Testing the limits of the phonetic mnemonic system

Three experiments tested the efficacy of the phonetic mnemonic system under varying conditions of application. The first study attempted unsuccessfully to replicate and extend the work of Morris and Greer (1984), who had shown training in the phonetic mnemonic method to facilitate memorization of a serial list of two-digit numbers. In the present study, subjects trained in the phonetic mnemonic method failed to learn lists of two-, four-, and six-digit numbers better than control subjects. The second experiment partially replicated the first, the differences being that training in the phonetic mnemonic method was strengthened, and time allotted for number recall was extended. Under these circumstances the phonetic mnemonic group recalled the two-, four-, and six-digit numbers significantly better than the control groups, a finding conforming with Morris and Greer's (1984) results. The third experiment partially replicated the second, everything being the same except that, in this case, subjects constructed their own key words representing each number, instead of these words being supplied by the experimenter. Under these conditions, subjects trained in the phonetic mnemonic method recalled significantly fewer numbers than control subjects.     

“P300” and memory: Individual differences in the von Restorff effect

Event-related brain potentials (ERPs) were elicited by words in a free recall paradigm that included a novel item. The P300 component of the ERP is elicited by novel, task-relevant events, and we tested the hypothesis that P300 is a manifestation of the cognitive processing invoked during “context updating.” If the degree to which current representations in working memory need revision is related to P300 amplitude, then the P300 elicited by a given item should be related to the ability to recall that item on a subsequent test. Forty lists were presented to 12 subjects in each of two sessions. The lists were 15 words long, and 1 word, in position 6 through 10, was “isolated” by changing its size. Most subjects recalled these isolated words more often than other words in the same positions (von Restorff effect), and these words also elicited larger P300s than other words. Analysis of variance on the component scores from a principal components analysis revealed that words recalled had a larger amplitude P300 (on initial presentation) than words not recalled. Striking individual differences emerged, and there were strong relationships between the von Restorff effect, overall recall performance, mnemonic strategies, and the association between components of the ERP and recall performance. The overall recall performance of subjects who reported simple (rote) mnemonic strategies was low, but they showed a high von Restorff effect. For these subjects the amplitude of the P300 elicited by words during initial presentation predicted later recall. In contrast, subjects who reported complex mnemonic strategies remembered a high percentage of words and did not show a von Restorff effect. For these subjects P300 did not predict later recall, although a later “slow wave” component of the ERP did. The initial response to isolated items was the same for all subjects (a large P300), and all subjects recognized the isolates faster than other words in a recognition test given at the end of each session. The subjects in whom P300 did not predict recall reported mnemonic strategies that involved organizing the material. These strategies continue long after the time period reflected by P300 (600 msec). Because they were so effective they may have overshadowed the relationship between P300 and recall, which is based on the initial encoding of an event. Our interpretations were further confirmed and clarified from data obtained in a final grand recall and in the recognition test.     

Short-term recall by deaf signers of American Sign Language: implications of encoding strategy for order recall

Two experiments were conducted on short-term recall of printed English words by deaf signers of American Sign Language (ASL). Compared with hearing subjects, deaf subjects recalled significantly fewer words when ordered recall of words was required, but not when free recall was required. Deaf subjects tended to use a speech-based code in probed recall for order, and the greater the reliance on a speech-based code, the more accurate the recall. These results are consistent with the hypothesis that a speech-based code facilitates the retention of order information.     

The importance of the keyword-generation method in keyword mnemonics

Keyword mnemonics is under certain conditions an effective approach for learning foreign-language vocabulary. It appears to be effective for words with high image vividness but not for words with low image vividness. In this study, two experiments were performed to assess the efficacy of a new keyword-generation procedure (peer generation). In Experiment 1, a sample of 363 high-school students was randomly into four groups. The subjects were required to learn L1 equivalents of a list of 16 Latin words (8 with high image vividness, 8 with low image vividness), using a) the rote method, or the keyword method with b) keywords and images generated and supplied by the experimenter, c) keywords and images generated by themselves, or d) keywords and images previously generated by peers (i.e., subjects with similar sociodemographic characteristics). Recall was tested immediately and one week later. For high-vivideness words, recall was significantly better in the keyword groups than the rote method group. For low-vividness words, learning method had no significant effect. Experiment 2 was basically identical, except that the word lists comprised 32 words (16 high-vividness, 16 low-vividness). In this experiment, the peer-generated-keyword group showed significantly better recall of high-vividness words than the rote method groups and the subject generated keyword group; again, however, learning method had no significant effect on recall of low-vividness words.     

