Scrub jays (Aphelocoma coerulescens) form integrated memories of the multiple features of caching episodes

Four experiments examined whether food-storing scrub jays remember when and where they cached different foods. The scrub jays cached and recovered perishable and nonperishable foods in visuospatially distinct and trial-unique cache sites. They rapidly learned to avoid searching for foods that had perished by the time of recovery, while continuing to search for the same foods after shorter retention intervals when the foods were still fresh. The temporal control of searching at recovery was also observed when the familiarity of cache sites did not provide any information about the time of caching and when the same food was cached in distinct sites at different times. The authors argue that the jays formed an integrated memory for the location and time of caching of particular foods.     

Interacting Cache memories: evidence for flexible memory use by Western Scrub-Jays (Aphelocoma californica)

When Western Scrub-Jays (Aphelocoma californica) cached and recovered perishable crickets, N. S. Clayton, K. S. Yu, and A. Dickinson (2001) reported that the jays rapidly learned to search for fresh crickets after a 1-day retention interval (RI) between caching and recovery but to avoid searching for perished crickets after a 4-day RI. In the present experiments, the jays generalized their search preference for crickets to intermediate RIs and used novel information about the rate of decay of crickets presented during the RI to reverse these search preferences at recovery. The authors interpret this reversal as evidence that the birds can integrate information about the caching episode with new information presented during the RI.     

The genomic action potential

Neurons compute in part by integrating, on a time scale of milliseconds, many synaptic inputs and generating a digital output-the "action potential" of classic electrophysiology. Recent discoveries indicate that neurons also perform a second, much slower, integration operating on a time scale of minutes or even hours. The output of this slower integration involves a pulse of gene expression which may be likened to the electrophysiological action potential. Its function, however, is not directed toward immediate transmission of a synaptic signal but rather toward the experience-dependent modification of the underlying synaptic circuitry. Commonly termed the "immediate early gene" (IEG) response, this phenomenon is often assumed to be a necessary component of a linear, deterministic cascade of memory consolidation. Critical review of the large literature describing the phenomenon, however, leads to an alternative model of IEG function in the brain. In this alternative, IEG activation is not directed at the consolidation of memories of a specific inducing event; instead, it sets the overall gain or efficiency of memory formation and directs it to circuits engaged by behaviorally significant contexts. The net result is a sharpening of the selectivity of memory formation, a recruitment of temporally correlated associations, and an ultimate enhancement of long-term memory retrieval.     

On objectivity and subjectivity in statistical inference: A response to Mayo

In this paper we respond to the article An Objective Theory of Statistical Testing by D. G. Mayo (1983). We argue that the theory of testing developed by Mayo, NPT*, is neither novel nor objective. We also respond to the claims made by Mayo against Bayesian theory.     

Interference with real world knowledge

Two experiments are described in which subjects studied made-up, fantasy facts about well-known persons and then were asked to verify actual facts about these persons. Reaction time to the actual facts was longer the more fantasy propositions studied about a person. Reaction time was also longer when the verification test involved a mixture of actual and fantasy facts rather than just actual facts. A mathematical version of the ACT model (Anderson, 1976) was fit to the data. It provides a satisfactory fit, better than an alternate model. However, some of the parameter values estimated for the ACT model seemed unreasonable.     

Measures of free recall of 900 English nouns: Correlations with imagery,concreteness, meaningfulness,and frequency

Forty groups of subjects were given six lists of 25 nouns each for immediate free written recall. A measure of free recall was thereby obtained for each of 900 nouns in the Paivio, Yuille, and Madigan (1968) norms, each noun’s measure based on the recall of 32 subjects. First-order correlations showed recall to be correlated with imagery, concreteness, meaningfulness, Thorndike-Lorge frequency, and Kuěra-Francis frequency. Partial correlations showed meaningfulness to be essentially unrelated to recall and concreteness only moderately related. In contrast to previous comparisons, which were based on smaller ranges of frequency and were more susceptible to list-specific effects, imagery and frequency were found to be approximately equal in their influence on free recall.