An empirical note on the role of verbal labels in motor short-term memory tasks

Previous studies of motor short-term memory have shown that when a criterion movement on a semicircular positioning task is accompanied by an appropriate verbal label (a clock-face position), recall of the movement is more accurate than when only the movement is presented. This increased accuracy could be due to either the additional spatial information provided by the label or enhanced retention of the movement information. These two alternatives cannot be distinguished on the basis of previous studies because the studies have not evaluated movement accuracy following presentation of the label alone. The present study employed such a condition in addition to the movement-only and movement-plus-label conditions to distinguish between the two hypotheses. In all conditions, subjects were asked to move to the criterion position after a retention interval of either 5 sec or 60 sec. Evidence indicated that subjects who received both the label and the movement tended to use the spatial information provided by the label at the 60-sec interval. The evidence did not indicate that the verbal label actually enhanced retention of the movement information.     

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.     

An application of the empirical Bayes approach to directly adjusted rates: a note on suicide mapping in California

A simple, reliable, and comparable measure for suicide mapping and other health problems is needed. Because standardized mortality ratios (SMRs) may not indicate the relative meaning of their magnitudes when compared with one another, and statistical significance levels of tests for SMRs overlook the areas that have small populations, neither of these approaches provides a satisfactory index. The results using directly adjusted rates can be ordered directly according to their magnitudes. However, because of the lack of reliable estimates of local age-specific rates, the usefulness of directly adjusted rates in mapping suicide is also limited. To extend the usefulness of directly adjusted rates, an empirical Bayes approach whereby information from other areas is borrowed to improve the precision of the estimates of local age-specific rates in calculating directly adjusted rates--especially in the areas with small population sizes--is proposed. When an empirical Bayes approach was applied to the 1983 suicide data for California counties, a more reasonable conclusion than could be obtained by using directly adjusted rates was reached.     

An eye movement analysis of the spatial contiguity effect in multimedia learning

In three studies, eye movements of participants were recorded while they viewed a single-slide multimedia presentation about how car brakes work. Some of the participants saw an integrated presentation in which each segment of words was presented near its corresponding area of the diagram (integrated group, Experiments 1 and 3) or an integrated presentation that also included additional labels identifying each part (integrated-with-labels group, Experiment 2), whereas others saw a separated presentation in which the words were presented as a paragraph below the diagrams (separated group, Experiments 1 and 2) or as a legend below the diagrams (legend group, Experiment 3). On measures of cognitive processing during learning, the integrated groups made significantly more eye-movements from text to diagram and vice versa (integrative transitions; d = 1.65 in Experiment 1, d = 0.85 in Experiment 2, and d = 1.44 in Experiment 3) and significantly more eye-movements from the text to the corresponding part of the diagram (corresponding transitions; d = 2.02 in Experiment 1 and d = 1.35 in Experiment 3) than the separated groups. On measures of learning outcome the integrated groups significantly outperformed the separated groups on transfer test score in Experiment 1(d = .80) and Experiment 2 (d = .73) but not in Experiment 3 (d = .35). Spatial contiguity encourages more attempts to integrate words and pictures and enables more successful integration of words and pictures during learning, which can result in meaningful learning outcomes.     

A note on the development of recall of spatial location

Recall of spatial location was studied with 5, 8, 12--13, and 17--18 year old subjects. Pictures of objects were shown one at a time in one of the four quadrants of a projection screen which was either blank (NF) or divided by a cross into four quadrants (F). The presence of the frame (F) did not affect item recall, but facilitated location recall more, the younger the subjects. Intentional learning of location was superior to incidental learning in the youngest but not in older children. The results are in agreement with Bryant's (1974) analysis of perceptual development which emphasizes the use of external spatial frames of reference in the encoding of attributes of visual objects in young children.     

Interference with spatial working memory: An eye movement is more than a shift of attention

In the present experiments, we examined whether shifts of attention selectively interfere with the maintenance of both verbal and spatial information in working memory and whether the interference produced by eye movements is due to the attention shifts that accompany them. In Experiment 1, subjects performed either a spatial or a verbal working memory task, along with a secondary task requiring fixation or a secondary task requiring shifts of attention. The results indicated that attention shifts interfered with spatial, butnot with verbal, working memory, suggesting that the interference is specific to processes within the visuospatial sketchpad. In Experiment 2, subjects performed a primary spatial working memory task, along with a secondary task requiring fixation, an eye movement, or an attention shift executed in the absence of an eye movement. The results indicated that both eye movements and attention shifts interfered with spatial working memory. Eye movements interfered to a much greater extent than shifts of attention, however, suggesting that eye movements may contribute a unique source of interference, over and above the interference produced by the attention shifts that accompany them.     

