Timothy J. Perfect

Does Context Discriminate Recollection from Familiarity in Recognition Memory

Five experiments were conducted to examine subjects’ ability to make contextual judgements about recognized items for which they report recollective experience or only familiarity within the context of the experiment. In the first four experiments, subjects were able to make judgements of the spatiotemporal context of items that were accompanied by recollective experience significantly better than for items they merely found familiar. In only one of the four studies did subjects display above-chance performance on spatiotemporal judgements for merely familiar items. A fifth experiment examined the frequency with which subjects report the presence of different kinds of contextual knowledge during a standard recognition experiment. All aspects of contextual knowledge were reported with higher frequencies for recollected items than for items only found familiar, although no single contextual feature was strongly associated with recollective experience. Thus, the five studies together provide converging evidence for the validity of the “recollect-know” distinction in recognition memory and supplement studies that have already demonstrated that the two kinds of response are dissociable. The implications of these data for group comparisons of memory-impaired patients, and the role of context in recognition memory are discussed.

Differential Effects of Aging on Executive and Automatic Inhibition

One of the major accounts of cognitive aging states that age effects are related to a deficiency of inhibitory mechanisms (Hasher & Zacks, 1988). Given that inhibition has traditionally been associated with the frontal cortex, and that the frontal cortex deteriorates early with age (Raz, 2000), this is consistent with the frontal hypothesis of aging (West, 1996). However, not all inhibitory processes require executive control, and so they are not all equally supported by the frontal cortex. As a consequence, one would expect dissociations between inhibitory tasks in the sense of a greater susceptibility of executive/frontal inhibition to aging. Based on Niggs (2000) working inhibition taxonomy, we tested this hypothesis by combining inhibitory paradigms with different levels of executive control within the same participants. The results showed that age affects Stroop interference but not negative priming (Experiment 1) and stop signal responsiveness but not negative priming (Experiment 2). These findings suggest that tasks with a high executive (or effortful) inhibitory control are more sensitive to aging than tasks with a lower executive (more automatic) inhibitory control. The results are discussed in relation to the inhibitory and frontal accounts of aging.

Assessing the Inhibitory Account of Retrieval-Induced Forgetting With Implicit-Memory Tests

Five experiments examined whether retrieval-induced-forgetting effects are observed for implicit tests of memory. In each experiment participants first studied category-exemplar paired associates, then practiced retrieval for a subset of items from a subset of categories before finally completing memory tests for all the studied items. In standard fashion, inhibition was measured as the performance difference of unpracticed items from practiced categories and unpracticed items from unpracticed categories. Across the 5 experiments poorer performance for unpracticed items was seen in conceptual implicit memory (category generation and category matching) but not in perceptual implicit memory (stem completion, perceptual identification). Thus, retrieval-induced-forgetting effects are limited to tests of conceptual memory.

Age Differences in Reported Recollective Experience are Due to Encoding Effects, Not Response Bias

Three experiments examined whether reduced recollective experience reported in old age is due to a criterion shift towards more cautious responses by older subjects. In Experiment 1 Young and Old subjects took a recognition test without specific instructions on how they should encode the presented words. For recognised items subjects indicated whether they recollected the items previous occurrence or whether they just knew it had been on the list. They then rated their confidence that the word came from the study list. Although overall recognition levels were equivalent, older adults recollected less and reported more know responses than the younger subjects. However, there was no overall difference in confidence, contrary to a criterion shift explanation. In Experiment 2A specific encoding instructions removed the age-related change in recollective experience entirely. Experiment 2B reproduced the test conditions of Experiment 2A, but without specific encoding instructions, and replicated the pattern of know responding found in Experiment 1. Thus the three experiments together suggest that the amount of recollection experienced by the elderly is not explicable in terms of cautiousness, but is driven by the encoding carried out by the elderly at presentation.

What underlies the deficit in reported recollective experience in old age

In recognition memory, older adults report fewer occasions on which recognition is accompanied by recollection of the original encoding context. This study asks why this occurs. Two main hypotheses were tested: (1) Older adults fail to encode the items sufficiently when first they experience them. (2) Older adults have a retrieval deficit that prevents efficient reintegration of target and context. In addition, the hypothesis that frontal lobe integrity is essential for recollective experience was examined. Twenty older (mean age 70.7 years) and 20 younger (mean age 22.9 years) adults were asked to study a list of items and to verbalize the strategies they were using to remember. A further 20 older adults (mean age 70.0 years) were tested without the think-aloud protocol. Subsequently, subjects completed a battery of psychometric tests before completing a recognition test. As expected, older adults showed less recollective experience. They differed from the young in how they encoded the material, and once this difference was accounted for, no age differences in recollective experience remained. There was little evidence to support the hypothesis that frontal lobe integrity plays a role in the reduction of recollective experience with age.

