Spatial span under translation: A study of reference frames

The nature of the reference frame used to remember location sequences in a computer-presented version of spatial span was investigated by moving the template (a rectangular frame enclosing nine target squares) across the screen during presentation and/or during recall. Movement of the display during presentation substantially impaired memory in comparison with a stationary display (Experiment 1). However, there was no effect of template movement during recall (Experiment 2). In Experiments 3 and 4, the template was moved through the same screen locations during presentation and recall. When the extrinsic, or screen location, of each position was repeated identically on each trial but the sequence on the template varied, learning was not facilitated (Experiment 3). When the template sequences were repeated across trials but extrinsic location varied, the sequences were rapidly learned (Experiment 4). In this version of spatial span, location sequences appear to be encoded in an intrinsic frame of reference that is based on the template. Movement of the template during encoding impairs this process, possibly because concurrent attention shifts prevent the encoding of locations. The results are discussed with respect to recent studies of positional encoding in which multiple reference frames were available.     

Effects of short-term retrieval on adult age differences in long-term recall of actions.

In Experiment 1 young and elderly subjects either recalled or repeated after every block of 4 actions, whereas control subjects received neither interpolated short-term recall nor action repetition. On a later long-term memory test, experimental subjects, regardless of age or condition, recalled slightly more actions than control subjects. In Experiment 2 young adult and elderly subjects received 12 short-term memory trials in which 2 actions were performed on each trial, but only 1 was cued for recall after a brief retention interval filled with a distracting activity. On a later long-term memory test for the actions performed on the short-term trials, both young and elderly subjects recalled significantly more previously cued than noncued actions. The Age X Cuing Condition interaction was negligible. Prior retrieval of actions appears to enhance later recall regardless of age but seemingly only when prior retrieval requires considerable cognitive effort (as in Experiment 2).     

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.     

The influence of acoustic similarity on serial recall of letter sequences

Acoustic similarity is known to impair short-term memory (STM) for letter sequences. The present series of experiments investigated the effects of acoustic similarity on long-term retention. In the first experiment, subjects were asked to learn one of two lists of 8 letters, the letters being either of high or low acoustic similarity. Lists were visually presented for three trials, with subjects responding after each trial. Then subjects participated in an immediate memory task for digits which lasted for 20 min. Finally, subjects tried to recall the list of letters they had learned previously. Lists having items of high acoustic similarity were more difficult to recall on the first trial, but were better recalled on the delayed retention test. In a second experiment, groups of subjects were again asked to learn one of two lists of 8 letters differing in acoustic similarity, using different orders of the letters used previously. The procedures were identical except that in two groups, a STM task for digits intervened between the presentation and test of the letters. This intervening task minimized the effects of STM and eliminated the differences in retention found previously. In a third experiment, better long-term retention for material having high acoustic similarity was also obtained when subjects used a backward recall procedure. In the last experiment 14 item lists were learned to a criterion of two correct trials, and retention was tested after each trial and at a delay of 20 min. and 23 hr. No effect of acoustic similarity was found and little retention loss occurred. These results suggest that reducing the STM component by introducing a STM control or by lengthening the list caused the effect of acoustic similarity to disappear.     

The independence of recall and recognition in motor learning

A basic tenet of both current closed-loop theories of motor learning (Adams, 1971; Schmidt, 1975) is that the generation of response specifications during learning is required for the development of recall memory. Two experiments were performed to test this tenet by attempting to demonstrate the development of recall memory in the absence of response specification production. The task in both experiments required blindfolded subjects to learn to produce a rapid, novel criterion movement on a linear positioning device. Control subjects in both experiments actively produced movements during learning with knowledge of results (KR) while experimental subjects in Experiment 1 experienced only the endpoint locations and in Experiment 2 were passively moved to the endpoint locations. Following initial KR trials, both experimental and control groups attempted to actively produce the criterion movement in the absence of KR. The results of both experiments support closed-loop theory that active practice is required to develop recall memory. There was some suggestion, however, that passive experience with sensory feedback may also aid recall memory development, contrary to the two closed-loop theories.     

