Influence of practice on response-selection and response-implementation processes involved in the response-interference effect

In a choice reaction-time task, the response-interference effect is an increase in reaction times when the two possible responses are from the same hand compared to when the two possible responses are from different hands [Psychonomic Science 2 (1965) 55-56; Human Motor Control, Academic Press, San Diego, CA, 1991]. Although the influence of practice on other reaction-time effects (i.e., the complexity effect and precuing) has been examined, research evaluating the influence of practice on the response-interference effect is limited. Therefore, two experiments were conducted to determine the influence of practice on the response-interference effect. In Experiment 1, a bilateral transfer task was used to assess the influence of practice on the response-selection processes associated with the response-interference effect. The practice results indicated decreased reaction times, but did not influence the response-interference effect. In Experiment 2, a priming task was used to assess the influence of practice on response-implementation processes associated with the response-interference effect. The reaction time results indicated a change in the response-interference effect. The results of these two experiments suggest that with only two fingers on response keys, practice alters the mechanical constraints affecting the response-implementation processes and thereby decreases the response-interference effect.     

Balancing cognitive control: How observed movements influence motor performance in a task with balance constraints

We investigated the influence of observed movements on executed movements in a task requiring lifting one foot from the floor while maintaining whole-body balance. Sixteen young participants (20–30 years) performed foot lift movements, which were either cued symbolically by a letter (L/R, indicating to lift the left/right foot) or by a short movie showing a foot lift movement. In the symbol cue condition, stimuli from the movie cue condition were used as distractors, and vice versa. Anticipatory postural adjustments (APAs) and actual foot lifts were recorded using force plates and optical motion capture. Foot lift responses were generally faster in response to the movie compared to the symbol cue condition. Moreover, incongruent movement distractors interfered with performance in the symbol cue condition, as shown by longer response times and increased number of APAs. Latencies of the first (potentially wrong) APA in a trial were shorter for movie compared to symbol cues but were not affected by cue-distractor congruency. Amplitude of the first APA was smaller when it was followed by additional APAs compared to trials with a single APA. Our results show that automatic imitation tendencies are integrated with postural control in a task with balance constraints. Analysis of the number, timing and amplitude of APAs indicates that conflicts between intended and observed movements are not resolved at a purely cognitive level but directly influence overt motor performance, emphasizing the intimate link between perception, cognition and action.     

The effect of priming on interceptive actions

Time constraints in ball sports encourage players to take advantage of any relevant advance information available to prepare their actions. Advance information, therefore, can serve to prime movement parameters (e.g. movement direction) and reduce the amount of time required to prepare the upcoming movement. Regularly, however, players face situations in which the information used to prepare the action turns out to be outdated just prior to movement initiation and the prepared action needs to be changed as soon as possible. The aim of the experiment presented here was to determine whether the priming effect, generally reported for reaction time tasks, could be generalised to interceptive actions. A secondary aim was to examine the strategies employed by the participants to cope with valid, invalid, or no advance information. The results indicate that, when available, the participants used advance information to prepare their movements. More specifically, in comparison with valid advance information, hit rate and spatial accuracy were reduced when the participants had no advance information and were even smaller when the information conveyed was invalid. The results also suggest that in the absence of valid advance information, the strategies employed to intercept the moving target were tuned to the time remaining until the interception was due to occur.     

Moving and memorizing: Motor planning modulates the recency effect in serial and free recall

Motor planning has generally been studied in situations where participants carry out physical actions without a particular purpose. Yet in everyday life physical actions are usually carried out for higher-order goals. We asked whether two previously discovered motor planning phenomena - the end-state comfort effect and motor hysteresis - would hold up if the actions were carried out in the service of higher-order goals. The higher-order goal we chose to study was memorization. By focusing on memorization, we asked not only how and whether motor planning is affected by the need to memorize, but also how memory performance might depend on the cognitive demands of motor planning. We asked university-student participants to retrieve cups from a column of drawers and memorize as many letters as possible from the inside of the cups. The drawers were opened either in a random order (Experiment 1) or in a regular order (Experiments 2 and 3). The end-state comfort effect and motor hysteresis were replicated in these conditions, indicating that the effects hold up when physical actions are carried out for the sake of a higher-order goal. Surprisingly, one of the most reliable effects in memory research was eliminated, namely, the tendency of recent items to be recalled better than earlier items - the recency effect. This outcome was not an artifact of memory being uniformly poor, because the tendency of initial items to be recalled better than later items - the primacy effect - was obtained. Elimination of the recency effect was not due to the requirement that participants recall items in their correct order, for the recency effect was also eliminated when the items could be recalled in any order (Experiment 3). These and other aspects of the results support recent claims for tighter links between perceptual-motor control and intellectual (symbolic) processing than have been assumed in the past.     

