Alan J. Parkin

Attention and recollective experience in recognition memory.

The functional relation between recognition memory and conscious awareness was assessed in an experiment in which undivided attention at study was compared with two divided attention conditions, one more demanding than the other. When recognizing a word from the study list, subjects indicated whether they could consciously recollect its-prior occurrence or recognized it on some other basis, in the absence of consciousrecollection. Divided attention at study progressively impaired word recognition accompanied by conscious recollection. Recognition in the absence of conscious recollection was not affected by divided attention. These findings are interpreted as providing further support for the idea that recognition memory entails two distinct components, one based on associative and contextual information, the other based on a “traceless” awareness of familiarity.

Naming impairments following recovery from herpes simplex encephalitis: Category-specific?

An apparently clear case of category-specific naming impairment selectively affecting animals was detected in a patient who had recovered from herpes simplex encephalitis. However, subsequent investigation demonstrated that these category-specific effects could be eliminated by controlling simultaneously for three factors in picture naming: word frequency, concept familiarity, and visual complexity. The results emphasize the importance of controlling for all factors pertinent to picture naming when attempting to demonstrate category specificity in picture naming. Further testing indicated that deficits were also apparent when naming to definition was required, and some impairment in the ability to answer questions about objects and living things was also noted. Theoretical implications of these data are considered.

On the differential nature of implicit and explicit memory

In this article, we report two experiments that provide further evidence concerning the differential nature of implicit and explicit memory. In Experiment 1, subjects first undertook a sentenceverification task. While carrying out this task, half of the subjects were also required to carry out a secondary processing task involving tone monitoring. Twenty-four hours later, the subjects’ memory for target items in the sentence-verification task was tested explicitly by means of a recognition task and implicitly by examining the extent to which the items primed fragment completion. Recognition performance was significantly impaired by the imposition of secondary processing demands during the original learning phase. In contrast, fragment completion was completely unaffected by this additional processing, even though substantial priming was observed. In Experiment 2, we examined whether priming in fragment completion is influenced by the nature of repetition during initial learning. Subjects studied a list of target items that were each repeated twice. Halfthe items were repeatedimmediately (lag 0) and halfwere repeated after six intervening items (lag 6). Memory for the itemswas assessed by recognition and by priming in fragment completion. Recognition was affected by lag, with lag 6 items being recognized better than lag 0 items. However, although significant priming was obtained, the extent of this priming was uninfluenced by lag. These data indicate two additional dimensions along which implicit and explicit memory differ and, furthermore, they support recent conceptualizations of processing differences underlying these two forms of memory.

Deterioration of frontal lobe function in normal aging: influences of fluid intelligence versus perceptual speed.

A group of young participants were compared with 2 groups of older participants (young-old, 65-74 years and old-old, 75 years or over) on a range of frontal lobe tasks. They were also assessed on the Digit Symbol Substitution Test (DSST), a test of digit cancellation (DC), the AH4 test of fluid intelligence, and the National Adult Reading Test (NART)-a measure of crystalized intelligence. Reliable age differences on all frontal measures except word fluency (FAS) were found. However, age effects were radically attenuated when either DSST speed or Alice Heim 4 (AH4) performance was used as a covariate. In contrast, DC and NART attenuated age-related variance to a much lesser degree. The authors conclude that a large proportion of age-related variance on measures of frontal lobe function may be attributed to a more general factor characterized jointly by DSST and AH4 performance.

Things that go bump in your life : Explaining the reminiscence bump in autobiographical memory

Two experiments explore the reminiscence bump (RB)--the disproportionately higher recall of early-life memories--by older adults. In Experiment 1, participants in the age ranges of 36-40, 46-50, and 56-60 recalled events freely or under instructions to avoid recent memories. Constraint did not affect older participants but resulted in the appearance of an RB in younger participants. In Experiment 2, recall was constrained to particular life periods. Memories from these periods were compared for ease of retrieval and along subjective dimensions (e.g. vividness). Memories from early life were more easily retrieved, but this was not due to differences in subjective qualities. A higher proportion of memories for first-time events were identified from early life, and these memories were more easily retrievable. The results are discussed in relation to an existing model of autobiographical memory, and a revised model is put forward.