Generality of a strength model for three conditions of repeated recall

A Markovian model of repeated recall is presented that is based on four memory processes: (a) a presentation increment that strengthens the memory trace of a word when the word is shown to a subject, (b) a recall increment that strengthens the trace when the subject successfully recalls the word, (c) a cueing decrement that weakens the trace as contextual cues for retrieving a word change over successive trials of attempted recall, and (d) a sampling rule that translates the strength of a memory trace into a probability of recall. Mathematically, the model predicts the relative frequencies of the recall patterns that are defined by sequences of recalls and forgets for individual words over trials. According to the model, the recallability of a word depends on its state, which is a function of (a) whether the word has been recalled for the first time, and if so, then (b) how many consecutive forgets of the word immediately precede the current trial, (c) how many successful recalls of the word have accumulated, and (d) how many previous trials of attempted recall have elapsed. Paradigms that were well described by the model were (a) no reminding, in which words were presented once and then recalled repeatedly without additional presentations; (b) restricted reminding, in which words were presented before each trial of attempted recall up to their first successful recall but not thereafter; and (c) complete reminding, in which all words were presented befor each attempted recall, whether previously recalled or not. Differences in recall among these conditions were explained in terms of differences in values of the model's parameters.     

The effects of verbal labeling on short-term and incidental memory: A cross-cultural and developmental study

Effects of induced verbal labeling on short-term and incidental memory were studied in Yucatan, Mexico. The 208 subjects, evenly divided by sex, were selected from four age groups (7–8, 10–11, 13–15, 20–21 years) from a large public school. Stimuli were cards depicting both animals and objects familiar to all subjects, and were presented over 14 trials. Short-term memory was tested with a probed serial recall task on each trial; incidental memory was tested following the 14 trials. Several results conformed to findings with earlier studies using American subjects: short-term memory improved with age; primacy and recency recall were influenced by both age and labeling; and the typical inverted U-shaped incidental memory function was found. Verbal labeling apparently aided recall by focusing attention on the relevant items, but such overt labeling also impeded the strategy of verbal rehearsal used by older subjects. Cultural factors appeared to play a limited role in the present study; the common element of formal schooling, among both American and Yucatecan subjects, was hypothesized as a possible explanation of such cross-cultural similarities.     

Memory for Constrained and Preselected Movement Location and Distance

These experiments assessed the interrelationship between location and distance cues in the coding of movements. In separate experiments subjects recalled either the terminal location or the distance of constrained (Experiment 1) or preselected (Experiment 2) movements following a 15-sec retention interval. Changes in direction amd amplitude of starting position were used to ascertain whether recall errors were related to these changes. The findings of both experiments indicated that location and distance were recalled with similar accuracy when the starting position was identical for the criterion and recall movement. However, analysis of constant errors when the recall starting position was varied in either direction clearly indicated neither terminal location nor distance are coded independently, and memory for movement is based on an interaction between these cues.     

Different rates of forgetting following study versus test trials

Two experiments investigated recall following two study conditions, (1) repeated test: a study trial followed by multiple recall trials, and (2) repeated study: multiple study trials with no tests. At a retention interval of 5 minutes, repeated study produced a higher level of recall than repeated test. When the retention interval was extended, forgetting was much more rapid in the study condition, with the repeated test manipulation leading to higher recall at an interval of 7 days. We conclude that study and test trials have different effects upon memory, with study trials promoting memory acquisition, and test trials enhancing the retrieval process itself, which protects against subsequent forgetting.     

Different rates of forgetting following study versus test trials

Two experiments investigated recall following two study conditions, (1) repeated test: a study trial followed by multiple recall trials, and (2) repeated study: multiple study trials with no tests. At a retention interval of 5 minutes, repeated study produced a higher level of recall than repeated test. When the retention interval was extended, forgetting was much more rapid in the study condition, with the repeated test manipulation leading to higher recall at an interval of 7 days. We conclude that study and test trials have different effects upon memory, with study trials promoting memory acquisition, and test trials enhancing the retrieval process itself, which protects against subsequent forgetting.     

