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.     

Developmental study of short-term memory characteristics for kinesthetic movement information

The present experiment was designed to examine age-related characteristics of short-term retention of kinesthetic movement information. 20 children from each age group (6, 8, 10 yr.) were tested for recall of kinesthetic end-location. The results indicate that 6- and 8-yr.-old children became less accurate and more variable in recall performance following a delay interval. However, 10-yr.-old children were capable of maintaining performance accuracy during a delay interval.     

Serial-position effects in motor short-term memory

This study examined the effect of the length of a series of movements on the recall of those movements. Subjects (n = 45) were randomly assigned to one of three experimental groups with each group recalling either three, six, or nine movements on a linear-slide apparatus. The subjects, while blindfolded, were presented with each movement by actively moving to a stop. Recall occurred 5 sec after the last movement to a stop on a trial. All subjects were given nine trials, each containing a different series of to-be-recalled movements. Results indicated that absolute error of recall of the three movements increased in a linear fashion. However, for six and nine movements, a bowing effect of the recall curve was noted following the fifth position. A primacy effect was more evident than was a recency effect. Accuracy of recall was a function of list length up to six movements, after which accuracy was not further impaired.     

Preselection in short-term motor memory.

Recent studies by Jones (1974) have posited that accurate movements in short-term motor memory (STMM) are mediated by the subject's ability to preset effector mechanisms and monitor their efferent output. Three experiments were conducted to examine this hypothesis. Experiment 1 involved comparisons between the reproduction of the end-location and the reproduction of the distance of a preselected movement. The results revealed that preselected location was superior to preselected distance, indicating that the efference attached to movement extent was not primary. Experiment 2 examined whether location cues were primarily encoded independent of the movement presentation mode. The subjects recalled target locations under preselected, constrained, and passive movement conditions. Recall in the preselected condition was superior to that in the constrained and passive conditions, which showed no difference, suggesting that afferent location information per se was not totally responsible for recall accuracy. Experiment 3 examined the processing requirements of preselected, constrained, and passive location information by filling the retention interval with interpolated processing activity. While preselected location was clearly superior, the three conditions were not differentially affected by processing activity. These overall findings were interpreted as contrary to Jones (1974) and pointed to the importance of preselection in short-term motor memory.     

Language-induced motor perturbations during the execution of a reaching movement

In a recent study Boulenger et al. (2006) found that processing action verbs assisted reaching movement when the word was processed prior to movement onset and interfered with the movement when the word was processed at movement onset. The present study aimed to further corroborate the existence of such cross-talk between language processes and overt motor behaviour by demonstrating that the reaching movement can be disturbed by action words even when the words are presented delayed with respect to movement onset (50 ms and 200 ms). The results are compared to studies that show language-motor interaction in conditions where the word is presented prior to movement onset and are discussed within the context of embodied theories of language comprehension.     

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.     

Preselection and response biasing in short-term motor memory

Two experiments were performed comparing preselected (subject defined) and constrained (experimenter defined) movements. In the first experiment, subjects made reproduction responses immediately or under unfilled and filled 15-sec retention intervals. Results indicated that recall of preselected movements was clearly superior until the interpolation of information processing activity. In addition, preselected movements demonstrated no forgetting over a 15-sec retention interval while constrained movements evidenced spontaneous memory lass, suggesting that preselected movements possess a stronger representation in memory. The second experiment examined this interpretation in a response biasing paradigm. Subjects made criterion responses under preselected or constrained conditions, while the interpolated movement was always in the constrained mode and ± 40 deg from the criterion. The subjects' task was to attend to both movements and recall each when instructed. While preselected recall was clearly superior' to constrained recall, response biasing was clearly evident in both. The failure to find differential biasing effects was discussed in terms of the relative trace strength hypothesis (Stelmach & Welsh, 1972).     

Criterion movements in motor short-term memory experiments

Analysis of both the criterion and reproduction movements from a motor short-term memory experiment using preselected movement is presented. The movement cues under imvestigation, location and distance, were found to interact significantly with amplitude for both the criterion and reproduction movements. It seems that movement cue affects the amplitude of criterion as well as reproduction movements. Thus previous findings by Gundry (1975) are replicated and extended. An increase in a central tendency effect over trials was found which indicated that the criterion movements were effected by proceding movements. The theoretical and methodological implications of these findings are discussed.     

Methodological issues in short-term motor memory research

Four methodological issues identified and studied by short-term motor memory researchers were examined in this paper: (a) the distributions of three commonly used measures of error (AE, CE, and VE); (b) statistical analysis of these scores as dependent measures in an experiment; (c) within-cell and experiment-wise estimates of the reliability of CE; and (d) the power of the statistical test with CE as the dependent measure. The first two sub-problems were explored theoretically, while the latter two were subjected to empirical examination using four data sets from previously published experiments. The distributions of AE and VE scores were described as non-normal under certain conditions, while the CE score distribution was shown to be normal. Therefore analyses of these three dependent measures may require different statistical procedures. In light of this information, the assumptions affecting estimates of reliability and power in an experimental framework were examined. Based on an analysis of the four data sets, a strategy was proposed in which a relatively small number of subjects could be utilized in an experiment without sacrificing desired experimental controls.     

Embodied grounding of memory: Toward the effects of motor execution on memory consolidation

Behavioural and neuroscientific research has provided evidence for a strong functional link between the neural motor system and lexical–semantic processing of action-related language. It remains unclear, however, whether the impact of motor actions is restricted to online language comprehension or whether sensorimotor codes are also important in the formation and consolidation of persisting memory representations of the word's referents. The current study now demonstrates that recognition performance for action words is modulated by motor actions performed during the retention interval. Specifically, participants were required to learn words denoting objects that were associated with either a pressing or a twisting action (e.g., piano, screwdriver) and words that were not associated to actions. During a 6–8-minute retention phase, participants performed an intervening task that required the execution of pressing or twisting responses. A subsequent recognition task revealed a better memory for words that denoted objects for which the functional use was congruent with the action performed during the retention interval (e.g., pepper mill–twisting action, doorbell–pressing action) than for words that denoted objects for which the functional use was incongruent. In further experiments, we were able to generalize this effect of selective memory enhancement of words by performing congruent motor actions to an implicit perceptual (Experiment 2) and implicit semantic memory test (Experiment 3). Our findings suggest that a reactivation of motor codes affects the process of memory consolidation and emphasizes therefore the important role of sensorimotor codes in establishing enduring semantic representations.     

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.     

Memory trace strength and response biasing in short-term motor memory

Two experiments, which attempted to create differential memory trace strengths in a response biasing paradigm, were performed. After the presentation of the criterion location, an interpolated target was presented which was either ±40 deg from the criterion. The S’s task was to attend to both targets and recall each when instructed. The first experiment involved strengthening the criterion trace via repetition (0, 5, or 14 rep.) while the second involved providing additional feedback via visual, auditory, and heightened kinesthetic cues. In the initial experiment, a Repetition by Response Biasing interaction revealed that repetition systematically reduced error shifts at recall. The second experiment found that, in the combined feedback and visual conditions, response biasing was reduced. It seems feasible to suggest that both studies successfully manipulated memory trace strength which appears to be one determiner of error shifts at recall.     

The effect of invalid task parameters on short-term motor memory

Two experiments tested the influence of information from an invalid movement parameter on short-term motor memory for a valid task parameter. Experiment 1 showed that invalid task distance information affected location retention. Experiment 2 showed that invalid task location information affected task distance retention. These findings strengthen the evidence that the codes important for short-term motor retention are affected by a variety of factors within the movement context.