Short-term memory coding by deaf signers: the primary language coding hypothesis reconsidered

Shand (Cognitive Psychology, 1982, 14, 1-12) hypothesized that strong reliance on a phonetic code by hearing individuals in short-term memory situations reflects their primary language experience. As support for this proposal, Shand reported an experiment in which deaf signers' recall of lists of printed English words was poorer when the American Sign Language translations of those words were structurally similar than when they were structurally unrelated. He interpreted this result as evidence that the deaf subjects were recoding the printed words into sign, reflecting their primary language experience. This primary language interpretation is challenged in the present article first by an experiment in which a group of hearing subjects showed a similar recall pattern on Shand's lists of words, and second by a review of the literature on short-term memory studies with deaf subjects. The literature survey reveals that whether or not deaf signers recode into sign depends on a variety of task and subject factors, and that, contrary to the primary language hypothesis, deaf signers may recode into a phonetic code in short-term recall.     

Recall of order information by deaf signers: Phonetic coding in temporal order recall

To examine the claim that phonetic coding plays a special role in temporal order recall, deaf and hearing college students were tested on their recall of temporal and spatial order information at two delay intervals. The deaf subjects were all native signers of American Sign Language. The results indicated that both the deaf and hearing subjects used phonetic coding in short-term temporal recall, and visual coding in spatial recall. There was no evidence of manual or visual coding among either the hearing or the deaf subjects in the temporal order recall task. The use of phonetic coding for temporal recall is consistent with the hypothesis that recall of temporal order information is facilitated by a phonetic code.     

The attentional demands of mnemonic control processes

In order to assess the processing (i.e., attentional) demands of different control processes, subjects were required to perform a secondary choice reaction time task in addition to primary verbal tasks. The performance of the secondary task yielded a measure termedexpended processing capacity (EPC), which was used to infer the attentional demands of the primary tasks. Two factors, mediator type (experimenter-supplied vs. subject-generated) and intentionality (incidental vs. intentional), were varied in a paired-associate situation in an effort to affect the degree of elaboration processing. Only mediator type had an effect on recall accuracy and on EPC during both initial processing and recall. Subject-generated mediators resulted in higher recall and in higher EPC during initial processing, but in lower EPC during recall, than did experimenter-supplied mediators. Implications of these findings are discussed.     

A developmental study of facilitation by mnemonic instruction

First- and fourth-grade children, as well as adults, were given mnemonic instructions to image or to verbalize a sentence in order to study either a sentence or a noun pair provided aurally. Uninstructed control subjects also were included at each age level. A test of cued recall evaluated the amount of facilitation by mnemonic instruction in each of the groups. Both types of instruction enhanced children's memory, most notably when verbal pairs served as stimuli. However, whereas first graders under imagery instruction were inferior on pairs relative to sentence stimuli, fourth graders and adults recalled the two stimulus types equivalently. Also, whereas first graders performed at the same level on sentences and pairs under the verbalization instruction, fourth graders were superior on the pairs. These results indicate that greater requirements for subject-generated mediation to some degree penalized the younger subjects and benefited the older ones.     

Depth of phonological recoding in short-term memory

In testing the hypothesis that surface phonetic form is included in short-term memory (STM) representation, the tone sandhi phenomenon in Mandarin Chinese was exploited, and, as a prerequisite, the hypothesis that tonal similarity affects STM of verbal material in a tone language was also tested. In Experiment 1, subjects recalled visually presented sequences of seven monosyllabic Chinese morphemes having either the same tone or different tones. More errors were made on the monotonal sequences than on the multitonal sequences, confirming the effect of tonal similarity on STM. In Experiment 2, subjects recalled visually presented sequences of disyllabic nonsense words. The sequences were designed in such a way that half of them were subject to the tone sandhi rule in Mandarin Chinese, whereas the other half were not. The consequence of applying the tone sandhi rule, as designed, was to make all the first characters in the sequences identical in pronunciation, thus creating potential phonological confusion. More errors, indeed, occurred on the sequences subject to the tone sandhi rule than on those not subject to it, indicating the existence of a surface phonetic representation in STM. The findings in this study provide further insight into the phonological mechanism of STM. Different accounts for this mechanism are also discussed in the light of the new findings.     

