Executive processing in free recall of categorized lists

The present study examines the cognitive processes that operate in free recall of categorized lists by manipulating semantic structure of the lists and using a dual task methodology to restrict the processes that make demands on limited-capacity resources, the central executive resources. Relying on the assumption that, in free recall of categorized lists, the search for category names is a strategic controlled process that demands executive resources, lists with different numbers of categories ranging from 2 to 6 were employed. The results showed an effect of a secondary task on retrieval in the 4- and the 6-category list conditions, but not in the 2-category list condition. In contrast to retrieval, the secondary task interference at encoding produced an effect on recall of all three types of lists. An interesting finding was that an effect on clustering was found only when interference was present at encoding, not when it was at retrieval. This finding was in line with the suggestion (Troyer, Moscovitch, Winocur, Alexander, & Stuss, 1998) that switching (shifting between different category items) rather than clustering is related to executive functioning, and suggested that clustering may be a measure of two different types of processing: (1) executive processing at encoding and (2) automatic processing at retrieval. In addition, a different pattern of results was obtained when low frequency category words were used, indicating that the frequency of category words is an important determinant in free recall of categorized lists. Overall, the present results support the two-process account of retrieval of category words (Rosen & Engle, 1997) and the view that there are fundamental differences between encoding and retrieval processes (Naveh-Benjamin, Craik, Guez, & Dori, 1998; Naveh-Benjamin & Guez, 2000).     

Retrieval strategies in recall of natural categories and categorized lists

Experiments 1 and 2 examined the effect of retrieval strategies on 3 or 12 min of recall from a natural category. Experiment 3 examined the effect of strategy on 6 min of recall from a subset of a category presented as a list. In Experiments 1 and 2, a large recall deficit was produced by retrieval strategies involving recall in alphabetic order and by size of the words' referents, relative to free recall. In Experiment 3, four strategies, alphabetic, size, serial order, and free recall, gave similar levels of recall after 6 min, though the growth rate of the cumulative output functions differed among the strategies. An extension of the search of associative memory (SAM) model of Raaijmakers and Shiffrin was developed to explain these results; the new model postulates attention sharing among probe cues and the use of idiosyncratic strategies for free recall from natural categories.     

Rehearsal and retrieval processes in free recall of categorized lists

The relationships between rehearsal and subsequent retrieval characteristics were examined in the context of free recall of categorized lists. The results indicated a direct correspondence between the frequency of rehearsal and the order and speed of retrieval within categories. The same relationship obtained for the categories themselves. It was suggested that both retrieval time and order effects can be predicted in terms of the organization of input processing and the resultant repetition frequency of categories and exemplars.     

Dissociating early- and late-selection processes in recall: The mixed blessing of categorized study lists

Two experiments are reported in which we used type-2 signal detection theory to separate the effects of semantic categorization on early- and late-selection processes in free and cued recall. In Experiment 1, participants studied cue–target pairs for which the targets belonged to two, six, or 24 semantic categories, and later the participants were required to recall the targets either with (cued recall) or without (free recall) the studied cues. A confidence rating and a report decision were also required, so that we could compute both forced-report quantity and metacognitive resolution (type-2 discrimination), which served as our estimates of early- and late-selection processes, respectively. Consistent with prior research, having fewer categories enhanced the early-selection process (in performance, two > six > 24 categories). However, in contrast, the late-selection process was impaired (24 > six = two categories). In Experiment 2, encoding of paired associates, for which the targets belonged to either two or 20 semantic categories, was manipulated by having participants either form interactive images or engage in rote repetition. Having fewer categories again was associated with enhanced early selection (two > 20 categories); this effect was greater for rote repetition than for interactive imagery, and greater for free recall than for cued recall. However, late selection again showed the opposite pattern (20 > two categories), even with interactive-imagery encoding, which formed distinctive, individuated memory traces. The results are discussed in terms of early- and late-selection processes in retrieval, as well as overt versus covert recognition.     

Spacing and lag effects in free recall of pure lists

Repeating list items leads to better recall when the repetitions are separated by several unique items than when they are presented successively; thespacing effect refers to improved recall for spaced versus successive repetition (lag > 0 vs. lag = 0); thelag effect refers to improved recall for long lags versus short lags. Previous demonstrations of the lag effect have utilized lists containing a mixture of items with varying degrees of spacing. Because differential rehearsal of items in mixed lists may exaggerate any effects of spacing, it is important to demonstrate these effects in pure lists. As in Toppino and Schneider (1999), we found an overall advantage for recall of spaced lists. We further report the first demonstration of a lag effect in pure lists, with significantly better recall for lists with widely spaced repetitions than for those with moderately spaced repetitions.     

The effects of noise on recall of lists of associated words

An experiment investigated the effect of noise on recall of lists consisting of pairs of strong and weak associates. Noise improved recall (both number recalled and organization of recall) and did so with both types of list. The subjects who were initially tested in noise continued to show better recall and organization of recall even when they were transferred to the quiet condition. This finding shows that noise may reinforce the use of the dominant strategy and that this strategy may be used more in noise when experimental conditions are changed and even when the subject is transferred from the noise to the quiet. This research was supported by a grant from the Social Science Research Council.     

