On spatial response code activation in a Simon task

The Simon effect refers to the performance advantage for trials where the task-irrelevant location of a target spatially corresponds with the location of the response. It is thought that the irrelevant spatial code of the target facilitates responding by automatically pre-activating the spatially corresponding response code. This spatial code is thought to passively decay shortly after its activation. In this investigation, the response was selected according to the identity of a central cue. The selected response was executed or withheld depending the identity (Experiment 1) or the presence (Experiment 2) of the target. Varying the stimulus-onset asynchrony (SOA), between the central response cue and the peripheral target, allowed for a time-course analysis of the Simon effect. The results of two experiments provided no indication that the activation level of the irrelevant spatial code decayed while the relevant response was prepared. Although reaction times increased as the SOA decreased, the Simon effect was additive with SOA, suggesting that the automatic activation of the task-irrelevant spatial code was delayed until the task-relevant response code was mostly prepared, perhaps due to the capacity limitations of response selection.     

Evidence for gating of direct response activation in the Simon task

TheSimon effect denotes faster responses when the task-irrelevant stimulus position corresponds to the response position than when it does not. Accounts of this effect assume that stimulus position automatically activates a spatially corresponding response while the correct response is being computed. Yet the Simon effect has been found to be reduced after noncorresponding trials. Some authors have interpreted these sequential modulations of the Simon effect as evidence for a mechanism gating positionbased response activation. Alternatively, sequential modulations have been explained in terms of feature-integration processes, which depend upon the fact that different sequences of spatial-correspondence conditions covary with different degrees of feature overlap between subsequent trials. The present study investigates whether sequential modulations of the Simon effect can occur when feature overlap in the different conditions is the same. Therefore, a Simon task with four stimulus positions and two response positions was used. Sequential modulations of the Simon effect were found in trial sequences with constant amounts of feature overlap between trials. Although the feature-integration account cannot explain this result, it is consistent with the idea of a gating (i.e., cognitive control) mechanism.     

Validity and boundary conditions of automatic response activation in the Simon task.

Three experiments were conducted to determine whether spatial stimulus-response compatibility effects are caused by automatic response activation by stimulus properties or by interference between codes during translation of stimulus into response coordinates. The main evidence against activation has been that in a Simon task with hands crossed, responses are faster at the response location ipsilateral to the stimulus though manipulated by the hand contralateral to the stimulus. The experiments were conducted with hands in standard and in crossed positions and electroencephalogram measures showed coactivation of the motor cortex induced by stimulus position primarily during standard hand positions with visual stimuli. Only in this condition did the Simon effect decay with longer response times. The visual Simon effect appeared to be due to specific mechanisms of visuomotor information transmission that are not responsible for the effects obtained with crossed hands or auditory stimuli.     

Priming processes in the Simon task: more evidence from the lexical decision task for a third route in the Simon effect

Recently, it was proposed that the Simon effect would result not only from two interfering processes, as classical dual-route models assume, but from three processes. It was argued that priming from the spatial code to the nonspatial code might facilitate the identification of the nonspatial stimulus feature in congruent Simon trials. In the present study, the authors provide evidence that the identification of the nonspatial information can be facilitated by the activation of an associated spatial code. In three experiments, participants first associated centrally presented animal and fruit pictures with spatial responses. Subsequently, participants decided whether laterally presented letter strings were words (animal, fruit, or other words) or nonwords; stimulus position could be congruent or incongruent to the associated spatial code. As hypothesized, animal and fruit words were identified faster at congruent than at incongruent stimulus positions from the association phase. The authors conclude that the activation of the spatial code spreads to the nonspatial code, resulting in facilitated stimulus identification in congruent trials. These results speak to the assumption of a third process involved in the Simon task.     

Task-set reconfiguration and perceptual processing: behavioral and electrophysiological evidence

Oriet and Jolic?ur (2003) proposed that an endogenous task-set reconfiguration process acts as a hard bottleneck during which even early perceptual processing is impossible. We examined this assumption using a psychophysiological approach. Participants were required to switch between magnitude and parity judgment tasks within a predictable task sequence while event-related potentials (ERPs) were recorded. Stimulus contrast and response stimulus interval (RSI) were manipulated. Behavioral data demonstrated typical task switch costs that decreased as RSI increased. However, whereas ERP analysis of visual ERP component latencies sensitively revealed the contrast effect, a switch-specific postponement of perceptual processing during task-set reconfiguration at short RSIs was not observed. The present findings indicate that the process of task-set reconfiguration does not constitute a hard bottleneck that delays perceptual processing.     

