The repeated letter effect in the misspellings

The study consisted of a comparison of the spontaneous misspellings of a dysgraphic (L. H. Oswald) with the ease of perception and recall of similar misspellings by normal Ss. The main results were as follows: (1) Oswald frequently misspelled repeated letters in words (e.g., ELDERY). Similarly, normal Ss found repeated-letter misspellings more difficult to perceive and recall than nonrepeated-letter misspellings. (2) Oswald frequently misspelled repeated letters which were close together as in ANLYZE (for ANALYZE), but he rarely misspelled widely separated repeated letters as in MISSPELLNG. Similarly, normal Ss found repeated-letter misspellings hardest to perceive and recall when the repeated letters were close together, and very easy when they were widely separated. (3) Oswald misspelled the second of two repeated letters (as in ELDERY) more frequently than the first (as in EDERLY). Similarly, normal Ss found repeated-letter misspellings easier to perceive and recall when the first of the repeated letters was misspelled, as in EDERLY, than when the second was misspelled. (4) Oswald sometimes repeated a letter on his own, as in HABITITUATED—but more frequently he dropped a repeated letter as in ELDERY. However, repeated-letter misspellings involving deleted letters were easier for the normal Ss to recall than those involving deletions. Evidence suggesting that repeated phonemes induce analogous errors in normal speech production was discussed, and implications for general models of the serial order of speech behavior were pointed out.     

Developing the theory of working memory

The theory of working memory was devised to explain the effects of a concurrent memory load in various experimental situations in terms of the operation of a central executive processor and a phonemic response buffer. It also explains the effects of phonemic similarity, articulatory suppression, word length, and unattended speech. Experiment 1 demonstrated that a concurrent memory load markedly reduced the phonemic similarity effect in immediate serial recall, which was taken to support the concept of a limited-capacity phonemic response buffer. A more detailed analysis of the results suggested that a concurrent memory load may affect the storage capacity of the central executive processor and the translation of orthographic stimuli into phonological representations, as well as the storage capacity of the phonemic response buffer. Experiment 2 showed that a concurrent free-recall task reduced the phonemic similarity effect in immediate serial recall, but only in the case of visually presented sequences of items. Moreover, unattended speech was found to have no effect upon performance in immediate free recall. These results were taken to imply that the phonemic response buffer contributes only to performance in cognitive tasks that require the accurate retention of serial-order information.     

Total retrieval time and hypermnesia: Investigating the benefits of multiple recall tests

Hypermnesia is an increase in recall over repeated tests. A core issue is the role of repeated testing, per se, versus total retrieval time. Prior research implies an equivalence between multiple recall tests and a single test of equal total duration, but theoretical analyses indicate otherwise. Three experiments investigated this issue using various study materials (unrelated word lists, related word lists, and a short story). In the first experimental session, the study phase was followed by a series of short recall tests or by a single, long test of equal total duration. Two days later, participants took a final recall test. The multiple and single test conditions produced equivalent performance in the first session, but the multiple test group exhibited less forgetting and fewer item losses in the final test. In a fourth experiment, using a brief delay (15 min) between the recall sessions, the multiple recall condition produced greater hypermnesia as well as fewer item losses. In addition, final recall was significantly higher in the multiple than in the single test condition in three of the four experiments. Thus, single and repeated recall tests of equal total duration are not functionally equivalent, but rather produce differences observable in subsequent recall tests.     

From A to Z? Retrieval-induced forgetting of non-verbal information indicates how writing systems can shape memory organisation

We investigated retrieval-induced forgetting of motor sequences in samples of Chinese participants. Retrieval-induced forgetting occurs when selective retrieval of a subset of information stored in memory causes forgetting for the non-retrieved rest. This phenomenon critically depends on the organised storage of separate categories of memory representations. In studies with participants from a Western culture (Germany), a categorization in left- and right-hand movements previously had been supported by letter stimuli based on a spatial mental representation of the Roman alphabet. The same assignment of letters from the beginning or end of the alphabet to motor sequences performed either with the left- or the right-hand did not entail retrieval-induced forgetting in the present study, however (Experiment 1). In Experiment 2, visual features of displaying to-be-learned sequences additionally supported a distinction into left and right. In Experiment 3, learning trials provided verbal category labels. The occurrence of retrieval-induced forgetting in the latter two experiments suggests language-dependent organisation of non-verbal items in memory.     

