In psychology, a stimulus is any type of input that can be detected by one or more of the senses. Stimuli can be external, meaning that they come from the environment, or internal, meaning that they come from within the individual's own body.
Stimuli are an important part of psychological research, as they are used to study how individuals perceive, process, and respond to different types of input. For example, researchers may use visual stimuli, such as images or videos, to study visual perception, or they may use auditory stimuli, such as sounds or music, to study auditory perception.
In psychology, stimuli are often used to study learning and conditioning, which is the process by which individuals learn to associate certain stimuli with specific responses or outcomes. For example, in classical conditioning, an individual learns to associate a neutral stimulus (such as the sound of a bell) with an unconditioned stimulus (such as food) by repeatedly presenting the two stimuli together. After learning this association, the individual will respond to the neutral stimulus as if it were the unconditioned stimulus.
Stimuli can also be used in therapy to help individuals change their thoughts, feelings, or behaviors. For example, cognitive-behavioral therapy often involves identifying and modifying the stimuli that trigger negative thoughts or behaviors, in order to help individuals develop more adaptive responses.