Bilingualism, aging, and cognitive control: evidence from the Simon task

Previous work has shown that bilingualism is associated with more effective controlled processing in children; the assumption is that the constant management of 2 competing languages enhances executive functions (E. Bialystok, 2001). The present research attempted to determine whether this bilingual advantage persists for adults and whether bilingualism attenuates the negative effects of aging on cognitive control in older adults. Three studies are reported that compared the performance of monolingual and bilingual middle-aged and older adults on the Simon task. Bilingualism was associated with smaller Simon effect costs for both age groups; bilingual participants also responded more rapidly to conditions that placed greater demands on working memory. In all cases the bilingual advantage was greater for older participants. It appears, therefore, that controlled processing is carried out more effectively by bilinguals and that bilingualism helps to offset age-related losses in certain executive processes.     

Decreased functional brain activation in Friedreich ataxia using the Simon effect task

The present study applied the Simon effect task to examine the pattern of functional brain reorganization in individuals with Friedreich ataxia (FRDA), using functional magnetic resonance imaging (fMRI). Thirteen individuals with FRDA and 14 age and sex matched controls participated, and were required to respond to either congruent or incongruent arrow stimuli, presented either to the left or right of a screen, via laterally-located button press responses. Although the Simon effect (incongruent minus congruent stimuli) showed common regions of activation in both groups, including the superior and middle prefrontal cortices, insulae, superior and inferior parietal lobules (LPs, LPi), occipital cortex and cerebellum, there was reduced functional activation across a range of brain regions (cortical, subcortical and cerebellar) in individuals with FRDA. The greater Simon effect behaviourally in individuals with FRDA, compared with controls, together with concomitant reductions in functional brain activation and reduced functional connectivity between cortical and sub-cortical regions, implies a likely disruption of cortico-cerebellar loops and ineffective engagement of cognitive/attention regions required for response suppression.     

Mechanisms of percept-percept and image-percept integration in vision: behavioral and electrophysiological evidence

Previous research has shown that the detection of a visual target can be guided not only by the temporal integration of two percepts, but also by integrating a percept and an image held in working memory. Behavioral and event-related brain potential (ERP) measures were obtained in a target detection task that required temporal integration of 2 successively presented stimuli in the left or right hemifield. Task performance was good when both displays followed each other immediately (percept-percept integration) and when displays were separated by a 300- or 900-ms interval (image-percept integration), but was poor with intermediate interstimulus intervals. An enhanced posterior negativity at electrodes contralateral to the side of the target was observed for percept-percept and for image-percept integration, demonstrating that both are based on spatiotopic representations. However, this contralateral negativity emerged later and was more sustained on trials with long interstimulus intervals, indicating that image-percept integration is slower and involves a sustained activation of working memory.     

Implicit word learning benefits from semantic richness: electrophysiological and behavioral evidence

Words differ considerably in the amount of associated semantic information. Despite the crucial role of meaning in language, it is still unclear whether and how this variability modulates language learning. Here, we provide initial evidence demonstrating that implicit learning in repetition priming is influenced by the amount of semantic features associated with a given word. Electroencephalographic recordings were obtained while participants performed a visual lexical decision task; the complete stimulus set was repeated once. Repetition priming effects on performance accuracy and the N400 component of the event-related brain potential were enhanced for words with many semantic features. These findings suggest a novel and important impact of the richness of semantic representations on learning and plasticity within the lexical-conceptual system; they are discussed in their relevance for assumptions concerning basic mechanisms underlying word learning.     

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.     