Limits of end-state planning

The end-state comfort effect is the tendency to use an uncomfortable initial grasp posture for object manipulation if this leads to a comfortable final posture. Many studies have replicated the end-state comfort effect across a range of tasks and conditions. However, these tasks had in common that they involved relatively simple movements, such as picking up a dowel or sliding a pan from one place to another. Here we asked whether the end-state comfort effect extends to more complex tasks. We asked participants to grasp a transparent bowl and move the bowl to an instructed location, positioning it in an instructed orientation. We either found an initial-state comfort effect or equal degrees of comfort for end-grasps and start-grasps depending on task instructions. The end-state comfort effect was not consistently observed. The results suggest that the end-state comfort effect may be restricted to relatively simple grasping movements.     

The role of attention in the occurrence of the affordance effect

It has been demonstrated that visual objects activate responses spatially corresponding to the orientation (left or right) of their graspable parts. To investigate the role of attention orienting in the generation of this effect, which we will refer to as affordance effect, we ran three experiments in which the target stimulus could either correspond or not with a dynamic event capturing attention. Participants were required to press a left or right key according to the vertical orientation (upward or inverted) of objects presented with their handles oriented to the right or to the left. In Experiments 1 and 2, the objects were located above or below fixation, while in Experiment 3, to assess the contemporary presence of the affordance and Simon effects, the objects were located to the left or right of fixation. The results showed that while the affordance effect, when evident, was always relative to the target object, irrespective of its attentional capturing properties, the Simon effect occurred relative to the event capturing attention. These findings suggest that automatic and controlled processes of visual attention may play a differential role in the occurrence of the two effects.     

Whole-body posture planning in anticipation of a manual prehension task: Prospective and retrospective effects

This study examined the extent to which the anticipation of a manual action task influences whole-body postural planning and orientation. Our participants walked up to a drawer, opened the drawer, then grasped and moved an object in the drawer to another location in the same drawer. The starting placement of the object within the drawer and the final placement of the object in the drawer were varied across trials in either a blocked design (i.e., in trials where the same start and end location were repeated consecutively) or in a mixed fashion. Of primary interest was the posture adopted at the moment of grasping the drawer handle before pulling it out prior to the object manipulation task. Of secondary interest was whether there were sequential effects such that postures adopted in preceding trials influenced postures in subsequent trials. The results indicated that the spatial properties of the forthcoming object manipulation influenced both the postures adopted by the participants and the degree to which the drawer was opened, suggesting a prospective effect. In addition, the adopted postures were more consistent in blocked trials than in mixed trials, suggesting an additional retrospective effect. Overall, our findings suggest that motor planning occurs at the level of the whole body, and reflects both prospective and retrospective influences.     

Cross-talk of instructed and applied arbitrary visuomotor mappings

Humans are able to perform any voluntary motor response to any environmental stimulus. This cornerstone of the flexibility of human behaviour has been investigated under the label of arbitrary visuomotor mapping. The focus of research has been the question as to how these mappings are executed once the subjects have been instructed appropriately. However, one question has been rather neglected thus far: what, in the first place, enables humans to instantaneously implement any arbitrary S-R mapping by mere instruction! We report an experiment assessing the cross-talk of arbitrary S-R mappings as a part of the instructed task representation, on the one hand, and the cross-talk of repetitively applied mappings, on the other hand. The results show a behavioural dissociation of the cross-talk elicited by instructed and applied mappings, suggesting that the first occurs on the level of task-set, whereas the latter occurs on the level of specific S-R associations.     

