Fitts' reciprocal tapping task, a measure of motor capacity?

Employing Fitts' reciprocal tapping task, the capacity of the motor system in bits processed/second was assessed across different ages. In Exp. I a comparison was made among Grades 1, 5, 9, and university females. Motor capacity and average movement time/tap were significantly lower for Grade 1 girls than the other three grades. In addition, within-subject variability and percentage error rate decreased with increasing grade level. These findings were discussed in comparison to other studies looking at motor capacity changes across ages. Exp. II was designed to study the changes in motor capacity throughout 25 days of practice by two 5-yr.-old children. Two different methods were used to calculate motor capacity. One method (Kay, 1962) which assessed motor capacity separately for each tapping condition led to the conclusion that capacity increased with practice. A second method (Fitts & Peterson, 1964) treating all tapping conditions together in a regression equation and measuring capacity as the reciprocal of the slope (1/b) showed capacity to decrease with practice for one subject and oscillate with practice for the other subject. The general conclusion drawn from the two experiments was that motor capacity, as assessed by Fitts' tapping task, is not an extremely useful measure. Consideration of movement time is usually just as informative.     

Force Increase in a Repetitive Motor Task Inducing Motor Fatigue

To evaluate task induced motor fatigue in a well-established finger tapping task, we analyzed tapping parameters and included the time course of measures of force. We hypothesized that a decline in tapping force would reflect task induced motor fatigue, defined by a lengthening of inter-tap intervals (ITI). A secondary aim was to investigate the reliability of tapping data acquisition with the force sensor. Results show that, as expected, tapping speed decreased linearly over time, due to both an increase of ITI and tap duration. In contrast, tapping force increased non-linearly over time and was uncorrelated to changes in tapping speed. Force data could serve as a measure to characterize task induced motor fatigue. Force sensors can assess a decline in tapping speed as well as an independent increase of tapping force. We argue that the increase of force reflects central compensation, i.e. perception of fatigue, due to an increase in task effort and difficulty.     

Synchronization in repetitive smooth movement requires perceptible events

Accurate timing performance during auditory–motor synchronization has been well documented for finger tapping tasks. It is believed that information pertaining to an event in movement production aids in detecting and correcting for errors between movement cycle completion and the metronome tone. Tasks with minimal event-related information exhibit more variable synchronization and less rapid error correction. Recent work from our laboratory has indicated that a task purportedly lacking an event structure (circle drawing) did not exhibit accurate synchronization or error correction (Studenka & Zelaznik, in press). In the present paper we report on two experiments examining synchronization in tapping and circle drawing tasks. In Experiment 1, error correction processes of an event-timed tapping timing task and an emergently timed circle drawing timing task were examined. Rapid and complete error correction was seen for the tapping, but not for the circle drawing task. In Experiment 2, a perceptual event was added to delineate a cycle in circle drawing, and the perceptual event of table contact was removed from the tapping task. The inclusion of an event produced a marked improvement in synchronization error correction for circle drawing, and the removal of tactile feedback (taking away an event) slightly reduced the error correction response of tapping. Furthermore, the task kinematics of circle drawing remained smooth providing evidence that event structure can be kinematic or perceptual in nature. Thus, synchronization and error correction, characteristic of event timing (Ivry, Spencer, Zelaznik, & Diedrichsen, 2002; Repp, 2005), depends upon the presence of a distinguishable source of sensory information at the timing goal.     

Effects of feedback from active and passive body parts on spatial and temporal parameters in sensorimotor synchronization

Previous research on sensorimotor synchronization has manipulated the somatosensory information received from the tapping finger to investigate how feedback from an active effector affects temporal coordination. The current study explored the role of feedback from passive body parts in the regulation of spatiotemporal motor control parameters by employing a task that required finger tapping on one’s own skin at anatomical locations of varying tactile sensitivity. A motion capture system recorded participants’ movements as they synchronized with an auditory pacing signal by tapping with the right index finger on either their left index fingertip (Finger/Finger) or forearm (Finger/Forearm). Results indicated that tap timing was more variable, and movement amplitude was larger and more variable, when tapping on the finger than when tapping on the less sensitive forearm. Finger/Finger tapping may be impaired relative to Finger/Forearm tapping due to ambiguity arising through overlap in neural activity associated with tactile feedback from the active and the passive limb in the former. To compensate, the control system may strengthen the assignment of tap-related feedback to the active finger by generating correlated noise in movement kinematics and tap dynamics.     