A note on data smoothing for movement analysis: the relevance of a nonlinear method

The goal of this experiment was to test a potentially useful nonlinear method for smoothing noisy position data, which often is encountered in the analysis of data. This algorithm (7RY) uses a nonlinear smoothing function and behaves like a low-pass filter, automatically removing aberrant points; it is used prior to differentiation of time series so that usable acceleration information can be obtained. The experimental procedure comprises position data collection along with direct accelerometric data recording. From the position-time data, (a) 7RY and (b) Butterworth algorithms have been used to compute twice-differentiated acceleration curves. The directly recorded acceleration measurements were then compared with the acceleration computed from the original position data. Although the results indicated an overall good fit between the recorded and the calculated acceleration curves, only the nonlinear method led to reliable acceleration curves when aberrant points were present in the position data.     

Learning new movement patterns: a study on good and poor writers comparing learning conditions emphasizing spatial, timing or abstract characteristics

In the earliest stages of motor-skill learning cognitive, visuo-spatial and dynamic processes play an important role. Which of these should be addressed first when children need to learn a new complex movement sequence? This study compares three learning methods in a within-subject design by having 18 good and 18 poor 8-year-old writers master unfamiliar, letter-like patterns by (1) tracing a trajectory on a screen, (2) tracking a moving target (pursuit), and (3) performing the pattern using written explicit instructions. Following each 10-trial learning phase, the children completed a short test phase. Besides errors and kinematic data, Dynamic Time Warping (DTW) was used to calculate the deviation for each pattern from the ideal shape (DTW-distance). As predicted, the number of errors and DTW-distance were very low during the learning phase of the tracing and pursuit conditions and higher in the explicit condition. Conversely, in the test phase, tracing yielded the highest DTW-distance and the explicit condition the lowest DTW-distance and error percentages. The results were remarkably similar for the good and poor writers. The poor learning results of the tracing condition and the good results of the explicit condition have important implications for the teaching of handwriting and remedial therapy.     

The influence of spatial contrast on the frequency-dependent nature of vibration sensitivity

Several stimulus configurations have been described for measuring the threshold for vibration perception. One such configuration, used primarily for screening for peripheral nervous system function, for example, consists of a matrix of 24 rows and 6 columns of tiny pins vibrating at 230 Hz, with the even rows of pins vibrating in opposite phase to the uneven rows. In order to determine which class of mechanoreceptors is being tested with such a stimulus, the frequency dependence of the threshold for vibration perception was measured with a similar stimulus configuration in a group of younger subjects and in a group of older subjects. Moreover, the stimulus configuration could be changed from opposite phase stimulation to equal phase stimulation, wherein all pins vibrated with equal phase. In the range above 160 Hz, it appeared that in younger subjects the threshold of the Pacinian receptor system was evaluated with both modes of stimulation, although the sensitivity for opposite phase stimulation was reduced relative to the sensitivity for equal phase stimulation. In the older subjects, equal phase stimulation also appeared to evaluate the Pacinian receptor system. However, with the opposite phase stimulation, the non-Pacinian receptors tended to be evaluated. Below 100 Hz, sensitivity was greater for opposite phase than for equal phase stimulation in both groups. Moreover, with both modes of stimulation, a sensitivity maximum at 40 Hz could be obtained, which was tentatively ascribed to the rapidly adapting class of mechanoreceptors.     

The after effect of seen movement on a plain field

Twenty laboratory subjects were asked to fixate the centre of a rotating spiral disc, under conditions where all of them, on stopping the disc, obtained the well known illusion of apparent expansion outwards. In this experiment, instead of stopping the disc, a completely uniform white surface was substituted and it was found that though the borders of the surface appeared to remain still, the surface itself showed apparent expansion in nearly all cases.     

An Empirical Note on Attaining a Spatial Target after Distorting the Initial Conditions of Movement via Muscle Vibration

Can one’s limb be accurately positioned to a spatial location without a veridical estimate of the initial conditions of movement? The experiment reported here examined this question by distorting perception of a limb’s starting position via muscle vibration. Subjects executed rapid flexion movements under no-vibration, contralateral arm vibration, and ipsilateral arm vibration conditions. Vibration was applied to the biceps for 10 sec prior to the start of a reproduction movement. The results showed that vibration on the ipsilateral arm caused a significant increase in reproduction error, relative to the no-vibration and contralateral-vibration conditions. This finding provides additional evidence that accurate knowledge about the initial conditions of movement is a necessary component in positioning a limb.     