Age-related effects in interlimb practice on coding complex movement sequences

Hikosaka et al. (1999) proposed that sequential movements are acquired in independent visual-spatial and motor coordinate systems with coding initially represented in visual-spatial coordinates, and later after extended practice in motor coordinates. One aspect of sequence learning that has not been systematically studied, however, is the question of whether or not older adults show the same pattern of coding in inter-limb practice as younger learners. In the present experiment an inter-limb practice paradigm was designed to determine the role that visual-spatial (Cartesian) and motor (joint angles, activation patterns) coordinates play in the coding and learning of a complex movement sequence. Younger and older adults practiced a 16-element movement sequence with one limb on Day 1 and the contra-lateral limb on Day 2. Practice involved the same sequence with either the same visual-spatial or motor coordinates on the two days. Retention tests were conducted on Day 3. Results indicated that keeping the visual-spatial coordinates the same during acquisition resulted in superior retention only for younger adults. Results also indicated the overall slowing of sequential movement production for older adults which appears to result from these participants inability to impose a structure on the sequence. This provides strong evidence that the visual-spatial code plays a dominant role in complex movement sequences and this code is represented in an effector-independent manner for younger adults, but not for older adults.     

Contributions from associative and explicit sequence knowledge to the execution of discrete keying sequences

Research has provided many indications that highly practiced 6-key sequences are carried out in a chunking mode in which key-specific stimuli past the first are largely ignored. When in such sequences a deviating stimulus occasionally occurs at an unpredictable location, participants fall back to responding to individual stimuli (Verwey & Abrahamse, 2012). The observation that in such a situation execution still benefits from prior practice has been attributed to the possibility to operate in an associative mode. To better understand the contribution to the execution of keying sequences of motor chunks, associative sequence knowledge and also of explicit sequence knowledge, the present study tested three alternative accounts for the earlier finding of an execution rate increase at the end of 6-key sequences performed in the associative mode. The results provide evidence that the earlier observed execution rate increase can be attributed to the use of explicit sequence knowledge. In the present experiment this benefit was limited to sequences that are executed at the moderately fast rates of the associative mode, and occurred at both the earlier and final elements of the sequences.     

Categorization and action: What about object consistence?

Categorization studies have focused on the importance of a variety of perceptual properties (shape, size, weight). The present study explored whether the softness or hardness of an object might influence the way we categorize and consider category members. Of additional interest was whether information on consistence is automatically activated and whether it is modulated by the kind of task and of response modality. Three experiments demonstrated that information on consistence is automatically activated, and it helps us to distinguish between artefacts and natural objects. Interestingly, the results are in agreement with the simulation hypothesis; namely, when we consider artefacts, we simulate using them and information on their consistence is activated; this simulation is modulated by the task. The way we differently process artefacts and natural objects across the experiments confirms the simulation hypothesis and our sensitivity to the response modality.     

Automatic sequential response priming and intentional response preparation in choice reaction tasks: Evidence from response repetition and response cuing

This study examined the interaction of response repetition and response cuing in a finger cuing task with a short and a long cue-stimulus interval (CSI). We observed shorter reaction times (RTs) with increasing CSI and a substantial response repetition benefit. However, this benefit was abolished at the long CSI, suggesting that response cuing neutralized the repetition effect. According to additive-factors logic, the observed interaction suggests that both repetition and cuing exert their influence on a common processing stage, which we identify as the response selection stage. We argue that cuing and repetition effects are expressions of distinct mental operations: cuing is based on intentional response code activation, whereas repetition is based on sequential, automatic response code priming. Cue-based intentional code activation starts slowly and increases with CSI, but sequential response priming is independent of CSI, explaining why cuing abolishes the response repetition benefit at the long CSI.     

Being prepared on time: on the importance of the previous foreperiod to current preparation, as reflected in speed, force and preparation-related brain potentials

How do participants adapt to temporal variation of preparatory foreperiods? For reaction times, specific sequential effects have been observed. Responses become slower when the foreperiod is shorter on the current than on the previous trial. If this effect is due to changes in motor activation, it should also be visible in force of responses and in EEG measures of motor preparation, the contingent negative variation (CNV) and the lateralized readiness potential (LRP). These hypotheses were tested in a two-choice reaction task, with targets occurring 500, 1500, or 2500 ms after an acoustic warning signal. The reaction time results showed the expected pattern and were accompanied by similar effects on a fronto-central CNV and the LRP. In contrast, the increase of response force with brief current foreperiods did not depend on previous foreperiods. Thus, EEG measures confirm that sequential effects on RT are at least partially due to changes in motor activation originating from previous trials. Effects found on response force may be related to general response readiness rather than activation of motor-hand areas, which may explain the absence of a sequential effect on force in the current experiment.     