Learning a list for free recall: Selective reminding versus the standard procedure

Almost all free-recall experiments involve an acquisition phase in which the set of to-be-learned items is presented repeatedly in its entirety. Two experiments are described that pit this standard procedure against theselective reminding procedure (Buschke, 1973), wherein only items incorrect on trial n are presented again on trial n+ 1. The two methods were virtually identical in terms of (1) trials to reach an acquisition criterion of one errorless recall, (2) number of items correct on each recall trial during acquisition, (3) number of items correct on a 3-week delayed-recall test, (4) number of items correctly relearned after the 3-week retention interval, (5) extent of subjective organization on all retention tests, and (6) pattern of errors over all test trials. These results generalized to both single-category and random lists of 20 words, and were thoroughly consistent across the two experiments. However, the standard procedure required that many more items be presented over trials, and more subjects failed to learn the list within 1 h using the standard procedure. Because the selective reminding procedure is more efficient and has no apparent drawbacks, it is recommended that memory researchers switch to selective reminding as the preferred way to teach a subject a free-recall list.     

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.     

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.     

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.     

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.     

Incorporating multiple secondary targets into learning trials for individuals with autism spectrum disorder

The current study examined the outcome of presenting multiple secondary targets in learning trials for individuals with autism spectrum disorder. We compared conditions in which (a) a secondary target was presented in the antecedent and consequence of trials, (b) two secondary targets were presented in the consequence of trials, (c) one secondary target was presented in the consequence of each trial, and (d) no additional targets were presented trials. The participants acquired the majority of secondary targets. Presenting one or multiple secondary targets per trial, regardless of the location of these secondary targets, increased the efficiency of instruction in comparison to a condition with no secondary target.     

Orienting task specificity in incidental motor learning

The manipulation of the retention of a linear movement by means of different orienting tasks in an incidental learning paradigm was investigated. Subjects were presented with a target position followed by a different nontarget position on each of four presentation trials. After the presentation trials subjects were required to recall the target and nontarget positions. One group made verbal estimates of the distance between the target and nontarget positions, another group discriminated between the target and nontarget positions, while no verbal responses were required for a third group. The verbal-response groups, while not differing from each other, had less error at recall than the nonverbalizing group. These findings were discussed in terms of the levels of processing framework for memory research (Craik & Lockhart, 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.     

Attentional requirements for location and distance of movement: encoding and recognition

The purpose of this experiment was to study the early processing stages of encoding and recognition of slow movement in a short-term motor-memory paradigm. These stages were examined by determining whether Laabs' (1973) differential decay rates for location of movement and distance of movement could be replicated when the interfering activity was performed during the criterion and replication movements. 20 subjects performed a linear-positioning task in a 2 X 2 X 2 (count X movement type X retention interval) experimental design. 10 subjects in one condition counted backwards by 3s during the criterion and replication movements. There were no detrimental effects for location and distance-cue reproduction when attention was shared with counting backwards. Like Laabs' results, location of movement was maintained over the 15-sec. interval while distance of movement spontaneously changed. These results supported the notion that the early stages of encoding and recognition of cues for movement can occur unaffected by a secondary task.     

When distractors and to-be-remembered items compete for the control of action: a new perspective on serial memory for spatial information

In serial memory for spatial information, performance is impaired when distractors are interpolated between to-be-remembered (TBR) stimuli (Tremblay, Nicholls, Parmentier, & Jones, 2005). The so-called sandwich effect, combined with the use of eye tracking, served as a tool for examining the role of the oculomotor system in serial memory for spatial information. Participants had to recall the order in which sequences of TBR locations were presented. In some trials, to-be-ignored blue dots were presented after each TBR location. Our results show that response locations shift toward the location of the distractors, and this deviation is related to the eye movement deviation toward the distractor location. These results suggest that TBR and to-be-ignored locations are encoded onto a common map that could lie within the oculomotor system. Interference in memory for spatial information is interpreted in light of a model of oculomotor behavior (Godijn & Theeuwes, 2002b).