Executive control in the Simon task: A dual-task examination of response priming and its suppression

Executive control processes are supposed to regulate behaviour and to resolve conflicts in information processing. Recently, Stürmer and colleagues (Stürmer et al., 2002; Stürmer & Leuthold, 2003) reported electrophysiological findings in a Simon task that indicated control over a location-based processing route that mediates response priming. Importantly, when a response conflict occurred on a given trial, a suppression of response priming on the immediately following trial was demonstrated. The present study examines boundary conditions of such control in the Simon paradigm by comparing single-task with dual-task performance. In four experiments a second task, alternating trial-by-trial with the Simon task, was systematically manipulated in its control demands. Whereas reaction time (RT) analysis of single-task conditions revealed the absence of location-based response priming in the Simon task, such priming reappeared when the second task required an overt response. In contrast, working memory load as such did not touch the Simon effect. Therefore, not the response conflict itself but capacity-limited response monitoring processes seem to be critical for executive control in the Simon task and the suppression of response priming.     

The interaction between surface color and color knowledge: behavioral and electrophysiological evidence

In this study, we used event-related potentials (ERPs) to evaluate the contribution of surface color and color knowledge information in object identification. We constructed two color-object verification tasks - a surface and a knowledge verification task - using high color diagnostic objects; both typical and atypical color versions of the same object were presented. Continuous electroencephalogram was recorded from 26 subjects. A cluster randomization procedure was used to explore the differences between typical and atypical color objects in each task. In the color knowledge task, we found two significant clusters that were consistent with the N350 and late positive complex (LPC) effects. Atypical color objects elicited more negative ERPs compared to typical color objects. The color effect found in the N350 time window suggests that surface color is an important cue that facilitates the selection of a stored object representation from long-term memory. Moreover, the observed LPC effect suggests that surface color activates associated semantic knowledge about the object, including color knowledge representations. We did not find any significant differences between typical and atypical color objects in the surface color verification task, which indicates that there is little contribution of color knowledge to resolve the surface color verification. Our main results suggest that surface color is an important visual cue that triggers color knowledge, thereby facilitating object identification.     

Individual differences in children's performance during an emotional Stroop task: a behavioral and electrophysiological study

Two studies using the emotional Stroop with 11-year-old children were completed. In Study 1, children were assigned to either the "interference group" or the "facilitation group" based on their performance on the task. The interference group was slower to respond to emotion words (positive and negative) versus control words. The facilitation group was faster to respond to the emotion words. The groups were then compared on a set of cognitive, emotional, and social measures collected at ages 4, 7, and 11. The interference group showed greater signs of emotional and social, but not cognitive, maladjustment across time. Study 2 replicated the findings of Study 1. In addition, event-related potentials (ERPs) were collected in Study 2. The ERP data replicated earlier traditional Stroop studies. In addition, positive and negative words showed differences in processing across components. In particular, negative words appeared to tax attentional and processing resources more than positive words.     

Temperamental contributions to children's performance in an emotion-word processing task: a behavioral and electrophysiological study

Seven-year-old children (N=65) participating in a study of the influence of infant temperament on socioemotional development performed an auditory selective attention task involving words that varied in both affective (positive vs. negative) and social (social vs. nonsocial) content. Parent report of contemporaneous child temperament was also collected, and individual differences in self-regulation in the affective (soothability) and cognitive (attentional control) domains were noted. Overall, children showed slower responses to stimuli that were either social or negative in content, with the largest effect elicited by words that possessed both traits. Children rated high in soothability and attentional control showed slower responses to social negative words. The other children showed little to no differential response patterns across the word categories. ERPs collected during the task indicated that processing differences were evident in the later more cognitive components of the ERP, especially in children low in attentional control. These findings indicate that performance on an auditory selective attention task can assist in identifying underlying patterns of affective processing.     

Suppression of irrelevant activation in the horizontal and vertical Simon task differs quantitatively not qualitatively

The Simon effect is usually explained by the assumption that the irrelevant stimulus location automatically activates the corresponding response. In the case of incongruent stimulus–response assignments automatically activated responses therefore have to be suppressed to ensure correct responses. This account, however, has been called into question for other than horizontally arranged visual Simon tasks. We investigated whether there is a qualitative or quantitative difference in suppression of irrelevant activation between horizontally and vertically arranged Simon tasks, using delta-function analyses. Sequential analyses revealed suppression after incongruent trials in both tasks, supporting the idea of a quantitative rather than a qualitative difference between the tasks. We conclude that automatic response activation is weaker in vertical tasks resulting in lower inhibitory demands as compared to horizontal tasks.     

