Perceptual distinctiveness and proactive interference in the primacy effect

When subjects monitor a list of verbal items for one item which is to be selected and remembered, they are more likely to recall the critical item if it is the first member of the list than if it is presented towards the centre of the list. The present experiment examined the possibility that this primacy results from an accumulation of proactive interference from incidentally processed early members of the list which would cause a decrement in the recall of later members. By changing the semantic category of the list members before presentation of the critical item any accumulated interference would have been released, but this procedure produced no weakening of the primacy effect and so the interference theory of primacy was not supported. An alternative explanation of the effect was discussed in which it is assumed that the first member of a series is perceptually distinct from central members.     

Serial position effects in recall of television commercials

Does the position of a television commercial in a block of commercials determine how well it will be recalled? The findings of naturalistic studies can be affected by uncontrolled presentation, viewing, and retention variables. In the present article, college students viewed lists of 15 commercials in a laboratory simulation and recalled the product brand names. In an immediate test, the first commercials in a list were well recalled (a primacy effect), as were the last items (a recency effect), in comparison with the recall of middle items. In an end-of-session test, the primacy effect persisted, but the recency effect disappeared. Embedding lists within a television program again produced better recall of the first items during end-of-session tests of recall and recognition. These results offered convergent validity for the naturalistic studies of commercial memory, and they supported the usefulness of combining laboratory and field methods to answer questions about everyday memory.     

Retrieval failure, rehearsal deficiency, and short-term memory loss in the aphasic adult

Studies show that aphasic patients typically are grossly impaired in short-term memory performance. Since aphasics generally experience difficulty in word retrieval, it is conceivable that short-term memory loss is partially the result of verbal rehearsal deficiency which, in turn, is caused by the word retrieval problem. This paper reports an experiment in which five aphasic adults were nonverbally to recall individualized lists of pictures they could easily name and lists of pictures they could not name. Final items in the two lists were recalled with equal accuracy; this was expected in that the recency effect usually reflects sensory rather than verbal storage. Initial items were recalled with greater accuracy than middle-list items in the nameable sets but not in the unnameable sets. This primacy effect suggests the aphasics rehearsed the nameable pictures, but both lists were recalled so poorly that rehearsal deficit was considered responsible for no more than a fraction of the aphasics' reduction in short-term memory.     

Perceptual processing in dichotic listening.

Subjects heard two lists of 4 items each presented simultaneously to the two ears at a rate of four pairs of items per sec. A recall cue presented immediately after the test list signalled report of 4 of the 8 items. In recall by spatial location, the cue indicated whether the items on the right ear on left ear should be recalled. In recall by category name, the cue indicated the superset category (e.g., letters or words) of the items to be recalled. Recall by spatial location was not significantly different than recall by category name. This results argues against the idea of a preperceptual auditory storage that holds information along spatial channels for 1 or 2 sec. The final experiment showed that recall by spatial location is significantly better than recall by category name when the report cue is given before, not after, the list presentation. These results show that spatial location can be used to enhance semantic processing and/or memory of 1 of 2 simultaneous items, but only if the relevant location is known at the time of the item presentation.     

Do updating tasks involve updating? Evidence from comparisons with immediate serial recall

Updating tasks require participants to process a sequence of items, varying in length, and afterwards to remember only a fixed number of the elements of the sequence; the assumption being that participants actively update the to-be-recalled list as presentation progresses. However recent evidence has cast doubt on this assumption, and the present study examined the strategies that participants employ in such tasks by comparing the serial position curves found in verbal and visuo-spatial updating tasks with those seen in standard serial recall tasks. These comparisons showed that even when the same number of items are presented or recalled, participants perform less well in an updating than a serial recall context. In addition, while standard serial position effects were observed for serial recall, marked recency and reduced or absent primacy effects were seen in updating conditions. These findings suggest that participants do not typically adopt a strategy of actively updating the memory list in updating tasks, but instead tend to wait passively until the list ends before trying to recall the most recently presented items.     

