The relative weightings of visual and nonvisual coding in a simple motor learning task

A linear positioning task was used to examine the effects of visual and nonvisual inputs on motor learning. The experiment had three factors with two levels of each namely: sensory modality (visual-nonvisual), transfer at recall (changed-unchanged), size of movement (25.4 cm, 50.8 com). Three dependent variable were used: absolute error (AE), constant error (CE), and variable error (VE). The results suggest that visual dominance causes disruption of recall in the visual, changed conditions. No disruption of recall was found for the nonvisual condition other than in terms of CE with respect to movement sizes. The results are taken to follow Posner et al.'s (1976) theory of visual dominance, but some account of the spatial qualities of visual and kinesthetic information is needed.     

Success modulates consolidation of a visuomotor adaptation task

Consolidation is a time-dependent process that is responsible for the storage of information in long-term memory. As such, it plays a crucial role in motor learning. Prior research suggests that some consolidation processes are triggered only when the learner experiences some success during practice. In the present study, we tested whether consolidation processes depend on the objective performance of the learner or on the learner's subjective evaluation of his or her own performance (i.e., how successful the learner believes he or she is). Four groups of participants performed 2 sessions of a visuomotor adaptation task for which they had to learn a new internal model of limb kinematics; these sessions were either 5 min or 24 hr apart. The task was identical for all participants, but each group was given a difficult or an easy objective that affected the participants' evaluation of their own performance during the initial practice session. All groups adapted their movements similarly to the rotation of the visual feedback during the first session. However, when retested the following day, participants who had a 24-hr rest interval and had initially experienced success performed significantly better than those who did not feel successful or who were given a 5-min rest interval. Our results indicate that a certain level of subjective success must be experienced to trigger certain consolidation processes.     

Conformity as a function of task generalization and relative competence

Subject correctness and group agreement were varied for college subjects engaged in a light discrimination task. On another task, employing multiple-choice questions about Canada, the dependent variable of conformity was assessed to examine generalization of relative competence formed on the light discrimination task. It was seen that (1) relative competence was seen to mediate conformity for a specific task (Canadian Knowledge Inventory), but did not generalize across tasks (i.e. from the light discrimination task to the Canadian Knowledge Inventory); (2) with respect to the Canadian Knowledge Inventory, subjects who perceived themselves as more competent than the group did not conform as much as those who either perceived themselves as less competent than or as competent as the group; (3) the experimental manipulations did not affect conformity, further supporting the findings that perceived competence does not generalize across classes of tasks; (4) females conformed more than males: and (5) nonsuspicious subjects conformed more than suspicious subjects.     

The relative influence of place and direction in the Morris water task

Previous work from our laboratory has demonstrated that rats display a preference for directional responding over true place navigation in the Morris water task. The present study evaluated the range of situations in which this preference is observed and attempted to identify methods that favor navigation to the precise location of the escape platform in the room. A preference for directional responding over place navigation was observed in a wide range of procedures that included providing extensive training (Experiment 1), providing only platform placement experience in the absence of active swim training (Experiment 2), training navigation to multiple platform locations in a moving platform variant of the task (Experiment 3), and explicitly training navigation to a precise location in the room, versus navigation in a particular direction, regardless of the pool's position in the room (Experiments 4-5). A modest preference for navigation to the precise spatial location of the platform was observed when the pool wall was virtually eliminated as a source of control by filling it to the top with water (Experiment 6).     

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.     

Stimulus conflict predicts conflict adaptation in a numerical flanker task

Conflict monitoring theory states that response conflict triggers conflict adaptation, resulting in reduced congruency effects after response-incongruent trials (Botvinick, Braver, Barch, Carter, & Cohen, 2001). Verbruggen, Notebaert, Liefooghe, and Vandierendonck (2006) observed conflict adaptation after stimulus-incongruent trials without any response conflict. In this study, we further explore the hypothesis that stimulus conflict is an important trigger for conflict adaptation. We propose a measure for stimulus conflict that adequately explains the data of Verbruggen et al. and new data from a numerical flanker task. We conclude that stimulus conflict and response conflict have dissociable effects on behavior Whereas response conflict is a good predictor of response times, stimulus conflict is a better predictor of the adaptation effect.     

