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Biomedical subjects

L Proteau

Publications and source records attributed to L Proteau.

At least 37 records · Page 2Linked to original sources
PubMed1994

On the cognitive processes underlying contextual interference and observational learning.

The main goal of the present study was to determine whether observation of an unskilled model learning a timing task enables the observer to develop a cognitive representation of the task similar to the one acquired through physical practice (Adams, 1986; Bandura, 1977; Lee & White, 1990). To reach that goal, we tested whether a contextual interference effect would be obtained in a retention test of subjects who had observed an individual practicing three variations of a timing task under a random or a blocked schedule of practice. Similar patterns of results in an immediate retention test were found following observation and physical practice. This suggests that observation indeed engaged the observers in the same type of cognitive activities as did physical practice. Moreover, a schedule of practice made up of 100% physical practice led to improved learning compared with a schedule of practice made up of 50% observation followed by 50% physical practice. This suggests that learning is enhanced more by numerous implementations of a motor program than by its mere construction or retrieval.

Journal Article↗
PubMed1994

Combined effects of movement velocity and duration on programming time: Spijkers (1989) revisited.

The goal of the present study was to determine the combined effects of movement velocity and duration on motor programming. Subjects were submitted to a two-choice reaction time task that could be completed by aiming movements differing in the mean velocity at which they were to be produced as well as by their movement time. The results of the present study indicate that, in each pair of responses used, the responses having the higher mean velocity were initiated faster that those having the lower mean velocity. Contrary to Spijkers' (1989) study, the different movement time pairings did not modify the effect of movement velocity on response programming time. Moreover, the same pattern of results was observed whether or not the subjects were permitted to visually guide their ongoing movement. Thus, Spijkers' proposition, that the type of control one may use to guide an aiming movement needs to be determined before movement initiation can take place, was not confirmed.

Journal Article↗
PubMed1994

Differential roles with aging of visual and proprioceptive afferent information for fine motor control.

The goal of this study was to determine whether aging brings modifications to the role played by different sources of afferent information for movement control. Older and younger subjects practiced an aiming task for either 40 or 200 trials while different sources of afferent information were available. Following the practice phase, all subjects were submitted to transfer tests in which the afferent information was either maintained or modified. Results indicate that modifying the sources of afferent information available for motor control from acquisition to transfer minimal effects for the older subjects but caused large increase in error for the younger subjects. These results suggest that learning is specific to the sources of afferent information available while practicing the task for the younger subjects, whereas older subjects show more flexibility in their utilization of afferent information for motor control.

Adult↗
PubMed1993

Determining movement onsets from temporal series.

With the advent of recent measurement techniques, kinematic and kinetic measures commonly are used to describe events over time. Often, the central and peripheral nature of the control processes involved are derived from these temporal series. For example, movement onset often arbitrarily defines the end of the central and the beginning of the peripheral processes. Because of its critical temporal location, we examined whether response dynamics (average movement velocity) affects the determination of movement onset. Interactive graphics and numerical methods of determining movement onsets from temporal series were evaluated on various kinematic signals. Variations in the initial rate of change in a given signal significantly affected the determination of movement onset. Consequently, measurements of component latency must be regarded with caution. A cursory description of related problems elucidated in previous research is discussed, and procedures that can minimize these artifacts are suggested.

Journal Article↗
PubMed1992

A sensorimotor basis for motor learning: evidence indicating specificity of practice.