Acute aerobic exercise and information processing: Modulation of executive control in a Random Number Generation task

The immediate and short-term aftereffects of a bout of aerobic exercise on young adults’ executive functions were assessed. Sixteen participants performed a Random Number Generation (RNG) task, which measured two aspects of executive function, before, during, and after ergometer cycling exercise. In a separate session, participants completed the same sequence of testing while seated on an ergometer without pedaling. Results suggest that aerobic exercise: (1) selectively influences RNG indices related to the ability to alternate ascending and descending runs throughout the entire exercise bout; (2) induces a shift to a less effortful number generation strategy, particularly during the first few minutes of the exercise; and (3) has no significant influence on RNG performance as soon as the exercise terminates. The strategic adjustments observed during the exercise are interpreted in the framework of Hockey’s [Hockey, G. R. J. (1997). Compensatory control in the regulation of human performance under stress and high workload: A cognitive-energetical framework. Biological Psychology, 45, 73-93.] compensatory control model and suggest that concurrent effortful processes induced by cycling exercise may draw upon available attention resources and influence executive processing.     

Repetitive antisaccade execution does not increase the unidirectional prosaccade switch-cost

An antisaccade is the execution of a saccade to the mirror-symmetrical location (i.e., same amplitude but opposite visual field) of a single and exogenously presented visual target. Such a response requires top-down decoupling of the normally direct spatial relations between stimulus and response and results in increased planning times and directional errors compared to their spatially compatible prosaccade counterparts. Moreover, antisaccades are associated with diffuse changes in cortical and subcortical saccade networks: a finding that has, in part, been attributed to pre-setting the oculomotor system to withhold a stimulus-driven prosaccade. Moreover, recent work has shown that a corollary cost of oculomotor pre-setting is that the planning time for a to-be-completed prosaccade is longer when preceded by an antisaccade (i.e., the unidirectional prosaccade switch-cost). Notably, this result has been attributed to antisaccades imparting a residual inhibition of the oculomotor networks that support the planning of stimulus-driven prosaccades. In the current investigation, we sought to determine if the number of antisaccades preceding a prosaccade increases this residual inhibition and thus influences the magnitude of the unidirectional prosaccade switch-cost. To that end, participants alternated between pro- and antisaccades after every second (i.e., AABB schedule) and every fourth (i.e., AAAABBBB schedule) trial. In addition, participants completed pro- and antisaccades in separate blocks of trials. Results demonstrated that task-switch prosaccades produced longer reaction times than their task-repetition and blocked condition counterparts, whereas antisaccade reaction times did not vary across task-repetition, task-switch and blocked condition trials. Most notably, the magnitude of the unidirectional prosaccade switch-cost was not modulated across the different task-switching schedules. Thus, we propose that the top-down requirements of the antisaccade task do not produce additive inhibition of stimulus-driven saccade networks.     

Perceived distance during golf putting

This study examined the effect of anxiety states on the relationship between golf-putting distance and performance in an environment requiring high movement accuracy. Twenty-three amateur golfers attempted 15 putts at each of three putting distances, 1.25, 1.50, and 1.75 m, under conditions characterized by both control demands and pressure. All attempts were recorded, and kinematic features were analyzed. Under conditions involving an audience and a monetary reward, the mean score on the State-Trait Anxiety Inventory Y-1 and the mean heart rate increased by 14 points and 11 bpm, respectively. We grouped participants on an a posteriori basis using the median split. The backswing of high-anxiety performers shortened, the downswing speed declined, and the relative time to peak club-head velocity changed when putting under pressure from 1.25 m. In contrast, no change in backswing or relative time to peak velocity was observed in low-anxiety performers, although impact velocity increased under this condition. These results indicate that the degree to which both low- and high-anxiety golfers were anxious about failure affected motor control at the 1.25-m distance, suggesting that a distortion in perceived distance may result from the interaction between putting distance and anxiety related to failure during golf putting.     

