Imagery,rehearsal, and the compatibility of input-output tasks

Two experiments tested the proposition that recall in an imagery task would be facilitated when the processes instigated during original input and during a rehearsal interval were similar to (compatible with) processes assumed to be initiated by two retrieval formats. In both experiments the subjects listened to tape-recorded messages which described the placements of numbers in an imaginary mental matrix. Experiment 1 used four modes of presenting the original information about the placement of the numbers. Two of the input modes were expected to foster the use of imagery: listening to the tape-recorded messages (L), and listening while shadowing (vocalizing) the messages (LV). The other modes of presentation were expected to encourage verbalized rather than imaginal encoding: listening plus silent reading (LR), and listening plus reading aloud (LRV). Two types of recall tasks were used, one which emphasized imaginal coding (matrix recall) and one which emphasized verbal coding (direction recall). Recall was highest when the input and output tasks were assumed to involve similar types of processing. Thus, Groups L and LV showed higher recall than Groups LR and LRV on the matrix task, but the converse was true for the direction task. In addition, rotation of the information yielded different characteristics for the input-output conditions. Experiment 2 introduced rehearsal instructions. Visualizing rehearsal was more beneficial to matrix recall than verbalizing rehearsal or no explicit rehearsal instructions, and verbalizing rehearsal aided direction recall more than visualizing rehearsal. Various models were discussed.     

Memory for movement: Interaction of location and distance cues and imagery ability

The present experiments examined the role of imagery ability in recall of either the terminal location or the distance of a preselected horizontal linear movement following changes in the recall starting position. Subjects were selected on the basis of their scores on a shortened version of the Betts Questionnaire upon Mental Imagery (Betts Q.M.I., Sheehan 1967). Both high and low imagers were assigned to one of four groups, HIL, LIL, HID, LID, the last letter indicating the movement cue (terminal location or distance moved) to be recalled. Recall of the appropriate movement cue from one of four new recall starting positions occurred after either a 5-sec or 30-sec unfilled retention interval. Analysis of constant error indicated all groups were unable to recall the specified movement cue independent of the other source of information, even when subjects were given explicit instructions to utilise an imagery strategy. The data corroborate our earlier findings that memory for self paced movements is based on an interaction of location and distance cues derived from the criterion movement.     

Coding strategies and cerebral laterality effects

In a short-term recognition memory task, Ss were given relational imagery and rehearsal coding strategies in different sessions, with probes presented to the left or right cerebral hemisphere. Consistent with a model of separate processing systems for verbally and visually coded information, Ss yielded significantly faster response latencies for probes to the left hemisphere than the right when employing the rehearsal strategy, and significantly faster latencies for probes to the right hemisphere than the left when using the imagery code. This suggests that cerebral laterality effects are functionally related to coding strategies, and argues for the inclusion of imagery, or generated visual information, as part of the visual processing system. As such, generated visual information may be viewed as a coding alternative to verbal mediation.     

Manipulation of visual information does not change the accuracy of distance estimation during a blindfolded walking task

While humans rely on vision during navigation, they are also competent at navigating non-visually. However, non-visual navigation over large distances is not very accurate and can accumulate error. Currently, it is unclear whether this accumulation of error is due to the visual estimate of the distance or to the locomotor production of the distance. In a series of experiments, using a blindfolded walking test, we examine whether enhancing the visual estimate of the distance to a previously seen target, through environmental enrichment, visual imagery, or repeated exposure would improve the accuracy of blindfold navigation across different distances. We also attempt to decrease the visual estimate in order to see if the opposite effect would occur. Our results would indicate that manipulation of the static visual distance estimate did not change the navigation accuracy to any great extent. The only condition that improved accuracy was repeated exposure to the environment through practice. These results suggest that error observed during blindfold navigation may be due to the locomotor production of the distance, rather than the visual process.     

