A Simon Effect With Stationary Moving Stimuli.

To clarify whether motion information per se has a separable influence on action control, the authors investigated whether irrelevant direction of motion of stimuli whose overall position was constant over time would affect manual left-right responses (i.e., reveal a motion-based Simon effect). In Experiments 1 and 2, significant Simon effects were obtained for sine-wave gratings moving in a stationary Gaussian window. In Experiment 3, a direction-based Simon effect with random-dot patterns was replicated, except that the perceived direction of motion was based on the displacement of single elements. Experiments 4 and 5 studied motion-based Simon effects to point-light figures that walked in place--displays requiring high-level analysis of global shape and local motion. Motion-based Simon effects occurred when the displays could be interpreted as an upright human walker, showing that a high-level representation of motion direction mediated the effects. Thus, the present study establishes links between high-level motion perception and action. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The prepared emotional reflex: Intentional preparation of automatic approach and avoidance tendencies as a means to regulate emotional responding.

Advance preparation of action courses toward emotional stimuli is an effective means to regulate impulsive emotional behavior. Our experiment shows that performing intentional acts of approach and avoidance in an evaluation task influences the unintended activation of approach and avoidance tendencies in another task in which stimulus valence is irrelevant. For the evaluation-relevant blocks, participants received either congruent (positive-approach, negative-avoidance) or incongruent (positive-avoidance, negative-approach) mapping instructions. In the evaluation-irrelevant blocks, approach- and avoidance-related lever movements were selected in response to a stimulus feature other than valence (affective Simon task). Response mapping in the evaluation task influenced performance in the evaluation-irrelevant task: An enhanced affective Simon effect was observed with congruent mapping instructions; in contrast, the effect was reversed when the evaluation task required incongruent responses. Thus, action instructions toward affective stimuli received in one task determined affective response tendencies in another task where these instructions were not in effect. These findings suggest that intentionally prepared short-term links between affective valence and motor responses elicit associated responses without a deliberate act of will, operating like a “prepared reflex.” (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Simon effect occurs relative to the direction of an attention shift.

We investigated whether the Simon effect depends on the orienting of attention. In Experiment 1, participants were required to execute left-right discriminative responses to 2 patterns that were presented to the left or right of fixation. The 2 patterns were similar, and the discrimination was difficult. A letter at fixation signaled whether the current trial was a catch trial. The results showed a reversal of the Simon effect. That is, spatially noncorresponding responses were faster than spatially corresponding responses. In Experiment 2, the discrimination of the relevant stimulus attribute was easy. In Experiment 3, the discrimination of the relevant stimulus attribute was difficult, but the stimulus exposure time was long. In either experiment, the regular Simon effect was reinstated. In Experiment 4, the letter that signaled a catch trial appeared to the left or right of the imperative stimulus. The Simon effect occurred relative to the position of the letter. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus–target compatibility for reaching movements.

Reaction time, movement time, and initial direction of reaching movements toward a target in left or right hemispace were measured. In Experiment 1, the target of movement and hand had to be selected; movements toward the imperative stimulus were initiated faster than movements toward the alternate target, and ipsilateral reaches were initiated faster than contralateral reaches. In Experiment 2, the difference between ipsilateral and contralateral reaches disappeared when no selection of the hand had to occur. In Experiment 3, no target had to be selected, and only a stimulus-hand compatibility effect appeared. The results reveal different compatibility effects (stimulus-target, stimulus-hand, target-hand), implying that participants exploit different correspondences, depending on the degrees of freedom of the action. The notion of compatibility effects relating to movement targets offers a new perspective on the negative Simon effect and it questions the general concept of response codes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The object-based Simon effect: Grasping affordance or relative location of the graspable part?

Reaction time is often shorter when the irrelevant graspable handle of an object corresponds with the location of a keypress response to the relevant attribute than when it does not. This object-based Simon effect has been attributed to an affordance for grasping the handle with the hand to the same side. Because a grasping affordance should differentially affect keypress responses only when they are made with different hands, we conducted three experiments that measured the object-based Simon effect for frying pan stimuli using between- and within-hand response sets. When the relevant stimulus dimension was color, neither the object-based Simon effect nor the location-based Simon effect varied across response sets. When upright-inverted orientation judgments were made for the frying pan and for nongraspable stimuli derived from it, there again was no significant difference in size of the between- and within-hand Simon effects for any of the stimuli. The results provide evidence that the Simon effect for graspable frying pan stimuli is because of relative location of the handle and not to a grasping affordance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parametric exploration of the Simon effect across visual space.

