Altruism: Providing a benefit to someone else at a cost to oneself, without expecting future reciprocation.
Biological determinism: The idea that behaviors are determined exclusively by genes.
Costly signaling theory: A theory by which individuals provide honest signals about personal attributes through costly displays.
Ecology: The physical and social environment, including food resources, predators, terrain, weather, social rules, behavior of other people, and cultural rules.
Evolutionary history: An understanding of how traits (including behaviors) may be the result of natural selection in our hominin past.
Human Behavioral Ecology: The field of anthropology that explores how ecological factors and evolutionary history combine to influence how humans behave.
Kin selection: A type of natural selection whereby people help relatives, which can evolve because people are helping other individuals with whom they share genes.
Naturalistic fallacy: The incorrect belief that what occurs is what ought to be.
Population aging: An increase in the number and proportion of people who are over the age of 60.
Proximate explanation: The mechanism that is immediately responsible for an event.
Reciprocal altruism: Helping behavior that occurs because individuals expect that any help they provide will be reciprocated in the future.
Total fertility rate: the number of children a hypothetical female would have at the end of their reproductive period if they experienced fertility rates of a given year for each year of their reproductive period and were not subject to mortality. It represents the fertility of all females in a given year. It is reported as children per woman.
Ultimate explanation: An explanation for an event that is further removed than a proximate explanation but provides a greater insight or understanding. In human behavioral ecology, ultimate explanations usually describe how a behavior is linked to reproduction and survival.