Our previous work (Proteau, Marteniuk, Girouard, & Dugas, 1987) was concerned with determining whether with relatively extensive practice on a movement aiming task, as the skill theoretically starts becoming open-loop, there would be evidence for a decreasing emphasis on visual feedback for motor control. We eliminated vision of the moving limb after moderate and extensive practice and found that the movement became more dependent on this feedback with greater amounts of practice. In the present study, we wished to test the hypothesis, developed from our previous work, that at the base of movement learning is a sensorimotor representation that consists of integrated information from central processes and sensory feedback derived from previous experiences on the movement task. A strong test of this hypothesis would be the prediction that for an aiming task, the addition of vision, after moderate and relatively extensive practice without vision, would lead to an increasingly large movement decrement, relative to appropriate controls. We found good support for this prediction. From these and our previous results, and the idea of the sensorimotor representation underlying learning, we develop the idea that learning is specific to the conditions that prevail during skill acquisition. This has implications for the ideas of the generalized motor program and schema theory.

Feedback↗
PubMed1990

Vision of the stylus in a manual aiming task: the effects of practice.

Nearly a decade ago, Carlton (1981) showed that in a manual aiming task, vision of the ongoing stylus led to a better accuracy than when that source of information was not available. However, Elliott (1988) recently failed to replicate that finding and, rather, showed that being able to see an ongoing stylus did not result in a significant improvement of accuracy over a conventional no-vision condition. In the experiment to be reported here, we, on the one hand, replicated Elliott's results for the low level of practice condition (15 acquisition trials). On the other hand, the results obtained after moderate practice (150 acquisition trials) supported Carlton's earlier conclusion. These results therefore indicate that after sufficient practice one is able to use effectively the information provided by the ongoing stylus to help control his/her movement. This conclusion was further substantiated by the results obtained in a transfer task. Collectively, the results gave added support to a specificity of learning hypothesis (Proteau, Marteniuk, Girouard, & Dugas, 1987; Proteau, Marteniuk, & Lévesque, 1990).

Adult↗
PubMed1990

[Analysis of non-optimal behavior in a dichotomous choice situation].

Proteau and Girouard (1987) have recently proposed a model to explain the decisional process that takes place in a two-choice reaction time situation. Although the model was well supported by the experimental data reported by these authors, a few unexplained results were observed and hypotheses were suggested to account for them. The goal of the present experiment was, first, to replicate the results presented by Proteau and Girouard (1987) to support their model. Our second goal was to determine if the unexpected results reported by these authors can be linked to some particular conditions occurring in the normal course of an experiment. The results obtained in the present experiment totally supported the proposed model. Furthermore, a detailed analysis of the circumstances under which unexpected results occurred did not permit the identification of any particular conditions favoring their occurrence. In conclusion, the proposed model, although reliable for about 95% of the trials, is still imperfect.

Choice Behavior↗
PubMed1989

Decision making in sport: the effect of stimulus-response probability on the performance of a coincidence-anticipation task.

The purpose of the present study was to evaluate the quality of a motor response for different levels of expectancy and time constraint, in a two-choice coincidence-anticipation task. The probability of each of the two events likely to be presented were varied across different levels as well as the speed of the stimulus to be intercepted. The results indicated that neither the choice reaction time (CRT) and movement time, nor the performance of coincidence-anticipation were affected by the probability of the stimulus for the low and moderate stimulus speeds. However, when the stimulus traveled at a high speed a trade-off took place. The CRT decreased as the probability of the event increased, whilst the proportion of response initiation errors increased for the low probability events. This trade-off resulted in a better coincidence-anticipation as the probability of the event increased. The results obtained in the present experiment are clearly different from those obtained in a classic CRT-deadline paradigm, in that the trade-off observed between CRT and response initiation errors was far less pronounced in the coincidence-anticipation task. This difference was attributed to the higher negative consequences associated with a response initiation error in a coincidence-anticipation task. It is thus concluded that the tasks used to study the nature of the decision processes taking place in sports and sports-like situations must have some ecological validity to be of some help for the practitioner.

Adult↗
PubMed1986

[Decision strategy: effect of the proportion of total response time taken by choice reaction time].