Relation between self-paced and synchronized movement in persons with mental retardation

The relation between self-paced and synchronized tapping in 64 persons with mental retardation whose mental ages ranged from 2 to 11 years and chronological ages from 13 to 23 years was investigated. In a self-paced tapping task no stimulus was presented, and subjects' easy and spontaneous tapping was measured. In a synchronized tapping task their synchronous tapping with an auditory stimulus present at a quick or slow tempo was measured. Under both tempo conditions, the lower the subjects' mental age, the larger the errors in the intertap interval they made. The subjects of low mental age showed significantly larger errors in the intertap interval in the Slow than in the Quick Tempo condition and tended to tap at a rate near the self-paced tapping. These results may suggest that ability to adjust one's self pace is one of the key factors in the development of motor synchronization in persons with mental retardation.     

Body movement enhances the extraction of temporal structures in auditory sequences

Auditory and motor systems interact in processing auditory rhythms. This study investigated the effect of intuitive body movement, such as head nodding or foot tapping, on listeners’ ability to entrain to the pulse of an auditory sequence. A pulse-finding task was employed using an isochronous sequence of tones in which tones were omitted at pseudorandom positions. Musicians and non-musicians identified their subjectively fitting pulse either using periodic body movement or through listening only. The identified pulse was measured subsequently by finger tapping. Movement appeared to assist pulse extraction especially for non-musicians. The chosen pulse tempi tended to be faster with movement. Additionally, movement led to higher synchronization stabilities of the produced pulse along the sequence, regardless of musical training. These findings demonstrated the facilitatory role of body movement in entraining to auditory rhythms and its interaction with musical training.     

Effects of age, task, and frequency on variability of finger tapping

The goal was to assess whether prior studies might have overestimated performance variability in older adults in dual task conditions by relying on primary motor tasks that are not constant with aging. 30 younger and 31 older adults performed a bimanual tapping task at four different frequencies in isolation or concurrently with a secondary task. Results showed that performance of younger and older adults was not significantly different in performing the tapping task at all frequencies and with either secondary task, as indicated by mean tapping performance and low number of errors in the secondary tasks. Both groups showed increased variability as tapping frequency increased and with the presence of a secondary task. Tapping concurrently while reading words increased tapping variability more than tapping concurrently while naming colours. Although older participants' performances were overall more variable, no interaction effects with age were found and at the highest frequencies of tapping, younger and older participants did not differ in performance.     

Effects of action on children’s and adults’ mental imagery

The aim of this study was to investigate whether and which aspects of a concurrent motor activity can facilitate children’s and adults’ performance in a dynamic imagery task. Children (5-, 7-, and 9-year-olds) and adults were asked to tilt empty glasses, filled with varied amounts of imaginary water, so that the imagined water would reach the rim. Results showed that in a manual tilting task where glasses could be tilted actively with visual feedback, even 5-year-olds performed well. However, in a blind tilting task and in a static judgment task, all age groups showed markedly lower performance. This implies that visual movement information facilitates imagery. In a task where the tilting movement was visible but regulated by means of an on-and-off remote control, a clear age trend was found, indicating that active motor control and motor feedback are particularly important in imagery performance of younger children.     

Circle drawing does not exhibit auditory-motor synchronization

Differences in timing control processes between tapping and circle drawing have been extensively documented during continuation timing. Differences between event and emergent control processes have also been documented for synchronization timing using emergent tasks that have minimal event-related information. However, it is not known whether the original circle-drawing task also behaves differently than tapping during synchronization. In this experiment, 10 participants performed a table-tapping and a continuous circle-drawing task to an auditory metronome. Synchronization performance was assessed via the value and variability of asynchronies. Synchronization was substantially more difficult in circle drawing than in tapping. Participants drawing timed circles exhibited drift in synchronization error and did not maintain a consistent phase relationship with the metronome. An analysis of temporal anchoring revealed that timing to the timing target was not more accurate than timing to other locations on the circle trajectory. The authors conclude that participants were not able to synchronize movement with metronome tones in the circle-drawing task despite other findings that cyclical tasks do exhibit auditory motor synchronization, because the circle-drawing task is unique and absent of event and cycle position information.     

Unilateral agraphia after section of the posterior half of the truncus of the corpus callosum

Children ranging in age from 3 to 12 tapped on a morse key with their index finger as fast as possible. After a control test, they concurrently tapped and recited a nursery rhyme, recited animal names, and memorized shapes. Previous results suggested that more interference in a motor task results from attempting at the same time to perform another task controlled by the same, than by a different, hemisphere. Right-handed tapping and talking both used left hemisphere space; left-handed tapping and talking were controlled by different hemispheres. Relative to silent tapping concurrent talking caused a greater drop in right-hand tapping rate than in left-hand tapping rate in both the rhyme and animal conditions. Interference by shape memorizing was equal across hands. The differential effect of speaking on right-hand preference indicates the left lateralization of speech output control. The size of this effect did not vary with increasing grade level. The findings support the view that speech output control is fully lateralized at least by age 3 years.     