Individual differences in imagery vividness and voluntary heart rate control

Dispositional differences in imagery vividness may account partially for the large individual differences in learning heart rate control. Based upon scores on the Betts QMI Vividness of Imagery Scale, 10 subjects were defined as a high imagery group and 10 subjects were defined as a low imagery group. All subjects were instructed to try to alter their heart rate as indicated by appropriately labeled lights. Six increasing, six decreasing and six rest, 45-sec trials were presented. During the trials, visual heart rate feedback was provided by a digital voltmeter. The dependent measure was computed by subtracting the mean of the last 5 beats of a 15-sec intertrial interval from the mean rate per trial. Results indicated that subjects were able to significantly raise and lower heart rate relative to rest trials. Furthermore, high imagery subjects demonstrated significantly larger changes than low imagery subjects on increase trials but not on decrease trials. Subjects in both groups typically reported using more specific images for increasing heart rate than for decreasing heart rate. These data suggest that dispositional differences in imagery vividness may have contributed to the differential performance of the two groups during the increase task.     

The retention of imagined and seen spatial matrices

The nature of imagery and its relationship to perception were probed by having students recall the contents of 4 × 4 spatial matrices after they constructed the matrices through processes of imagery, seeing, or verbal coding. In the imagery and verbal conditions, students listened to auditory messages which described the matrices. Students in the imagery condition were instructed to imagine the matrix being described; students in the verbal condition received no imagery instructions; and students in the seeing condition saw the matrix for an inspection period prior to recall. Recall was best when students saw the matrices, intermediate in the imagery situation, and poorest in the verbal situation. Recall was best for the corner cells of seen and imagined matrices, indicating the spatial nature of these processes; no such effect was found for verbal processing. Forgetting over a 10-sec interval occurred only for verbal processing. Implications for understanding the nature of visual imagery and perception are discussed.     

Rehearsal of visual and auditory stimuli while shadowing.

Memory trigrams were presented by one of three methods: visual-concurrent (all three letters appeared simultaneously), visual-successive, and auditory-successive. During the 12-sec retention interval, subjects shadowed and reported their rehearsals and mnemonic associations via switches. On trials without associations, recall performance was interpreted as support for the hypothesis that the form of rehearsal is related to presentation modality. However, the frequency and temporal patterning of the rehearsals over the retention interval were virtually identical for all three presentation conditions, suggesting that the "control processes" were relatively independent of both method of presentation and modality of rehearsal. Most importantly, these data in combination with earlier data suggest that the efficiency of each rehearsal was also independent of those same factors, in each case quite comparable to that of a concurrent visual stimulus.     

The Influence of Music on Memory

Allan Paivio's dual-coding hypothesis of retention predicts that stimuli high in imagery value facilitate imaginal processing, while high meaningfulness stimuli facilitate verbal processing. When verbal and imaginal instructional sets have been used to test the predicted interactions, as mentioned above, the findings have almost always been negative, indicating a lack of support for a dual-process theory of coding in retention.

In the present study it was hypothesized that instructional sets offer inadequate tests of dual or multiple-process theories because the proactive history of the verbal and imaginal semantic properties of the word lists determine coding in retention. That hypothesis was tested in two studies, one with children and one with adults. Verbal and imaginal attributes were varied in instructional sets and in word lists. As hypothesized, the interaction predicted by a dual-process theory of coding occurred in both studies (p < .0001). The interaction involved verbal and imaginal word attributes, but not the instructional sets.

The findings are relevant to the testing of predictions from dual-process theories of retention and to reinterpretation of the results of earlier findings. In this study and in many related ones reviewed in the introduction, the “elusive” interaction predicted by a dual-process theory regularly does occur, and it seems to be determined by attributes of word lists.     

Rehearsal capacity and dimensional independence in retardates

Retardate use of retention strategies and the independence of color and form retention were compared with predictions of the Attention-Retention theory of retardate discrimination learning. Lists of two-choice discrimination problems were increased in length from one to capacity, which was defined through criterion retention across a 20-sec interval. It was demonstrated that (a) capacity and rate of adjustment of retentional strategy were directly related to intelligence, (b) at capacity limits the retention of problems in one dimension interfered with retention in a second dimension, and (c) results consistent with a capacity allocation strategy were obtained. The results were interpreted as reflecting short-term memory capacity constraints on the use of rehearsal.     

