How big is human memory, or on being just useful enough.

Dudai, Yadin

doi:10.1101/lm.3.5.341

Cited by 32 publications

(29 citation statements)

References 103 publications

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“…The bigger, but not unlimited, memory of baboons suggests they live in a richer cognitive world than pigeons do. Directly comparable tests of human long-term memory capacity have not been conducted because of practical reasons, but various theoretical estimates indicate we have evolved an enormous capacity for long-term information (19,(21)(22)(23). Our results suggest that the ability to store large amounts of information is widespread and substantial in vertebrates, but that memory capacity also varies among species (see also refs.…”

Section: Discussionmentioning

confidence: 79%

Evidence for large long-term memory capacities in baboons and pigeons and its implications for learning and the evolution of cognition

Fagot¹,

Cook

2006

Proc. Natl. Acad. Sci. U.S.A.

135

105

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Previous research has shown that birds and primates have a rich repertoire of behavioral and cognitive skills, but the mechanisms underlying these abilities are not well understood. A common hypothesis is that these adaptations are mediated by an efficient long-term memory, allowing animals to remember specific external events and associate appropriate behaviors to these events. Because earlier studies have not sufficiently challenged memory capacity in animals, our comparative research examined with equivalent procedures the size and mechanisms of long-term memory in baboons and pigeons. Findings revealed very large, but different, capacities in both species to learn and remember pictureresponse associations. Pigeons could maximally memorize between 800 and 1,200 picture-response associations before reaching the limit of their performance. In contrast, baboons minimally memorized 3,500 -5,000 items and had not reached their limit after more than 3 years of testing. No differences were detected in how these associations were retained or otherwise processed by these species. These results demonstrate that pigeons and monkeys have sufficient memory resources to develop memory-based exemplar or feature learning strategies in many test situations. They further suggest that the evolution of cognition and behavior importantly may have involved the gradual enlargement of the long-term memory capacities of the brain.intelligence ͉ primate ͉ bird ͉ categorization ͉ picture processing B irds and primates have demonstrated a wide variety of cognitive capacities in different settings and are especially adept at learning visual discriminations (1-3). There has been a long and active debate on how such discriminations are learned. One prominent view has been an exemplar approach in which learning is mediated by the memorization of large number of stimulus-specific exemplars (4-7). Previous examinations of the size and durability of associative memory capacity in animals provide some credence for this possibility. Clark's Nutcrackers can remember 18-25 caches in a room containing 69 cache sites for as long as 180-285 days (8) and have been indirectly estimated to retrieve food from 3,000 to 6,000 stored caches over the winter, likely by using memory. In an earlier operantdiscrimination task, pigeons were able to memorize up to 320 randomly assigned pictorial stimuli (9). Comparable capacity studies have not been conducted in monkeys, but experimental evidence has demonstrated that objects viewed three to four times continue to be categorized as familiar by macaques 6 months later (10). In addition, macaques could reliably recognize pictures 6 months after an initial brief exposure of 30 sec (11). Despite these remarkable accomplishments of birds and monkeys, we postulated that earlier animal studies did not sufficiently challenge memory capacity over extended periods of time (12) and therefore had underestimated memory size in these different animals. These studies also were limited by their use of different procedures, making...

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Section: Discussionmentioning

confidence: 79%

Evidence for large long-term memory capacities in baboons and pigeons and its implications for learning and the evolution of cognition

Fagot¹,

Cook

2006

Proc. Natl. Acad. Sci. U.S.A.

135

105

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“…The availability of memory performance scores that sample events every 20 sec in a 27-min episode renders it tempting to attempt tapping into long-term memory capacity per unit time, or density (Dudai 1997). Any such attempt is bound to yield only rough estimates.…”

Section: Memory Densitymentioning

confidence: 99%

“…And fourth, the items retrieved are not necessarily independent, because the narrative of the movie might link them to each other. All of these confounds notwithstanding, because of the scarcity of estimates of long-term memory (Dudai 1997), we did consider this mental exercise informative and worthwhile.…”

Section: Memory Densitymentioning

confidence: 99%

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They saw a movie: Long-term memory for an extended audiovisual narrative

Furman¹,

Dorfman²,

Hasson³

et al. 2007

Learn. Mem.

