CONTEXTUAL INTERFERENCE AND INTROVERSION/EXTRAVERSION IN MOTOR LEARNING

Extroversion-Related Differences in Gaze Behavior during a Computer Task for Assessing Speed-Accuracy Trade-Off: Implications for Sensor-Based Applications

The principle of Fitts' law explains that the difficulty of movement increases when targets are farther away and narrower in width, particularly when touching two parallel targets as quickly as possible. Understanding the differences in motor and gaze behaviors between extroverts and introverts when performing tasks that require speed and accuracy is crucial for the development of sensor-based interfaces for games and rehabilitation. This study aimed to investigate such differences in a computer task that assesses the speed-accuracy trade-off (Fitts' task). Twenty introverts and seventeen extroverts wore an eye tracker and an accelerometer attached to their hand while performing 12 trials through six levels of difficulty presented on a computer screen. The results showed that introverts had longer visual fixations at the higher difficulty levels and reduced pupil diameter variability when difficulty was intermediate, suggesting that their gaze behavior may be different from that of extroverts. However, no significant differences were found in the speed and accuracy performance or kinematic variables between extroverts and introverts. These findings have important implications for the design of interventions that require both speed and accuracy in movement, such as in the development of virtual reality/games for rehabilitation purposes. It is important to consider individual differences in motor and gaze behaviors, particularly in those who may struggle with longer visual fixations, for the design of sensor-based applications and to promote successful interventions and recovery.

Caffeine Produces Neutral Effects on Extraverts' and Introverts' Performance of Fundamental Motor Skills

Extraverts are active and talkative, while introverts are quiet and calm. This difference has been attributed to the cortical activation level (arousal), which is low in extraverts and high in introverts. Thus, to reach an optimal level of arousal, extraverts seek stimulation and introverts avoid it. As caffeine increases arousal levels, our primary aim was to investigate the effect of caffeine on the performance of extraverted and introverted university students in the execution of stability, manipulative, and locomotor tasks. Considering the above, we evaluated side effects, such as restlessness and trembling of hands, we also analyzed the individual's perception regarding caffeine intake and the placebo. Forty two volunteers were classified as 21 extraverts and 21 introverts by the Eysenck Personality Questionnaire. Participants performed three tasks on two different days, having previously ingested caffeine and a placebo in counterbalanced order. A double-blind technique was employed. The dependent variable was the execution time to perform the tasks. The analyses of variance [2 (extraversion/introversion) x 2 (caffeine x placebo)] for each task did not show significant differences. Regarding the secondary aim, the chi-square test showed that introverts had a better perception of the substance they had ingested than did extraverts. Our findings indicate that in the execution of stability, manipulative, and locomotor tasks, either caffeine or the placebo produced the same effect, regardless of the participants' extraversion score. In addition, introverts were more sensitive to perceive which substance was ingested, caffeine or the placebo, than extraverts.

Self-Controlled Feedback and Learner Impulsivity in Sequential Motor Learning

Many studies have attributed self-controlled feedback benefits associated with motor learning to learners' greater information processing during practice. However, individual learner characteristics like their impulsivity can also influence how people engage cognitively during learning. We investigated possible dissociations between the types of interaction in self-controlled knowledge of results (KR) and learner impulsivity levels in learning a sequential motor task. Ninety volunteers responded to the self-restraint section of the Barkley deficits in executive functioning scale, and those 60 participants with the highest ( n = 30) and lowest ( n = 30) impulsivity scores practiced a motor task involving sequential pressing of four keys in predetermined absolute and relative times. We further divided participants into four experimental groups by assigning the high- and low-impulsivity groups to two forms of KR—self-controlled absolute and yoked. Study results showed no interaction effect between impulsivity and self-controlled KR, and, contrary to expectation, self-controlled KR did not benefit learning, independently of impulsivity. However, low-impulsivity participants performed better than high-impulsivity participants on the absolute dimension of the transfer task, while high-impulsivity learners were better at the relative dimension. Cognitive characteristics of automatic and reflexive processing were expressed by the strategies used to direct attention to relative and absolute task dimensions, respectively. Low-impulsivity learners switched their attention to both dimensions at the end of practice, while high-impulsivity learners did not switch their attention or directed it only to the relative dimension at the end of the practice. These results suggest that the cognitive styles of high- and low-impulsive learners differentially favor learning distinct dimensions of a motor task, regardless of self-controlled KR.

EXTRAVERSION/INTROVERSION AND AGE-RELATED DIFFERENCES IN SPEED-ACCURACY TRADEOFF

ABSTRACT Introduction: Extraversion/introversion and age differences might influence speed-accuracy tradeoff. Objective: The speed-accuracy tradeoff was investigated in extroverted and introverted female children, young adults and older adults. Method: Participants carried out an alternative version of Fitts’ task, which involved making alternate clicks with the mouse held in the dominant hand, moving as fast as possible, on two rectangular targets on a computer screen in order to make twelve attempts at six random levels of difficulty (twelve combinations of target widths and distances between targets). Each of the three groups was composed of 16 introverted and 16 extroverted subjects, based upon Brazilian versions of Eysenck’s questionnaire. Results: Elderly introverts fell short of the target more often and committed more overall errors than the elderly extroverts. Additionally, compared to their younger adult counterparts, the elderly subjects fell short of the target more often and committed more overall errors, besides taking longer to complete the task with higher levels of difficulty. Conclusion: The findings were interpreted in light of theories designed to explain the main processes underlying extroversion/introversion and age-related differences. Level of Evidence II; Lesser quality prospective study.