Consistent reproduction of movement sequences during acquisition of a pursuit tracking task

A pursuit tracking task is used as a vehicle to investigate the manner in which response consistency is affected by practice. Detailed examination of movement patterns shows that subjects can reproduce the mid-phase of a movement relatively consistently while the accelerative and decelerative phases of the movement remain highly variable. The findings are discussed with reference to Sparrow's 1983 concept of efficiency in conjunction with Norman and Shallice's 1980 model of automated action.     

Monitoring running-wheel movement using a serial mouse and an IBM-compatible system

A running-wheel-movement-detection system is described for use with an IBM-compatible system and a serial mouse. It is an adaptation of a system developed for use on a Commodore 64. The IBM-compatible system provides obvious advantages in speed, memory, data storage, and programming ease over the earlier Commodore 64 system.     

An evaluation of the minimal constraining information during observation for movement reproduction

An important question in the field of imitation is what information is used for movement reproduction. While it is argued that relative motion information is perceived and minimised, direct evidence is lacking. In this experiment relative motion was manipulated to convey a novel kicking action. Twenty-four adults were assigned to one of the three impoverished relative motion display groups showing only the TOE, FOOT or LEG. After practise with partial information, participants watched a full-body display and in a final condition performed the action with an additional context constraint (i.e., a ball). Movement kinematics were collected and difference scores between participants and the model were analysed. The groups did not differ in terms of knee-ankle coordination. For hip-knee, the TOE group performed more like the model than the FOOT and LEG group. When transferred to the full-body display, there were no significant improvements. End-point trajectory information can provide sufficient information to reproduce key characteristics of the movement form.     

The coding of constrained and preselected movement distance: Same-limb versus switched-limb reproduction

Three experiments were conducted to investigate the codes subserving the retention of movement extent information. Each experiment compared preselected and constrained movements in two independent movement tasks: same-limb reproduction and switched-limb reproduction. When movement direction was the same for both criterion and reproduction movements (experiment 1), same-limb reproduction was more accurate than switched-limb performance. With movement direction altered, however, switched-limb reproduction was equal to same-limb reproduction (experiment 2). These results were confirmed in experiment 3 which manipulated both movement direction and reproduction limb in a within-subject design. Furthermore, while preselected reproduction was superior to constrained reproduction in all three experiments, the two groups were not differentially affected by either the movement task or direction variables. The overall findings were interpreted as providing support for a multiple-cue memorial representation of movement extent and the notion of coding flexibility.     

A new breed of computer users: Rats control a cursor via joystick manipulation

Many exciting findings have been reported in the 15 years since monkeys were first demonstrated to have the capacity to perform computerized tasks. The present data indicate that albino rats can also learn to respond to computer-generated stimuli by manipulating a joystick. Although the rat’s control of the cursor is not as skillful as has been reported for primate species, it is clearly better than chance and suggests the great potential for comparative investigation afforded by use of the computer test system.     

MICELAB: Spatial processing of mouse movement in Turbo Pascal

Pointing tasks with a mouse are very useful in psychological experiments concerned with a subject’s ability to track a visual object or to move to a target location (e.g., to find a word in text). Such tasks are quite easily performed by subjects, and numerous variables may be obtained from the mouse movement. In this article we describe a set of Turbo Pascal 6.0 units and a program running on the IBM PC family that show how data (x,y coordinates) recorded from a mouse movement can be analyzed to give dispersion, direction, and distance of the movement.     

Performance of able-bodied subjects on a text-typing task using a head-operated device and expanded membrane cursor keys

Children and adults with disabilities frequently rely on computers to complete written tasks. Those with significant motor limitations typically use alternative computer-input devices since the traditional keyboard and mouse are insufficient to accommodate their abilities. For persons unable to isolate their fingers, input devices controlled by movements of the head or whole hand or arm movements may be among the options considered. This study investigated the performance of a head-operated device and expanded membrane cursor keys for text entry. Data from 24 young adults indicated the head-operated device performed significantly faster given reduced cognitive demands for device operation, increased stimulus-response compatibility, and simplicity of movement. Use of the expanded membrane cursor keys resulted in significantly lower error rates. No significant differences in comfort or ease of use were reported for the two devices. The relative performance of device options for users sharing similar motor challenges provides rehabilitation specialists with important clinical information.     

A new breed of computer users: rats control a cursor via joystick manipulation.

Many exciting findings have been reported in the 15 years since monkeys were first demonstrated to have the capacity to perform computerized tasks. The present data indicate that albino rats can also learn to respond to computer-generated stimuli by manipulating a joystick. Although the rat's control of the cursor is not as skillful as has been reported for primate species, it is clearly better than chance and suggests the great potential for comparative investigation afforded by use of the computer test system.     

Not the same old hindsight bias: Outcome information distorts a broad range of retrospective judgments

The hindsight bias (e.g., Fischhoff, 1975) illustrates that outcome information can make people believe that they would have (or did) predict an outcome that they would not (or did not) actually predict. In two experiments, participants (N = 226) made a prediction immediately before receiving outcome information. Therefore, participants could not distort or misremember their predictions to make them align with the outcome information. In both experiments, participants distorted their reports of how certain they recalled having been in their prediction, how good of a basis they had for making the prediction, how long they took to make the prediction, and so forth. Experiment 2 showed that these effects were diminished when participants engaged in private thought about the upcoming questions prior to receiving outcome information, suggesting that the effect is not due to impression management concerns.     

