Serial position effects in recognition memory for odors: A reexamination

Seven experiments examined recognition memory for sequentially presented odors. Following Reed (2000), participants were presented with a sequence of odors and then required to identify an odor from the sequence in a test probe comprising 2 odors. The pattern of results obtained by Reed (2000, although statistically marginal) demonstrated enhanced recognition for odors presented at the start (primacy) and end (recency) of the sequence: a result that we failed to replicate in any of the experiments reported here. Experiments 1 and 3 were designed to replicate Reed (2000), employing five-item and seven-item sequences, respectively, and each demonstrated significant recency, with evidence of primacy in Experiment 3 only. Experiment 2 replicated Experiment 1, with reduced interstimulus intervals, and produced a null effect of serial position. The ease with which the odors could be verbally labeled was manipulated in Experiments 4 and 5. Nameable odors produced a null effect of serial position (Experiment 4), and hard-to-name odors produced a pronounced recency effect (Experiment 5); nevertheless, overall rates of recognition were remarkably similar for the two experiments at around 70%. Articulatory suppression reduced recognition accuracy (Experiment 6), but recency was again present in the absence of primacy. Odor recognition performance was immune to the effects of an interleaved odor (Experiment 7), and, again, both primacy and recency effects were absent. There was no evidence of olfactory fatigue: Recognition accuracy improved across trials (Experiment 1). It is argued that the results of the experiments reported here are generally consistent with that body of work employing hard-to-name visual stimuli, where recency is obtained in the absence of primacy when the retention interval is short.     

Is there a modality effect? Evidence for visual recency and suffix effects

In Experiment 1, four groups of 16 subjects performed ordered recall of six-syllable lists in both suffix and nonsuffix conditions. Sequential presentation of the lists varied for each group. In the auditory presentation, the syllables were delivered from one location only and were read aloud by the subjects. For the visual, spatially nondistributed presentation, the syllables appeared in one location only and were read silently. For visual, spatially distributed presentations, the syllables were spread out either vertically or horizontally and were read silently. Very robust recency and suffix effects were found in the auditory presentation, as well as in visual, spatially distributed presentations. In Experiment 2, 16 subjects performed ordered recall of visually presented lists with the items spread out vertically and conflicting spatial and temporal orders. A reliable recency effect was found for the final block of trials. In Experiment 3, 16 subjects performed ordered recall in the same conditions as in Experiment 2, except that they were instructed to recall the temporal order in which the spatial positions would be filled in. A bow-shaped curve and a strong recency effect were obtained.     

Enhanced recency effects with changing-state and primary-linguistic stimuli

A number of explanations for the modality effect in immediate serial recall have been proposed. The auditory advantage for recall of recency items has been explained in terms of (1) the contributions of precategorical acoustic storage (PAS), (2) an advantage of changing-state over static stimuli, and (3) an advantage of primary-linguistic coding. Four experiments were conducted to evaluate these hypotheses. In the first, subjects viewed seven consecutive rectangles of different colors on a computer monitor. A small recency effect was obtained when the task was to recall the colors of the rectangles in order, with the size of the effect being independent of whether the rectangles remained stationary on the screen or moved in one of four directions. However, when the task was to recall the direction of movement of the rectangles, a larger recency effect was found. This pattern of results was interpreted as suggesting that recency effects are enhanced by changing-state stimulus information, but only when the changing-state information serves to identify the stimulus. Experiments 2 and 3 provided converging evidence by demonstrating an analogous recency advantage for changing-state visual stimuli that were somewhat different from those of Experiment 1. Experiment 4 demonstrated recency effects with synthesized speech stimuli that were substantially greater than were those found with the changing-state visual stimuli of the first three experiments. Implications of the results for the PAS, changing-state, and primary-linguistic hypotheses, as well as temporal-distinctiveness theories of recency, are discussed.     

Influence of recall procedures on the modality effect with numbers and enumerated stimuli

Experiment 1 extended J. S. Nairne and W. L. McNabb's (1985) counting procedure for presenting numerical stimuli to examine the modality effect. The present authors presented participants with dots and beeps and instructed participants to count the items to derive to-be-remembered numbers. In addition, the authors presented numbers as visual and auditory symbols, and participants recalled items by using free-serial written recall. Experiment 1 demonstrated primacy effects, recency effects, and modality effects for visual and auditory symbols and for counts of dots and beeps. Experiment 2 replicated the procedure in Experiment 1 using strict-serial written recall instead of free-serial written recall. The authors demonstrated primacy and recency effects across all 4 presentation conditions and found a modality effect for numbers that the authors presented as symbols. However, the authors found no modality effect when they presented numbers as counts of beeps and dots. The authors discuss the implications of the results in terms of methods for testing modality effects.     