The effects of mediated word lists on false recall and recognition

False memory effects were explored using unrelated list items (e.g., slope, reindeer, corn) that were related to mediators (e.g., ski, sleigh, flake) that all converged upon a single nonpresented critical item (CI; e.g., snow). In Experiment 1, participants completed either an initial recall test or arithmetic problems after study, followed by a final recognition test. Participants did not falsely recall CIs on the initial test; however, false alarms to CIs did occur in recognition, but only following an initial recall test. In Experiment 2, participants were instructed to guess the CI, followed by a recognition test. The results replicated Experiment 1, with an increase in CI false alarms. Experiment 3 controlled for item effects by replacing unrelated recognition items from Experiment 1 with both CIs and list items from nonpresented lists. Once again, CI false alarms were found when controlling for lexical characteristics, demonstrating that mediated false memory is not due simply to item differences.     

Strategies in the recall of clusterable lists

The present study assessed the effectiveness of a multi-session training aproach intended to teach mildly retarded adolescents to discover and utilize categorical list structure. The performance of a group of trained retarded individuals was compared with that of another group of retarded individuals who had simply received practice with the training materials. The performance of both retarded groups was evaluated relative to that of a group of equivalent-CA normal adolescents. Recall transfer with a new word list was indicated by the finding that trained retarded subjects achieved a criterion of perfect recall in fewer trials than untrained retarded subjects. Differences in the use of categorization strategies by normal and retarded subjects were interpreted in the light of the automatic-controlled processing distinction of Schneider and Shiffrin (1977).     

Immediate serial recall of mixed-modality lists

Seven experiments are reported in which subjects were tested for immediate serial recall of mixed-modality lists. On mixed auditory-visual lists, there was an advantage for auditory items at all serial positions. This was due to both a facilitation of auditory items and an inhibition of visual items on mixed lists, as compared with single-modality lists. When presented on a list containing items read silently, recall of items that were silently mouthed by the subject demonstrated patterns similar to those found with auditory items. When presented on a list containing items read aloud, recall of mouthed items showed patterns similar to those found with silently read items. The auditory advantage on mixed lists was found even when the list items were acoustically similar or identical and was not reduced by midlist auditory suffixes. The results suggest that modality differences in recall of mixed-modality lists are based on information different from that responsible for modality differences in recall of single-modality lists.     

Memory for actions: Item and relational information in categorized lists

Enacting action phrases in subject-performed tasks (SPTs) leads to better free recall than hearing or reading the same materials in verbal tasks (VTs). This enactment effect is usually explained by better item-specific information in SPTs than in VTs. The role of relational information is controversial. In the present paper, we will take the multiple recall approach to study the role of item and relational information in memory for actions by computing the number of item gains and the number of item losses over trials. This approach has previously been applied to lists of unrelated action phrases. We applied it to categorically related lists, also allowing a measure of relational information by clustering scores. It was found that SPTs produced more item gains than VTs. This finding confirmed the assumption that SPTs provide better item-specific information than VTs. The number of item losses did not differ between VTs and SPTs. This finding suggests that relational information is equally provided by VTs and SPTs. However, the organizational scores showed a more differentiated picture. Clustering was greater in SPTs than in VTs with randomly presented lists, but not with blocked lists. We suggested that these results, as well as other findings from the literature, could be explained by distinguishing automatic and strategic processes and the types of item associations that are addressed by these processes.     

Developmental aspects of categorized recall in a West African Society

Studies are reported among West African populations on the relationship between preferred mode of organization of categorizable material and use of organization in recall. Various child and adult groups differed in the types of organization they imposed on the material in a sorting task, with those exposed to school and modernizing influences showing a preference for taxonomic organization. All subjects, however, used their own form of organization to order their subsequent recall of the material, supporting the idea that organizing processes in recall are universal.     

Associative asymmetry in probed recall of serial lists

For pairs of meaningful items (e.g., words), recall accuracy is nearly identical for forward and backward probes. That is, after studying an A-B pair, subjects can recall A given B as well as they can recall B given A (Kahana, 2002). To assess whether this symmetry property is unique to pairs, we investigated the effects of study direction on probed recall of word triples and serial lists. Two experiments revealed a forward-recall advantage in both triples and serial lists. In addition, compound cues produced better recall than did single-item adjacent cues, which, in turn, produced better recall than did remote cues. These findings suggest a discontinuity between the associative processes supporting memory for pairs and those supporting memory for sequences of three or more items.     