Processing sets of letters for order: Evidence from reaction time experiments

In two experiments, subjects were required to impose different levels of organization on randomly ordered letters. In a between-subject design, the subject was to identify the letter in the set coming first in the alphabet or to reorganize the set into an alphabetic sequence. In a within-subject design, presentation of the letters was followed by an instruction to carry out the identification or reorganization task or to recite the letters in left-to-right order. Reaction time varied systematically with level of required organization, size of the presented set, and position and spacing of the letter set in the alphabet. The results are discussed in terms of two simple models.     

Effects of repeated retrieval of central and peripheral details in complex emotional slides

Research has demonstrated that repeated retrieval enhances memory for practised verbal information, but undermines correct recall of unpractised related verbal information, a phenomenon known as retrieval-induced forgetting (RIF). This paper addresses the question of what happens with memory for unrehearsed aspects of an emotional picture when retrieval of other aspects of that picture is practised. In two experiments we investigated whether repeated retrieval of certain details of negative emotional slides undermines recall of unrehearsed details of such slides. In Experiment 1 retrieval of peripheral details was practised. The results demonstrated that recall for peripheral details was enhanced. However, correct recall of unpractised central details remained unaffected. Furthermore, retrieval practice did not alter the number of commission errors. Experiment 2 revealed that repeated retrieval of central details enhanced memory for these details. Although more commission errors were produced, again correct recall was not impaired for the unrehearsed central and peripheral details. This failure to find retrieval-induced forgetting effects for complex visual material is at odds with the RIF literature, and potential reasons for this are discussed. The data also extend previous studies in demonstrating that extensive retrieval can increase the number of commission errors.     

Evidence for graded central processing resources in a sequential movement task

In the present experiment, we examined slowing of the individual key presses of a familiar keying sequence by four different versions of a concurrent tone counting task. This was done to determine whether the same cognitive processor that has previously been assumed by the dual processor model (DPM) to initiate familiar keying sequences and assist in their execution, is involved also in the central processes of a very different task (viz. identifying tones and counting target tones). The present results confirm this hypothesis. They also suggest that in this particular situation the central processing resources underlying the cognitive processor can be distributed across the central processes of different tasks in a graded manner, rather than that they continue to behave like a single, central processor that serially switches between the central processes of the concurrently performed tasks. We argue that the production of highly practiced movement sequences can be considered automatic in the sense that execution of familiar movement sequences can continue without cognitive control once they have been initiated.     

The origin of the interaction between learning method and delay in the testing effect: The roles of processing and conceptual retrieval organization

Recent research has demonstrated a relationship between retrieval organization and the efficacy of prior repeated retrieval on delayed tests. The present study asked why repeated study engenders higher recall at a short delay despite lower retrieval organization but produces a decline at a long delay, and why repeated retrieval engenders lower recall at a short delay despite higher retrieval organization but produces stable recall over time. This relationship was examined through the inclusion of two successive recall tests—one immediately after learning method and one a week later. Results replicated the interaction in recall between learning method and delay characterizing the testing effect and, critically, revealed the qualitative differences inherent in the retrieval organization of each method. Specifically, stable recall in repeated retrieval was accompanied by strong and sustained conceptual organization, whereas organization for repeated study was tenuous and weakened across tests. These differences quantitatively were assessed through the use of five targeted analyses: specifically, the examination of cumulative recall curves, the accumulation of organization across time (a curve akin to cumulative recall), item gains and losses across time, changes in the size of categories across time, and the fate of specific clusters of recalled items across time. These differences are discussed within the context of differential processes occurring during learning method.     

Adult counting is resource demanding

Several recent studies on both the development of counting and working‐memory span tasks have provided results that could be interpreted as ruling out any cognitive resource model for counting. The aim of this study was to test the hypothesis that, even in adults, counting is a demanding task that requires the allocation of cognitive resources. In a first experiment, we asked adults to count arrays of dots while maintaining 5 items in memory (either digits or letters). As we predicted, the concurrent memory load did not increase the rate of errors but induced longer counting times. In a second experiment, we asked adults to count using either the numeric chain or the alphabet while they maintained 1, 3 or 5 items in memory (digits or letters). First, we replicated the load effect observed in Experiment 1. Second, though both types of counting required similar amounts of time, counting with the less automatized chain (i.e. the alphabet) resulted in a poorer recall performance. Finally, this detrimental effect in recall was all the more pronounced the greater the number of items to be recalled. These results are interpreted within theoretical frameworks that consider cognitive resources as attentional capacities.     

