Specific-cue effects of interpolated movements on distance and location retention in short-term motor memory

A short-term motor retention paradigm was used to examine the effect of interpolated movements on the recall of individual distance- and location-cue information. Subjects were instructed to learn either a distance or a location cue during the execution of simple, discrete original movements. Interpolated movements were then made which varied and repeated distance and location either individually or jointly. Changes in variable, absolute, and algebraic error from immediate to delayed recall were totally determined by interpolation of the individual instructed cue. No added recall changes were produced by interpolation of noninstructed cues. The data were interpreted as supporting the presence of a stimulus-selection process that dissociates kinesthetic information as a function of instructional set. The effects of inter-poated movements, then, are determined partially by this selection process.     

Interference Between Location and Distance Information in Motor Short-Term Memory: The Respective Roles of Direct Kinesthetic Signals and Abstract Codes

Interference between location and distance information in motor short-term memory has been hypothesized on the basis of the systematic pattern of undershooting and overshooting in movement reproduction that occurs when the starting position for reproduction movements is shifted. To determine the possible contribution of limb-specific kinesthetic information to this systematic undershooting-overshooting pattern, we compared the reproduction of linear arm positioning movements performed under either same-limb or switched-limb conditions. Ten subjects were assigned to either a location or distance cue condition, and each subject completed a total of 40 trials, 20 under same-limb and 20 under switched-limb conditions. Each trial consisted of criterion and reproduction movements, separated by a 10-s retention interval. The starting position for the reproduction movement was shifted by 0, 2, or 4 cm in either direction from that of the criterion movement. The systematic undershooting-overshooting pattern, which occurs when either the movement location or distance is reproduced, arose under both the same-limb and switched-limb conditions, suggesting that the primary cause of the location-distance interference is not limb-specific kinesthetic information. Rather, more abstract information in the form of a conceptual memory code appears to be the probable cause of the location distance interference phenomenon.     

Memory Characteristics of Kinesthetic Information

Several kinesthetic cues may underlie the retention of movements: joint position receptors, muscle stretch receptors, tendon stretch receptors, cutaneous senses, duration of movements, and motor outflow all provide cues. An attempt was made to separate subsets of cues used for movement reproduction by varying the characteristics of the movements. Ss reproduced either the end Location of a movement or the Distance plus Location. The original and reproduction movements involved either the same or different muscle tensions. These manipulations failed to result in different retention characteristics. In all cases there was little loss of accuracy over a 7-sec. retention interval unless the retention interval was filled with a distracting task. These results are quite different from those of a number of other studies of movement retention, suggesting that different cues do have different retention characteristics.     

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.     

Imagery ability and the acquisition and retention of movements

In this study, we examined the relationship between imagery ability, as measured by the Movement Imagery Questionnaire (MIQ), and the acquisition, retention, and reacquisition of movements. Based on their MIQ scores, 10 subjects were selected for the following imagery groups: high visual/high kinesthetic (HH), high visual/low kinesthetic (HL), and low visual/low kinesthetic (LL). The subjects learned four movements to a criterion level. Before each trial, subjects kinesthetically imaged the movement about to be produced. Following each acquisition trial, subjects were provided visual feedback. The acquisition phase was followed by a 2-day retention interval, a retention test consisting of three trials on each movement (no feedback provided), and a reacquisition phase. The HH group acquired the movements in the least number of trials, the LL group required the greatest number of trials, and the HL group required an intermediate number of trials. The data for the reacquisition phase showed the same trend. There was only weak evidence for a relationship between imagery ability and the retention of the movements. These findings support the position that high imagery ability facilitates the acquisition, but probably not the short term retention, of movements.     

Age differences in visual and kinesthetic short-term memory

30 elderly subjects were matched with 30 young subjects and tested on a kinesthetic short-term memory task which required the replication of criterion moves after a variable retention interval under conditions of either rest, differing interpolated movement tasks, or mental activity. A visual control condition was used. Differing interference and temporal decrements were observed. Both old and young subjects differed significantly between sighted and blindfold conditions; however, there was no difference between the performance of the old and the young in the blindfold (kinesthetic) condition. These findings were discussed with respect to practical implications for the retraining of old subjects on certain motor tasks.     