Simon says: Reliability and the role of working memory and attentional control in the Simon task

TheSimon effect refers to the observation that subjects identify targets (e.g., colors) faster when the irrelevant spatial location of the target corresponds to the location of the response key. Theoretical accounts of the Simon effect typically explain performance in terms of automatic and controlled processes. Furthermore, the relative contributions of automatic and controlled processes are held to change as a function of the proportion of compatible to incompatible trials (compatibility proportion). Data are presented demonstrating that the reliability of the Simon effect, indexed by correlating its magnitude within subjects across blocks of trials, varied substantially as a function of the compatibility proportion. When the compatibility proportion was high, so was reliability. When the compatibility proportion was low, reliability was low as well. The results are discussed in terms of the relative reliability of automatic and controlled processes and the role of working memory and attentional control in goal maintenance.     

Conflict and error adaptation in the Simon task

We present recent empirical and theoretical advances in conflict and error monitoring in the Simon task. On the basis of the adaptation by binding account for conflict adaptation and the orienting account for post-error slowing, we predict a dissociation between conflict and error monitoring. This prediction is tested and confirmed as conflict adaptation is task-specific while post-error slowing is not.     

Enculturation to musical pitch structure in young children: evidence from behavioral and electrophysiological methods

Children learn the structure of the music of their culture similarly to how they learn the language to which they are exposed in their daily environment. Furthermore, as with language, children acquire this musical knowledge without formal instruction. Two critical aspects of musical pitch structure in Western tonal music are key membership (understanding which notes belong in a key and which do not) and harmony (understanding which notes combine to form chords and which notes and chords tend to follow others). The early developmental trajectory of the acquisition of this knowledge remains unclear, in part because of the difficulty of testing young children. In two experiments, we investigated 4‐ and 5‐year‐olds' enculturation to Western musical pitch using a novel age‐appropriate and engaging behavioral task (Experiment 1) and electroencephalography (EEG; Experiment 2). In Experiment 1 we found behavioral evidence that 5‐year‐olds were sensitive to key membership but not to harmony, and no evidence that 4‐year‐olds were sensitive to either. However, in Experiment 2 we found neurophysiological evidence that 4‐year‐olds were sensitive to both key membership and harmony. Our results suggest that musical enculturation has a long developmental trajectory, and that children may have some knowledge of key membership and harmony before that knowledge can be expressed through explicit behavioral judgments.     

Fast and unintentional evaluation of emotional sounds: evidence from brief segment ratings and the affective Simon task

In the present study, we raised the question of whether valence information of natural emotional sounds can be extracted rapidly and unintentionally. In a first experiment, we collected explicit valence ratings of brief natural sound segments. Results showed that sound segments of 400 and 600?ms duration—and with some limitation even sound segments as short as 200?ms—are evaluated reliably. In a second experiment, we introduced an auditory version of the affective Simon task to assess automatic (i.e. unintentional and fast) evaluations of sound valence. The pattern of results indicates that affective information of natural emotional sounds can be extracted rapidly (i.e. after a few hundred ms long exposure) and in an unintentional fashion.     

The relationship between stimulus processing and response selection in the Simon task: Evidence for a temporal overlap

Summary As is indicated by the Simon effect, choice reactions can be carried out faster when the response corresponds spatially to the stimulus, even if the stimulus location is irrelevant to the task. In Experiments 1–4 the relationships between the Simon effect and stimulus eccentricity, signal quality, and signal-background contrast are investigated. The Simon effect was found to interact with all of these factors, at least when manipulated blockwise. These results are at odds with previous results and are difficult to interpret from an additive-factor-method view. An alternative interpretation is suggested that attributes the results to the temporal relationship between the processing of the relevant stimulus information and stimulus location. The assumption is that a decrease in the Simon effect is caused by every experimental manipulation that markedly increases the temporal distance between the coding of the relevant stimulus information and that of the irrelevant stimulus location. This assumption was tested in Experiment 5 in a more direct way. The stimuli were built up on a screen over time, so that the temporal distance between the presence of location and identity information could be controlled experimentally. The results provide further support for a temporal-delay interpretation of interactions between irrelevant stimulus-response correspondence and factors that affect early stages of information processing.