The Simon effect refers to the performance advantage for responding to the nonspatial identity of the target when the target's irrelevant location corresponds with the relative location of the response. The present study is a parametric examination of the magnitude of the Simon effect across visual space. Response keys were arranged along vertical, horizontal, and two diagonal axes, and stimuli were arranged in two concentric circles (near and far from fixation) along the same axes. The results show that the Simon effect is of similar magnitude regardless of stimulus-response axis. In contrast to findings from stimulus-response compatibility paradigms, there was no evidence in this study for the presence of an orthogonal compatibility effect or left-right prevalence effect, suggesting that these effects only arise when response location is relevant. The results demonstrate the robust generalizability of the Simon effect under different spatial conditions and thus broaden the relevance of the Simon effect to a variety of applications. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conflicts during response selection affect response programming: Reactions toward the source of stimulation.

In the Simon effect, participants make a left or right keypress in response to a nonspatial attribute (e.g., color) that is presented on the left or right. Reaction times (RTs) increase when the response activated by the irrelevant stimulus location and the response retrieved by instruction are in conflict. The authors measured RTs and movement parameters (MPs) of pointing responses in a typical Simon task. Their results show that the trajectories veer toward the imperative stimulus. This bias decreased as RTs increased. The authors suggest that the time course of trajectory deviations reflects the resolution of the response conflict over time. Further, time pressure did not affect the size of the Simon effect in MPs or its time course, but strongly reduced the Simon effect in RTs. In contrast, response selection before the onset of a go signal on the left or right did not affect the Simon effect in RTs, but reduced the Simon effect in MPs and reversed the time course. The authors speculate about independent Simon effects associated with response selection and programming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Goal Congruency in Bimanual Object Manipulation.

In 3 experiments, the authors investigated the impact of action goals on the production of discrete bimanual responses. Similar to a bartender putting 2 glasses simultaneously on a shelf, participants placed 2 objects into either parallel or opposite orientations by carrying out either mirror-symmetrical or mirror-asymmetrical movements. In Experiment 1, performance was strongly affected by the congruency of the intended object orientations but was essentially unaffected by movement symmetry. Experiment 2 replicated this instrumental goal-congruency effect (and the absence of motor-symmetry effects) when actions were cued in advance. Experiment 3 revealed substantial motor-symmetry effects, provided the movements themselves became the action goal. The authors concluded that performance in bimanual choice reaction tasks is constrained by the creation and maintenance of goal codes rather than by properties inherent in the neuromuscular system that carries out these responses. These goals can relate to either body-intrinsic states or to body-extrinsic states according to the actor's current intentions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transfer of noncorresponding spatial associations to the auditory Simon task.

Four experiments examined transfer of noncorresponding spatial stimulus-response associations to an auditory Simon task for which stimulus location was irrelevant. Experiment 1 established that, for a horizontal auditory Simon task, transfer of spatial associations occurs after 300 trials of practice with an incompatible mapping of auditory stimuli to keypress responses. Experiments 2-4 examined transfer effects within the auditory modality when the stimuli and responses were varied along vertical and horizontal dimensions. Transfer occurred when the stimuli and responses were arrayed along the same dimension in practice and transfer but not when they were arrayed along orthogonal dimensions. These findings indicate that prior task-defined associations have less influence on the auditory Simon effect than on the visual Simon effect, possibly because of the stronger tendency for an auditory stimulus to activate its corresponding response. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vicarious Agency: Experiencing Control Over the Movements of Others.