Auditory recency in immediate memory

Six experiments investigated the locus of the recency effect in immediate serial recall. Previous research has shown much larger recency for speech as compared to non-speech sounds. We compared two hypotheses: (1) speech sounds are processed differently from non-speech sounds (e.g. Liberman & Mattingly, 1985); and (2) speech sounds are more familiar and more discriminable than non-speech sounds (e.g. Nairne, 1988, 1990). In Experiments 1 and 2 we determined that merely varying the label given to the sets of stimuli (speech or non-speech) had no effect on recency or overall recall. We varied the familiarity of the stimuli by using highly trained musicians as subjects (Experiments 3 and 4) and by instructing subjects to attend to an unpracticed dimension of speech (Experiment 6). Discriminability was manipulated by varying the acoustic complexity of the stimuli (Experiments 3, 5, and 6) or the pitch distance between the stimuli (Experiment 4). Although manipulations of discriminability and familiarity affected overall level of recall greatly, in no case did discriminability or familiarity alone significantly enhance recency. What seems to make a difference in the occurrence of convincing recency is whether the items being remembered are undegraded speech sounds.     

Comparisons of memory for nonverbal auditory and visual sequential stimuli

Properties of auditory and visual sensory memory were compared by examining subjects' recognition performance of randomly generated binary auditory sequential frequency patterns and binary visual sequential color patterns within a forced-choice paradigm. Experiment 1 demonstrated serial-position effects in auditory and visual modalities consisting of both primacy and recency effects. Experiment 2 found that retention of auditory and visual information was remarkably similar when assessed across a 10 s interval. Experiments 3 and 4, taken together, showed that the recency effect in sensory memory is affected more by the type of response required (recognition vs. reproduction) than by the sensory modality employed. These studies suggest that auditory and visual sensory memory stores for nonverbal stimuli share similar properties with respect to serial-position effects and persistence over time.     

Recency and the modality effect in immediate ordered recall

In immediate ordered recall, recency is the improved recall of the last item of a presentation, and the modality effect is the advantage for an acoustic presentation over a subvocalized visual presentation, primarily occurring at the last serial position. Experiment 1 tested grouped presentations. There was a modality effect for the first item of the last group, even though that item was at the third-to-last or fourth-to-last serial position. In Experiment 2, for vocalized presentations of syllables ending in a, recency was larger for staccato speech than legato speech; for subvocalized presentations, there was a substantial recency for the legato style. In Experiment 3, recency was larger for a set of syllables ending in ATE than for a set of syllables ending in AME. These results suggest that recency cannot be explained by the existence of a fixed-capacity store, auxiliary to the auditory short-term store, that retains only some types of presentations. It is suggested instead that recency might reflect an auxiliary method of using the information in the auditory short-term store.     

A recency-based account of the primacy effect in free recall

Seven experiments investigated the role of rehearsal in free recall to determine whether accounts of recency effects based on the ratio rule could be extended to provide an account of primacy effects based on the number, distribution, and recency of the rehearsals of the study items. Primacy items were rehearsed more often and further toward the end of the list than middle items, particularly with a slow presentation rate (Experiment 1) and with high-frequency words (Experiment 2). Recency, but not primacy, was reduced by a filled delay (Experiment 3), although significant recency survived a filled retention interval when a fixed-rehearsal strategy was used (Experiment 4). Experimenter-presented schedules of rehearsals resulted in similar serial position curves to those observed with participant-generated rehearsals (Experiment 5) and were used to confirm the main findings in Experiments 6 and 7.     

Conditions for positive and negative recencies in running memory-span recognition

A positive recency effect in a running-span recognition procedure was obtained in Experiment 1 for hits and for intratrial false alarms. In running recall procedures, recency does not fit well with an active updating hypothesis. In Experiment 2, in which the beginning of the target set was marked with a cue upon presentation, the recency effects disappeared. In Experiments 3 and 4 participants were forced to maintain 2 items in memory until the last one was presented for recognition. These three items were the target set. When the last item presentation was uncertain—because of the variable length list—an unexpected negative recency effect appeared. An explanation for this change from positive to negative recency is offered based on the sharing of attentional resources put forward by others for similar procedures.     

Serial position effects in 2-alternative forced choice recognition: Functional equivalence across visual and auditory modalities

Two experiments examined Ward, Avons, and Melling's (2005) proposition that the serial position function is task, rather than modality, dependent. Specifically, they proposed that for backward testing the 2-alternative forced-choice (2AFC) recognition paradigm is characterised by single-item recency irrespective of the modality of the stimulus presentation. In Experiment 1 the same nonword sequences, presented both visually or auditorily, produced qualitatively equivalent serial position functions with 2AFC testing. Forward testing produced a flat serial position function, while backward testing produced two-item recency in the absence of primacy. In order to rule out the possibility that the serial position functions for visual stimuli were the product of sub-vocal rehearsal, Experiment 2 employed articulatory suppression during the presentation phase. Serial position function equivalence was again observed together with a modest impairment in overall recognition rates. Taken together, these data are consistent with the Ward et al. proposition and further support the existence of a visual memory that can facilitate storage of visual-verbal material (e.g. Logie, Della Sella, Wynn, & Baddeley, 2000). However, the observation of two-item recency contradicts the original duplex account of single-item recency traditionally observed for backwards recognition testing of visual stimuli (Phillips & Christie, 1977).     

