Recency, immediate recognition memory, and reaction time

Four classes of possible mechanisms for short-term item recognition are distinguished: (I) pure list-search, (II) direct-access activation (or trace strength) discrimination, (III) mixtures (of I and II), and (IV) response-association. Manipulations of recency, particularly of negative probe items, provide critical tests between them. Two experiments are reported using Sternberg' s 1966 varied-set reaction time paradigm, coupled with procedures intended to minimize rehearsal and control the recency of probes and memory set items. RT and error rate were greater for negative probe items that had recently been presented than for items less recently presented, and this effect increased with positive set size. In contrast, positive RT was, except for the initial item, a decreasing function of recency (= serial position), and there was no additional effect of set size per se. A brief filled delay between list and probe increased positive RT but not the slope of the set size function. These and other findings appear to reject models of Classes I and IV and, while implying some direct discrimination of an item's recency, require modification of the models of Classes II and III. The implications are discussed with respect to the relation between the two versions of Sternberg's paradigm and also in connection with facilitatory “priming” effects in memory.     

Writing and overwriting short-term memory

An integrative account of short-term memory is based on data from pigeons trained to report the majority color in a sequence of lights. Performance showed strong recency effects, was invariant over changes in the interstimulus interval, and improved with increases in the intertrial interval. A compound model of binomial variance around geometrically decreasing memory described the data; a logit transformation rendered it isomorphic with other memory models. The model was generalized for variance in the parameters, where it was shown that averaging exponential and power functions from individuals or items with different decay rates generates new functions that are hyperbolic in time and in log time, respectively. The compound model provides a unified treatment of both the accrual and the dissipation of memory and is consistent with data from various experiments, including thechoose-short bias in delayed recall, multielement stimuli, and Rubin and Wenzel’s (1996) meta-analyses of forgetting.     

The strength-based mirror effect in subjective strength ratings: The evidence for differentiation can be produced without differentiation

Criss (Cognitive Psychology 59:297?C319, 2009) reported that subjective ratings of memory strength showed a mirror effect pattern in which strengthening the studied words increased ratings for targets and decreased ratings for lures. She interpreted the effect on lure items as evidence for differentiation, a process whereby lures produce a poorer match to strong than to weak memory traces. However, she also noted that participants might use different mappings between memory evidence and levels of the rating scale when they expected strong versus weak targets; that is, the effect might be produced by decision processes rather than differentiation. We report two experiments designed to distinguish these accounts. Some participants studied pure lists of weak or strong items (presented once or five times, respectively), while others studied mixed lists of half weak and half strong items. The participants from both groups had pure-strength tests: Only strong or only weak items were tested, and the participants were informed of which it would be before the test. The results showed that strength ratings for lures were lower when strong versus weak targets were tested, regardless of whether the study list was pure or mixed. In the mixed-study condition, the effect was produced even after identical study lists, and thus the same degree of differentiation in the studied traces. Therefore, our results suggest that the strength-rating mirror effect is produced by changes in decision processes.     

Judgments of frequency and recency: how they relate to reports of subjective awareness.

In 2 experiments, the author explored the relations of remember versus familiar ratings to judgments of frequency (JOFs) and to judgments of recency (JORs). In both cases, remembered items were associated with more accurate memory judgments. In general, familiar items were judged to have occurred less frequently and less recently than remembered items. However, JOFs and JORs associated with familiar items were more accurate than chance. Implications for theories of remember versus familiar ratings, JOFs, and JORs are considered. Some basic findings that constrain these theories are that (a) remember versus familiar ratings were less sensitive than JOF to presentation frequency and less sensitive than JOR to recency and (b) although remember versus familiar ratings are strongly related to both JOF and JOR, as measured by gamma, the relations are far from perfect.     

Visual list memory in capuchin monkeys (Cebus apella)

Memory of 3 capuchin monkeys, Cebus apella, was tested with lists of 4 travel-slide pictures and different retention intervals. They touched different areas of a video monitor to indicate whether a test picture was in a list. At short retention intervals (0 s, 1 s, 2 s), memory was good for the last list items (recency effect). At a 10-s retention interval, memory improved for 1st list items (primacy effect). At long retention intervals (20 s and 30 s), primacy effects were strong and recency effects had dissipated. The pattern of retention-interval changes was similar to rhesus monkeys, humans, and pigeons. The time course of recency dissipation was similar to rhesus monkeys. The capuchin's superior tool-use ability was discussed in relation to whether it reflects a superior general cognitive ability, such as memory. In terms of visual memory, capuchin monkeys were not shown to be superior to rhesus monkeys.     

Serial-position effects for items and relations in short-term memory

Two experiments used immediate probed recall of words to investigate serial-position effects. Item memory was tested through probing with a semantic category. Relation memory was tested through probing with the word's spatial location of presentation. Input order and output order were deconfounded by presenting and probing items in different orders. Primacy and recency effects over input position were found for both item memory and relation memory. Both item and relation memory declined over output position. The finding of a U-shaped input position function for item memory rules out an explanation purely in terms of positional confusions (e.g., edge effects). Either these serial-position effects arise from variations in the intrinsic memory strength of the items, or they arise from variations in the strength of item–position bindings, together with retrieval by scanning.     

