A behavioral trait is an action commonly observed in individuals throughout a species, such as human beings laughing and smiling or cats grooming themselves. In animals, such traits are generally ascribed to instinct, though they can often be modified. In humans, behavioral traits are often learned rather than instinctive.
Behavioral traits are at the heart of the nature versus nurture controversy debating which human behaviors are inborn and which are learned, according to Scitable. It was thought for a long time, for example, that addicts were weak-willed, but more recent science has shown that addicts are often genetically predisposed to addictive behaviors. Today scientists generally agree that human behaviors are made up of complex interactions between socially learned behaviors and inherited behavioral traits.
The human ability to modify behavioral traits through learning has proven to be evolutionarily advantageous. Humans were able to leave the warm climate of African and move into Europe, for instance, because they figured out how to clothe themselves and hunt new animals. Tool-making appears to be an instinctive behavioral trait among primates, but teaching the young how to make and use tools is a social behavior. Other instinctive human behavioral traits, such as the fight-or-flight response, can be modified in some people but appear to be relatively hard-wired in most.