Recency and suffix effects with immediate recall of olfactory stimuli

In contrast to our understanding of the immediate recall of auditory and visual material, little is known about the corresponding characteristics of short-term olfactory memory. The current study investigated the pattern of immediate serial recall and the associated suffix effect using olfactory stimuli. Subjects were trained initially to identify and name correctly nine different odours. Experiment 1 established an immediate correct recall span of approximately six items. In Experiment 2 participants recalled serially span equivalent lists which were followed by a visual, auditory, or olfactory suffix. Primacy was evident in the recall curves for all three suffix conditions. Recency, in contrast, was evident in the auditory and visual suffix conditions only; there was a strong suffix effect in the olfactory suffix condition. Experiment 3 replicated this pattern of effects using seven-item lists, and demonstrated that the magnitude of the recency and suffix effects obtained in the olfactory modality can equate to that obtained in the auditory modality. It is concluded that the pattern of recency and suffix effects in the olfactory modality is reliable, and poses difficulties for those theories that rely on the presence of a primary linguistic code, sound, or changing state as determinants of these effects in serial recall.     

Visual working memory in young children

Five experiments investigated immediate memory for drawings of familiar objects in children of different ages. The aims were to demonstrate younger children’s greater dependence on visual working memory and to explore the nature of this memory system. Experiment 1 showed that visual similarity of drawings impaired recall in young (5-year-old) children but not in older (10-year-old) children. Experiment 2 showed that younger and older children were affected in contrasting ways when the temporal order of recall was manipulated. Experiment 3 explored a recency effect found in backward recall and investigated its sensitivity to the presentation modality of materials used to produce retroactive interference (RI). For younger children, recency was reduced by visual but not by auditory-verbal RI; for older children, recency was more sensitive to auditoryverbal RI. Experiment 4 confirmed the effect of visual RI on visual recency in young children and showed that the same RI had little effect on their recall of spoken words. These results confirm younger children’s dependence on visual working memory. A final experiment showed that the effects of visual similarity and visual RI are additive, suggesting that they reflect different modes of accessing stored visuospatial information. Implications of these findings for developmental issues and for the nature of visual working memory are discussed.     

The word-length effect in probed and serial recall

The word-length effect in immediate serial recall has been explained as the possible consequence of rehearsal processes or of output processes. In the first experiment adult subjects heard lists of five long or short words while engaging in articulatory suppression during presentation. Full serial recall or probed recall for a single item followed the list either immediately or after a 5-second delay to encourage rehearsal. The word-length effect was not influenced by recall delay, but was much smaller in probed than in serial recall. Examination of the serial position curves suggested that this might be due to a recency component operating in probed recall. Experiment 2 confirmed a word-length-insensitive recency effect in probed recall and showed that this was resistant to an auditory suffix, unlike the small recency effect found in serial recall. Experiment 3 used visual presentation without concurrent articulation. Under these conditions there was no recency effect for either recall method, but the word-length effect was again much smaller in probed than in serial recall. This was confirmed in Experiment 4, in which the presentation of serial and probed recall was randomized across trials, showing that the differences between recall methods could not be due to encoding strategies. We conclude that for visual presentation, at least part of the word-length effect originates in output processes. For auditory presentation the position is less clear, as serial and probed recall appear to draw on different resources. The nature of the output processes that may give rise to word-length effects is discussed.     

Serial position effects in short-term visual memory: A SIMPLE explanation?

A version of Sternberg's (1966) short-term visual memory recognition paradigm with pictures of unfamiliar faces as stimuli was used in three experiments to assess the applicability of the distinctiveness-based SIMPLE model proposed by Brown, Neath, and Chater (2002). Initial simulations indicated that the amount of recency predicted increased as the parameter measuring the psychological distinctiveness of the stimulus material (c) increased and that the amount of primacy was dependent on the extent of proactive interference from previously presented stimuli. The data from Experiment 1, in which memory lists of four and five faces varying in visual similarity were used, confirmed the predicted extended recency effect. However, changes in visual similarity were not found to produce changes in c. In Experiments 2 and 3, the conditions that influence the magnitude of c were explored. These revealed that both the familiarity of the stimulus class before testing and changes in familiarity, due to perceptual learning, influenced distinctiveness, as indexed by the parameter c. Overall, the empirical data from all three experiments were well fit by SIMPLE.     