Do updating tasks involve updating? Evidence from comparisons with immediate serial recall

Updating tasks require participants to process a sequence of items, varying in length, and afterwards to remember only a fixed number of the elements of the sequence; the assumption being that participants actively update the to-be-recalled list as presentation progresses. However recent evidence has cast doubt on this assumption, and the present study examined the strategies that participants employ in such tasks by comparing the serial position curves found in verbal and visuo-spatial updating tasks with those seen in standard serial recall tasks. These comparisons showed that even when the same number of items are presented or recalled, participants perform less well in an updating than a serial recall context. In addition, while standard serial position effects were observed for serial recall, marked recency and reduced or absent primacy effects were seen in updating conditions. These findings suggest that participants do not typically adopt a strategy of actively updating the memory list in updating tasks, but instead tend to wait passively until the list ends before trying to recall the most recently presented items.     

Components of verbal learning in children: Analysis by selective reminding

Free recall verbal learning by 5- and 8-year-old children was analyzed by selectively reminding them only of items not recalled on the preceding trial (instead of continuing to present the entire list before each recall trial) to show learning by retrieval from long-term storage without presentation. Concurrent analysis of long-term storage, consistent and random retrieval from long-term storage, and recall from short-term storage indicates that, while 5-year-olds showed slower acquisition than 8-year-olds, lower recall by 5-year-olds also was due to less effective retrieval from longterm storage. Repeated retrieval, without any further presentation after an item has been recalled just once, indicates that lower recall by 9-year-old children than by adults also reflects retrieval difficulty, since these children showed storage and retention of almost as many items as adults by eventual spontaneous retrieval without further presentation.     

DRM paradigm for people's name lures and effects of delaying conscious thought of the lure at encoding

The experiment was conducted to test whether or not presentation order is an important factor to explain why Critical Lures of people's names are falsely recalled relatively rarely in the Deese-Roediger-McDermott paradigm. For half of the participants, the most highly associated items were presented at the start of the list (Standard condition). For the other half, presentation of the most strongly associated items was delayed until the middle of the list (Delayed condition). This manipulation had no significant effect on the probability of falsely recalled Critical Lures or on that of veridical recall of list items, but in the Delayed condition the mean number of intrusions other than the Critical Lures was higher than that in the Standard condition.     

Suffix effects and probe modality in probed recall: Implications for readout from sensory memory

The effect of a redundant stimulus suffix was investigated in three experiments using a probed recall task. The probe modality was auditory in the first experiment and visual in the second. In the third experiment, both probe modalities were tested. The presentation rate was varied in all three experiments and was confounded with the delay of the suffix. The suffix was found to have a small and approximately equal effect on the last six serial positions. In contrast to the predictions from Crowder and Morton's (1969) PAS model, presentation rate and suffix delay did not interact with the suffix effect. The results indicate that at least six items can be simultaneously represented in PAS, that there is no appreciable decay of information from PAS during presentation of the last list items, and that readout of PAS information does not occur either during list presentation or between the end of list presentation and the beginning of overt report.     

Conditional recall and the frequency effect in the serial recall task: an examination of item-to-item associativity

The frequency effect in short-term serial recall is influenced by the composition of lists. In pure lists, a robust advantage in the recall of high-frequency (HF) words is observed, yet in alternating mixed lists, HF and low-frequency (LF) words are recalled equally well. It has been argued that the preexisting associations between all list items determine a single, global level of supportive activation that assists item recall. Preexisting associations between items are assumed to be a function of language co-occurrence; HF?CHF associations are high, LF?CLF associations are low, and mixed associations are intermediate in activation strength. This account, however, is based on results when alternating lists with equal numbers of HF and LF words were used. It is possible that directional association between adjacent list items is responsible for the recall patterns reported. In the present experiment, the recall of three forms of mixed lists??those with equal numbers of HF and LF items and pure lists??was examined to test the extent to which item-to-item associations are present in serial recall. Furthermore, conditional probabilities were used to examine more closely the evidence for a contribution, since correct-in-position scoring may mask recall that is dependent on the recall of prior items. The results suggest that an item-to-item effect is clearly present for early but not late list items, and they implicate an additional factor, perhaps the availability of resources at output, in the recall of late list items.     