Interactions of speech and manual movement in a syncopated task

The present study examined interactions of speech production and finger-tapping movement, using a syncopated motor task with two movements in 10 male right-handed undergraduate students (M age = 21.0 yr.; SD = 1.4). On the syncopated task, participants were required to produce one movement exactly midway between two other movements (target interresponse interval: 250 msec.). They were divided into two groups, the tap-preceding group and speech-preceding group. The author observed that the right hand showed a more variable peak force and intertap interval than the left hand in the speech-preceding group, indicating an asymmetrical interference of two movements. On the other hand, the mean differences between onsets of speech and tapping movement were shorter than 250 msec. over all conditions (the shortest mean difference was 50 msec.), suggesting a mutual entrainment of two movements. An asymmetry of entrainment was observed in the speech-preceding group, in which speech production was more strongly entrained with movements of the right hand than with those of the left hand.     

Development of sensorimotor synchronization abilities: Motor and cognitive components

The aim of the present study was to examine both the development of sensorimotor synchronization in children in the age range from 5 to 8 years and the involvement of motor and cognitive capacities. Children performed a spontaneous motor tempo task and a synchronization–continuation task using an external auditory stimulus presented at three different inter-stimulus intervals: 500, 700, and 900 ms. Their motor and cognitive abilities (short-term memory, working memory, and attention) were also assessed with various neuropsychological tests. The results showed some developmental changes in synchronization capacities, with the regularity of tapping and the ability to slow down the tapping rate improving with age. The age-related differences in tapping were nevertheless greater in the continuation phase than in the synchronization phase. In addition, the development of motor capacities explained the age-related changes in performance for the synchronization phase and the continuation phase, although working memory capacities were also involved in the interindividual differences in performance in the continuation phase. The continuation phase is thus more cognitively demanding than the synchronization phase. Consequently, the improvement in sensorimotor synchronization during childhood is related to motor development in the case of synchronization but also to cognitive development with regard to the reproduction and maintenance of the rhythm in memory.     

Programming precision in repetitive tapping

The present paper reports an experiment using the Fitts' tapping paradigm. It is concerned with a comparison of movement times and accuracy during blind and visual repetitive tapping. A blind condition was used to investigate rapid aiming movements under motor program control, whilst visual aiming was used to assess the role of visual feedback for control purposes. Subjects in the blind conditions were able to replicate the amplitude specifications of the task, whereas effective target width was constant for a set amplitude and did not reflect specified target width. Subjects, furthermore, responded more rapidly when tapping blind. These results are discussed in terms of the magnitude of forces being attempted as a result of performing a set amplitude, and the role of visual feedback.     

Programming Precision in Repetitive Tapping

The present paper reports an experiment using the Fitts’ tapping paradigm. It is concerned with a comparison of movement times and accuracy during blind and visual repetitive tapping. A blind condition was used to investigate rapid aiming movements under motor program control, whilst visual aiming was used to assess the role of visual feedback for control purposes. Subjects in the blind conditions were able to replicate the amplitude specifications of the task, whereas effective target width was constant for a set amplitude and did not reflect specified target width. Subjects, furthermore, responded more rapidly when tapping blind. These results are discussed in terms of the magnitude of forces being attempted as a result of performing a set amplitude, and the role of visual feedback.     

Developmental differences in motor task integration: A test of Pascual-Leone's Theory of Constructive Operators

This study assessed the ability of Pascual-Leone's Theory of Constructive Operators to predict the minimum age or maturational level at which integration of a motor task could be achieved. Children 5–12 years of age (n=114) performed a discrete motor task requiring a constrained circular movement to be integrated with an unconstrained linear movement to a target. The Theory of Constructive Operators and the principles of constructive cognition were used to generate a model of task performance. Based on the model and in accordance with the theory, it was predicted that 5- to 6-year-old subjects would lack the cognitive capacity (M-capacity) to efficiently integrate this task. An analysis of covariance for age was performed on task parameters reflecting integration (and highest M-demand) with movement speed as the covariate. Scheffé contrasts supported the prediction as 5- to 6-year-old subjects were inferior to each of the other age groups (p < .05). Furthermore, no significant differences were found to exist between any of the older age groups.     

Motor response inhibition and execution in the stop-signal task: development and relation to ADHD behaviors.

The main aim of this study was to investigate the developmental course of motor response inhibition and execution as measured by the stop-signal task in a population-based sample of 525 4- to 12-year-olds. A further aspiration of the study was to enhance the limited knowledge on how the various stop-signal measures relate to ADHD behaviors in a normal sample. We also wanted to contribute to the theoretical understanding of the various stop-signal measures by examining the relations between the stop-signal measures and performance on tasks reflecting other aspects of response inhibition and execution. Our results showed that the ability to inhibit as well as to execute a motor response as measured by the stop-signal task improved with age during childhood. Of specific interest are the findings suggesting that this task captures the development of motor response inhibition in the late preschool years (age 5 years). Both of the inhibition measures derived from the stop-signal task (i.e., SSRT and probability of inhibition) related significantly to teacher ratings of inattention as well as to performance on tasks tapping other aspects of inhibition. The data provided by this study have thus contributed to the scarce knowledge on early development of motor response inhibition, as well as suggested that the stop-signal task may be a valuable tool for capturing deficient motor response inhibition in ADHD behaviors in normal samples.     