Implicit processing in the cued recall of young and old adults.

Two cued recall experiments were reported in which younger and older subjects studied target words varying in number of preexperimental associates. In Experiment 1, targets were studied in either the absence or presence of meaning-related context cues, with recall always prompted by the cues. In the absence of context, words with smaller sets of associates were easier to recall than those with larger sets, but this effect was reduced for older subjects. The presence of a study context cue facilitated recall and eliminated the effect of associative set size for both ages. In Experiment 2, targets were studied and tested in the presence of unrelated words. In this situation, words with smaller sets of associates were less likely to be recalled than words with larger sets; again the effect was reduced for older subjects. The results are interpreted as an age decrement in processing implicitly activated information.     

Efficacy of the keyword mnemonic method in adults

Two experiments were used to assess the efficacy of the keyword mnemonic method in adults. In Experiment 1, immediate and delayed recall (at a one-day interval) were assessed by comparing the results obtained by a group of adults using the keyword mnemonic method in contrast to a group using the repetition method. The mean age of the sample under study was 59.35 years. Subjects were required to learn a list of 16 words translated from Latin into Spanish. Participants who used keyword mnemonics that had been devised by other experimental participants of the same characteristics, obtained significantly higher immediate and delayed recall scores than participants in the repetition method. In Experiment 2, other participants had to learn a list of 24 Latin words translated into Spanish by using the keyword mnemonic method reinforced with pictures. Immediate and delayed recall were significantly greater in the keyword mnemonic method group than in the repetition method group.     

Generalizing everyday memory: Signs and handedness

Memory for frequently encountered road signs was investigated. In Experiment 1, the average level of recall of road sign features was found to be only 47%. In Experiment 2, more left-handed than righthanded people recalled that a walking figure faces right on one sign, whereas more right-handed than left-handed people recalled that a digging figure faces left on another sign. Performance thus reflected not a difference in level of mnemonic ability between left-handed and right-handed groups but instead the compatibility between group and task. In Experiment 3, participants were asked to draw any figure walking and any figure digging, with a pattern of results similar to that of Experiment 2. It is suggested that handedness effects in recall are mediated by motor imagery.     

Memory in educable mentally retarded adults: Deficit in subject or experimenter?

Educable mentally retarded (EMR) and nonretarded adults free recalled lists of (a) words, (b) minitasks performed by the subjects (SPTs), (c) minitasks performed by the experimenter (EPTs), or (d) task instructions. The EMR subjects were significantly inferior to the nonretarded subjects in the immediate recall of words, EPTs and instructions, but not in the immediate recall of SPTs. This proficiency of the EMR subjects in SPT recall was attributed to the nonstrategic nature of this test. The EMR subjects were, however, inferior to the nonretarded subjects in a final free recall (recall of all lists) of all four types of item.     

Memory for sentences: The subject superiority effect

Three experiments are reported on subject noun superiority in cued recall from S-V-O sentences. In Experiment I surface subjects were superior cues across a wide variety of conditions when the order of nouns/pronouns was matched in sentences and probes. The effect was less clear-cut in Experiment II, when cues and responses were confined to single key words.

The final experiment showed that cue superiority depends on the cue which subjects learn to use in retrieving information from sentences, and can be reversed by brief training. Several other aspects of the results, including a contrast in recall and recognition patterns, suggest that subject cue superiority results from the way subjects process remembered sentences rather than from memory trace structure. It is suggested that failure to control the utilisation of cues for memory retrieval may account for the sometimes elusive nature of the subject superiority effect.     

Eye movements under different rehearsal strategies.