105

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We measured long-term memory for a narrative film. During the study session, participants watched a 27-min movie episode, without instructions to remember it. During the test session, administered at a delay ranging from 3 h to 9 mo after the study session, long-term memory for the movie was probed using a computerized questionnaire that assessed cued recall, recognition, and metamemory of movie events sampled ∼20 sec apart. The performance of each group of participants was measured at a single time point only. The participants remembered many events in the movie even months after watching it. Analysis of performance, using multiple measures, indicates differences between recent (weeks) and remote (months) memory. While high-confidence recognition performance was a reliable index of memory throughout the measured time span, cued recall accuracy was higher for relatively recent information. Analysis of different content elements in the movie revealed differential memory performance profiles according to time since encoding. We also used the data to propose lower limits on the capacity of long-term memory. This experimental paradigm is useful not only for the analysis of behavioral performance that results from encoding episodes in a continuous real-life-like situation, but is also suitable for studying brain substrates and processes of real-life memory using functional brain imaging.Experimental protocols that probe brain correlates of episodic memory formation commonly use paradigms in which memoranda are presented as individual items devoid of continuous context outside of the laboratory setting (Winocur and Weiskrantz 1976;Buckner et al. 2000). In contrast, real-life episodic memory is the result of ongoing encoding within a highly contextualized and dynamically changing perceptual, cognitive, and affective framework (Tulving 1983(Tulving , 2002Suddendorf and Busby 2005). Though the importance of real-life conditions in memory research has long been recognized (Neisser 1978;Cohen 1996), it is rather difficult to harness its naturalistic attributes in controlled, reproducible laboratory settings (Dudai 2002). Using movies as stimulus material can remedy some of these difficulties.Movies are capable of simulating aspects of real-life experiences by fusing multimodal perception with emotional and cognitive overtones (Eisenstein 1969;Morin 2005). They also permit controlled, reproducible presentation of continuous, contextualized, and dynamic sets of stimuli to-be-remembered, and selection of cognitive and affective types of content. The use of cinematic material to probe memory can be traced to the early days of cinema (Boring 1916), but did not catch on, a few exceptions notwithstanding (Beckner et al. 2006). Realizing the potential advantage of movies as multimodal stimuli on-the-go, Hasson et al. (2004) used a trade fiction movie to analyze brain circuits that process perceptual and affective information while attending the ongoing cinematic narrative, and unveiled correlated spatiotemporal brain activation pa...

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“…One challenging issue concerns the storage capacity and information retrieval of these longer term memory mechanisms. Attempts to examine the capacity of such longer term memory stores have been limited and mainly computational (Dudai, 1997;Landauer, 1986;Standing, 1973). Although there is general agreement that the human capacity for recognizing pictorial information is considerable (Shepard, 1967;Standing, 1973) and the storage needs for language use substantial, the empirical study of long-term memory capacity has been virtually absent because of the impractical requirements of testing humans over extended periods.…”

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confidence: 99%

Capacity and limits of associative memory in pigeons

Cook

Levison

Gillett

et al. 2005

Psychonomic Bulletin & Review

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How does the brain encode, store, and retrieve an entire lifetime of experiences? Biological memory capacity has been extensively studied with regard to the short-term retention of recent information (Miller, 1956;Nelson, 2001), and a system with a limited capacity in the single digits has consistently been suggested. Such findings suggest that the brain may have multiple memory systems, and numerous longer term stores (e.g., procedural, episodic, long-term, semantic, associative, and reference memory) have been proposed to capture the extensive knowledge and memories stored beyond those of the recent past. One challenging issue concerns the storage capacity and information retrieval of these longer term memory mechanisms. Attempts to examine the capacity of such longer term memory stores have been limited and mainly computational (Dudai, 1997;Landauer, 1986;Standing, 1973). Although there is general agreement that the human capacity for recognizing pictorial information is considerable (Shepard, 1967;Standing, 1973) and the storage needs for language use substantial, the empirical study of long-term memory capacity has been virtually absent because of the impractical requirements of testing humans over extended periods.Nonhuman animals are similarly guided by a combination of acquired knowledge and recent experiences, but here as well, little effort has been directed at understanding the capacity of their longer term memory systems. Vaughan and Greene (1984) conducted the most extensive study of animal memory capacity. They showed that pigeons could discriminate among 320 randomly assigned pictorial stimuli (160 positive and 160 negative) in a successive go/no-go discrimination. On the basis of a smaller stimulus set (160), they further demonstrated that some of these memories endure for at least 2 years. There are some important limitations, however, to these findings. Their rate-based discrimination procedure and rankorder measure of performance were not designed to yield a measure of how many stimuli were retained, for example. Thus, their pigeons' above-chance discrimination could have been accomplished with considerably fewer than the 320 pictures being memorized. Furthermore, the testing of all 320 stimuli was quite brief, making it impossible to judge the long-term effects of high memory load. Since then, the capacity of pigeons to remember large numbers of pictures has been confirmed. Von Fersen and Delius (1989) used a two-alternative choice proceThis research was supported by a grant from the Animal Behavior program of the National Science Foundation to R.G.C., who thanks everyone in the Cook lab for assistance in conducting these experiments over the last 3 years and Taylor Johnson and Angie Koban for their comments on earlier drafts. Correspondence concerning this article should be addressed to R. G. Cook, Department of Psychology, Tufts University, 530 Bacon Hall, Medford, MA 02155 (e-mail: robert.cook@tufts.edu; home page, www.pigeon.psy.tufts.edu). How much information can a brain store over a li...

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How big is human memory, or on being just useful enough.

Cited by 32 publications

References 103 publications

Evidence for large long-term memory capacities in baboons and pigeons and its implications for learning and the evolution of cognition

Evidence for large long-term memory capacities in baboons and pigeons and its implications for learning and the evolution of cognition

They saw a movie: Long-term memory for an extended audiovisual narrative

Capacity and limits of associative memory in pigeons

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