Letters as visual action-effects in skilled typing

In the present study, action-(visual)-effect associations in participants who type using the 10-finger-system and participants who do hunt-and-peck typing were investigated. Following responses (on either a keyboard or an external response device) to colored squares, participants were presented response corresponding or non-corresponding letters. In Experiment 1, evidence for action activation by anticipated action-effects was found. In Experiment 2, evidence that actions can activate the corresponding action-effects was obtained, but only when participants responded on a keyboard and only in the first half of the experimental trials. In both experiments, effects were only present in participants who type using the 10-finger-system. Thus, results provided evidence for bidirectional action-effect associations in 10-finger-system typists. Anticipated visual action-effects are important for action selection in expert typists. Visual action-effects also have a function for performance monitoring, but only in an appropriate context. The functional use of existing action-effect associations is flexible.     

When two actions are easier than one: How inhibitory control demands affect response processing

Numerous studies showed that the simultaneous execution of multiple actions is associated with performance costs. Here, we demonstrate that when highly automatic responses are involved, performance in single-response conditions can actually be worse than in dual-response conditions. Participants responded to peripheral visual stimuli with an eye movement (saccade), a manual key press, or both. To manipulate saccade automaticity, a central fixation cross either remained present throughout the trial (overlap condition, lower automaticity) or disappeared 200 ms before visual target onset (gap condition, greater automaticity). Crucially, single-response conditions yielded more performance errors than dual-response conditions (i.e., dual-response benefit), especially in gap trials. This was due to difficulties associated with inhibiting saccades when only manual responses were required, suggesting that response inhibition (remaining fixated) can be even more resource-demanding than overt response execution (saccade to peripheral target).     

The effect of a cross-trial shift of auditory warning signals on the sequential foreperiod effect

When a warning signal (WS) precedes an imperative signal (IS) by a certain amount of time (the foreperiod, FP), responses are speeded. Moreover, this effect is modulated by the FP length in the previous trial. This sequential FP effect has lately been attributed to a trace-conditioning mechanism according to which individuals learn (and re-learn) temporal relationships between the WS and the IS. Recent evidence suggests that sensory WS attributes are critical to trigger time-related response activation. Specifically, when WS modality is shifted in subsequent trials (e.g., from auditory to visual modality), the sequential FP effect becomes attenuated. This study examined whether the sequential FP effect is reduced only by between-modality shifts or whether this attenuation generalizes to cross-trial shifts of WS attributes within modalities. We compared dimensional (low vs. high tone frequency) and qualitative shifts (pure tone vs. noise) of equal-intense auditory WS events. The results of four experiments revealed that shifts of tone frequency did not, whereas shifts of qualitative tone characteristics did attenuate the sequential FP effect. These results support the view that the WS acts as a trigger cue that unintentionally activates responses at previously reinforced critical moments.     

Display-control arrangement correspondence and logical recoding in the Hedge and Marsh reversal of the Simon effect

When left and right keypresses are made to stimuli in left and right locations, and stimulus location is irrelevant to the task, responses are typically faster when stimulus location corresponds with response location than when it does not (the Simon effect). This effect reverses when the relevant stimulus-response mapping is incompatible, with responses being slower when stimulus and response locations correspond (the Hedge and Marsh reversal). Simon et al. (Acta Psychol. 47 (1981) 63) reported an exception to the Hedge and Marsh reversal for a situation in which the relevant stimulus dimension was the color of a centered visual stimulus and the irrelevant location information was left or right tone location. In contrast, similar experiments have found a reversal of the Simon effect for tone location when relevant visual locations were mapped incompatibly to responses. We conducted four experiments to investigate this discrepancy. Both results were replicated. With an incompatible mapping, irrelevant tone location showed a small reverse Simon effect when the relevant visual dimension was physical location but not when the color of a centered stimulus or the direction in which an arrow pointed conveyed the visual location information. The reversal occurred in a more standard Hedge and Marsh task in which the irrelevant dimension was location of the colored stimulus, but only when the response keys were visibly labeled. Several of the results suggest that display-control arrangement correspondence is the primary cause of the Hedge and Marsh reversal, with logical recoding playing only a secondary role.