Glossary

allometry altricial behavioral drive hypothesis behavioral flexibility

The scaling relationship between two characters A and B (e.g., brain mass and body mass), where changes in A and B are not proportional. (Proportional change in A and B is termed isometry.) Allometry is thought to reflect design constraints, so predictions on the effects of directional selection are usually conducted on residual trait variance after removal of allometric scaling. A relatively slow mode of juvenile development, where offspring are usually not mobile and are strongly dependent on parental care. The term can be opposed to 'precocial.' The idea that generalism, exploration, opportunism, social learning, and behavioral flexibility can have accelerating effects on evolutionary rate, by increasing the range and frequency of selective contexts in which randomly occurring mutations can confer higher fitness. A general term describing the capacity to modify behavior. Often used as blanket term that ecological intelligence encephalization encompasses learning (a change in behavior contingent on an association with a stimulus and/or a reward), opportunism (exploitation of a temporarily abundant resource not part of the usual diet of a species), or innovation (see definition below).

Cognitive complexity selected in the context of interactions with the physical environment. Usually contrasted with Machiavellian (or social) intelligence, which is selected in the context of social interactions. In comparative biology, the term describes the difference between animals in the amount of neurons available beyond the average determined by allometric body design. In paleoanthropology, it designates the observed increase over evolutionary time in the absolute and relative size of the brain in hominids. In neuroanatomy, it describes the increased importance that higher brain structures play over lower ones in birds and mammals compared to other vertebrates and to invertebrates.

One extreme of a continuum where the other extreme is specialization, generalism refers to the use of a relatively broad range of foods or habitats by a taxonomic group or an individual.

The most widely used procedure for removing the effects of common ancestry on taxonomic similarities or differences between traits. The technique measures 'differences' between related taxonomic groups in the values of biological traits, rather than actual trait values on extant taxa. Relatedness between groups is usually measured through mitochondrial or nuclear DNA data. A behavior pattern performed for the first time by an animal and that is not the result of a genetic change or a pathology. The novel behavior is an attempt to solve a problem (feeding, social) that the standard repertoire cannot resolve. Also defined as a new or modified learned behavior not previously found in the population (Reader and Laland, 2003, p. 14). Cognitive abilities that are specific to a restricted selective context (e.g., spatial memory, learned song) and whose neural substrate is often a restricted brain area (e.g., hippocampus, nucleus HVC). The terms 'adaptive specialization' (implying adaptation to a particular selective context, e.g., food caching, brood parasitism) or 'module' (implying that information relevant to one specialized context or domain is not available in other contexts) embody related ideas. The term can be opposed to general process skills, where cognitive differences between taxonomic groups are thought to reflect broad, unspecia-lized abilities based on large and/or diffuse neural substrates.

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