Spatio-temporal working-memory and short-term object-location tasks use different memory mechanisms

Spatial short-term memory for objects' locations was investigated in a spatial relocation task. During maintenance, dynamic visual noise or spatial tapping were administered as visual or spatial secondary tasks, respectively. Because memory for location should tap the visual component of working memory, a visual but not a spatial secondary task should impair location memory. In fact, neither of the tasks impaired memory (Experiment 1), although the expected dissociation between visual and spatial components was clearly confirmed for a spatio-temporal main task (Corsi test) (Experiment 2). We then contrasted location memory for pictures of objects and of nonsense figures under visual interference. Real objects were relocated much better than nonsense figures, and visual noise was again ineffective (Experiment 3). When spatial tapping was combined with the same material (Experiment 3a), again no influence on memory for locations of objects was observed and only a small influence on remembering nonsense figures. We suggest that the Corsi and the relocation VSWM-tasks use different memory mechanisms. The configuration of objects is reconstructed from perceptual records in an episodic buffer, provided by the same structures that enable visual memory after longer intervals. Rehearsal is not necessary for the persistence of these traces. In contrast, in the Corsi task remembering, a temporal sequence across homogeneous locations needs spatio-temporal marking and therefore active rehearsal of the locations by shifting spatial attention. A spatially demanding secondary task during retention interrupts this rehearsal.     

Comparison of the efficacy of two name-learning techniques: expanding rehearsal and name-face imagery

Two name-learning techniques were compared: expanding rehearsal and name-face imagery. Participants studied name-face associations and were given a cued recall test in which they were presented with a face and were to recall the name. They were presented with either an expanding rehearsal schedule (expanding condition), a distinctive facial feature coupled with a word phonologically similar to the last name and an interactive image linking the name and facial feature (name-face imagery condition), or a no memory (control) strategy. The expanding rehearsal schedule led to superior name learning relative to the name-face imagery and control conditions after a 15-min (Experiment 1) or 48-hr (Experiment 2) retention interval. In Experiment 3, the retrieval practice explanation was tested but not supported; we argue that an encoding variability interpretation is consistent with the overall pattern of results. Applied implications are also discussed.     

Sex and coding strategy effects on reaction time to hemispheric probes

Two experiments were conducted to investigate the influence of coding instructions on cerebral laterality differences. Experiment I required 20 subjects (10 female) to use either rehearsal or imagery coding strategies in a recognition task with word probes to the right and left hemispheres. No hemispheric differences were found, but sex of subject was found to be related to coding strategy. Ten subjects (5 female) in Experiment II performed a similar task, except picture probes were used. Subjects using rehearsal coding responded faster to left-hemisphere probes, but faster to right-hemisphere probes when imagery coding was employed. The differing laterality effects in these experiments were attributed to naming responses implicitly required in Experiment II.     

Speech imagery is not always faster than visual imagery

One approach to the study of mental imagery is to examine the performance characteristics of different forms of mental imagery when used in various tasks. To demonstrate the utility of this functional approach, the use of speech and visual imagery processes in the serial mental rehearsal of common verbal sequences le.g., letters of the alphabet and familiar object arrays (objects found in familiar rooms) was examined in the present experiments. Rehearsal rates and self-reporte were consistent with the hypothesis that mental rehearsal efficiency is a function of the compatibility of characteristics of the rehearsal materials and rehearsal mode. While verbal sequences were rehearsed faster under speech than under visual imagery conditions, object arrays were rehearsed as fast under visual as under speech imagery conditions. In addition, evidence was found that covert verbal rehearsal is faster than overt verbal rehearsal under some circumstances.     

Short-term temporal changes in free recall

An experimental study of short-term memory for lists of familiar English words is reported. Lists of 10, 20, and 30 unrelated words were presented at a 1-sec. rate. Retention was measured by free recall after intervals of 0, 15 and 30 sec. A counting task was used to prevent rehearsal during the retention interval. The absolute level of recall increased with length of list whereas the percentages retained showed the reverse trend. The recall scores decreased steadily as a function of retention interval, with the rates of forgetting comparable for the three lengths of list. The decline in the amount recalled was due in large measure to the loss of the terminal items in the list. Consequently, the pronounced recency effect present on the immediate test of recall was progressively reduced as a function of time. By contrast retention of the initial part of the list was relatively stable. These variations in rate of forgetting are attributed to differences among serial positions in susceptibility to proactive inhibition.     