Results from two series of studies on decision strategies suggested that subjects appeared to chose between two response modes. Subjects could use a decision strategy based either on anticipatory responses or on reaction responses. It appeared that certain characteristics specific to the task could be responsible for the discrepancy in the response mode. The aim of the present study was to ascertain whether the choice of a decision strategy could be dictated by the proportion of total response time taken up by the choice reaction time (TRC). For instance, if the TRC takes up a large proportion of the total time, reducing it in view of an anticipatory response could considerably reduce the total time. The advantage to be gained from an anticipatory response could thus be considered sufficient to warrant adoption of a decision strategy based on anticipation. On the contrary, when TRC takes up only a small portion of total time, a decision strategy based upon reactions is preferred since the cost related to an error in response would largely exceed the advantage related to anticipation. Results from the two series of experiments presented in this paper support the importance of this variable. More specifically, results revealed that the error that an individual allows himself to make depends upon the proportion of total time that is devoted to choice reaction time. An extension of the model presented by Proteau et al. is proposed in order to account for the present observations.

Choice Behavior↗
PubMed1984

Motor programming: does the choice of the limb which is to carry out the response imply a delay?

In many activities, the human being must quickly decide on the response to be produced following a change in the environment. In some of these situations, the limb that the individual chooses to carry out a response seems to be a significant element in performance. Thus, if the individual carries out the response with the limb closest to the target, the performance can improve because it will take less time to achieve the goal. However, it seems that in these situations, the human being does not take this decrease in movement time into consideration and that the response is carried out with the dominant hand. Why is this so? It may be because the reaction is faster when there doesn't have to be a choice as to which limb will carry out the response. The goal of this study was to check this possibility. In order to do so, the subjects performed a two choice reaction-time task. For this task, some subjects knew beforehand which hand they had to use to carry out the response while other subjects were unaware of this fact. The results of two experiments indicated that the choice of the limb which is to carry out the response requires no particular delay when the movement to be produced is externally guided.

Journal Article↗
PubMed1984

On the nature of the probe reaction-time task to uncover the attentional demands of movement.

McLeod (1980) reported some findings which showed that no phase of a movement was more attention-demanding than the other phases, contrary to all the results previously reported (e.g., Ells, 1973; Glencross, 1980). However, McLeod used a paradigm in which the two tasks were serial. Each task consisted of a series of 50 reaction time (RT) trials and/or 50 aiming movement trials. In addition to this, the interval of time between a response and the following signal within each series was constant. In order to try to replicated McLeod's findings, two experiments were conducted in which the response-signal interval was manipulated. The hypothesis was that time certainty associated with a constant interval would facilitate the allocation of time and would thus artificially reduce the interference between tasks. In Experiment 1, manual responses were used for the RT task; in Experiment II, they were vocal. Manipulation of the response-signal interval does not change one of the conclusions reached by McLeod: when the RT task involves vocal responses and the results on the RT task are analyzed in terms of response rather than stimulus arrival during the movement, then there is no phase of the movement which is more attention-demanding than the other phases. However, the results of Experiment II in which both the vocal RT task and the movement task significantly deteriorated in the dual-task condition were taken as an indication that the movement studied involved central attentional demands.

Journal Article↗
PubMed1983

[Decision strategy as a function of event probability: 2. Latency of the decision and covering the field].

A fair number of studies have been conducted in order to assess the effect of event probability on decision strategy in a two choice reaction time (CRT) task. Results showed that increasing the probability of an event from 0.5 to 0.8 did not affect CRT. In fact, a significant decrease in CRT was obtained only when one of the two stimuli reached a probability of 0.9. It was concluded from these studies that subjects used a very conservative decision strategy. It should be pointed out that in these studies the instructions given to subjects emphasized both speed and accuracy of response. In many sport situations however, a player must choose speed of response over accuracy. For example the tennis player who knows that the opponent will smash the ball either to his right or hs left. The purpose of the present study was to determine whether or not in such situations the defensive player might not choose a less conservative decision strategy than that presented earlier. Fourteen subjects were submitted to a two CRT task, where the probability of each event and the time allotted (TA) to complete the appropriate response were systematically manipulated. The results obtained for each level of TA were similar to those discussed earlier. More specifically, a significant decrease in CRT was obtained only when one of the two possible events reaches a probability of 0.9. However, it appeared that, reducing TA forced subjects to reduce CRT and to base their responses more and more on anticipation than on reaction.

