not depend on the kind of attentional operation presumably performed to focus onto the stimulus. It is argued that the available data are consistent with a coding approach to the Simon effect which, however, needs to be developed to be more precise as to the conditions for spatial stimulus coding.     

Effects of irrelevant spatial S-R compatibility depend on stimulus complexity

Summary Choice-reaction time is known to depend on the spatial correspondence of stimulus and response, even if the stimulus location is irrelevant to the task (Simon effect). An experiment investigated whether this effect depends on stimulus complexity — i. e., on whether properties of the stimulus render stimulus discrimination easy or difficult. It was hypothesized that high demands on discrimination slow down the processing of stimulus identity in relation to location, so that the facilitating or conflicting location code has more time to decay, thus losing impact on response selection. In fact, the results revealed an effect of irrelevant spatial S-R correspondence with easy, but not with difficult, stimulus discrimination. This finding resolves an apparent contradiction between the results of several previous experiments on the Simon effect.The other central argument rests on findings of Stoffer (1991) obtained with a single frame. These, however, have recently been challenged by Hommel (1993 b).     

语音反应方式下情绪效价对空间Simon效应的影响

通过3个实验考察语音反应方式下情绪效价对空间Simon效应的影响。实验1采用空间Simon任务范式考察语音反应方式下空间Simon效应的存在;实验2增加刺激的情绪效价维度,采用同样任务考察无关情绪效价对空间Simon效应的影响;实验3在实验2基础上进一步探讨当情绪效价为相关维度时对空间Simon效应的影响。研究结果表明:语音反应方式下,只有当情绪效价为相关维度时,才会对空间Simon效应产生影响,且该影响主要表现在积极效价对认知控制的促进作用而导致空间Simon效应减小或消失,此结果与极性编码一致性假说一致,也拓宽了躯体特异性假说,扩展了以往对情绪影响空间认知的理解。     

The Simon Effect With Wheel-Rotation Responses

The authors examined clockwise and counterclockwise wheel-rotation responses to high- or low-pitched tones presented in participants' (N = 96, Experiment 1; N = 48, Experiment 2; N = 48, Experiment 3) left and right ears. In Experiment 1, a Simon effect (fastest responding when tone location and direction of wheel turn corresponded) was obtained when participants' hands were at the top or middle of the wheel but not at the bottom. With line bottom hand placement, a Simon effect was induced by instructions emphasizing hand movements but not by instructions emphasizing wheel movements (Experiment 2), and by a visual cursor controlled by the wheel but not one triggered by the response (Experiment 3). The results of the experiments showed that the nature of the task and the instructed action goal influence the direction of the Simon effect.     

Go/No-Go范式中非反应手状态对Simon效应性质的影响

为了探讨非反应手对标准Simon任务改装的go/no-go任务的影响,被试只对其中一种颜色进行按键反应,通过指导语来操控非反应手的状态,结果发现：(1)实验一中当不提醒非反应手如何放置时,不会产生Simon效应;(2) 实验二中要求非反应手放在固定的桌面位置上,产生了视觉运动Simon效应,其随反应时的增大而减小;(3) 实验三中要求非反应手放在固定的非反应键上,却产生了认知Simon效应,其随反应时的增大而增大。这说明非反应手的状态影响Simon效应的产生及其性质。     

A computational model of the Simon effect

Even though stimulus location is task irrelevant, reaction times are faster when the location of the stimulus corresponds with the location of the response than when it does not. This phenomenon is called the Simon effect. Most accounts of the Simon effect are based on the assumption that it arises from a conflict between the spatial code of the stimulus and that of the response. In this paper a computational model of this hypothesis is presented. It provides a computationally explicit mechanism of the Simon effect. Consistent with human performance, the model provides reaction times that indicate both an advantage for the ipsilateral, corresponding response (i.e., facilitation) and a disadvantage of the contralateral, noncorresponding response (i.e., inhibition). In addition, the model accounts for the fact that the size for the effect depends on task difficulty.     