Decay and interference effects in motor short-term memory

Trace decay and interference effects in motor short-term memory were investigated by contrasting the predictions of two recent models (Pepper and Herman 1970; Laabs 1973) in regard to these two variables. Laabs' prediction that forgetting in motor short-term memory is indexed by greater variability of reproduction was supported in that movement reproduction after a 20 sec retention interval, either filled or unfilled, produced greater variable error. Further, his model was again supported in that analysis of constant error over five movement extents indicated interference effects through formation of an adaptation level which caused short movements to be overshot and long movements to be undershot. Pepper and Herman's concept of spontaneous trace decay indexed by a negative shift in constant error was not supported as was their prediction that interpolated activity would alter the strength of the criterion trace through an assimilation process. Finally, some evidence was found supporting the view that a memory trace can be strengthened through proprioceptive feedback entering through an unattended channel.     

Encoding specificity principle in motor short-term memory for movement extent

The hypothesis was tested that, when the mode of presentation matches the mode of reproduction in memory for movement extent, there is less error in reproduction than when the modes are not matched. Female undergraduates (n = 24) were tested under active and passive criterion movements presented either under preselected or constrained conditions. All subjects underwent 36 trials involving the combination of three retention conditions (immediate, 20-sec unfilled, and 20-sec filled) and two reproduction conditions (active and passive). Results for absolute error showed that for constrained presentations, when the mode of presentation and the mode of reproduction were the same, accuracy was greater than when the modes of presentation and reproduction were different.     

Effects of field-articulation and feedback on perception of intermediate visual-kinesthetic position.

High and low field-articulators were compared on the accuracy with which they could adjust a rod to intermediate visual-kinesthetic positions while blindfolded, under four sensory-feedback conditions. Independent groups of 10 Ss were given auditory, visual, kinesthetic, or no sensory feedback for 16 trials and then tested on 8 trials without sensory feedback. High field-articulators were significantly more accurate on the feedback trials for all sensory-feedback conditions but not in terms of mean absolute error. The mean constant error on the test trials was significantly lower for the high field-articulators on all feedback conditions except for visual feedback where the low field-articulator had a lower constant error. Both the high and low field-articulators became more accurate and learned more in judging visual-kinesthetic position when auditory feedback was given. Low field-articulators showed significant improvement in accuracy with kinesthetic feedback. The results supported the hypothesis that intermediate directions can be learned and supported previous perceptual research.     

The relative weightings of visual and nonvisual coding in a simple motor learning task

A linear positioning task was used to examine the effects of visual and nonvisual inputs on motor learning. The experiment had three factors with two levels of each namely: sensory modality (visual-nonvisual), transfer at recall (changed-unchanged), size of movement (25.4 cm, 50.8 com). Three dependent variable were used: absolute error (AE), constant error (CE), and variable error (VE). The results suggest that visual dominance causes disruption of recall in the visual, changed conditions. No disruption of recall was found for the nonvisual condition other than in terms of CE with respect to movement sizes. The results are taken to follow Posner et al.'s (1976) theory of visual dominance, but some account of the spatial qualities of visual and kinesthetic information is needed.     

Performance on trials without knowledge results (KR) in reduced relative frequency presentations of KR

Following Salmoni, Schmidt, & Walter's (1984) discussion of knowledge of results (KR) as a variable influencing learning, the effect of varying relative frequency of KR while holding absolute number of trials constant was examined. In two experiments, the same treatment groups were compared in acquisition, retention (after 2 min and 24 hr), and on their pattern of responses on the sequence of no-KR trials following a KR trial. In Experiment 1, differences between groups in acquisition were consistent with the number of KR trials received, and there were no differences between groups in either of the retention conditions. Experiment 2 replicated Experiment 1 with a more difficult task. There were no between-group differences in acquisition. In Retention 1, the 100% and 33% relative frequency groups outperformed the less frequent KR groups, whereas in Retention 2, this trend was reversed. The findings from Experiment 2 provide qualified support for the hypothesis that reduced relative frequency of KR in acquisition facilitates performance in retention. The pattern of responses on the sequence of no-KR trials following a KR trial were consistent with Adams' (1971) perceptual-trace decay hypothesis.     