Effects of age and sex on reciprocal tapping performance

Using a reciprocal tapping task (Fitts's task), the speed and accuracy of small-amplitude motor movements of the hand were measured for 62 men and 84 women, 20 to 89 yr. of age. Men and women in their 20s and 30s performed similarly, although men in their 20s displayed a tendency to trade accuracy in favor of speed. Movement time increased noticeably for both men and women beginning with the 40s decade and continued to increase through the 80s decade. Error rates were lower for women than men and were relatively uniform for both men and women across all age decades past 30 yr. Older subjects of both sexes appeared to sacrifice speed (slowed down) to maintain accuracy on the task. The slope of the linear regression relating movement time to task difficulty was steeper for men than for women and increased more for men than women with advancing age, indicating that older men slowed down relatively more than older women on more difficult tasks.     

Bimanual interference in children performing a dual motor task

The present study addressed the development of bimanual interference in children performing a dual motor task, in which each hand executes a different task simultaneously. Forty right-handed children (aged 4, 5-6, 7-8 and 9-11years, ten in each age group) were asked to perform a bimanual task in which they had to tap with a pen using the non-preferred hand and simultaneously trace a circle or a square with a pen using the preferred hand as quickly as possible. Tapping and tracing were also performed unimanually. Differences between unimanual and bimanual performance were assessed for number of taps, length of tap trace and mean tracing velocity. It was assumed that with increasing age, better bimanual coordination would result in better performance on the dual task showing less intermanual interference. The results showed that tapping and tracing performance increased with age, unimanually as well as bimanually, consistent with developmental advancement. However, the percentage of intermanual interference due to bimanual performance was not significantly different in the four age groups. Although performing the dual task resulted in mutual intermanual interference, all groups showed a significant effect of tracing shape. More specifically, all age groups showed a larger percentage decrease in tracing velocity when performing the circle compared to the square in the dual task. The present study reveals that children as young as four years are able to coordinate both hands when tapping and tracing bimanually.     

Effects of smoking abstinence on movement regulation

The effect of smoking abstinence on performance of a reciprocal tapping task was investigated. 6 habitual smokers performed a single-plate and two versions of a two-plate tapping task. Fitts' Law was used to compute an index of difficulty (ID) in bits for the tasks which was 0 bits for the single-plate and 3.32 and 4.17 bits for the two-plate versions of the task. While smoking abstinence had no effect on performance of the single-plate tapping task, it increased movement time on performance of both two-plate task versions. These findings may provide a coherent explanation for the prior findings of nicotine deprivation on psychomotor performance in the literature. This explanation suggests that the effects of nicotine deprivation as incurred through smoking abstinence may be on the central mechanisms regulating information-processing rate for successful movement regulation. Thus nicotine deprivation may not affect performance of simple psychomotor tasks which require minimal information processing but will affect the performance of more complex tasks requiring significantly more information processing for successful movement regulation.     

Development of rule-based eye-hand-decoupling in children and adolescents

In the present study, we characterize how the ability to decouple guiding visual information from a motor action emerges during childhood and adolescence. Sixty-two participants (age range 8–15 yrs.) completed two eye-hand coordination tasks. In a direct interaction task, vision and motor action were in alignment, and participants slid their finger along a vertical touch screen to move a cursor from a central target to one of four peripheral targets. In an eye-hand-decoupled task, eye and hand movements were made in different planes and cursor feedback was 180° reversed. We analyzed whether movement planning, timing and trajectory variables differed across age in both task conditions. There were no significant relationships between age and any movement planning, timing, or execution variables in the direct interaction task. In contrast, in the eye-hand-decoupled task, we found a relationship between age and several movement planning and timing variables. In adolescents (13–15 yrs.), movement planning and timing was significantly shorter than that of young children (8–10 yrs.). Eye-hand-decoupled maturation emerged mainly during late childhood (11–12 yrs.). Notably, we detected performance differences between young children and adolescents exclusively during the eye-hand decoupling task which required the integration of rule-based cognitive information into the motor action. Differences were not observed during the direct interaction task. Our results quantify an important milestone for eye-hand-decoupling development in late childhood, leading to improved rule-based motor performance in early adolescence. This eye-hand-decoupling development may be due to frontal lobe development linked to rule-based behavior and the strengthening of fronto-parietal networks.