Participants watched themselves in a mirror while another person behind them, hidden from view, extended hands forward on each side where participants' hands would normally appear. The hands performed a series of movements. When participants could hear instructions previewing each movement, they reported an enhanced feeling of controlling the hands. Hearing instructions for the movements also enhanced skin conductance responses when a rubber band was snapped on the other's wrist after the movements. Such vicarious agency was not felt when the instructions followed the movements, and participants' own covet movement mimicry was not essential to the influence of previews on reported control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual perception modifies goal-directed movement control: supporting evidence from a visual perturbation paradigm

It is well known that dynamic visual information influences movement control, whereas the role played by background visual information is still largely unknown. Evidence coming mainly from eye movement and manual tracking studies indicates that background visual information modifies motion perception and might influence movement control. The goal of the present study was to test this hypothesis. Subjects had to apply pressure on a strain gauge to displace in a single action a cursor shown on a video display and to immobilize it on a target shown on the same display. In some instances, the visual background against which the cursor moved was unexpectedly perturbed in a direction opposite to (Experiment 1), or in the same direction as (Experiment 2) the cursor controlled by the subject. The results of both experiments indicated that the introduction of a visual perturbation significantly affected aiming accuracy. These results suggest that background visual information is used to evaluate the velocity of the aiming cursor, and that this perceived velocity is fed back to the control system, which uses it for on-line corrections.     

What is matched in direct matching? Intention attribution modulates motor priming.

Converging evidence has shown that action observation and execution are tightly linked. The observation of an action directly activates an equivalent internal motor representation in the observer (direct matching). However, whether direct matching is primarily driven by basic perceptual features of the observed movement or is influenced by more abstract interpretative processes is an open question. A series of behavioral experiments tested whether direct matching, as measured by motor priming, can be modulated by inferred action goals and attributed intentions. Experiment 1 tested whether observing an unsuccessful attempt to execute an action is sufficient to produce a motor-priming effect. Experiment 2 tested alternative perceptual explanations for the observed findings. Experiment 3 investigated whether the attribution of intention modulates motor priming by comparing motor-priming effects during observation of intended and unintended movements. Experiment 4 tested whether participants' interpretation of the movement as triggered by an external source or the actor's intention modulates the motor-priming effect by a pure instructional manipulation. Our findings support a model in which direct matching can be top-down modulated by the observer's interpretation of the observed movement as intended or not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response coding and visuomotor transformation in the Simon task: The role of action goals.

Manual responses can be defined by differing response parameters. Any of them may generate a Simon effect. For all those response parameters, the same implementation of the Simon effect (in terms of subserving mechanism) is assumed. In 3 experiments, subjects had to respond with either fingers or sticks. Temporal properties of the Simon effect changed with response parameters relevant in a task. The Simon effect for manual responses decayed. For stick responses, in which the action goal differed from the anatomical mapping of the acting hand, a sustained Simon effect was observed. However, if the action goal for stick responses was not instrumental for selecting the correct response, the Simon effect decayed. The findings are consistent with the notion of different mechanisms involved in generating a Simon effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hand to mouth: Automatic imitation across effector systems.

The effector dependence of automatic imitation was investigated using a stimulus–response compatibility (SRC) procedure during which participants were required to make an open or closed response with their hand or their mouth. The correct response for each trial was indicated by a pair of letters in Experiments 1 and 2 and by a colored square in Experiment 3. Each of these imperative stimuli was accompanied by task-irrelevant action images depicting a hand or mouth opening or closing. In relation to the response, the irrelevant stimulus was movement compatible or movement incompatible, and effector compatible or effector incompatible. A movement compatibility effect was observed for both hand and mouth responses. These movement compatibility effects were present when the irrelevant stimulus was effector compatible and when it was effector incompatible, but were smaller when the irrelevant stimulus and response effectors were incompatible. Consistent with the associative sequence learning (ASL) model of imitation, these findings indicate that automatic imitation is partially effector dependent and therefore that the effector dependence of intentional imitation reflects, at least in part, the nature of the mechanisms that mediate visuomotor translation for imitation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the inclusion of externally controlled actions in action planning.

According to ideomotor theories, perceiving action effects produced by others triggers corresponding action representations in the observer. We tested whether this principle extends to actions performed by externally controlled limbs and tools. Participants performed a go–no-go version of a spatial compatibility task in which their own actions resulted in the movement of a limb or tool, whereas a second, externally controlled limb or tool was seen performing a complementary go–no-go task. Spatial compatibility effects, indicating inclusion of the externally controlled effector in action planning, were observed when the externally controlled limb was identical to the controlled limb (Experiment 1) and when actions of limbs and tools (Experiment 2) or pairs of tools (Experiment 3 and 4) were combined according to participants' motor experience. When participants acted together, controlling a tool each, spatial compatibility effects occurred regardless of motor experience (Experiment 5). These findings demonstrate that (a) externally controlled tool actions are included in action planning and (b) social context modulates how externally controlled actions are mapped onto action representations. Implications of these findings for theories of perception–action links and object processing are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Stimulus–response compatibility as a function of stimulus code and response modality.