Auditory List Memory in Rhesus Monkeys

Auditory memory of 2 rhesus monkeys was tested in a serial probe recognition task. Lists of four environmental or natural sounds were followed by a retention interval and a test. The test matched one of the list items on half of the trials. The retention interval was varied across sessions. Six experiments showed similar results and changes in the serial position function. At short retention intervals, there was good memory for first list items (primacy effect) and poor memory for last list items. At intermediate retention intervals, memory improved for last list items (recency effect). At long retention intervals (20 s and 30 s), the recency effect was strong, and the primacy effect had dissipated. These auditory primacy and recency effects and their changes with retention interval were opposite to those for visual memory. Implications for processes and mechanisms of memory are discussed.     

Free recall and complexity of pictorial stimuli

In order to explore variables underlying primacy and recency effects in free recall of pictorial material, norms were developed using 120 subjects who rated the vividness and complexity of slides. Two experiments were then run in which two levels of each of these variables (extreme high and low ratings) were factorially combined. In the first experiment 24 subjects were shown three mixed lists, two short and one long (consisting of materials of all four combinations of vividness and complexity), and in the second experiment 12 subjects were shown four pure lists (consisting of materials of a single type). Analysis of variance showed list length in the mixed list experiment and complexity in both experiments to be strong determinants of recall. Greatest recall was for items of low complexity in short lists. Weak, but statistically significant, serial position effects were evident, particularly for less complex items. The effects of primacy and recency seem to decrease with increasing complexity of visual materials, perhaps because of the greater difficulty in rehearsing more complex pictures either verbally or iconically.     

Context matching and judgments of recency

An experiment was done to test a context-matching explanation of memory for recency under steady-state conditions. Subjects went through a list of 550 names, in which individual names were repeated at lags of 5–30 other items. The names were shown in two different styles or contexts. An old versus new recognition decision was made on each name, and eachold response was followed by a numerical judgment of recency (JOR). When first- and second-presentation contexts were the same, recognition hit rates were higher, and mean JORs were shorter (more recent), than when the two contexts were different. The JOR result is as predicted by the context-matching hypothesis.     

Diffusion model drift rates can be influenced by decision processes: An analysis of the strength-based mirror effect

Improving memory for studied items (targets) often helps participants reject nonstudied items (lures), a pattern referred to as the strength-based mirror effect (SBME). Criss (2010) demonstrated the SBME in diffusion model drift rates; that is, the target drift rate was higher and the lure drift rate was lower for lists of words studied 5 times versus lists of words studied once. She interpreted the drift rate effect for lures as evidence for the differentiation process, whereby strong memory traces produce a poorer match to lure items than do weak memory traces. However, she noted that strength may have also affected a model parameter called the drift criterion-a participant-controlled decision parameter that defines the zero point in drift rate. We directly contrasted the differentiation and drift-criterion accounts by manipulating list strength either at both encoding and retrieval (which produces a differentiation difference in the studied traces) or at retrieval only (which equates differentiation from the study list but provides the opportunity to change decision processes based on strength). Across 3 experiments, results showed that drift rates for lures were lower on strong tests than on weak tests, and this effect was observed even when strength was varied at retrieval alone. Therefore, results provided evidence that the SBME is produced by changes in decision processes, not by differentiation of memory traces. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Memory strength and the decision process in recognition memory

We investigated the role that memory strength plays in the decision process by examining the extent to which strength is used as a cue to dynamically modify recognition criteria. The study list consisted of strong and weak items, with strength a function of study duration or repetition. The recognition test list was divided into two consecutive blocks; strong items appeared in one block, weak items in the other. If the change in item strength across blocks leads to a shift in criterion, the false alarm rate should change accordingly. In four experiments, the false alarm rates did not change across blocks, even when the difference between the strong and the weak items was magnified and marked with semantic cues. However, the strength of the items in the first test block affected the false alarm rate. Thus, strength cues influence initial criterion placement but fail to induce criterion shifts following permanent and even dramatic changes in item strength. These null findings are contrasted with those in a fifth experiment, in which accuracy feedback produced dynamic criterion shifts.     

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.     

The influence of forward and backward associative strength on false memories for encoding context

Two experiments examined the effects of forward associative strength (FAS) and backward associative strength (BAS) on false recollection of unstudied lure items. Themes were constructed such that four associates were strongly related to a lure item in terms of FAS or BAS and four associates were weakly related to a lure item in terms of FAS or BAS. Further, when FAS was manipulated, BAS was controlled across strong and weak associates, while FAS was controlled across strong and weak associates when BAS was manipulated. Strong associates were presented in one font while weak associates were presented in a second font. At test, lure items were disproportionately attributed to the source used to present lures' strong associates compared to lures' weak associates, both when BAS was manipulated and when FAS was manipulated. This outcome demonstrates that both BAS and FAS influence lure item false recollection, which favours global-matching models' explanation of false recollection over the explanation offered by spreading activation theories.     