Response coding in the Simon task

Recent findings indicate that two distinct mechanisms can contribute to a Simon effect: a visuomotor information transmission on the one hand and a cognitive code interference on the other hand (see for e.g., Wiegand & Wascher, in Journal of Experimental Psychology: Human Perception and Performance 2005a). Furthermore, it was proposed that the occurrence of one or the other mechanism strongly depends on the way responses are coded. Visuomotor information transmission seems to depend on a correspondence between stimulus position and spatial anatomical status of the effector, whereas cognitive code interference is thought to be based on relative response location codes. To further test the spatial anatomic coding hypothesis, three experiments were conducted, in which the Simon effect with unimanual responses was investigated for horizontal (Experiment 1 and 2) and vertical (Experiment 3) stimulus-response (S-R) relations. Based on the finding of a decreasing effect function (indicating the presence of visuomotor information transmission) for horizontal and vertical S-R relations, it was concluded that visuomotor information transmission occurs whenever there is an overlap between the spatial stimulus feature and parameters of the motor representation of the response. Furthermore, the specific motor representation seems to be task dependent, that is, it entails those response parameters that clearly differentiate between the two response alternatives in a given task situation.     

A Simon effect in memory retrieval: Evidence for the response-discrimination account

According to the traditional view, the effects of irrelevant stimulus location on the selection of a spatial response to a nonspatial stimulus feature (Simon effect) result from long-term associations between spatial stimulus codes and spatially corresponding response codes. According to an alternative view, the response-discrimination account, Simon effects arise from interactions between spatial stimulus codes and response labels in working memory (WM). The latter account predicts Simon effects when participants use spatial labels for response representation in WM, even when the actual responses have no spatial features (e.g., saying the word "plate"). The prediction was tested in an experiment, in which participants first encoded two words at different locations, and then responded to a stimulus by saying the word from the location indicated by stimulus color. The manipulation concerned the correspondence between irrelevant location of the colored stimulus and the retrieval cue for the vocal responses (i.e., word location in the encoding display). A Simon effect in memory retrieval was observed, supporting the response-discrimination account.     

Effect of conflicting cues on information processing: the 'Stroop effect' vs. the 'Simon effect'

This study examined the relationship between two sources of interference in human information processing: the Stroop effect and the Simon effect. Forty subjects pressed a left- or right-hand key in response to a Stroop color word located on the left or right side of a screen. For one group, ink color was the relevant cue and, for another group, word meaning was the relevant cue. Independent variables were: congruence, i.e., agreement or lack thereof between the ink color and meaning of the Stroop word; spatial correspondence, i.e., agreement or lack thereof between the location of the Stroop word and the location of the key used to make the response; and stimulus duration, i.e., 400 or 100 ms. Each of these variables had a significant effect on RT, and there were no significant interactions. According to Sternberg's additive-factor logic, these findings suggest that the Stroop effect (congruence) and the Simon effect (spatial correspondence) involve separate stages of processing. If one assumes that manipulation of stimulus duration effects the encoding stage, then results also suggest that neither the Stroop effect nor the Simon effect involves the stimulus encoding stage.     

Anticipatory response control in motor sequence learning: evidence from stimulus-response compatibility

Three experiments using a serial four-choice reaction-time (RT) task explored the interaction of sequence learning and stimulus-based response conflict. In Experiment 1, the spatial stimulus-response (S-R) mapping was manipulated between participants. Incompatible S-R mappings produced much higher RTs than the compatible mapping, but sequence learning decreased this S-R compatibility effect. In Experiment 2, the spatial stimulus feature was made task-irrelevant by assigning responses to symbols that were presented at unpredictable locations. The data indicated a Simon effect (i.e., increased RT when irrelevant stimulus location is spatially incompatible with response location) that was reduced by sequence learning. However, this effect was observed only in participants who developed an explicit sequence representation. Experiment 3 replicated this learning-based modulation of the Simon effect using explicit sequence-learning instructions. Taken together, the data support the notion that explicit sequence learning can lead to motor 'chunking', so that pre-planned response sequences are shielded from conflicting stimulus information.     