Decomposing intuitive components in a conceptual problem solving task

Research into intuitive problem solving has shown that objective closeness of participants' hypotheses were closer to the accurate solution than their subjective ratings of closeness. After separating conceptually intuitive problem solving from the solutions of rational incremental tasks and of sudden insight tasks, we replicated this finding by using more precise measures in a conceptual problem-solving task. In a second study, we distinguished performance level, processing style, implicit knowledge and subjective feeling of closeness to the solution within the problem-solving task and examined the relationships of these different components with measures of intelligence and personality. Verbal intelligence correlated with performance level in problem solving, but not with processing style and implicit knowledge. Faith in intuition, openness to experience, and conscientiousness correlated with processing style, but not with implicit knowledge. These findings suggest that one needs to decompose processing style and intuitive components in problem solving to make predictions on effects of intelligence and personality measures.     

Effects of attentional modulation of a stationary surround in adaptation to motion

The effect of varying the spatial relationships between an adapt/test grating and a stationary surrounding reference grating, and their interaction with diversion of attention during adaptation, were investigated in two experiments on the movement aftereffect (MAE). In experiment 1, MAEs were found to increase as the separation between the surrounding grating and the adapt/test grating decreased, but not with the area of the adapt/test grating. Although diversion during adaptation (repeating changing digits at the fixation point) reduced MAE durations, its effects did not interact with any of the stimulus variables. In experiment 2, MAE durations increased as the outer dimensions of the reference grating were increased, and this effect did interact with diversion, so that the effects of diversion were smaller when the surround grating was larger. This suggests that diversion may be affecting the inputs to an opponent process in motion adaptation, with a smaller effect on the surrounds than on the centres of antagonistic motion-contrast detectors with large receptive fields. A third experiment showed that, although repeating the word 'zero' during adaptation reduced MAEs, this reduction was smaller than that from naming a changing sequence of digits (and not significantly different from that from simply observing the changing digits), suggesting that MAE reductions are not produced only, if at all, by putative movements of the head and eyes caused by speaking.     

The development of a general associative learning account of skill acquisition in a relative arrival-time judgment task

Current theory assumes that individuals only use information from the immediate environment to perform relative arrival-time judgment tasks. This article presents a theoretical analysis of the memory requirements of this task. The authors present an analysis of the inputs to the memory system and the processes that map those inputs onto outputs. The analysis generates a set of predictions regarding the specificity of transfer and the role of context during learning. In 3 experiments, participants decided whether pairs of aircraft would violate a minimum separation standard or pass each other safely. Participants were presented with pairs of aircraft in which properties of the pair varied along 3 structural and 3 surface dimensions. Contexts were defined by the co-occurrence of specific values along stimulus dimensions and the use of a neutral label. The results suggest that transfer was limited by the dimensions that were varied in training and the context in which those dimensions were varied. The discussion focuses on the problems that complex tasks like relative judgment pose for associative learning mechanisms and the development of precise models of cognition.     

On-the-fly adaptation of selectivity in the flanker task

The processing selectivity in the flanker task has been shown to depend on the ratio of congruent trials to incongruent trials in a task (Gratton, Coles, & Donchin, 1992). If congruent trials are more frequent than incongruent ones, the flankers are more attended and, consequently, the flanker congruency effect is increased. Recent results suggest that participants can even allocate attention on the fly to the flankers-that is, in a highly flexible way after stimulus onset-depending on the frequency of incongruent trials on a certain stimulus location. Because location plays a unique role in stimulus selection, we investigated in two experiments whether selectivity can also be adjusted on the fly depending on stimulus color. The results demonstrate that color can be used for such an adjustment, but only if the association between color and frequency has be enpreviously learned under blocked conditions.     

Age differences in integration of components of a motor task.

To study effects of practice on the ability of 6-, 11-, and 18-yr.-old Ss to integrate the components of the Rho task 3 groups of 50 boys performed 30 consecutive trials. (a) With practice all age groups improved in total movement time; (b) 11-yr.-old Ss attained the 18-yr.-olds' level of performance in both components, initial differences existing only the linear component; (c) relative to the 18-yr.-old Ss, the 6-yr.-olds achieved proportionally less improvement in the linear component; (d) unlike 11- and 18-yr.-old Ss, the 6-yr.-olds evidenced increasing specificity of task components across trials. Unlike the two older age groups, the 6-yr.-old Ss were unable to achieve a high degree of integration of task components. The findings were discussed in light of Pascual-Leone's neo-Piagetian model of learning and development.     