Attenuating the visual suffix effect with color

In previous studies using a short-duration visual presentation (200-340 msec), presentation of a different colored suffix did not attenuate the visual suffix effect. In Experiment 1, color attenuated the suffix effect for a longer duration visual presentation (approximately 3-4 sec) during which the subject engaged in articulatory suppression to prevent auditory recoding. Experiments 2 and 3 confirmed that color does not attenuate the suffix effect for the short-duration presentations. In Experiment 4, recall of a long-duration presentation was not improved when the last digit was a different color, suggesting that the different color of the suffix improves recall by allowing the suffix to be excluded from visual short-term memory. The attenuation by color is consistent with the hypothesis that preattentive grouping governs the entry of information into visual short-term memory.     

前分类声音存储器对声调和情绪韵律的加工

采用系列位置回忆任务, 探讨作为声调语言的汉语普通话中声调及情绪信息是否具有近因及后缀效应, 从而揭示同为超音段信息的声调和情绪韵律在前分类声音存储器(Precategorical Acoustic Storage, PAS)中是否具有单独的表征, 及该表征可能受到哪些因素的影响。实验一和二分别考察了声调是否具有近因和后缀效应, 实验三和四分别考察了情绪信息是否具有近因和后缀效应。实验结果发现两者均在PAS存储器中有单独的表征, 但这种表征会受到一些因素的影响, 且受影响的方式不一样。研究结果表明作为超音段信息的声调和情绪信息在表征上的不稳定性和脆弱性, 及在短时记忆加工过程中的特殊性。     

Recency and suffix effects with immediate recall of olfactory stimuli

In contrast to our understanding of the immediate recall of auditory and visual material, little is known about the corresponding characteristics of short-term olfactory memory. The current study investigated the pattern of immediate serial recall and the associated suffix effect using olfactory stimuli. Subjects were trained initially to identify and name correctly nine different odours. Experiment 1 established an immediate correct recall span of approximately six items. In Experiment 2 participants recalled serially span equivalent lists which were followed by a visual, auditory, or olfactory suffix. Primacy was evident in the recall curves for all three suffix conditions. Recency, in contrast, was evident in the auditory and visual suffix conditions only; there was a strong suffix effect in the olfactory suffix condition. Experiment 3 replicated this pattern of effects using seven-item lists, and demonstrated that the magnitude of the recency and suffix effects obtained in the olfactory modality can equate to that obtained in the auditory modality. It is concluded that the pattern of recency and suffix effects in the olfactory modality is reliable, and poses difficulties for those theories that rely on the presence of a primary linguistic code, sound, or changing state as determinants of these effects in serial recall.     

Echoic memory and voice quality: Recency recall is not enhanced by varying presentation voice

Three experiments explored the effects on immediate recall of varying voice of presentation. Experiment 1 showed that the free-recall recency effect was not enhanced by presenting list words alternately in a male and a female voice. Experiment 2 replicated this result and also showed that recall of a given recency item from such a list was no more probable when the subjects were informed immediately following presentation that they need not recall the words presented in the other voice. Experiment 3 replicated previous findings of a reduction in the “suffix effect” when presentation voice is changed for the suffix item. The relation of this result to those of Experiments 1 and 2 is discussed.     

Recency effects in delayed recall of mouthed stimuli

Auditory presentation leads to greater recency effects in recall than does visual presentation. This phenomenon (the modality effect) is found in both free and serial recall and in both immediate and delayed recall. Silent mouthing of visually presented stimuli also leads to enhanced recency effects in immediate serial recall. Two experiments reported here extend the generality of the mouthing effect by demonstrating that enhanced recency effects of mouthed stimuli occur in delayed serial and free recall. These results are inconsistent with theories that attribute the modality effect to a purely auditory sensory memory.     

On estimating the difference limen in duration discrimination tasks: a comparison of the 2AFC and the reminder task

This article assesses whether the two-alternative forced-choice (2AFC) and the reminder tasks (i.e., method of constant stimuli) yield identical estimates of the difference limen (DL). In a series of six experiments, participants discriminated between two duration stimuli. Experiments 1-5 employed auditory stimuli, and Experiment 6 employed visual stimuli. Experiments 1 and 2 combined each of the two tasks with an adaptive and a nonadaptive procedure for threshold estimation. Experiment 3 varied the distribution of the comparison levels, whereas Experiment 4 employed random interstimulus intervals. Experiments 5 and 6 examined the influence of the presentation order of the standard and comparison stimuli. Results indicate that both the adaptive and the nonadaptive procedures yield virtually identical DL estimates; yet, the 2AFC task produces consistently larger DLs than does the reminder task. In addition, DL increases when the standard occurs in the second rather than in the first stimulus position. In order to account for these results, we assume that participants use an internal standard instead of the actually presented standard as a reference for their judgment.