Eye movements were recorded while subjects studied lists of simultaneously presented words. The 24 subjects in the storage group studied for immediate recall, and the 24 subjects in the coding group studied primarily for a later, final recall. Those subjects in the coding group had longer eye fixations and fewer regressions than did subjects in the storage group. In addition, the subjects in the coding group recalled fewer words in immediate recall and more words in final recall than did the subjects in the storage group. These results were interpreted as supporting the elaboration hypothesis of coding in rehearsal, which states that coding into long-term store consists of rehearsing both old and new information in short-term store. The results did not support the concentration hypothesis, which states that coding into long-term store consists of intensively rehearsing a smaller number of items than rehearsed under a storage strategy. The eye movement data also indicate that subjects read about twice as many words as they overtly rehearse.     

False memory for associated word lists in individuals and collaborating groups

Using the Deese/Roediger-McDermott (DRM) paradigm, we investigated recall of presented and nonpresented associated words by collaborating groups, nominal groups, and individuals. In Experiment 1, participants recalled individually and then recalled in collaborating groups. Nominal groups made up of individual recall produced more presented and nonpresented associated words than did collaborating groups. Collaborating groups recalled more presented words than did individuals, but not more nonpresented words. In Experiment 2, collaborating groups versus individuals was a between-subjects variable, and everyone made two recall attempts. For recall, the pattern was the same as that in Experiment 1, in that collaborating groups recalled more presented words than did individuals but about the same number of nonpresented words. In a DRM paradigm, collaborating groups were able to produce more presented words than were individuals, without increasing their false recall.     

The availability explanation of excessive plausibility assessments

The assessment of hypotheses in hypothesis generation involves a comparison between those hypotheses that have been generated (specified) and those that are not generated (unspecified). Experiment 1 was an investigation of an “availability explanation” for subjects' overconfidence in the probability of specified hypotheses. The conjecture is that subjects have difficulty retrieving unspecified hypotheses from memory. Therefore, the underpopulated set of unspecified hypotheses is assessed as less probable then it actually is and the specified set is assessed as more probable. Two manipulations to increase the availability of unspecified hypotheses were investigated. One involved explicitly requesting subjects to populate the unspecified set; the other was a computer presentation of candidate unspecified hypotheses. Results of experiment 1 were that assessment overconfidence for both experimental groups was reduced. The results support the conjecture that the availability heuristic is at least partially responsible for subjects' overconfidence. The main result of experiment 2 was that the overconfidence bias persisted with different assessment methods for both subject-generated and experimenter-supplied hypotheses.     

Does collaborative remembering reduce false memories?

Collaborative remembering refers to recall by groups rather than by an individual. Three experiments investigated whether, relative to individual remembering, collaborative remembering decreased correct recall and false recall using the Deese‐Roediger‐McDermott paradigm. Participants were first asked to study and recall five lists of 15 words that were each semantically associated with a critical non‐presented word. Half the participants recalled the words by themselves, while the remaining half were assigned to pairs and collaboratively recalled the words. In Experiment 1, pairs produced the same number of false or correct words as individuals who were tested alone. In Experiment 2, the interpersonal closeness of the groups was also manipulated: friends and pairs who were not friends were assigned to the collaborative groups. Both friends and non‐friends produced fewer false or correct words than individuals. Experiment 3, in which the performance of the individuals and non‐friend pairs were compared using a recall test of the same 75 words as the previous experiments, replicated the results of Experiment 2. These results are discussed in terms of the retrieval‐strategy disruption.     

Novices,Apprentices, and Mnemonists: Acquiring Expertise with the Phonetic Mnemonic

Three kinds of participants can be identified in research with the phonetic mnemonic—novices, apprentices, and mnemonists, and most research has involved novices. Two experiments investigated whether ordinary college students using the phonetic mnemonic could duplicate two feats of Luria's memorist identified as S: memorizing a 20-digit matrix in 40 seconds, and memorizing a 50-digit matrix in 3 minutes. Experiment 1 was a large-n study in which novices were provided with phonetic keywords along with the matrices; nearly half of the students successfully memorized each matrix with no errors in recall. Experiment 2 was a small-n study in which apprentices were not given the keywords with the matrices; three of the four students also successfully memorized each matrix with perfect recall. The results suggest that ordinary college students are capable of acquiring a level of skilled memory that rivals the abilities that appear to be innate or idiosyncratic in memorists and mnemonists, and that additional research with mnemonic apprentices might be beneficial. © 1997 by John Wiley & Sons, Ltd.