基于客体的空间一致性效应:功能可见性或空间位置编码?

采用空间Simon任务范式,考察基于客体空间一致性效应到底是手柄的功能可见性引起,还是其空间位置编码导致。实验1采用Pellicano等(2010)研究中的带手柄电筒,要求被试完成与抓握功能相关的形状判断任务,结果表明,唯有当电筒开时,被试产生了基于客体的空间一致性效应。实验2去除电筒可抓握的手柄,发现无论电筒开或关,均出现了更大的基于客体空间一致性效应。上述结果与空间编码假说一致,表明空间位置编码是产生基于客体空间一致性效应的原因。     

Perceptual and attentional factors in encoding irrelevant spatial information

Numerous studies found superior performance when the irrelevant location of a stimulus and response location were corresponding than when they were not corresponding (Simon effect), suggesting that stimulus location is processed in an obligatory manner. The present study compared Simon effects from the location of a relevant (i.e., to-be-attended) object to those from the location of an irrelevant (i.e., to-be-ignored) object. In four experiments, participants were presented with a rectangular frame and a square, with the relevant object in green or red color and the irrelevant object in gray or white color. Participants’ task was to respond with a lateral keypress to the color of the relevant object, and we varied spatial correspondence between the location of the relevant or the irrelevant object and the response, respectively. Results consistently showed larger Simon effects from the location of the relevant than from the irrelevant object, even when the irrelevant object was made very salient. These results suggest that location processing is largely confined to relevant (i.e., attended) objects, stressing the role of attention shifts for location encoding.     

Processing of irrelevant location information under dual-task conditions

This study deals with the problem of whether the processing of irrelevant location information in Simon-like tasks is triggered exogenously or endogenously. In Experiment 1, the primary task required one to press, as fast as possible, a left-hand-side key or a right-hand-side key (R1) to the pitch of a tone that was presented binaurally (S1). The secondary task required identifying, without time constraints, a visual stimulus (S2) that appeared randomly to the left or right of screen center. Results showed that there was a correspondence (i.e., a cross-task Simon effect) between the location of R1 and the location of S2 when S2 was presented alone. The cross-task Simon effect became much smaller (and in-significant) when a noise stimulus was presented contralateral to S2. Experiment 2 was similar to Experiment 1, except that S2 appeared unpredictably in only one-third of the trials. Results of Experiment 2 closely replicated those of Experiment 1: the cross-task Simon effect was much greater when S2 was presented alone. Experiment 3 differed from Experiment 1 because S2 had to be processed in only one-third of the trials, in which its identity was to be reported. In the remaining two-thirds of the trials, participants could ignore S2. Results confirmed that the cross-task Simon effect was much greater when S2 was presented alone. In contrast, it did not matter whether S2 had to be processed or not. In conclusion, the present study supports the hypothesis that the task-irrelevant spatial code of the stimulus is formed automatically, likely through an exogenously triggered selection. The role of endogenously initiated selection, if any, is much less important.     

Logical recoding of S-R rules can reverse the effects of spatial S-R correspondence

Two experiments investigated competing explanations for the reversal of spatial stimulus—response (S—R) correspondence effects (i.e., Simon effects) with an incompatible S—R mapping on the relevant, nonspatial dimension. Competing explanations were based on generalized S—R rules (logical-recoding account) or referred to display—control arrangement correspondence or to S—S congruity. In Experiment 1, compatible responses to finger—name stimuli presented at left/right locations produced normal Simon effects, whereas incompatible responses to finger—name stimuli produced an inverted Simon effect. This finding supports the logical-recoding account. In Experiment 2, spatial S—R correspondence and color S—R correspondence were varied independently, and main effects of these variables were observed. The lack of an interaction between these variables, however, disconfirms a prediction of the display—control arrangement correspondence account. Together, the results provide converging evidence for the logical-recoding account. This account claims that participants derive generalized response selection rules (e.g., the identity or reversal rule) from specific S—R rules and inadvertently apply the generalized rules to the irrelevant (spatial) S—R dimension when selecting their response.     