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.     

Very rapid forgetting: Reply to Muter

We reply to the commentary in which Muter (1995) disputes the findings and arguments of Cunningham, Healy, Till, Fendrich, and Dimitry (1993) concerning the rate of forgetting from primary memory. Although Muter (1980) had reported very rapid forgetting when secondary memory processes were minimized, Cunningham et al. found that the rate of forgetting from primary memory was no more rapid when secondary memory processes were minimal than it was when secondary memory processes were substantial. We locate the discrepancy between the two studies specifically at recall performance on the 0-sec retention interval, and we argue that the very rapid forgetting found by Muter (1980) can be attributed in large part to the fact that although subjects in his experiments did not expect to recall the letters after a filled retention interval, at the time of encoding and after an unfilled delay they did have a high overall expectancy to recall the letters.     

Forgetting motor programmes: Retrieval dynamics in procedural memory

When motor sequences are stored in memory in a categorised manner, selective retrieval of some sequences can induce forgetting of the non-retrieved sequences. We show that such retrieval-induced forgetting (RIF) occurs not only in cued recall but also in a test assessing memory indirectly by providing novel test cues without involving recall of items. Participants learned several sequential finger movements (SFMs), each consisting of the movement of two fingers of either the left or the right hand. Subsequently, they performed retrieval practice on half of the sequences of one hand. A final task then required participants to enter letter dyads. A subset of these dyads corresponded to the previously learned sequences. RIF was present in the response times during the entering of the dyads. The finding of RIF in the slowed-down execution of motor programmes overlapping with initially trained motor sequences suggests that inhibition resolved interference between procedural representations of the acquired motor sequences of one hand during retrieval practice.     

Concatenating familiar movement sequences: the versatile cognitive processor

Earlier studies demonstrated that practicing a series of key presses in a fixed order yields memory representations (i.e., motor chunks) that can be selected and used for sequence execution as if familiar key pressing sequences are single responses. In order to examine whether these motor chunks are robust in different situations and whether preparation for one sequence may overlap with execution of another one, two experiments were carried out in which participants executed two highly practiced keying sequences in rapid succession in response to two simultaneously presented stimuli. The results confirmed robustness of motor chunks, even when the sequences included only two elements, and showed that preparation (and in particular, selection) of a forthcoming sequence may occur during execution of the earlier sequence. Sequences including only two keys appeared to be slowed more by concurrent preparation than longer sequences. Together these results suggest that the execution of familiar keying sequences is predominantly carried out by a dedicated motor processor, and that the cognitive processor can be allocated to preparing a forthcoming sequence (e.g., during execution of an earlier sequence) or, some times, to selecting individual sequence elements in parallel to the motor processor.     

Levels of processing in speech perception

Four experiments are reported investigating previous findings that speech perception interferes with concurrent verbal memory but difficult nonverbal perceptual tasks do not, to any great degree. The forgetting produced by processing noisy speech could not be attributed to task difficulty, since equally difficult nonspeech tasks did not produce forgetting, and the extent of forgetting produced by speech could be manipulated independently of task difficulty. The forgetting could not be attributed to similarity between memory material and speech stimuli, since clear speech, analyzed in a simple and probably acoustically mediated discrimination task, produced little forgetting. The forgetting could not be attributed to a combination of similarity and difficutly since a very easy speech task involving clear speech produced as much forgetting as noisy speech tasks, as long as overt reproduction of the stimuli was required. By assuming that noisy speech and overtly reproduced speech are processed at a phonetic level but that clear, repetitive speech can be processed at a purely acoustic level, the forgetting produced by speech perception could be entirely attributed to the level at which the speech was processed. In a final experiment, results were obtained which suggest that if prior set induces processing of noisy and clear speech at comparable levels, the difference between the effects of noisy speech processing and clear speech processing on concurrent memory is completely eliminated.     

Effects of tactual and phonological similarity on the recall of Braille letters by blind children.

