Imagination involves the synthetic combining of aspects of memories or experiences into a mental construction that differs from past or present perceived reality, and may anticipate future reality. Imagination may be fantastic, fanciful, wishful, or problem-solving, and may differ from reality to a slight or great extent. Imagination is generally considered to be a foundation of artistic expression, and, within limits, to be a healthy, creative, higher mental function.
Observers have noted two contrasting types of imagination. One is largely imitative and concerned with mentally reconstructing past events or images. (Among the imitative types of imagination is eidetic imagery, which consists of rich and vividly recalled images and is especially characteristic of children up to the age of six.) In contrast to imitative images, creative imagination is associated with thought and involves the restructuring, rather than merely the retention, of sensory impressions. It was this faculty that experts call "imagination" as opposed to "fancy," his name for imitative imagining.
One common form of creative imagination is daydreaming. At one time, daydreaming and fantasies were regarded as compensatory activities that had the function of "letting off steam," but recent research has cast doubt on that theory. Creative imagination is the basis for achievements in the realms of both art and science, and students of behavior have analyzed the creative process in hopes of being able to encourage greater creativity through various types of training. New discoveries about the specialized functions of the right- and left-brain hemispheres have revealed that the right-brain hemisphere is the center for much of the mental functioning commonly regarded as creative: it is the side associated with intuitive leaps of insight and the ability to synthesize existing elements into new wholes. These findings have been applied by educators seeking to enhance individual creativity in areas including writing and drawing.
After falling into neglect as an area of inquiry during the period when behaviorism was preeminent, mental imagery has become a significant topic of study for cognitive psychologists. Researchers have found that imagery plays a significant role in emotion, motivation, sexual behavior, and many aspects of cognition, including learning, language acquisition, memory, problem-solving, and perception. Mental imagery has also been found to be a useful technique in clinical work. Mental images have also been used as a diagnostic tool to reveal feelings and attitudes not accessible through verbalization.