Reflexes.

The reflex is among the simplest forms of behavior studied widely by psychologists and neuroscientists. Reflexes involve two separate yet highly related events: the occurrence of an eliciting stimulus and the production of a specific response. Most organisms can display a variety of complex behaviors; however, because these behaviors are complex, it has been very difficult, if not impossible, to understand the biological or psychological processes involved in generating or modifying the variety of complex behaviors that most organisms can display. In attempts to study these complex behaviors, a number of researchers have adopted a strategy of studying simpler behaviors, such as reflexes, that are thought to make up, contribute to, or serve as a model of the more complex behavior.