Age-related differences in the von restorff isolation effect

When one item is made distinct from the other items in a list, memory for the distinctive item is improved, a finding known as the isolation or von Restorff effect (after von Restorff, 1933). Although demonstrated numerous times with younger adults and children, this effect has not been found with older adults (Cimbalo & Brink, 1982). In contrast to the earlier study, we obtained a significant von Restorff effect for both younger and older adults using a physical manipulation of font colour. The effect size for older adults was smaller than that obtained for younger adults, confirming a prediction of Naveh-Benjamin's (2000) associative deficit hypothesis, which attributes age-related differences in memory performance to older adults' reduced ability to form associations. The findings are consistent with related research in which older adults demonstrate similar—but smaller—benefits for distinctive information to those for younger adults.     

Age-related differences in the von Restorff isolation effect

When one item is made distinct from the other items in a list, memory for the distinctive item is improved, a finding known as the isolation or von Restorff effect (after von Restorff, 1933). Although demonstrated numerous times with younger adults and children, this effect has not been found with older adults (Cimbalo & Brink, 1982). In contrast to the earlier study, we obtained a significant von Restorff effect for both younger and older adults using a physical manipulation of font colour. The effect size for older adults was smaller than that obtained for younger adults, confirming a prediction of Naveh-Benjamin's (2000) associative deficit hypothesis, which attributes age-related differences in memory performance to older adults' reduced ability to form associations. The findings are consistent with related research in which older adults demonstrate similar—but smaller—benefits for distinctive information to those for younger adults.     

A motor isolation effect: When object manipulability modulates recall performance

Previous studies suggested that the language production architecture is recruited during verbal retention, and others proposed that spatial memory relies on the oculomotor system. The objective of the present study was to investigate the role of the motor system in object memory, by examining the effect of objects' affordances on retention. In a serial recall task, we manipulated the manipulability of objects to retain in memory. We used an isolation paradigm where we isolated the manipulability level of one object from the list. We showed that recall performance improved for the isolated object (Experiment 1) and that this advantage was abolished when participants were required to perform motor suppression during the task (Experiment 2). In Experiment 3, we showed that the abolition of the motor isolation effect in Experiment 2 was not due to an effect of distraction since motor suppression was shown not to interfere with a semantic isolation effect. It is argued that motor affordances play a role in object memory, but only when the motor characteristics of an object allow discriminating it from the other objects in the list.     

Children's suggestibility for an instance of a repeated event versus a unique event: the effect of degree of association between variable details

Are children who experience an event repeatedly more suggestible about an instance of the event than children who experience it once? Researchers have answered this question both in the affirmative and in the negative. In this study, we hypothesized that the degree of association between details that changed across instantiations of the event would help to explain the discrepancy. Preschoolers (4- and 5-year-olds) and first graders (6- and 7-year-olds) participated in either a single play session or four repeated play sessions, each of which contained 16 critical details. Across play sessions in the repeat-event condition, half of the critical details were associated and half were not associated. During a biasing interview 2 weeks later, children were misinformed about half of the critical details. The next day, children answered free and cued recall questions about the target play session. Among older children, repeat-event participants were more suggestible than single-event participants, especially for high-association details. Among younger children, repeat-event participants were more suggestible than single-event participants for low-association details. Consistent with some current theories of children's memory, older children were more suggestible than younger children.     

Two modality effects in verbal short-term memory: Evidence from sentence recall

This paper investigates the mechanisms underlying the standard modality effect (i.e., better recall performance for auditorily presented than for visually presented materials), and the modality congruency effect (i.e., better memory performance if the mode of recall and presentation are congruent rather than incongruent). We tested the assumption that the standard modality effect is restricted to the most recent word(s) of the sentences but occurs in both verbatim and gist recall (Experiments 1 and 2), whereas the modality congruency effect should be evident for the rest of the sentence when using verbatim recall (Experiment 3) but not when using gist recall (Experiment 4). All experiments used the Potter-Lombardi intrusion paradigm. When the target word was the most recent word of the sentence, a standard modality effect was found with both verbatim recall and gist recall. When the target word was included in the middle of the sentences, a modality congruency effect was found with verbatim recall but not with gist recall.     

Memory for reward location is enhanced even though acetylcholine efflux within the amygdala is impaired in rats with damage to the diencephalon produced by thiamine deficiency

Sleep facilitates declarative memory processing. However, we know little about whether sleep plays a role in the processing of a fundamental feature of declarative memory, relational memory – the flexible representation of items not directly learned prior to sleep. Thirty-one healthy participants first learned at 12 pm two sets of face–object photograph pairs (direct associative memory), in which the objects in each pair were common to both lists, but paired with two different faces. Participants either were given approximately 90 min to have a NREM-only daytime nap (n = 14) or an equivalent waking period (n = 17). At 4:30 pm, participants who napped demonstrated significantly better retention of direct associative memory, as well as better performance on a surprise task assessing their relational memory, in which participants had to associate the two faces previously paired with the same object during learning. Particularly noteworthy, relational memory performance was correlated with the amount of NREM sleep during the nap, with only slow-wave sleep predicting relational memory performance. Sleep stage data did not correlate with direct associative memory retention. These results suggest an active role for sleep in facilitating multiple processes that are not limited to the mere strengthening of rote memories, but also the binding of items that were not directly learned together, reorganizing them for flexible use at a later time.     