The relationship between memory performance and the number of rehearsals in free recall

The purpose of the present study was to examine the relationship between the number of rehearsals and long-term recall performance by means of an overt rehearsal procedure. Subjects were induced to concentrate their rehearsal activity on specific items in free recall tasks. In Experiment 1, both the primacy and the recency items that had received additional rehearsals were recalled with higher probability than were the ordinarily rehearsed items in immediate recall but not in final recall. Experiment 2 was designed to extend the occasions for subjects’ rehearsal by manipulating the rate of item presentation. The overall pattern of resulting data shewed that for neither recency items nor primacy items does the additional overt rehearsal reliably lead to facilitative effects on long-term recall performance. The possibility of a qualitative change in rehearsal is discussed.     

Output buffer storage and the modality of recall

In two experiments, subjects were presented with two lists of visual items simultaneously, both of which were to be recalled. The order of recall of the lists was manipulated. In Experiment 1, subjects were required to recall one list by speaking it and the other by writing it down. Prior knowledge of the particular mode of output required for each list resulted in significantly higher levels of recall than in a condition in which the output mode for each list was not known until after presentation. This result suggests that there may be at least two modality-specific output buffers. Experiment 2 employed the same method of presentation, but spoken recall of both lists was required. In addition, the priority of the lists was manipulated, and articulatory suppression was required in half of the trials. There was an effect of priority and of recall order, together with an interaction between the two. In contrast to the results of FitzGerald and Broadbent (1985a), however, who carried out a similar experiment but with written recall, articulatory suppression significantly reduced the priority and recall order interaction. It is concluded that there is one form of output buffer storage for written or manual output and one for spoken output.     

The auditory recency advantage in longer term free recall is not enhanced by recalling prerecency items first

Gardiner and Gregg (1979) showed that in a free-recall paradigm in which each list word is embedded in a continuous stream of subject-vocalized distractor activity, recency recall was greater when the words were presented auditorily rather than visually. The experiment described here showed that this auditory advantage persisted even when list and distractor items were both spoken at a controlled pace by the experimenter, and that it was little influenced by instructions to give priority in recall either to the beginning or to the end of the list. These results strengthen the conclusion that this effect cannot be accommodated by any echoic memory theory and, because the effect was not enhanced when prerecency items were recalled first, demonstrate an additional difference between it and the somewhat similar auditory advantage found in immediate recall.     

Presence and absence of serial position effects in short-term memory

The nature of serial position effects was examined with a method based on pooled observations. With standard list presentation procedures, primacy and recency effects in short and long-term memory were observed. When learning operations were directed away from end positions, by changes in presentation rate, by within-list repetitions, by focusing instructions, and by differential grouping of list items, the usual serial position pattern was found to be affected in several ways, primacy and recency effects often being absent. Attempts to create anchor points and to ascribe serial positions verbally, were generally found to favour recency over primacy effects. Taken as a whole, the results, all of them based on recall of lits given a single presentation, indicated that position phenomena are more easily influenced by functional than by structural factors. The findings were explained in terms of a two-stage conception of serial learning, doing without specific storage assumptions.     

Influence of the spacing of trait information on impressions of likability

Five experiments were conducted in which subjects were shown lists of trait adjectives that supposedly described particular individuals. Each list included both positive and negative traits, with all such traits occurring twice. The second occurrence of a trait followed the first either immediately (massed presentation) or after four other traits intervened (distributed presentation). For a given list, all positive traits received massed presentation and all negative traits were distributed, or vice versa. After list presentation, subjects judged how likable the person described would be. In Experiments 1–3 only, there was also a free recall test for the traits. The free recall test revealed both a spacing effect (distributed items being recalled better than massed) and a bias toward recalling negative traits better than positive. Likability judgments paralleled the recall pattern, with the judgments being more positive when positive traits were distributed (and negative massed), than in the opposite arrangement. Correlations calculated between recall and impressions were mostly nonsignificant, however, suggesting that judgments were not based on the recall of specific traits and that inferences formed at encoding were of primary importance.     

