Page:Mind (Old Series) Volume 11.djvu/75

 b-i J. M. CATTELL : determine the time we usually require to see and name an object, such as a letter or a colour. (1) I pasted letters on a revolving drum (a physiological kymograph) and determined at what rate they could be read aloud, as they passed by a slit in a screen. It was found that the time varied with the width of the slit. When the slit was 1 cm. wide (the letters being 1 cm. apart) one letter was always in view ; as the first disappeared the second took its place, &c. In this case it took the nine persons experimented on (university teachers and students) frorn^ to isec.to read e, letter. This does not however give the entire time needed to see and name a single letter, for the subject was finding the name of the letter just gone by at the same time that he was seeing the letter then in view. As the slit in the screen is made smaller the processes of perceiving and choosing cannot so well take place simultaneously, and the times become longer ; when the slit is 1mm. wide the time is isec., which other experiments I have made prove to be about the time it takes to see and name a single letter. When the slit on the contrary is taken wider than 1 cm., and two or more letters are always in view, not only do the procesess of seeing and naming overlap, but while the subject is seeing one letter, he begins to see the ones next follow- ing, and so can read them more quickly. Of the nine persons experimented on four could read the letters faster when five were in view at once, but were not helped by a sixth letter ; three were not helped by a fifth and two not by a fourth letter. This shows that while one idea is in the centre, two, three or four additional ideas may be in the background of consciousness. The second letter in view shortens the time about j 1 ^, the third J$, the fourth yi^, the fifth ^sec. (2) I find it takes about twice as long to read (aloud. possible) words which have no connexion as words which make. sentences, and letters which have no connexion as letters which make words. When the words make sentences and the let i words, not only do the processes of seeing and naming overlap, but by one mental effort the subject can recognise a whole group of words or letters, and by one will-act choose the motions to he made in naming them, so that the rate at which the words and letters are read is really only limited by the maximum rapidity at which the speech-organs can he moved. As the result of a large number of experiments (he. writer found that he had read words not making sentences at the rate of j-sec., words making sentences (a passage from Swift) at the rate of isec. per word. Letters not making words were read in ,',,sec. less time, than words not making sentences; capital and small letters were read at the same rate, small German letters slightly and capital (lei-man letters considerably more slowly than the Latin letters. The experiments were repeated on eleven other subjects, confirming these results; the time required to read each word when the-