Reduction and elimination of format effects on recall

Two experiments investigated whether the recall advantage of pictures and spoken words over printed words in working memory (Foos & Goolkasian, 2005; Goolkasian & Foos, 2002) could be reduced by manipulating letter case and sequential versus simultaneous presentation. Participants were required to remember 3 or 6 items presented in varied presentation formats while verifying the accuracy of a sentence. Presenting words in alternating uppercase and lowercase improved recall, and presenting words simultaneously rather than successively removed the effect of presentation format. The findings suggest that when forcing participants to pay attention to printed words you can make them more memorable and thereby diminish or remove any disadvantage in the recall of printed words in comparison with pictures and spoken words.     

Pictorial encoding effects and memory confusions in the Deese–Roediger–McDermott paradigm: Evidence for the activation of spontaneous imagery

The purpose of the experiments reported in this paper was to examine the possible role of spontaneous imagery and list-specific cues on pictorial encoding effects induced by the Deese-Roediger-McDermott (DRM) task. After viewing pictures and words referring to thematically related materials, by way of a picture/word source-judgement task, participants were asked to remember the way in which these materials were presented. Participants reported “seeing” pictures of items that were presented as words, an effect predicted by the imaginal activation hypothesis in its suggestion that incidental images experienced during encoding will later be mistaken as memories for pictures. Whether participants made the same picture misattributions on related lures (or non-presented related items) depended on the way in which the lures’ respective thematic lists were experienced during encoding (Experiments 1 and 2), pointing to the effects of list-specific cues in picture/word judgements. These findings have intriguing implications for interpretations of picture-encoding effects induced by the DRM task. The findings also speak to the use of DRM false-memory rates when marshalling evidence against the use of imagery in applied settings.     

The effects of conformity on recognition judgements for emotional stimuli

Exposure to another’s account of a shared event can influence the content of an individual’s memory report. We examine whether the emotionality of the to-be-remembered information influences the likelihood that socially encountered post-event information is accepted into memory. Participants were exposed to positive, negative or neutral emotional pictures. Subsequently, they had to discriminate these pictures from new pictures in a ‘yes/no’ recognition decision either before or subsequent to a confederate providing misinformation, accurate or no information. Post-event information influenced participants’ responding in the recognition test. Effects were larger for participants viewing neutral items and persisted for these items on a subsequent private source monitoring test. These findings indicate that people rely more on information from others when encountering non-emotional compared to emotional items. We suggest that increased memory strength in conjunction with access to strong retrieval cues in the recognition test serves to shield emotional items from vulnerability to effects of memory conformity.     

Making judgments in a two‐sequence cue environment: The effects of differential cue strengths,order sequence,and distraction

Consumers frequently evaluate multiple sequential cues of varying strengths in order to draw inferences about a product's quality. The results of three experiments show that when consumers are not distracted, they judge a product's quality more favorably following a strong–weak cue sequence relative to a weak–strong sequence (a primacy effect). However once consumers are distracted from the evaluation task, the primacy effect reverses to a recency effect, whereby consumers judge a product's quality more favorably following a weak–strong cue sequence. Process tests suggest that distraction crowds consumers' short-term working memory and inhibits the spontaneous rehearsal and the subsequent recall of the cue presented first in the information sequence.     

On the locus of the stimulus suffix effect

Two experiments contrasted short-term memory and sensory memory (precategorical acoustic storage) explanations of the stimulus suffix effect. Experiment 1 attempted to interfere with recency recall by forcing subjects to encode nonverbal acoustic suffixes into a verbal, articulatory code. Subjects in this condition showed recall that was comparable to that of subjects who were told to ignore the suffixes. However, Experiment 2 showed that silently mouthed articulation of a suffix can produce interference on recall of recency items, although not as much as that produced by vocal articulation. The results are discussed in terms of current models of the stimulus suffix effect.     

An experimental analysis of memory processing

Rhesus monkeys were trained and tested in visual and auditory list-memory tasks with sequences of four travel pictures or four natural/environmental sounds followed by single test items. Acquisitions of the visual list-memory task are presented. Visual recency (last item) memory diminished with retention delay, and primacy (first item) memory strengthened. Capuchin monkeys, pigeons, and humans showed similar visual-memory changes. Rhesus learned an auditory memory task and showed octave generalization for some lists of notes--tonal, but not atonal, musical passages. In contrast with visual list memory, auditory primacy memory diminished with delay and auditory recency memory strengthened. Manipulations of interitem intervals, list length, and item presentation frequency revealed proactive and retroactive inhibition among items of individual auditory lists. Repeating visual items from prior lists produced interference (on nonmatching tests) revealing how far back memory extended. The possibility of using the interference function to separate familiarity vs. recollective memory processing is discussed.