The relative dominance of schemata in a manual tracking task: input patterns, system dynamics, and movement patterns

As subjects repeatedly track the same spatiotemporal pattern, they learn to anticipate the pattern and thereby to reduce their effective time delay. The successive organization of perception hypothesis suggests that subjects progress from an error-nulling mode to a pursuit mode, in which they respond to the estimated instantaneous input pattern, and then to a precognitive mode, in which they rely on memory of the input pattern or movement pattern. We used a transfer of training experiment involving position and rate control systems to distinguish among these strategies by determining the relative dominance of schemata for the input pattern, system dynamics, and movement pattern. Results indicated that subjects relied on a memorized movement pattern, which is characteristic of the precognitive mode. Adaptations of this transfer methodology may be useful in testing other theories that postulate multiple schemata for the control of perceptual-motor behavior.     

Intentional Switching Between Patterns of Bimanual Coordination Depends on the Intrinsic Dynamics of the Patterns

Two predictions arising from previous theoretical and empirical work which demonstrated that spontaneous changes of bimanual coordination patterns result from a loss of pattern stability (i.e., a nonequilibrium phase transition) were tested: (a) that the time it takes to intentionally switch from one pattern to another depends on the differential stability of the patterns themselves; and (b) that an intention, defined as an intended behavioral pattern, can change the dynamical characteristics, e.g., the overall stability of the behavioral patterns. Subjects moved both index fingers rhythmically at one of six movement frequencies while performing either an in-phase or antiphase pattern of finger coordination. On cue from an auditory signal, subjects switched from the ongoing pattern to the other pattern. The relative phase of movement between the two fingers was used to characterize the ongoing coordinative pattern. The time taken to switch between patterns, or switching time, and relative phase fluctuations were used to evaluate the modified pattern dynamics resulting from a subject's intention to change patterns. Switching from the in-phase to the antiphase pattern was significantly slower than switching in the opposite direction for all subjects. Both the mean and distribution of switching times in each direction were found to be in agreement with model predictions. Movement frequency had little effect on switching time, a finding that is also consistent with the model. Relative phase fluctuations were significantly larger when moving in the antiphase pattern at the highest movement frequencies studied. The results show that, although intentional influences act to modify a coordinative pattern's intrinsic dynamics, the influence of these dynamics on the resulting behavior is always present and is particularly strong at high movement frequencies.     

Variability in practice: facilitation in retention and transfer through schema formation or context effects?

The main purpose of the study was to examine whether the effects of variability in practice within a class of movements, that is, enhanced retention and transfer performance relative to constant practice, are due to the formation of motor schemata (Schmidt, 1975) or to contextual interference effects, as suggested by Lee, Magill, and Weeks (1985). Forty-eight subjects were tested on a sequential timing task. One group of subjects (Schema) received variable practice within one movement class, practicing the same phasing pattern with different absolute durations. Practice conditions of another group (Context) involved the same absolute movement durations, as well as a different phasing pattern for each task version. Thus, contextual interference was about the same for both groups but only one group experienced different movement variations of the same class. On a retention test performed on a task version that had been practiced by both groups before as well as on a transfer test with the same phasing pattern but a longer absolute duration, the Schema group performed more effectively than the Context group, thus supporting schema theory. On a transfer task with new phasing requirements, however, the Context group demonstrated performance superior to that of the Schema group. In this case, the Context practice condition seemed to be more transfer-appropriate.     

The impact of concurrent visual feedback on coding of on-line and pre-planned movement sequences

The purpose of this study was to determine the extent to which participants could effectively switch from on-line (OL) to pre-planned (PP) control (or vice versa) depending on previous practice conditions and whether concurrent visual feedback was available during transfer testing. The task was to reproduce a 2000 ms spatial–temporal pattern of a sequence of elbow flexions and extensions. Participants were randomly assigned to one of two practice conditions termed OL or PP. In the OL condition the criterion waveform and the cursor were provided during movement production while this information was withheld during movement production for the PP condition. A retention test and two effector transfer tests were administered to half of the participants in each acquisition conditions under OL conditions and the other half under PP conditions. The mirror effector transfer test required the same pattern of muscle activation and limb joint angles as required during acquisition. The non-mirror transfer test required movements to the same visual–spatial locations as experienced during acquisition. The results indicated that when visual information was available during the transfer tests performers could switch from PP to OL. When visual information was withdrawn, they shifted from the OL to the PP-control mode. This finding suggests that performers adopt a mode of control consistent with the feedback conditions provided during testing.     