Forty-eight severly blind children, able to cope with set-sizes of two and three, four, five or six serial items were tested on probed recall of Braille letters they could either name or discriminate, when the letters were (1) dissimilar in tactual characteristics and name sounds, (2) similar in feel, but different in name sound, and (3) dissimilar in feel but similar in name sound. Results showed that tactual similarity produced recall decrements by subjects able to be tested under set-sizes of up to five items, while phonological similarity produced recall decrements by subjects testable under set-sizes of five and six items. It was argued that tactual information survives perception and affects recall, and that blind children can encode tactual inputs either tactually or verbally, but that this probably depends upon different processes.     

Short-term memory and the nature of interference from concurrent shadowing

Trigrams were presented visually or auditorily and followed by a 12 s retention interval filled with shadowing numbers or letters. Auditory memory letters followed by letter shadowing were recalled less than auditory memory letters followed by number shadowing or visual memory letters followed by either type of shadowing. The latter three conditions did not differ among themselves. An analysis of the recall intrusions suggested that forgetting of auditory memory letters followed by letter shadowing was caused mainly by a confusion between covert rehearsals and shadowing activity, while forgetting in the other three conditions was caused primarily by proactive interference from earlier memory trials.     

Directed forgetting in working memory: Age‐related differences

This study explored the effects of ageing on working memory by means of the directed forgetting procedure designed by Reed (1970). Memory for a letter trigram was compared in conditions where it was either presented alone (single‐item), or followed by a second trigram to be recalled (interference), or followed by a second trigram to be forgotten (directed forgetting). The results clearly indicated that elderly participants inhibited the no‐longer‐relevant information less efficiently (recall in the single‐item condition – recall in the directed forgetting condition), as predicted by the model of Hasher and Zacks (1988). However, the results also demonstrated that sensitivity to interference (recall in the single‐item condition – recall in the interference condition) increased in the condition in which no inhibition was directly required.     

Do two separate speech measures constrain verbal short-term memory in children?

Previous research has indicated that 2 processing rates may constrain verbal short-term memory performance. These have been linked to individual differences in (a) the time taken to articulate spoken words and (b) the duration of pauses that occur between words in the output responses to memory tasks. Two experiments examined whether evidence for these effects on memory can be obtained for measures taken from a single speech sample. Children articulated pairs of words as rapidly as possible. In both experiments, the spoken duration of words and the length of the pauses between them predicted significant variance in verbal short-term memory performance. It is argued that the duration of words is linked to memory performance through the processes underlying time-based forgetting in short-term memory. In contrast, the duration of pauses in speeded articulation may index individual differences in speech planning processes.     

ALPHABET LETTERS AS TOKENS: TRAINING PRESCHOOL CHILDREN IN LETTER RECOGNITION AND LABELLING DURING A TOKEN EXCHANGE PERIOD1

In token economies, we typically consider the instructional opportunities available during the periods of token delivery, but may overlook educational opportunities available at the time of token exchange. The present studies examined the use of labelled tokens and routines in the token exchange period to teach alphabet letter recognition to economically disadvantaged preschool children. The children earned points for a variety of academic behaviors in an early morning classroom setting. At no time were alphabet letters introduced or taught during class. Later, during a midmorning token exchange period, operated according to a department store model, the children were given their points in the form of poker chips inscribed with upper-case alphabet letters. They were required to discriminate among these lettered chips before exchanging them for backup reinforcers sold in four or five stores. To assess alphabet letter knowledge, probe evaluations were periodically conducted in which questions requiring alphabet letter recognition and labelling were asked. The answers to these questions were not reinforced. Alphabet letter training during token exchange periods consisted of having a child display the lettered chips, whereupon a teacher asked a number of recognition-type questions. Wrong answers were corrected, and correct answers praised. The child was allowed to exchange the tokens when the number required for a purchase had been recognized correctly. The periodic probe evaluations revealed consistent increases in correct alphabet letter recognition and, as a byproduct, alphabet labelling was facilitated, even though not explicitly trained. Thus, once the letters were recognized, correct labelling shortly followed. The sequential training of new sets of letters was used to demonstrate experimental control within subjects for two children. A control for exposure to the letters was provided by using the labelled tokens, but requiring the counting of chips rather than letter discrimination in the exchange period for two other children. This procedure produced chance levels of letter recognition, which were subsequently improved when the discrimination procedure was added. Posttraining probes, conducted at one and three weeks after training when the labelled tokens and discrimination routines were no longer in use, revealed the same high levels of recognition and labelling performance found during training. Thus, it appears that labelled tokens may be used to teach discriminations during token exchange periods so long as responses are differentiated on the basis of relevant dimensions of the stimuli.