Stimulus-response compatibility and the Simon effect: toward a conceptual clarification.

The current view that the Simon effect (Simon & Small, 1969) reflects stimulus-response compatibility (SRC) is questioned. Previous accounts of the Simon effect have overlooked stimulus congruity (SC), the correspondence relation borne by the two simultaneous aspects of the stimulus, a factor inevitably confounded in the Simon paradigm with irrelevant spatial S-R correspondence. The Hedge and Marsh (1975) reversal effect, replicated in Experiment 1, is reinterpreted as decisive evidence that the Simon effect is entirely accounted for by SC. Furthermore, in Experiment 2 irrelevant S-R correspondence was manipulated in the absence of any variation of SC, and the Simon effect vanished. It is concluded that the Simon effect, contrary to current opinion, represents a spatial variant of the Stroop effect and is irrelevant to the SRC issue. The view that mental operations proceed automatically at the stage of response determination loses one of its strongest empirical arguments.     

Searching for Memory Systems

The aim of the present study was to investigate the relationship between the affordance effect (i.e., the advantage for responses corresponding spatially with the location of an object's graspable part) and the Simon effect (i.e., the advantage for responses corresponding spatially with stimulus location) and to assess whether they both occur at the response selection stage. In two experiments participants were required to respond according to the vertical orientation (upward or inverted) of photographs of graspable objects, located to the left or right of fixation, with their handles oriented to the right or left. In Experiment 1 the response was a buttonpress; in Experiment 2 was a reaching movement. Our results showed that both Simon and affordance effects emerged in response times but not in movement times. In Experiment 1, the two effects did not interact, whereas a clear interaction emerged in Experiment 2. These results seem to suggest that the interaction between Simon and affordance effects may depend on the type of required action.     

The Simon Effect in Action: Planning and/or On‐Line Control Effects?

Choice reaction tasks are performed faster when stimulus location corresponds to response location (Simon effect). This spatial stimulus–response compatibility effect affects performance at the level of action planning and execution. However, when response selection is completed before movement initiation, the Simon effect arises only at the planning level. The aim of this study was to ascertain whether when a precocious response selection is requested, the Simon effect can be detected on the kinematics characterizing the online control phase of a non‐ballistic movement. Participants were presented with red or green colored squares, which could appear on the right, left, above, or below a central cross. Depending on the square's color, participants had to release one of two buttons (right/left), then reach toward and press a corresponding lateral pad. We found evidence of the Simon effect on both action planning and on‐line control. Moreover, the investigation of response conflict at the level of previous trials (i.e., n?1), a factor that might determine interference at the level of the current response, revealed a conflict adaptation process across trials. Results are discussed in terms of current theories concerned with the Simon effect and the distinction between action planning and control.     

Lateralized warning tones produce typical irrelevant-location effects on choice reactions

Simon, Acosta, and Mewaldt (1975) reported an experiment in which a 200-Hz warning-tone, presented in the left or right ear, was followed by an imperative stimulus of 500 Hz in either ear, to which a left- or right-key press was to be made. Simon et al. found a correspondence effect for warning location and response location (i.e., faster reactions when warning and response locations corresponded than when they did not) when the stimulus-response mapping was incompatible but not when it was compatible. These findings stand in contrast to typical results of (1) a correspondence effect for irrelevant location information when the mapping is compatible and (2) a reversed correspondence effect (i.e., faster responses when stimulus and response location do not correspond) when the mapping is incompatible. We conducted a direct replication of Simon et al.’s experiment and another experiment that differed only in the imperative stimulus being visual, in order to determine whether there are unique aspects of their method that yield atypical results. Our results failed to replicate those reported by Simon et al. but instead showed the patterns of correspondence effects typically found with other procedures, suggesting that the warning-signal method produces irrelevant-location effects consistent with those produced by other methods.