The concept of stimulus-response compatibility can be differentiated into set-level and element-level compatibility. The relation between these 2 types of compatibility was examined by varying stimulus code (spatial or verbal) and response modality (manual or vocal) in 2-choice tasks that used left-right stimuli and left-right responses. Element-level compatibility was an increasing function of set-level compatibility and larger for verbal than for spatial stimuli. The positive relation between set- and element-level compatibility was due to differences for the congruent mapping but not the incongruent mapping. The results can be characterized in terms of (a) a continuum along which the relative compatibility of the responses with spatial and verbal stimuli varies and (b) a dual-route conception of response selection in which a direct, or automatic, route is involved only when a congruent mapping is in effect. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Motor skills have diverse neural bases: Spared and impaired skill acquisition in Huntington's disease.

The striatum contributes to the learning of some, but not all, motor skills. The researchers suggest that the striatum plays a role when participants learn a repeating sequence of movements, but it does not contribute when they learn a new mapping between perceptual cues and the appropriate motor response. The researchers tested patients with striatal damage due to Huntington's disease (HD) on 2 versions of a tracking task. In 1 task, the target moved randomly, allowing participants to learn the relationship between the joystick and cursor. Patients showed normal learning. In the other task, the target moved in a repeating pattern, and participants could improve performance by learning the repeating sequence of movements necessary to track the pattern. Patients were impaired on this task. Learning sequences is impaired in HD, whereas learning new mappings between perceptual cues and responses is not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Taking a long look at action and time perception.

Everyone has probably experienced chronostasis, an illusion of time that can cause a clock's second hand to appear to stand still during an eye movement. Though the illusion was initially thought to reflect a mechanism for preserving perceptual continuity during eye movements, an alternative hypothesis has been advanced that overestimation of time might be a general effect of any action. Contrary to both of these hypotheses, the experiments reported here suggest that distortions of time perception related to an eye movement are not distinct from temporal distortions for other kinds of responses. Moreover, voluntary action is neither necessary nor sufficient for overestimation effects. These results lead to a new interpretation of chronostasis based on the role of attention and memory in time estimation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence on Simon and SNARC effects of a nonspatial stimulus-response mapping: Between-task logical recoding.

In 4 experiments, we intermixed trials in which the stimulus color was relevant with trials where participants had to judge the stimulus shape or parity and found that the logical-recoding rule (Hedge & Marsh, 1975) applied to the relevant dimension in a task can generalize to the irrelevant dimension of the other task. The mapping assigned to participants in color-relevant trials modulated the Simon and SNARC (spatial-numerical association of response codes) effects (Simon & Small, 1969; Dehaene, Bossini, & Giraux, 1993) observed in shape- and parity-relevant trials. Standard effects were obtained when color-relevant trials required participants to respond by pressing a key of the same color as the stimulus, whereas an alternate-color mapping caused either the disappearance or reversal of the effects. The present results demonstrate that for between-task transfer effects to occur the critical dimensions in the two alternative tasks do not have to share the same representation nor need the stimuli of the two tasks have any feature in common. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mixing location-relevant and location-irrelevant choice-reaction tasks: Influences of location mapping on the Simon effect.

The Simon effect refers to the finding that reaction times are faster when stimulus and response locations correspond than when they do not in tasks where stimulus location is defined as irrelevant. The authors examined the Simon effect for situations in which location-irrelevant trials were intermixed with trials for which stimulus location was relevant. Compatible mapping of the location-relevant trials enhanced the Simon effect relative to an unmixed condition, whereas incompatible mapping reversed the Simon effect. The reversal with incompatible mapping remained evident when task uncertainty was removed by use of a precue and was larger than the reversed effect produced by making incongruent trials more frequent than congruent trials. This result suggests that both attentional biases and task-defined associations contribute to the reversal of the Simon effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)