Decision Making↗
PubMed1983

[Decision strategy: effect of probability of the results and of the allowed time on choice reaction time and on movement time].

In many sport activities, the speed with which a performer can complete the required response is an important determinant of performance. In order to minimize this time an individual can initiate and execute the response faster. A number of studies (Alain & Proteau, 1977; Proteau & Dugas, 1982; Régnier & Salmela, 1980) in which individual was to move for two meters in a choice reaction time task have shown that, when the probability of one of the two events was 0,9, the movement time (MT) was significantly reduced. The results may perhaps be explained by the fact that subjects shifted their weight during the foreperiod (FP) preceding the stimulus and then facilitated the movement execution (reflected by a lower MT). The present experiment was designed to test the second possibility. Subjects initiated their responses from a dynamographic platform. The independent variables were the probabilities of the two events and the time allowed for subjects to complete the response. Results indicated that when the probability of one of the two events was sufficiently high (0,9), subjects did shift their weight during the FP in order to produce a faster response. The results supported the fact that subjects, in sport like situations, prepare themselves, at least partially, but only when the probability of the event is very high.

Decision Making↗
PubMed1983

[Decision strategy as a function of uncertainty of the result: I. Latency of the decision].

Until now, the decision strategy used by human beings faced with a dichotomous situation was studied considering that speed of reaction was the main dependent variable. It was found that, in a two choice reaction time (CRT) task, subjects used a very conservative decision strategy. That is, when compared with events of 0.5 probability, only those events with a probability of no less than 0.9 caused a significant decrease in CRT. In real sport situations however, the tennis player can not only increase his speed of response but can also change his position on the court in order to defend more appropriately the area of the court which appears more likely to be attacked. Two experiments were conducted in order to verify this hypothesis. In both experiments, a two CRT task was used; the independent variables being: (a) event probability and (b) time allotted to complete the appropriate response (TA). Results indicate that as soon as the probability of an attack reached 0.7, subjects started initiating defensive responses closer to the most probable area of attack. It thus appears that subjects were not as conservative as that reported in studies where CRT measures only were considered. On the other hand, subjects used a strategy which enabled them to reduce their total response time without increasing choice errors. In fact it seems that, when facing event uncertainty, the main concern of the human being is to keep his error rate as low as possible even if this is not the best strategy to use.

Analysis of Variance↗
PubMed1982

[Decision making by intercollegiate basketball players].

The results of several studies suggest that in an event incertitude situation, elite athletes can select the appropriate response faster than the novice. There are at least two possibilities to explain such a difference. First, it could be that the elite athlete has more facility to reduce the amount of information he/she is confronted with, that is he/she is able to identify more easily certain sequences and patterns in the play of his/her opponents. Secondly, it is possible that the athlete uses the available information in a different manner. The purpose of this study was to verify the second hypothesis. 10 subjects (5 novices and 4 intercollegiate basketball players) were submitted to a choice time task where the required response was a total body displacement over 2 meters. The results suggest that elite athletes use their knowledge of probability of events in the same way as the novice subjects.

Decision Making↗
PubMed1979

A physiological profile of Canadian Greco-Roman wrestlers.

The sport of Greco-Roman wrestling is relatively new in North America. However, this is the national sport of seven European countries and a great deal of research literature is available. The purpose of the present investigation was to establish baseline data for Canadian Greco-Roman wrestlers for a data bank which can be used to compare with World Class wrestlers. The results indicate that the Canadian National Team is made up of athletes with only average values for the physiological measures taken. However, the correlation between wrestling success and the physiological parameters measured is 0.91.

Adult↗