Using ecology to guide the study of cognitive and neural mechanisms of different aspects of spatial memory in food-hoarding animals

Abstract

Understanding the survival value of behaviour does not tell us how the mechanisms that control this behaviour work. Nevertheless, understanding survival value can guide the study of these mechanisms. In this paper, we apply this principle to understanding the cognitive mechanisms that support cache retrieval in scatter-hoarding animals. We believe it is too simplistic to predict that all scatter-hoarding animals will outperform non-hoarding animals on all tests of spatial memory. Instead, we argue that we should look at the detailed ecology and natural history of each species. This understanding of natural history then allows us to make predictions about which aspects of spatial memory should be better in which species. We use the natural hoarding behaviour of the three best-studied groups of scatter-hoarding animals to make predictions about three aspects of their spatial memory: duration, capacity and spatial resolution, and we test these predictions against the existing literature. Having laid out how ecology and natural history can be used to predict detailed cognitive abilities, we then suggest using this approach to guide the study of the neural basis of these abilities. We believe that this complementary approach will reveal aspects of memory processing that would otherwise be difficult to discover.

Evidence for cache surveillance by a scatter-hoarding rodent

“…One possible behavioural mechanism that could allow animals to reduce the rate of memory deterioration over time, and therefore remember cache locations over many months, is to repeatedly revisit cache sites to reinforce spatial memory (Huston & Oitzl 1989;Smulders et al 2010;Roth et al 2012), henceforth the 'memory enhancement hypothesis'. Roth et al (2012) speculated that the failure of prior studies to detect longterm memory abilities in parids was due to the one-trial nature of the studies.…”

Integrating ecology, psychology and neurobiology within a food-hoarding paradigm

“…Results of behavioural tests appeared inconclusive, as some studies have reported that caching species indeed perform better on spatial memory tasks while a few studies failed to support superiority of food-caching species (reviewed by Shettleworth 1995; . A potential cause of these apparent discrepancies is discussed by Smulders et al (2010).…”

“…The article by Smulders et al (2010) as well as that by Roth et al (2010a) provide a discussion of the problems associated with the current approach to linking the hippocampus to the adaptive specialization hypothesis. Smulders et al (2010) argue that the comparisons to date have used an oversimplified approach by looking for a single cognitive adaptation that applies to all aspects of spatial memory and across all foodhoarding species.…”

“…Another question is how long the memory for cache sites lasts (Smulders et al 2010). Some food-caching corvids have been well documented in their impressive use of long-term memory (Vander Wall 1990).…”

“…Some researchers (including one of us, T.V.S. : Smulders & Dhondt 1997;Smulders et al 2010;also Brodin 2005), think that this represents the situation in nature, and that food-caching parids do not need to use memory for long-term cache retrieval, as individual advantages can be guaranteed based on individual niche segregation for both foraging and food caching (Haftorn 1956;Pravosudov 1986;Brodin 1994;Lens et al 1994). Others (including the other one of us: V.V.P.)…”