Effect of response task on taste adaptation

Two experiments studied whether subjects reported complete adaptation of a taste sensation. Three tasks were chosen based on their use in other laboratories: hand lowering to connote stimulus absence, magnitude estimation, and cross-adaptation of a brief stimulus following a prolonged stimulus. In the first experiment, different groups of 9 subjects received the three different tasks; in the second experiment, all 20 subjects received all three tasks. In both experiments, subjects failed to demonstrate complete taste adaptation in at least 50% of adaptation trials. Response task did affect the likelihood of observing complete taste adaptation.     

Scaling movement amplitude: adaptation of timing and amplitude control in a bimanual task

Participants traced two circles simultaneously and the diameter of one circle was scaled as the diameter of the other circle remained constant. When the scaled circle was larger, amplitude error shifted from overshooting to undershooting, while shifting from undershooting to overshooting when this circle was smaller. Asymmetric coordination was unstable when the left arm traced a circle larger than the right arm, yet stable when the left arm traced a smaller circle. When producing symmetric coordination and the left arm traced the larger circle, relative phase shifted by 30°, but a right arm lead predominated. When the left arm traced the smaller circle and symmetric coordination was required, a 30° shift in relative phase occurred, but hand lead changed from left to right. The modulation of movement amplitude and relative phase emerged simultaneously as a result of neural crosstalk effects linked to initial amplitude conditions and possibly visual feedback of the hands' motion.     

Effects of load stressors, cognitive complexity and type A coronary prone behavior on visual-motor task performance

In two separate experiments, 25 and 42 adult working males participated in a visual-motor task modeled on a video game. The game was designed to permit measurement of strategy, risk taking, errors committed, and overall task performance. Predictions of complexity theory for task performance were supported. In the second experiment, participants were divided into four subgroups on the basis of Type A versus Type B coronary-prone behavior (measured on the structured interview) and on the basis of unidimensional versus multidimensional responding (measured by a complexity interview with stems of the sentence completion test). Type A coronary-prone behavior did not contribute to differences in visual-motor performance. More multidimensional persons exceeded their unidimensional counterparts, especially in the application of strategy. The extension of complexity theory approaches to simpler tasks is discussed. It is noted that the frequently voiced assumptions of Type A individuals-that their behavior style tends to lead to higher performance levels-is not supported.     

Additivity of components of prismatic adaptation

Ss pointed with each hand at a light or at the unseen toe and looked in the direction of the unseen toe before, during, and after training one arm to point to a visual target which was progressively displaced to one side by a prism. Results show that a proprioceptive change in the trained arm is a universal component of the adaptation. When a change in the eye-head system occurs, it and the proprioceptive change in the arm sum to the total adaptation and it is accompanied by a predictable degree of intermanual transfer of the adaptation, as a felt-position theory of adaptation would predict. However, when there is no change in the eye-head system, the proprioceptive shift is not always sufficient to account for the total adaptive shift.     

Distinct consolidation outcomes in a visuomotor adaptation task: Off-line leaning and persistent after-effect

Consolidation is a time-dependent process responsible for the storage of information in long-term memory. As such, it plays a crucial role in motor learning. In two experiments, we sought to determine whether one’s performance influences the outcome of the consolidation process. We used a visuomotor adaptation task in which the cursor moved by the participants was rotated 30° clockwise. Thus, participants had to learn a new internal model to compensate for the rotation of the visual feedback. The results indicated that when participants showed good adaptation in the first session, consolidation resulted in a persistent after-effect in a no-rotation transfer test; they had difficulty returning to their normal no-rotation internal model. However, when participants showed poor adaptation in the first session, consolidation led to significant off-line learning (between sessions improvement) but labile after-effects. These observations suggest that distinct consolidation outcomes (off-line learning and persistent after-effect) may occur depending on the learner’s initial performance.     

Transformation of task components into an integrated representation during task switching

We combined task switching with a change paradigm to trace the transformation of the information conveyed by task cues into a readiness to perform the cued task. The tasks were composed of two components that allowed us to determine switch costs as a function of the number of changed task components. With a short stimulus-onset asynchrony (SOA) of 200ms, switch costs grew monotonically as a function of the number of changed components. With a SOA of 400ms, the switch-cost profile exhibited a nonmonotonic characteristic that was previously observed only with switches from an already performed task. Our observations suggest that task preparation can be considered as a process by which an unstructured representation of task components is gradually transformed into an integrated task representation that comprises asymmetrical associations between the task components.