Noun

behavior (countable and uncountable; plural behaviors) (US)

1. The way an animal or human behaves or acts.
2. The way a device or system operates.

Related terms

• behave
• behavioral
• behavioralism
• behavioralist

• behaviorism
• behaviorist
• behavioristic
• behavior pattern
• behavioral science

Behavior, or behaviour (see American and British spelling differences), refers to the actions of a system or organism , usually in relation to its environment, which includes the other systems or organisms around as well as the physical environment. It is the response of the system or organism to various stimuli or inputs, whether internal or external, conscious or subconscious, overt or covert, and voluntary or involuntary.

Biology

In humans, behavior is believed to be controlled primarily by the endocrine system and the nervous system. Thus, it is most often believed that the complexity of the behavior of an organism is related to the complexity of its nervous system. Generally, organisms with complex nervous systems have a greater capacity to learn new responses and thus adjust their behavior. Behaviors can be either innate or learned. However, current research in the Human Microbiome Project points towards a possibility that human behavior may be controlled by the composition of the microbe population within a human body.

More generally, behavior can be regarded as any action of an organism that changes its relationship to its environment. Behavior provides outputs from the organism to the environment.