IV. EESEAECH.

EXPERIMENTS ON THE ASSOCIATION OF IDEAS. By JAMES McKEEN CATTELL, Ph.D. The Association of Ideas has been a favourite subject with psychologists from Aristotle on, yet the results have not been very definite from the scientific point of view. An important paper by Mr. Galton 1 first applied experimental methods to the subject, and put it in a way where scientific advance was possible. Professor Wundt at once saw the importance of this work, and took it up in his laboratory with improved apparatus and methods. 2 Nothing further has, however, been published on the subject, which is a pity, as experimental psychology seems to have its most hopeful outlook in this direction. Experiments I described in a paper contributed to MIND, Nos. 42-4, on " The Time taken up by Cerebral Operations," showed that about f sec. was needed to see and name a word. When the physiological factors and the time taken up in seeing the word were eliminated, it was found that about -f^ sec. was spent in finding the name belonging to the printed symbol. The time was longer for letters, which we do not read as often as words, and still longer (about sec.) for colours and pictures. I called the time passing, while the motor expression was being found, a ' Will-time '. The process is, however, largely automatic, and consists in carrying out an association previously formed between the concept and the expression. There is no break between such a process and the other processes I ana about to describe. I. If an object is named in a foreign instead of in one's native language, the association between concept and expression is less intimate and takes up more time. It is an open question as to how far concepts are formed without the aid of words, and it is not evident what mental process takes place when an object is named in. a foreign language, it depending, of course, on the familiarity of the language. It need scarcely be said that we know almost nothing as to the physical basis of memory and thought ; we may hope that psychometric experiments, such as I am about to describe, will contribute something toward the study of this subject. In the paper above mentioned I showed how we can determine the time it takes to see and name the picture of an object ; in like manner the time we need to name 1 Brain, 1879 ; cp. MIND, iv. 551. 2 Physiologische Psychologie, c. xvi. ; Philosophische Studien, i. 1.