A psychological interpretation of science begins with the acute realization that science is a human creation, rather than an autonomous, non-human, or per se "thing" with intrinsic rules of its own. Its origins are in human motives, its goals are human goals, and it is created, renewed, and maintained by human beings. Its laws, organization, and articulations rest not only on the nature of the reality that it discovers, but also on the nature of the human nature that does the discovering. The psychologist, especially if he has had any clinical experience, will quite naturally and spontaneously approach any subject matter in a personal way by studying people, rather than the abstractions they produce, scientists as well as science.
The misguided effort to make believe that this is not so, the persistent attempt to make science completely autonomous and self-regulating and to regard it as a disinterested game, having intrinsic, arbitrary chesslike rules, the psychologist must consider unrealistic, false, and even anti-empirical.
... Scientists are motivated, like all other members of the human species, by species-wide needs for food, etc.; by needs for safety, protection, and care; by needs for gregariousness and for affection-and-love relations; by needs for respect, standing, and status, with consequent self-respect; and by a need for self-actualization or self-fulfillment of the idiosyncratic and species-wide potentialities of the individual person. These are the needs that are best known to psychologists for the simple reason that their frustration produces psychopathology.
Less studied but knowable through common observation are the cognitive needs for sheer knowledge (curiosity) and for understanding (the philosophical, theological, value-system-building explanation needed).
Finally, least well known are the impulses to beauty, symmetry, and possibly to simplicity, completion, and order, which we may call aesthetic needs, and the needs to express, to act out, and to motor completion that may be related to these aesthetic needs.
To date it seems as if all other needs or desires or drives are either means to the basic ends listed above, or are neurotic, or else are products of certain kinds of learning processes.
Obviously the cognitive needs are of most concern to the philosopher of science. It is man's persistent curiosity that is most responsible for science in its natural-history stage, and it is his equally persistent desire to understand, explain, and systematize that generates science in its more theoretical and abstract levels. However, it is this latter theoretical urge that is more specifically a sine qua non for science, for sheer curiosity is seen often enough in animals.
But the other motives are certainly also involved in science at all its stages. It is too often overlooked that the original theorizers of science often thought of science primarily as a means to help the human race. Bacon, for instance, expected much amelioration of disease and poverty from science. It has been shown that even for Greek science where pure unmanual contemplation of the Platonic sort was a strong tradition, the practical and humanistic trend was also fairly strong. The feeling of identification and belongingness with people in general, and even more strongly the feeling of love for human beings may often be the primary motivation in many men of science. Some people go into science, as they might into social work or medicine, in order to help people.
And then finally we must recognize that any other human need may serve as a primary motivation for going into science, for working at it, or for staying in it. It may serve as a living, a source of prestige, a means of self-expression, or as a satisfaction for any one of many neurotic needs.
In most persons, a single primary all-important motive is less often found than a combination in varying amounts of all motivations working simultaneously. It is safest to assume that in any single scientist his work is motivated not only by love, but also by simple curiosity, not only by prestige, but also by the need to earn money, etc.
Abraham Maslow, Motivation and Personality (2nd ed., 1970: 1-3)