Dual-memory processes in crack cocaine dependents: The effects of childhood neglect on recall

Exposure to adversities during sensitive periods of neurodevelopment is associated with the subsequent development of substance dependence and exerts harmful, long-lasting effects upon memory functioning. In this study, we investigated the relationship between childhood neglect (CN) and memory using a dual-process model that quantifies recollective and non-recollective retrieval processes in crack cocaine dependents. Eighty-four female crack cocaine–dependent inpatients who did (N = 32) or did not (N = 52) report a history of CN received multiple opportunities to study and recall a short list composed of familiar and concrete words and then received a delayed-recall test. Crack cocaine dependents with a history of CN showed worse performance on free-recall tests than did dependents without a history of CN; this finding was associated with declines in recollective retrieval (direct access) rather than non-recollective retrieval. In addition, we found no evidence of group differences in forgetting rates between immediate- and delayed-recall tests. The results support developmental models of traumatology and suggest that neglect of crack cocaine dependents in early life disrupts the adult memory processes that support the retrieval of detailed representations of events from the past.     

Walking before study enhances free recall but not judgement-of-learning magnitude

The authors investigated whether a brief bout of aerobic exercise can influence subsequent judgements of learning (JOLs) or memory performance. 80 college students (46 women and 34 men) completed 1 of 4 conditions using a 2×2 (encoding condition×retrieval condition) between-subjects factorial design. After a practice task, students either viewed an unrelated slide show while sedentary or completed a brisk 10-minute walk. Then, all students studied 30 English nouns and provided immediate JOLs. Finally, students again completed either the sedentary activity or exercised, followed by a free recall test. Exercise before encoding increased free recall scores by 25% compared with the sedentary condition; as a result, absolute metamemory accuracy also improved. Encoding condition did not influence mean JOLs, however, suggesting that students were unaware of the memory benefits from exercise. Overall, these results suggest that individuals can gain a memory advantage from a 10-minute walk before studying.     

Delayed search for a concealed imprinted object in the domestic chick

Five-day-old chicks were accustomed to follow an imprinted object (a small red ball with which they had been reared) that was moving slowly in a large arena, until it disappeared behind an opaque screen. In experiments, each chick was initially confined in a transparent cage, from where it could see and track the ball while it moved towards, and then beyond, one of two screens. The screens could be either identical or differ in colour and pattern. Either immediately after the disappearance of the ball, or with a certain delay, the chick was released and allowed to search for its imprinted object behind either screen. The results showed that chicks took into account the directional cue provided by the ball movement and its concealment, up to a delay period of about 180 s, independently of the perceptual characteristics of the two screens. If an opaque partition was positioned in front of the transparent cage immediately after the ball had disappeared, so that, throughout the delay, neither the goal-object nor the two screens were visible, chicks were still capable of remembering and choosing the correct screen, though over a much shorter period of about 60 s. The results suggest that, at least in this precocial bird species, very young chicks can maintain some form of representation of the location where a social partner was last seen, and are also capable of continuously updating this representation so as to take into account successive displacements of the goal-object. Received: 17 January 1998 / Accepted after revision: 29 March 1998     

Minorities remember more: The effect of social identity salience on group-referent memory

Research on the group-reference effect has confirmed that social identities can affect memory, but few studies have explored the role of identity salience in this effect. Two experiments were designed to fill the gap. In Experiment 1 Tibetan students at one predominantly Han Chinese university showed high ethnic identity salience and better memory for trait adjectives encoded in reference to Tibetans than in reference to Han Chinese. In Experiment 2 Tibetan students at one Tibetan-majority university demonstrated low ethnic identity salience and no differences were found between memory performance under Tibetan-referential processing and Han-referential processing conditions. In comparison, Han participants did not show high ethnic awareness or an ingroup-reference effect in either experiment, due to membership of an ethnic majority (Experiment1) and lack of inter-ethnic contact (Experiment 2). These findings suggest that high salience is a prerequisite for social identities to facilitate memory.     

Predicting immediate ordered recall of lists with products of probabilities

Immediate ordered recall performance is often reported in terms of recall of individual items or of lists. Schweickert, Chen and Poirier (Int. J. Psychol. 34 (1999) 447) proposed that the probability of recalling a list approximately equals the product of the conditional probabilities that each item is recalled, given its immediate predecessor is recalled. This Product of Adjacent Conditionals gave a close lower bound to the probability of recalling a list, although it is not exactly right. An alternative is that dependencies are expressed through probabilities conditioned on retrieval of higher level units such as chunks. An example is a key assumption of Anderson and Matessa (Psychol. Rev. 104 (1997) 728). This alternative is rejected here. Overall, the Product of Adjacent Conditionals formula and the Anderson and Matessa theory predicted recall of a list about equally well.