page_title: Adaptive memory
section_title: Evolutionary adaptations of memory in non-human species
hierarchical_section_title: Adaptive memory / Evolutionary adaptations of memory in non-human species
caption_attribution_description: meadow vole Source: downloaded from http://www.nps.gov/yell/kidstuff/Alphabet/v.htm
context_page_description: Adaptive memory is the study of memory systems that have evolved to help retain survival- and fitness-related information, i.e., that are geared toward helping an organism enhance its reproductive fitness and chances of surviving. One key element of adaptive memory research is the notion that memory evolved to help survival by better retaining information that is fitness-relevant. One of the foundations of this method of studying memory is the relatively little adaptive value of a memory system that evolved merely to remember past events. Memory systems, it is argued, must use the past in some service of the present or the planning of the future. Another assumption under this model is that the evolved memory mechanisms are likely to be domain-specific, or sensitive to certain types of information.
context_section_description: Adaptive memory behaviours have been observed in animal species, as well as humans. Dr. John Garcia discovered that taste aversion conditioning in rats results in a lasting association between sickness and an ingested substance, and that aversion can be established after only one trial. This rapid learning led others to the idea that rats have biological dispositions for learning to associate sickness with a taste memory as a result of its evolutionary history. The results of a study that compared rats and quail in the acquisition of taste aversion suggested that rats rely on their memory of taste to avoid nausea while quail relied on their visual memory. Since the rat is a nocturnal feeder and has poor vision, it was suggested that they rely on taste cues to learn to avoid toxic substances, leading to a highly developed chemical sense system.
  In a study of black-capped chickadees (Poecile atricapilla) from Alaska and Colorado, those birds from Alaska cached more food, remembered the hiding places more quickly and readily, and had significantly larger hippocampal volumes than black-capped chickadees from Colorado. This supports what is known as the adaptive specialization hypothesis. The adaptive specialization hypothesis states that animals that hide food should have bigger hippocampi than animals that do not hide food. Additionally, those animals that hide food performed better than non-hiding animals on spatial memory tests. This finding suggests that since the climate tends to be harsh in Alaska, there may be an increased need to remember where food is hidden, to help them survive through the winter.
  Under the pressure of natural selection, sex differences in spatial memory skills can develop under distinct mating systems. Comparing different vole species that are either polygamous or monogamous, researchers found that sex differences in spatial skills are only found in the polygamous mating meadow vole. Further examination found that unlike monogamous pine voles (who travel together on a permanent basis with their partners), polygamous males have increased mobility (compared to the females) in order to reap reproductive benefits. Male meadow voles with good spatial skills are more likely to be able to survive and reproduce. It is suggested that such evolutionary pressure led to greater spatial skills in comparison to female meadow voles and monogamous male pine voles. This suggestion is based on better performance by male meadow voles on route and place learning tasks in laboratory tests. Polygamous voles have a significantly larger relative hippocampus than females of the same species, and no such difference was found between the pine vole sexes. These findings suggest that when better spatial memory is more evolutionarily adaptive, as in polygamous species, these organisms may develop a larger hippocampus, to allow greater spatial memory.
caption: Polygamous meadow voles have shown to perform better in route and place learning tasks than the monogamous pine vole, likely attributable to their nomadic nature.
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