The capacity to learn and remember exists in most known animal species, which raises fascinating questions about the role of evolutionary processes. Logic suggests that processing and storing information for future use is likely to be fundamental for an animal’s survival and reproductive success. Foraging for food requires capacities to respond to cues that signal its availability and location, and store memories for future excursions; successful reproduction requires capacities to locate and choose a suitable mate; and, evading predators requires learning about and remembering cues associated with survival threats, such as the presence and location of predators; all of these capacities, either directly or indirectly, enhance reproductive success. Although logical deduction plays an important role in science, empirical tests are needed to confirm, in this case, evolutionary hypotheses about learning and memory. This book is about the ways in which evolutionary hypotheses inform the design of experiments on learning and memory, the empirical methods and tests that have been developed, and the knowledge derived from research programs that reveal relationships between learning, memory, and evolution. The contributors to each chapter provide unique insights into how evolution has influenced a broad array of learning and memory mechanisms across a diverse representation of invertebrate and vertebrate species.

In his Nichomachean ethics, Aristotle suggested that absolute judgments precede relative judgments. This chapter places this notion in an evolutionary context by centering on comparative research on successive negative contrast (SNC). SNC occurs when a downshift from a more preferred to a less preferred reward deteriorates behavior. SNC is observed in experiments with mammals, but not in experiments with goldfish (bony fish), toads (amphibian), or turtles (reptile). Pigeons and starlings (birds) have produced a mixed set of results. Since E. L. Thorndike, an understanding of animal learning has been influenced by the notion that rewards strengthen behavior and nonrewards weaken behavior — the strengthening/weakening principle. Outcomes fitting this principle provide evidence of control by absolute reward value, whereas results that violate this principle, like SNC, suggest control by relative reward value. Comparative research suggests that absolute reward effects are more general than relative reward effects.