Insight

   1) The Catalyst to Darwin's Discovery of the Principle of Natural Selection

   In October 1838 that is, fifteen months after I had begun my systematic enquiry, I happened to read for amusement "Malthus on Population," and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favorable variations would tend to be preserved, and unfavorable ones to be destroyed. (Darwin, 1911, p. 68)

   2) Insight in the Chimpanzee

   The insight of the chimpanzee shows itself to be principally determined by his optical apprehension of the situation. (KoЁhler, 1925, p. 267)

   3) Brevity, Suddenness and Immediate Certainty

   Then I turned my attention to the study of some arithmetical questions apparently without much success and without a suspicion of any connection with my preceding researches. Disgusted with my failure, I went to spend a few days at the seaside, and thought of something else. One morning, walking on the bluff, the idea came to me, with just the same characteristics of brevity, suddenness and immediate certainty, that the arithmetic transformations of indeterminate ternary quadratic forms were identical with those of non-Euclidean geometry. (Poincareґ, 1929, p. 388)

   4) Insight Is Not a Mysterious Mental Agent

   The direct awareness of determination . . . may also be called insight. When I once used this expression in a description of the intelligent behavior of apes, an unfortunate misunderstanding was, it seems, not entirely prevented. . . . Apparently, some readers interpreted this formulation as though it referred to a mysterious mental agent or faculty which was made responsible for the apes' behavior. Actually, nothing of this sort was intended . . . the concept is used in a strictly descriptive fashion. (KoЁhler, 1947, pp. 341-342)

   5) Insight in Animal Problem-Solving

   The task must be neither so easy that the animal solves the problem at once, thus not allowing one to analyze the solution; nor so hard that the animal fails to solve it except by rote learning in a long series of trials. With a problem of such borderline difficulty, the solution may appear out of a blue sky. There is a period first of fruitless effort in one direction, or perhaps a series of attempted solutions. Then suddenly there is a complete change in the direction of effort, and a cleancut solution of the task. This then is the first criterion of the occurrence of insight. The behavior cannot be described as a gradual accretion of learning; it is evident that something has happened in the animal at the moment of solution. (What happens is another matter.) (Hebb, 1949, p. 160)

   6) An Explanation of Sudden Insight

   If the subject had not spontaneously solved the problem [of how to catch hold at the same time of two strings hung from the ceiling so wide apart that he or she could only get hold of one at a time, when the only available tool was a pair of pliers, by tying the pliers to one string and setting it into pendular motion] within ten minutes, Maier supplied him with a hint; he would "accidentally" brush against one of the strings, causing it to swing gently. Of those who solved the problem after this hint, the average interval between hint and solution was only forty-two seconds. . . . Most of those subjects who solved the problem immediately after the hint did so without any realization that they had been given one. The "idea" of making a pendulum with pliers seemed to arise spontaneously. (Osgood, 1960, p. 633)

   7) Flashes of Insight Do Not Explain Problem-Solving

   There seems to be very little reason to believe that solutions to novel problems come about in flashes of insight, independently of past experience. . . . People create solutions to new problems by starting with what they know and later modifying it to meet the specific problem at hand. (Weisberg, 1986, p. 50)