A person has many needs at any given time. Some are biological, some are psychological. A need becomes a motive when it is aroused to a sufficient level of intensity.
A motive (or drive) is a need that is sufficiently pressing to direct the person to seek satisfaction.
Psychologists have developed theories of human motivation. Two of the most popular - the theories of Sigmund Freud and Abraham Maslow - have quite different meanings for consumer analysis and marketing.