The Influence of Motor Imagery on Postural Sway: Differential Effects of Type of Body Movement and Person Perspective

The present study examined the differential effects of kinesthetic imagery (first person perspective) and visual imagery (third person perspective) on postural sway during quiet standing. Based on an embodied cognition perspective, the authors predicted that kinesthetic imagery would lead to activations in movement-relevant motor systems to a greater degree than visual imagery. This prediction was tested among 30 participants who imagined various motor activities from different visual perspectives while standing on a strain gauge plate. The results showed that kinesthetic imagery of lower body movements, but not of upper body movements, had clear effects on postural parameters (sway path length and frequency contents of sway). Visual imagery, in contrast, had no reliable effects on postural activity. We also found that postural effects were not affected by the vividness of imagery. The results suggest that during kinesthetic motor imagery participants partially simulated (re-activated) the imagined movements, leading to unintentional postural adjustments. These findings are consistent with an embodied cognition perspective on motor imagery.     

Interaction between stimulus-driven orienting and top-down modulation in attentional capture

The present study investigated whether visual and kinesthetic stimuli are stored as multisensory or modality-specific representations in unimodal and crossmodal working memory tasks. To this end, angle-shaped movement trajectories were presented to 16 subjects in delayed matching-to-sample tasks either visually or kinesthetically during encoding and recognition. During the retention interval, a secondary visual or kinesthetic interference task was inserted either immediately or with a delay after encoding. The modality of the interference task interacted significantly with the encoding modality. After visual encoding, memory was more impaired by a visual than by a kinesthetic secondary task, while after kinesthetic encoding the pattern was reversed. The time when the secondary task had to be performed interacted with the encoding modality as well. For visual encoding, memory was more impaired, when the secondary task had to be performed at the beginning of the retention interval. In contrast, memory after kinesthetic encoding was more affected, when the secondary task was introduced later in the retention interval. The findings suggest that working memory traces are maintained in a modality-specific format characterized by distinct consolidation processes that take longer after kinesthetic than after visual encoding.     

Dissociating cognitive and motor interference effects on kinesthetic short-term memory

In two experiments, we investigated how short-term memory of kinesthetically defined spatial locations suffers from either motor or cognitive distraction. In Exp. 1, 22 blindfolded participants moved a handle with their right hand towards a mechanical stop and back to the start and then reproduced the encoded stop position by a second movement. The retention interval was adjusted to approximately 0 and 8 s. In half of the trials participants had to provide a verbal judgment of the target distance after encoding (cognitive distractor). Analyses of constant and variable errors indicated that the verbal judgments interfered with the motor reproduction only, when the retention interval was long. In Exp. 2, 22 other participants performed the same task but instead of providing verbal distance estimations they performed an additional movement either with their right or left hand during the retention interval. Constant error was affected by the side of the interpolated movement (right vs. left hand) and by the delay interval. The results show that reproduction of kinesthetically encoded spatial locations is affected differently in long- and short-retention intervals by cognitive and motor interference. This suggests that reproduction behavior is based on distinct codes during immediate vs. delayed recall.     

Inhibitory function in the stimulus-response compatibility task

Changes of a location-based inhibitory function were investigated by performing a Stimulus-Response Compatibility task under two conditions. This task allows study of the efficiency of the inhibitory function by analyzing differences in error rates and in response time under various conditions of stimulus and response compatibility. In Exp. 1, with 28 college students, the effect of a dual task on the Stimulus-Response Compatibility effect was examined. In a dual-task, a predetermined stimulus such as a color is identified and the number of times a color is displayed is counted. In this experiment, under a dual task using visual stimuli, a decline in error responses and reduction of the Stimulus-Response Compatibility effect were observed. In Exp. 2, 29 college students participated in an identical experiment with the exception that an auditory stimulus was presented as the dual task. Similar to Exp. 1, there was a significant reduction in the number of error responses in the dual-task condition. Conversely, there was no significant change in Stimulus-Response Compatibility effect as estimated by response time. These results suggest that the two visual pathways as proposed by Goodale (1995) and the evocation of intentional attention may affect the Stimulus-Response Compatibility effect.     