Selection of Movement Patterns During Functional Tasks in Humans

These experiments examine the role of vision and step height in the selection of a simple binary choice of movement pattern by human subjects. The subjects selected a heel strike movement pattern (HS) (as used during level surface locomotion) or a toe strike movement pattern (TS) (as used during stair descent). The functional task involved descending a step of adjustable height followed by level surface walking under vision and nonvision conditions. Triceps surae and tibialis anterior electromyographic (EMG) activity, ankle angle position, and vertical force were examined. As step height was increased, there was an indistinct threshold at which subjects switched from landing with a HS movement pattern to a TS movement pattern. The tibialis anterior and triceps surae precontact EMG bursts and subsequent ankle movement for HS and TS trials appear to be part of preprogrammed movement patterns, which are presumably of central origin. The particular mixture of voluntary, stereotypic, and reflex actions for any specified movement is based on the intent or functional outcome desired. The switching to the TS movement pattern as step height increased presumably results in the most efficient and stable movement.     

The Schematic Representation of Effector Function Underlying Perceptual-Motor Skill

Conceptual and methodological problems related to Schmidt’s (1975) motor schema theory are discussed. In particular, the motor schema is interpreted as representing the dynamics of the system being controlled, which may or may not be associated with a referent movement pattern. Furthermore, it is suggested that prior familiarity with a control system’s dynamics is a critical but uncontrolled factor in tests of the theory, and largely accounts for their equivocal findings. These ideas are examined by two experiments in which subjects had to bimanually control the movement of a computer-displayed cursor along a track on a CRT screen. Different track orientations required different patterns of movement not entailing a single generalized motor program. Experiment 1 shows that variable track performance with a given control system, results in better transfer to novel tracks than does fixed practice. Experiment 2 demonstrates that altering the control system disrupts performance whether or not the required movements remain the same. These results indicate the need for a fundamental modification of schema theory, such that a schematic representation of effector-environment relations (effector function) is available independently of particular movement patterns used in its acquisition.     

Embodiment Effects and Language Comprehension in Alzheimer's Disease

It has been shown that when participants are asked to make sensibility judgments on sentences that describe a transfer of an object toward or away from their body, they are faster to respond when the response requires a movement in the same direction as the transfer described in the sentence. This phenomenon is known as the action compatibility effect (ACE). This study investigates whether the ACE exists for volunteers with Alzheimer's disease (AD), whether the ACE can facilitate language comprehension, and also whether the ACE can still be produced if the order of the two events is inverted, that is, whether overt movement can prime comprehension of transfer sentences. In Study 1, participants with AD, younger, and older adults were tested on an adaptation of the ACE Paradigm. In Study 2, the same paradigm was modified to include an arm movement that participants had to perform prior to sentence exposure on screen. In Study 1, young, older adults, and individuals with AD were faster to respond when the direction of the response movement matched the directionality implied by the sentence (ACE). In Study 2, no traditional ACE was found; participants were faster when the direction of the movement immediately preceding the sentence matched the directionality of the sentence. It was found that compatibility effects generated a relative advantage, that transfer schemata are easier to process, and that an ACE‐like effect can be the result of mutual priming between language and movement. Results suggested preservation in AD of the neural systems for action engaged during language comprehension, and conditions under which comprehension in AD can be facilitated in real life may be identified.     

材料模式与认知负荷对小学生类比学习的影响

探讨学习材料不同模式和学习过程不同的认知负荷对小学生类比推理学习迁移的影响.包括两个分实验.实验1探讨学习材料的不同组织模式对小学生类比推理学习迁移的影响,两组小学生分别学习模式化与非模式化的材料,然后完成迁移程度远近不同的四类测题.结果表明,非模式化条件下完成远迁移题目的成绩显著优于模式化条件下的成绩.实验2探讨小学生在不同认知负荷条件下类比推理学习的迁移效果,两组小学生分别在高认知负荷与低认知负荷情况下学习类比推理的材料,然后完成上述四类测题.结果表明,高认知负荷条件下完成远迁移题目的成绩显著优于低认知负荷条件下的成绩.本实验结果表明,对于小学生类比推理的学习来说,非模式化、高负荷的学习更有利于促进迁移,支持了积极反应理论.     

Effects of precision of knowledge of results on performance of a gross motor coincidence-anticipation task

The purpose of the investigation was to determine the effects from three knowledge of results (KR) precision levels (qualitative; 0.10 sec, 0.001 sec) on the performance of a gross motor coincidence-anticipation task where subjects performed with visual and other sense modality input. Other variables included in the analysis were sex, movement distance, and practice over three blocks of trials. Absolute error (AE), constant error (CE), variable error (VE), and E scores (E) of the subjects from two experiments (N = 90; N = 54) were analyzed with 3 x 2 x 2 x 3 ANOVAs with repeated measures on the last two factors (feedback, sex, movement distance, blocks). Consistent finding from both experiments indicated that, for this gross motor coincidence-anticipation task, the subjects performed as accurately and as consistently when they received qualitative KR as when, in addition, they received more precise KR. Subjects performed with less error on the short as opposed to the long term distance pattern. Males performed with less error on the long movement pattern than females in Experiment 1; however, the only sex difference noted in Experiment 2, when the movement distances were shortened, was that males had a more on-time CE mean score.     