Pathological false alarm rates following damage to the left frontal cortex

In this study we present further data on case JB who developed memory impairment following a ruptured aneurysm of the anterior communicating artery which resulted in damage centered on the frontal cortex. The data reveal the JBs memory impairment is characterized by a recall impairment in which intrusion rates are abnormally high and a recognition deficit characterized by an exceptionally high false alarm rates. A comparison is made between this case and other recent cases involving impairments with a similar etiology. Theoretical interpretations of JBs deficit are also considered.

Are the benefits of errorless learning dependent on implicit memory

The effectiveness of errorless and errorful learning methods was compared in two experiments in which a group of memory-impaired individuals learned lists of single words. In both experiments, error prevention during learning resulted in higher levels of cued recall performance than trial-and-error learning. Experiment 1 showed that the beneficial effects of the errorless learning method extended over a delay of up to 48 hr and were also observed in free recall. The hypothesis that the benefits of errorless learning rely upon implicit memory was tested in Experiment 2. No evidence was found to support the hypothesis. Implicit memory was observed following both errorless and errorful learning, but there was no indication that enhanced performance in the errorless condition could be accounted for by implicit memory. There was no correlation between performance on a direct test (cued recall) and performance on an indirect test (fragment completion) for the same materials. Furthermore, the extent of priming was no greater for recalled items than non-recalled items in the cued recall test. It is proposed that the benefits of errorless learning in this paradigm stem from the effects of error prevention on residual explicit memory.

Errorless learning of novel associations in amnesia

In two experiments involving verbal association learning by people with memory impairments, the effectiveness of errorless learning (EL) was compared with errorful learning (EF). Experiment 1 examined the effectiveness of both methods in learning remotely linked word pairs. There was an advantage for items learned by EL at immediate test which was not sustained over a delay of 1 hr. Learning appeared to be stable over this delay in the EF condition. Analysis of responses at delayed cued recall showed more evidence of spontaneous recovery in EF than in EL. Elimination of these items from analysis resulted in a similar pattern of forgetting in both methods. Experiment 2 examined the effectiveness of EL and EF in teaching novel associations, and showed an advantage for EL at immediate and delayed test. Forgetting was apparently observed following EL, but not EF. As in Experiment 1, this discrepancy was attributed to recovered responses at delayed test in EF. Eliminating these responses showed a similar pattern of forgetting in both methods for items correctly recalled at immediate test. The study shows an advantage for EL techniques in learning novel associations. The two methods also differ in that learning via EF is associated with more spontaneous recovery.

Memory impairment following ruptured aneurysm of the anterior communicating artery

This study reports the case of a 42-year-old man who suffered a ruptured aneurysm of the anterior communicating artery. His memory capabilities were assessed after a considerable recovery period during which many of his memory deficits ameliorated. His scan revealed a left frontal lesion and many of his deficits were characteristic of frontal impairment. He was impaired on temporal discrimination, and he showed marked source forgetting. He also performed badly on the Brown-Peterson task, and we suggest that this is another task that may be characteristic of frontal impairment. In contrast, the patient showed normal or near normal performance on some memory tasks but not on others. It is concluded that the patients frontal signs are similar to those found in Korsakoffs Syndrome, but that his memory impairment is qualitatively different from that encountered in patients with the amnesic syndrome.

Age differences in implicit memory : more apparent than real

Elderly subjects and a group of young subjects identified fragmented picture sequences under conditions of focused attention. Two other groups of young subjects carried out this task under divided-attention conditions. Implicit memory, as measured by item-specific savings, was found in all groups, but this effect was smaller in the elderly group. The young subjects, but not elderly subjects, performed better on new items. The divided-attention conditions equated recall and recognition by the young and the elderly, but only the young subjects showed greater savings for recalled items. The elderly subjects’ reduced implicit memory therefore stemmed from their inability to facilitate implicit memory with explicit memory. A second experiment, involving only young subjects tested after delay, produced findings similar to those for the young divided-attention subjects. Implicit memory, as measured by savings in picture completion, does not show an age-related change when the role of explicit memory is considered. Age does, however, reduce skill learning.