Context effects in short-term memory: confirmatory evidence from recall of visually presented lists

Thirty-two subjects had tests of serial recall of visually presented nine-digit lists which were either presented in a single block of trials (constant context) or in between lists of much longer length (variable context). Other variables were vocalization-during-presentation versus silent memorization (within subject) and order of recall (between subjects). The results showed a negative effect of variable context on the penultimate serial positions in the case of silent memorization but not in the case of vocalization. Context had no effect on the first and middle parts of the list, which confirms earlier results with auditorily presented lists (Bunt 1976), but which disagrees with the original evidence from Crowder (1969). Subjects preferred forward recall in the case of silent memorization and echobox recall in the case of vocalization during presentation, irrespective of context.

The results are discussed within the framework of the notion of precategorical acoustic storage (PAS) and of positional retrieval cues. The latter theory seems to provide a better and more comprehensive account.     

Negative transfer in children's recall of categorized materials

A negative transfer paradigm was used to assess kindergarten, third-, and sixth-grade (approximately 5, 9, and 12 years old) children's use of category relations in lists presented for recall. Negative transfer effects increased with age, with kindergarten children showing no evidence of interference relative to a control group.     

On the nature of talker variability effects on recall of spoken word lists.

In a recent study, Martin, Mullennix, Pisoni, and Summers (1989) reported that subjects' accuracy in recalling lists of spoken words was better for words in early list positions when the words were spoken by a single talker than when they were spoken by multiple talkers. The present study was conducted to examine the nature of these effects in further detail. Accuracy of serial-ordered recall was examined for lists of words spoken by either a single talker or by multiple talkers. Half the lists contained easily recognizable words, and half contained more difficult words, according to a combined metric of word frequency, lexical neighborhood density, and neighborhood frequency. Rate of presentation was manipulated to assess the effects of both variables on rehearsal and perceptual encoding. A strong interaction was obtained between talker variability and rate of presentation. Recall of multiple-talker lists was affected much more than single-talker lists by changes in presentation rate. At slow presentation rates, words in early serial positions produced by multiple talkers were actually recalled more accurately than words produced by a single talker. No interaction was observed for word confusability and rate of presentation. The data provide support for the proposal that talker variability affects the accuracy of recall of spoken words not only by increasing the processing demands for early perceptual encoding of the words, but also by affecting the efficiency of the rehearsal process itself.     

Coding processes in the free recall of associated word lists

An experiment is reported on the free recall of lists of 18 words. The lists consisted of words that were strongly or weakly associated to the eliciting stimulus, were members of either a single category or more than one category and were arranged into sets of three associated words or six associated words. Each list was presented once only and free recall required after a filled interval of 18 s. One half of the subjects were provided with cues at recall: the remainder were given no assistance. Recall efficiency increased with association level and with restricted category membership of the words in a set. Clustering at recall (when adjusted for opportunity) was greater in the 6×3 lists than in the 3×6 lists. The provision of cues only led to a significant facilitation in recall with lists consisting of 6 sets of 3 words. A detailed analysis of the recall data suggested the importance of the category membership variable in the production of the later recall.     

Serial recall of two-voice lists: Implications for theories of auditory recency and suffix effects

Substantial recency effects are found in immediate serial recall of auditory items. These recency effects are greatly reduced when an irrelevant auditory stimulus (a stimulus suffix) is presented. A number of accounts that have been proposed to explain these phenomena assume that auditory items are susceptible to masking or overwriting in memory. Later items overwrite earlier items, leading to an advantage for the last item, unless it is masked by a suffix. This assumption is called into question by evidence that presenting list items in two voices has no beneficial effect in immediate serial recall. In addition, it is shown that suffix effects on both terminal and preterminal list items are influenced by the physical similarity of the suffix to the terminal item and not by the physical similarity of the suffix to preterminal items.     

Free recall and retrieval speed of categorized items by kindergarten children

Kindergarten Ss were presented with 16 pictorial items in four category sets or a partially random ordem with one item from each category composing the four presentation sets. The pictures were presented either on conceptually related background pictures or on white backgrounds. The categorically grouped presentation facilitated free recall performance, both in terms of number of items recalled and the speed with which the items were recalled, and increased the amount of clustering in recall. Categorical clustering in recall was associated with shorter within- than between-category intervals and for those Ss who recalled items from each of four categories successively, the over-all temporal pattern in recall closely approximated that found with adults. No background effects were found.     

The effects of divided attention at study and test on false recognition: A comparison of DRM and categorized lists

Three experiments investigated the effects of divided attention at encoding and retrieval on false recognition. In Experiment 1, participants studied word lists in either full or divided attention (random number generation) conditions and then took part in a recognition test with full attention. In Experiment 2, after studying word lists with full attention, participants carried out a recognition test with either full or divided attention. Experiment 3 manipulated attention at both study and test. We also compared Deese/Roediger-McDermott (DRM) and categorized lists, due to recent claims regarding the locus of false memories produced by such lists (Smith, Gerkens, Pierce, & Choi, 2002). With both list types, false "remember" responses were reduced by divided attention at encoding and increased by divided attention at retrieval. The findings suggest that the production of false memories occurs as a result of the generation of associates at encoding and failures of source monitoring retrieval. Crucially, this is true for both DRM and categorized lists.