Effect of starting position on reproduction of movement: further evidence of interference between location and distance information

Two experiments done with a short-term memory paradigm examined the influence of shifts in the starting position on the reproduction of kinesthetic location (Exp. 1) and on distance cues (Exp. 2). We assessed possible causes of the systematic pattern of undershooting and overshooting as related to the shift in the starting position. In each experiment, two groups of 10 students were given 25 trials, and each had criterion and reproduction tasks involving linear-positioning movements with a 10-sec. retention interval. Each experiment had two independent variables, the group of subjects and the shift in the starting position. The two groups differed in the possible sources of information, the distance moved (Exp. 1) or the end-location (Exp. 2), which were assumed to cause undershooting and overshooting during reproduction. Analysis showed that the information about the distance moved may produce undershooting and overshooting in reproduction of the end-location (Exp. 2). Also, the information about the end-location may produce undershooting and overshooting in reproduction of the distance moved (Exp. 2). The findings were further evidence of interference between location and distance cues in motor short-term memory.     

Children's autokinetic movement as a function of inferred movement of target shape

Four target shapes, a control stimulus (circle) and one each representing geometrical (arrow), representational (car), and symbolic (cross) implied movement were presented to 10 children in each of five age groups of boys and girls (4, 6, 8, 10, 12 yr.) in an autokinetic movement task. While there were no differences in direction of perceived movement with regard to the control stimulus (circle), all other target shapes showed a decrease in the effects of implied movement with increases in age. The minor sex differences were not reported.     

Programming time as a function of number of movement parts and changes in movement direction

The question of whether changes seen in simple reaction time (SRT) as a function of response complexity (i.e., number of movement parts) should be considered as differences in the time needed to centrally program a motor response was addressed. Using a large-scale tapping response, 14 subjects contacted from one to five targets positioned in a straight line, while a second group of 14 subjects executed 90 degrees changes in direction in striking the targets. Results revealed that mean SRT and mean premotor time increased linearly as the number of movement parts increased, regardless of whether changes in movement direction had to be programmed, with the greatest increase occurring between one-, and two-part responses. Increases in motor time were not sufficient to account for the sizeable SRT effect. These findings support the position of increased central programming time for more complex responses, and also help establish some of the boundaries of the complexity effect.     

Timing of movement phases of a repeated response

How can one determine the nature of timing control that exists among various distinct phases of movement in a repetitive activity? A statistical approach is suggested and is exemplified by reference to data on the timing of two phases of movement, arrival at and departure from the response plate, in repetitive finger tapping. Two contrasting models are presented, and the predictions for the covariation of the various intervals between the two movement phases are compared. Data on finger tapping support the model that assumes the initiation of each phase is centrally determined without reference to the time of occurrence of the immediately preceding phase.     

The movement of the hand towards a target

Previous work on the approach trajectories of hands to targets in tracking and aiming tasks had produced contradictory evidence about the shape of these curves. This paper shows that these trajectories are a function of the level of practice of the subject; an interpretation in terms of the theory of intermittent control of movements is advanced. Previous contradictory data can be resolved by reference to the subjects/ level of practice. In addition, this theory will encompass the differences between accurate and free movement trajectories reported earlier.     

Apparent size and duration of a movement after-effect

Four experiments were performed to study the relationship between Emmert's law and the duration of the movement after-effect (MAE). The duration of the MAE increased with increased distance of the test field; this result was shown to be produced by the correlative change in apparent size of the after image. The effect did not occur when cues for distance judgments were reduced. Reducing the duration of the MAE suppressed the variation in its duration at varying distances of the test field. Some implications for the mechanism of the MAE are discussed.     

Duration of mentally simulated movement: a review

The authors review studies of mentally simulated movements. In automatic or cyclical movements, actual and motor imagery (MI) durations are similar. When athletes simulate only dynamic phases of movement or perform MI just before competing, however, environmental and time constraints lead to an underestimation of actual duration. Conversely, complex attention-demanding movements take longer to image. Finally, participants can modify the speed of MI voluntarily when they receive specific instructions. To complete the available data, the authors compared imagined and actual durations in tennis and gymnastics. Results showed systematic and disproportionate overestimation of actual duration. The authors found a relationship between complex motor skills and MI duration. They discuss the factors leading to over- and underestimation and the hypotheses that could be tested.     

Interaction of vision and movement via a mirror

I have noticed a striking effect that vision can have on movement: when a person makes circular motions with both hands, clockwise with the left hand, counterclockwise with the right hand, while watching the reflection of one hand in a parasagitally placed mirror, if one arm makes a vertical excursion, the other arm tends to make the same vertical excursion, but not typically if the excursing arm is viewed in plain vision. This observation may help in understanding how visual feedback via a mirror may be beneficial for rehabilitation of some patients with movement deficits secondary to certain neurologic conditions, and illustrates that the traditional division of neural processes into sensory input and motor output is somewhat arbitrary.