The four main goals of psychology are to describe, explain, predict and change the behavior and mental processes of others.
Describing a behavior or cognition is the first goal of psychology. This can enable researchers to develop general laws of human behavior.
For example, through describing the response of dogs to various stimuli, Ivan Pavlov helped develop laws of learning known as classical conditioning theory.
Once researchers have described general laws behavior, the next step is to explain how or why this trend occurs. Psychologists will propose theories which can explain a behavior.
Psychology aims to be able to predict future behavior from the findings of empirical research. If a prediction is not confirmed, then the explanation it is based on might need to be revised.
For example, classical conditioning predicts that if a person associates a negative outcome with a stimuli they may develop a phobia or aversion of the stimuli.
Once psychology has described, explained and made predictions about behavior, changing or controlling a behavior can be attempted.
For example, interventions based on classical conditioning, such as systematic desensitization, have been used to treat people with anxiety disorders including phobias.