The role of overt language production in the Hebb repetition effect

The Hebb repetition effect (Hebb, 1961) occurs when recall performance improves for a list that is repeated during a serial-recall task. This effect is considered a good experimental analogue to language learning. Our objective was to evaluate the role of overt language production in language learning by manipulating recall direction during a Hebb repetition paradigm. In each trial, seven nonsense syllables were presented auditorily. Participants had to orally recall the items either in the presentation order or in reverse order. One sequence was repeated every third trial. In Experiment 1, we compared learning from a group that had recalled the items in their presentation order to learning from a group that had recalled the items in the reverse order. The two groups yielded similar learning rates. In Experiment 2, recall direction was varied between trials. The learning rate was not affected when recall direction varied between trials, suggesting a limited role of overt language production in language learning.     

A recency-based account of the list length effect in free recall

Free recall was examined using the overt rehearsal methodology with lists of 10, 20, and 30 words. The standard list length effects were obtained: As list length increased, there was an increase in the number and a decrease in the proportion of words that were recalled. There were significant primacy and recency effects with all list lengths. However, when the data were replotted in terms of when the words were last rehearsed, recall was characterized by extended recency effects, and the data from the different list lengths were superimposed upon one another. These findings support a recency-based account of episodic memory. The list length effect reflects the facts that unrehearsed words are less recent with longer lists, and that with longer lists, a reduced proportion of primacy and middle items may be rehearsed to later positions.     

Mechanisms of aural encoding: VII. Differences in consonant and vowel recall in a Peterson and Peterson short-term memory paradigm

Ss either saw or heard lists of three syllables which differed by their initial consonant phoneme or their final vowel phoneme. After 5 or 15 sec of mental arithmetic, Ss were required to recall the syllables. Following auditory presentation, vowels were recalled more accurately than consonants in all serial positions and at both delays. In addition, spoken consonants and vowels showed primacy and recency effects. Following visual presentation, consonants and vowels were recalled with equal accuracy at both delays, and no recency effects were observed. These data suggest that superior recall of vowels over consonants results from differential decay of these stimuli in an acoustic storage. These data are consistent with previous experiments showing that, during serial recall, the final vowels in a sequence are recalled more accurately than the final consonants.     

Serial recall of colors: Two models of memory for serial order applied to continuous visual stimuli

This study investigated the effects of serial position and temporal distinctiveness on serial recall of simple visual stimuli. Participants observed lists of five colors presented at varying, unpredictably ordered interitem intervals, and their task was to reproduce the colors in their order of presentation by selecting colors on a continuous-response scale. To control for the possibility of verbal labeling, articulatory suppression was required in one of two experimental sessions. The predictions were derived through simulation from two computational models of serial recall: SIMPLE represents the class of temporal-distinctiveness models, whereas SOB-CS represents event-based models. According to temporal-distinctiveness models, items that are temporally isolated within a list are recalled more accurately than items that are temporally crowded. In contrast, event-based models assume that the time intervals between items do not affect recall performance per se, although free time following an item can improve memory for that item because of extended time for the encoding. The experimental and the simulated data were fit to an interference measurement model to measure the tendency to confuse items with other items nearby on the list—the locality constraint—in people as well as in the models. The continuous-reproduction performance showed a pronounced primacy effect with no recency, as well as some evidence for transpositions obeying the locality constraint. Though not entirely conclusive, this evidence favors event-based models over a role for temporal distinctiveness. There was also a strong detrimental effect of articulatory suppression, suggesting that verbal codes can be used to support serial-order memory of simple visual stimuli.     

Separating central mechanisms by POCs: Evidence for an input—output buffer

Four experiments were performed, in each of which two sub-lists of items were presented for later recall, with varying priorities for success on each of the lists. All showed a trade-off, indicating that at some point the two lists were using the same mechanisms. In the two cases where presentation was simultaneous, however, the effects of priority interacted with those of recall order—that is, the items recalled first showed a larger effect of priority than did those recalled second. In the two cases where one sub-list arrived after the other, the low-priority items gave just as large an effect of recall order as the high-priority items. The second list presented did, however, show a larger effect of recall order than the first list presented. It is argued that the systems shared between two sublists involve some representations that are not disturbed by output, as well as an input—output buffer. The latter can hold a little extra information temporarily, but is disturbed by output; for successive lists it is dedicated largely to the most recently received list, but for simultaneous lists it is shared between the two lists in proportion to priority.