A psychophysiological analysis of response-channel activation and outcome states in Eriksen's noise-compatibility task

Summary Eleven subjects were tested with a modified version of Eriksen's noise-compatibility task. Four noise conditions were realized - neutral, compatible, fully incompatible, and partially incompatible context. Target and flanking stimuli had an intrinsic association to either the left- or the right-hand side. As a response subjects pulled, with either their left or their right hand, an ordinary bicycle handbrake from a preload position towards a stop. The EMG from the forearm muscles and the movement trajectory were recorded continuously. Trials were categorized according to the outcome states, i. e., whether a full movement or only a rudimentary EMG activation had occurred in the correct and in the incorrect response channels, respectively, and whether the correct-channel activation was leading or lagging.Incompatible noise delayed information transfer and increased the likelihood of errors, while compatible noise had an opposite effect, i. e., it facilitated transfer and reduced the likelihood of errors. The effect of noise on transfer times was the same for all outcome states. Moreover, in all cases, noise had an effect on transfer times only up to the point of EMG onset, while it left movement-execution times unaffected. These findings are seen as contradictory to a strong continuous flow conception according to which any response-related change in the input channel is continuously and immediately transferred to the response-execution device. At least the final stage of movement control seems to be autonomous and not subject to input control, except for the case that a movement already initiated has to be aborted completely.     

Movement and working memory: Patterns and positions in space

Five experiments are reported in which subjects were asked to remember short, visually presented sequences of whole body movement patterns, words, and spatial positions. The items were recalled in order in a memory span paradigm. During presentation of the items to be remembered subjects simply watched, or they carried out a concurrent activity involving articulatory suppression, movement to external spatial targets, or body-related movement. When the movement patterns to be remembered were familiar to subjects, movement span was not disrupted by articulatory suppression or movement to spatial targets but was disrupted by body-related movement. This movement suppression task, however, did not interfere with performance on a spatial span task or on verbal span. It is concluded that the memory for patterns of limb movement differs from memory for movement to spatial targets and that accounts of visuo-spatial processes in working memory involve the latter type of movement.     

Progression-regression effects in tracking repeated patterns

Subjects used a position control system to perform compensatory tracking of a repeated input pattern. Tracking error was roughly proportional to the velocity of the input signal. Error magnitude decreased with practice and increased with the addition of a concurrent memory task. These effects can be modeled as progressive and regressive changes in how well subjects used control movement velocity and displayed error velocity to anticipate the input pattern and thereby reduce their effective time delay. The weighting of velocity cues in this model progressed with practice and regressed with the secondary task, even though the secondary task required no concurrent visual scanning or simultaneous motor response. This regression effect appears to indicate cognitive interference with the anticipation process. Stationary linear models provide a good approximation to the movement patterns; however, these models do not account for episodes of rapid pulse-like movements that were revealed in the ensemble-averaged trajectories.     

Strength Recovery Patterns Following Isometric and Isotonic Exercise

In 3 experiments, the author tested the hypothesis that coordination dynamics is the content of a generalized motor program (GMP) for rhythmic interlimb coordination. In Experiment 1, learners (N = 14) practiced a ?90° movement with either identically timed or differently timed limbs. Both acquisition and transfer to novel (effector and pattern) timings were unaffected by the learning condition and were suggestive of the intrinsic dynamics for in-phase and antiphase. In Experiment 2, learners' (N = 13) acquisition of 2 different phase relations (?90° and ?45°) was qualitatively identical. Attractor reconstruction revealed an increase in the predictability of individual movement trajectories and a decrease in attractor dimensionality over learning. Transfer for both ?90° and ?45° was again suggestive of the intrinsic dynamics. In Experiment 3, learning altered participants' (N = 8) performance of in-phase and antiphase relations. Together, the results suggested a single continuum of phase relations, called an attractor landscape, that produces similar patterns of CE and VE for both previously stable and learned coordinations.     

Coordination dynamics of rhythmical and discrete prehension movements: Implications of the scanning procedure and individual differences

The aim of this study was to compare the coordination dynamics of discrete and rhythmical reaching and grasping movements from a dynamical systems perspective. Previous research from this theoretical perspective had focused on rhythmical actions and it is unclear to what extent discrete movements are amenable to a similar dynamical systems analysis. Six adult subjects performed prehension in two conditions: a discrete, non-continuous mode and a rhythmical, continuous mode. A `scanning procedure' was implemented between pre- and post-tests in which the required time of final relative hand closure (T_rfc) was systematically varied. It was shown that the error in the reaching and grasping pattern was least at an attractor region and systematically increased with deviation from the attractor. Results also indicated that there were no differences between condition or trial block for the group. However, there were several within-subject effects of interest. The validity of the scanning procedure was found to be questionable in the discrete condition, where four subjects showed differences in T_rfc between pre- or post-test and the predicted T_rfc of the scanning procedure. Four out of six subjects also had different preferred T_rfc values for discrete and rhythmical movement, indicating that individual specific models might need to be constructed for future dynamical modelling of discrete movement.PsycINFO classification: 2330     