Retrieval-induced forgetting in Alzheimer’s disease

It is claimed that Alzheimers disease (AD) patients show reduced inhibitory processing and this has been put forward as a reason why AD patients make intrusion errors at recall. However, the evidence to date has been equivocal, because non-inhibitory mechanisms can account for the pattern of findings. Recently, however, a paradigm has been developed that is claimed to give a purer measure of inhibitory processing in episodic memory, the retrieval-induced forgetting (RIF) paradigm [Inhibitory Processes in Attention, Memory and Language, Academic Press, San Diego, 1994, p. 265; J. Exp. Psychol.: Learning, Memory Cognition 20 (1994) 1063; Psychol. Rev. 102 (1995) 68]. Thus, we were interested whether AD patients would show a deficit in inhibitory processing using this procedure. Participants studied lists of category cue-exemplar pairs (e.g. fruit-orange) then practised retrieval for a subset of items from a subset of categories before taking a final memory test for all studied items. As in previous work, inhibition was measured as the difference between final memory performance for unpractised items from practised categories, and unpractised items from unpractised categories. The results show that AD patients showed normal levels of inhibition with both tests of cued recall and category generation (CG). This suggests that a deficit in inhibitory processes during retrieval is not behind the high levels of intrusion errors made in recall in AD.

Adult age differences in unconscious transference: Source confusion or identity blending?

Eyewitnesses are known often to falsely identify a familiar but innocent bystander when asked to pick out a perpetrator from a lineup. Such unconscious transference errors have been attributed to either identity confusions at encoding or source retrieval errors. Three experiments contrasted younger and older adults in their susceptibility to such misidentifications. Participants saw photographs of perpetrators, then a series of mug shots of innocent bystanders. A week later, they saw lineups containing bystanders (and others containing perpetrators in Experiment 3) and were asked whether any of the perpetrators were present. When younger faces were used as stimuli (Experiments 1 and 3), older adults showed higher rates of transference errors. When older faces were used as stimuli (Experiments 2 and 3), no such age effects in rates of unconscious transference were apparent. In addition, older adults in Experiment 3 showed an own-age bias effect for correct identification of targets. Unconscious transference errors were found to be due to both source retrieval errors and identity confusions, but age-related increases were found only in the latter.

Accuracy of Confidence Ratings Associated With General Knowledge and Eyewitness Memory

The confidence-accuracy (C-A) relation for general knowledge (GK) and eyewitness memory (EM) was compared in both withinand between-subjects analyses. Researchers in the cognitive tradition tend to use within-subjects designs and to find moderately positive C-A relations, whereas those in the forensic tradition tend to use between-subjects designs and to find no relation. Eighty subjects took part in one of two conditions—EM or GK. No difference between conditions was found on the within-subjects measure of the C-A relation, but there was differentiation with a between-subjects measure. There was a strong positive C-A correlation (r = .58, p < .01) for GK but not for EM (r = -.11, ns). One source of this difference may be the differing opportunities for calibration offered by the two kinds of memory.

Evidence for intact memory monitoring in Alzheimer's disease: metamemory sensitivity at encoding.

Previous research claiming that there is a metamemory deficit in Alzheimers Disease (AD) has been based on paradigms in which metamemory judgements are compared with performance. These methods confound predictive accuracy with very poor memory performance. In the experiments presented here this confound is removed by focusing on the sensitivity of metamemory judgements to item differences at encoding, rather than on predictive accuracy. In Experiment 1 participants studied words of high or low recallability, and either made judgements of learning (JOLs) or declared recall readiness. It was found that the AD group discriminate between items in their metamemory judgements to the same extent as age matched controls. Both groups rated the highly recallable words as being more likely to be recalled, and allocated more study time to low recallability items. In Experiment 2 participants were asked to rank the likelihood of recall of items that varied in objective recallability. Once again, AD patients were as sensitive to objective differences in stimuli as controls. Therefore, using measures based on sensitivity to item differences, we find no evidence of a metamemory deficit at encoding in AD. The findings are discussed in terms of metamemory functioning in AD, and its relationship with memory performance.

The tip-of-the-tongue phenomenon: do experimenter-presented interlopers have any effect?

When a person is in a tip-of-the-tongue (TOT) state, they will sometimes recall a word that is similar in sound to the word they are attempting to retrieve. Woodworth (1929) argued that these interloper words both cause and sustain TOT states, whereas Brown and McNeill (1966) suggested that they are part of the process that leads to TOT resolution. Jones and Langford (1987) and Jones (1989) explicitly presented interloper words along with definitions of words that subjects were asked to recall. They reported that interlopers that were phonologically related to the target word increased the incidence of TOTs and concluded that this supported Woodworths position. In three experiments, we adopted the interloper paradigm, but also included a control group who heard the definitions without interloper words. In Experiment 1, the definitions that Jones used with phonological interlopers created more TOTs even when no interlopers were presented. In Experiments 2a and 2b, we matched definitions for the number of TOTs they produced in the absence of interlopers. Under these circumstances we found no effect of interloper words at all. We conclude that there is no evidence from this paradigm to support the idea that interloper words are involved in either the causation or resolution of TOTs.