Coupling kinematics of memory and kinematics of movement: the conditions for a psychological relativity

The organization of spatial and temporal information relative to memory-movement interactions was studied in a recall task. Stimuli consisted of four different configurations of eight dots, presented sequentially. In two configurations, the stimuli were spatiotemporal congruent, with (constant or variable) inter-stimulus distances corresponding to (constant or variable) inter-stimulus time intervals. In the other two configurations, the stimuli were spatiotemporal incongruent, with (constant or variable) inter-stimulus distances not corresponding to (variable or constant) inter-stimulus time intervals. After a learning phase consisting of 20 presentations of the target configuration, participants performed a series of pointing movements to reproduce both spatial and temporal characteristics of the stimulus 60 times in succession without ever re-examining the target configuration. Classically, in incongruent spatiotemporal conditions, the reproduction of, respectively, constant distances or constant time intervals are strongly disturbed by the simultaneous perception of variable inter-stimulus time intervals (Tau effect) or variable distances (Kappa effect). We assume that these spatiotemporal dependencies, which occur when the response relates to one dimension only, crucially depend on the non-integration of motoric aspects in memory.     

An empirical test of a comprehensive model of intrapersonal empowerment in the workplace

A comprehensive model of intrapersonal empowerment in the workplace posits that empowerment mediates the relationship between the social structural context and behavioral outcomes. The social structural context is operationalized as perceptions of role ambiguity, sociopolitical support, access to strategic information and resources, and work unit culture, whereas behavioral outcomes are operationalized as innovativeness and effectiveness. The model is examined on a sample of 324 middle managers from different units of a Fortune 50 organization. Survey data are examined using a series of regression analyses to assess the mediating effect of intrapersonal. Results suggest that intrapersonal empowerment mediates the relationship between some elements of workplace social structure and innovativeness, but not effectiveness. Although not a mediating mechanism for effectiveness, intrapersonal empowerment is nonetheless directly related to effectiveness (as assessed by the respondent's subordinates). Implications of the results are discussed as are study limitations and directions for future research. This paper is based on the author's dissertation, presented in partial fulfillment of the requirement for the doctoral degree at the University of Michigan. I am grateful to my dissertation committee which included Robert E. Quinn (chair), Susan Ashford, Richard Bagozzi, Karl Weick, and Marc Zimmerman for their thoughtful guidance. Thanks is also extended to Neil Sendelbach for his help in facilitating data collection. The University of Michigan and the University of Southern California both provided financial support for this research. This paper was prepared while the author was a Zumberge Fellow at the University of Southern California.     

Timing precision in circle drawing does not depend on spatial precision of the timing target

The authors manipulated the width of a timing target in continuous circle drawing to determine whether a more stringent spatial-timing criterion would produce an increase in participants' (N = 30) temporal variability. They also examined the effect of the computational method of determining cycle duration. There was no effect of spatial precision on temporal variability in circle drawing, and tapping and circle drawing were found to use the same criterion. Those findings lend strong support to the earlier view of R. B. Ivry, R. M. Spencer, H. N. Zelaznik, and J. Diedrichsen (2002), who argued that continuous tasks such as circle drawing are timed differently from discrete-like tasks such as tapping. Therefore, the results of the present study provide support for the event and emergent timing frameworks.     

Qualitative influences on the perception of movement: An experimental study

One of the most puzzling features of “hyperactivity” in children is the importance of activity itself. Generalized overactivity has not been found to be a valid diagnostic marker. Could some qualitative features of activity be important determinants of the perceived quantity of activity? The analogue study reported here derives from a social-psychological hypothesis that anything that makes a behavior more noticeable or distracting can create an illusion of increased movement. Subjects performed a simple cognitive task while watching short films of adult actors. Two variables were manipulated: (a) The sound level was either loud or quiet, and (b) instructions to subjects were varied so that the behaviors shown were perceived as either appropriate or inappropriate. Results strongly supported the hypothesis. Loudness and contextual inappropriateness made the films more distracting, produced higher ratings of the amount of movement observed, and led to more negative evaluations of the behaviors seen. Implications for assessment and intervention are discussed.     

The facilitation of lexical decisions by a prime occurring after the target

Three experiments are reported that investigate priming effects in a lexical decision task. when the prime was presented after the target. In Experiment 1, the lexical decision target was presented for 50 msec, followed 80 msec later by the prime. No significant facilitation of responses was observed in the related prime condition. In Experiment 2, the target was presented for 30 msec, followed 35 msec later by the prime. Targets followed by related primes were responded to significantly faster than targets with unrelated primes. Experiment 3 replicated the result of Experiment 2. The data are interpreted as supporting parallel processing of the prime and target in semantic priming experiments. The theoretical implications of the “backward” priming effect are discussed.