Imagery and rehearsal as study strategies for written or orally presented passages

In the present research, we studied the influence of text presentation modality on recall under imagery, rehearsal, and no strategy instructions. It was hypothesized that imagery is a more effective recall strategy for an oral presentation and rehearsal for a written presentation, and that imagery and rehearsal are effective study strategies. One hundred twenty participants participated, 80 of whom were trained in the use of imagery or rehearsal in the study of passages and 40 of whom made up the control group. A text was presented orally or in writing; the trained participants were to memorize it using the strategy taught, and the participants in the control group were to memorize it using a freely chosen strategy. They were then asked for free written recall. The results confirmed that the participants using imagery recalled the oral presentation better than the written one, and those using rehearsal recalled the written presentation better than the oral one. The discussion focuses on a selective-interference explanation of the presentation modality effects. Practical suggestions are given, and implications for future research are discussed.     

The compression block technique

Remembering the distance or end-location of an interpolated movement interfered equally with the retention of criterion movement end-location. Interpolated distances were recalled less well than interpolated locations. These results were interpreted as evidence of capacity interference rather than structural interference with a visual/kinesthetic integrated store.     

Brain injury and movement recall: Preselection, active-passive and interference effects

Stroke patients with unilateral lesions were compared with age-controls and students on their ability to reproduce a terminal location established kinesthetically by a previous movement. Conditions for the criterion movement differed over active/passive and preselected/constrained (experiment 1) and whether the retention interval between the criterion and recall movements involved mental rehearsal of the criterion movement or yes/no responding to a mental arithmetic task (experiment 2). Whereas students showed more accurate recall with little effect of criterion movement condition, patient groups showed a preselection effect, but only with active movements. A preferred hand advantage observed for the patient controls did not occur with stroke patients, and prevention of mental rehearsal during the retention interval disrupted recall more for the stroke patients. These findings are interpreted in terms of hemisphere-specific coding strategies whose relative use depends on the attentional demands of the task.     

Cognitive Strategies and Short-term Memory for Movement Distance and Location

A number of researchers (e.g. Kerr, 1978; Walsh, Russell, Imanaka, & James, 1979) have previously demonstrated interference between location and distance information in motor short-term memory. This interference manifests itself in a characteristic pattern of undershooting and overshooting, with reproduction movement location being drawn in the direction of criterion movement distance and, conversely, the distance of reproduction movements being influenced by the terminal location of the criterion movement. We investigated the effects of different cognitive strategies upon the appearance of this location-distance interference during the reproduction of movement location (Experiment 1) and distance (Experiments 2 and 3) in a linear arm positioning task. Experiment 1 compared performance in location reproduction between two strategy groups differing in the availability of explicit information about the change in starting position. The characteristic undershooting-overshooting interference pattern was observed for the group without the explicit information about the change in starting position but disappeared for the group in which explicit information about the change in starting position was provided. Experiment 2 examined the systematic undershooting-overshooting pattern in distance reproduction for a location strategy (involving some extrapolation of the start and end locations), a counting strategy, and a distance sense strategy (involving the use of visual imagery). The systematic response bias pattern disappeared when the subjects used a location strategy but was clearly observed for the subjects using the other two strategies. This finding was generally confirmed by Experiment 3, which showed a typical undershooting-overshooting pattern in distance reproduction for a counting/distance sense strategy but not for two location strategies (a general location and an explicit location strategy). The location strategies differed in the availability of explicit information about starting and end locations for both the criterion and reproduction movements. The results from these three experiments indicate that explicit information about the start andlor end locations prevents the usual interference between location and distance information from arising in movement reproduction. The notions of automatic and controlled processing and cerebral hemispheric specialization are discussed as potential explanations of these results and of the interference typically observed in motor short-term memory between distance and location information.