Reaction time reduction after parafoveal preview in a lexical decision task

Time and the accuracy of a lexical decision performed on a letter string (either a word or nonword), presented foveally after a parafoveal preview displayed at 5 degrees of eccentricity and 100 msec. duration were measured. Students of Padova University, 10 women and 7 men, ages 19 to 23 years were subjects. The hypothesis investigated was whether the facilitatory effect, a reduction in lexical decision time due to the parafoveal preview, was tied to global visual information acquired in the visual periphery during the preview presentation. In Exp. 1, eight subjects performed the task either with no preview (No Preview) or with a preview presented at 5 degrees eccentricity in two conditions, preview of the same foveal string (Preview-Letters) and preview of symbols ("x xx...") of the same length as the foveal string (Preview Symbols). In Exp. 2, 9 subjects performed the task with two preview conditions, No Preview and preview of the foveal string in uppercase letters at 5 degrees of eccentricity (Preview Uppercase). Analyses suggested the reduction in lexical decision time due to the Preview with respect to the No Preview condition is tied to global information extracted during parafoveal presentation. The reduction in lexical decision time depends on word texture, i.e., letters' identities and also word boundary, in addition to word length.     

Alpha brain wave production as an interpolated task in a Brown-Peterson paradigm.

Rehearsal, backward counting, and production of alpha brain-waves were used as interpolated tasks in a Brown-Peterson paradigm to determine their effect upon verbal retention. A within-subjects design was used in which trained subjects were told on a given trial either to produce alpha rhythm, mentally rehearse, or count backward following presentation of a CCC trigram. Results for the backward-counting condition duplicate, for the retention intervals used, the shape of the classic Peterson and Peterson forgetting curve but indicate little loss of memory in either the rehearsal or alpha conditions. No siginificant difference was found between the alpha production and rehearsal conditions.     

Feedback — A determiner of forgetting in short-term motor memory

The retention of discrete movements was examined under augmented and minimal feedback conditions. The augmented condition was presented for both the criterion and recall movements and consisted of providing visual, auditory, and heightened proprioceptive cues with each movement. Under minimal conditions, no visual, auditory or heightened proprioceptive cues were provided. Absolute and constant error revealed that under augmented conditions recall accuracy was improved. The retention interval x feedback condition interaction failed significance for both sources of error indicating that there was no evidence of differential decay rates. Variable error appeared to be an informative index of forgetting. The results were interpreted to be in support of the view that a memory trace is imprinted with feedback from all modalities and that the amount of such feedback determines memory trace strength.     

Relative cues and absolute distance perception

It is possible, in theory, for the simultaneous occurrence of several different relative cues of distances to increase the veridicality of the perception of absolute distance. To test whether this actually occurs, a three-dimensional display was viewed monocularly while moving the head laterally, under conditions in which some error in perceived absolute distance was expected. The perceived absolute distance of the display was measured with the number of relative cues of distance within the display varied. No systematic reduction was found in the error in perceived absolute distance as a consequence of the variation in the number of relative cues. The study provides no evidence that the potential source of absolute distance information provided by relative cues is utilized by the visual system.     

Long-term retention as a function of word concreteness under conditions of free recall

Acquisition and long-term retention of concrete (C) and abstract (A) words were investigated under conditions of multiple-trial free recall. Both unmixed and mixed lists were used in original learning. Retention was tested either 1 rain or 1 week after attainment of the learning criterion. Acquisition was faster and retention was higher for C than for A words. These differences were more pronounced for mixed than for unmixed lists.