Patterns of interocular transfer of visuomotor coordination reveal differences in the representation of visual space

Acquisition and interocular transfer of adaptation to optical transformations of input were examined in strabismic and orthotropic subjects. Distinct patterns of behavior were displayed by three groups: strabismic alternating suppressors, strabismic and orthotropic constant suppressors, and orthotropes with normal binocularity of vision. It is suggested that these behaviors result from the way in which visual space is represented in each group, an outcome of the pattern of use of the eyes during early development. The conditions for modification of the representation of visual space appear to parallel those for initial acquisition.     

Effects of sine wave combinations on the development of precognitive mode in pursuit tracking

A pursuit tracking task was carried out to investigate the effects of combinations of sine waves on the development of precognitive mode, which is defined as open-loop mode with little feedback. Subjects were asked to track the targets, which contained two or three sine waves as components, and then to reproduce the target motion after the target had been removed. Frequency characteristics of tracking revealed the superiority of the faster component over the slower components in terms of both amplitude ratio and tracking lag. Subjects' reproduction after removing the target demonstrated that in general, subjects could learn and memorize also the slower component motion, which had yielded inferior performance during the tracking period. These results are discussed in terms of a model based on successive organization of perception.     

An eye for relations: eye-tracking indicates long-term negative effects of operational thinking on understanding of math equivalence

Prior knowledge in the domain of mathematics can sometimes interfere with learning and performance in that domain. One of the best examples of this phenomenon is in students’ difficulties solving equations with operations on both sides of the equal sign. Elementary school children in the U.S. typically acquire incorrect, operational schemata rather than correct, relational schemata for interpreting equations. Researchers have argued that these operational schemata are never unlearned and can continue to affect performance for years to come, even after relational schemata are learned. In the present study, we investigated whether and how operational schemata negatively affect undergraduates’ performance on equations. We monitored the eye movements of 64 undergraduate students while they solved a set of equations that are typically used to assess children’s adherence to operational schemata (e.g., 3 + 4 + 5 = 3 + __). Participants did not perform at ceiling on these equations, particularly when under time pressure. Converging evidence from performance and eye movements showed that operational schemata are sometimes activated instead of relational schemata. Eye movement patterns reflective of the activation of relational schemata were specifically lacking when participants solved equations by adding up all the numbers or adding the numbers before the equal sign, but not when they used other types of incorrect strategies. These findings demonstrate that the negative effects of acquiring operational schemata extend far beyond elementary school.     

Coding of on-line and pre-planned movement sequences

Recent experiments have demonstrated that complex multi-element movement sequences were coded in visual-spatial coordinates even after extensive practice, while relatively simple spatial-temporal movement sequences are coded in motor coordinates after a single practice session. The purpose of the present experiment was to determine if the control process rather than the difficulty of the sequence played a role in determining the pattern of effector transfer. To accomplish this, different concurrent feedback conditions were provided to two groups of participants during practice of the same movement sequence. The results indicated that when concurrent visual feedback was provided during the production of the movement, which was thought to encourage on-line control, the participants performed transfer tests with the contra-lateral limb better when the visual-spatial coordinates were reinstated than when the motor coordinates were reinstated. When concurrent visual feedback was not provided, which was thought to encourage pre-planned control, the opposite was observed. The data are consistent with the hypothesis that the mode of control dictates the coordinate system used to code the movement sequence rather than sequence difficulty or stage of practice as has been proposed.     

Should Common Optimal Movement Patterns Be Identified as the Criterion to Be Achieved?

Recently, a new paradigm has been proposed for the study of knowledge of performance (Schmidt & Young, 1991). In this paradigm, the experimenters identified an optimal kinematic movement pattern, based on the performance of a best subject, which was imposed on all subjects as the criterion to achieve. This approach, which assumes that this pattern is the best way for all subjects to do the task, was tested in the present experiment. In Experiment 1, a common optimal movement pattern could not be identified by an analysis of scatterplot graphs of the scores plotted as a function of various kinematic vanables or by correlating (within and across subjects [N = 14]) each kinematic variable with the score. In Experiment 2, subjects (N = 12) were retrained in 2 separate sessions, during which they tried to reproduce either a personal best or the best subject's template. Results indicated that scores were similar regardless of the template pattern being used. During training, however, subjects who used their personal template had a lower incidence of zero scores and were more consistent than those who used the template of the best subject. This provided a second line of evidence against the assumption that a common optimal movement pattern exists for this type of task.