Page:Mind (Old Series) Volume 11.djvu/388

THE TIME TAKEN UP BY CEEEBBAL OPERATIONS. 387 that the perception-time is about the same for the large and small letters, which agrees with experiments I have made by an entirely different method (see MIND 41). We now come to consider the time it takes to see a word, a process with which the brain is constantly occupied. Twenty-six words were taken, and when the expected one was seen the observer lifted his hand. The perception-time so determined is the time needed to distinguish the word from the other twenty- five ; the time is slightly longer when it is necessary to distinguish words from others very similar in form ; for example, hand from band. Indeed we must remember that perception is not a sharply defined process. As I have shown, we see a letter before we see what letter it is ; in like manner a further time passes before we see the letter in all its details, that it is not perfectly printed, for example. The perception-time for a painting by Eaphael is in- definitely long. The results of experiments with English and German words are given in the Tables XX VI. -VII. The Tables give us a perception-time for short English words B 132, C HI;/ ; for short German words B 118, C 150* ; for long English words B 154, C 158<r. The time was therefore slightly shorter (B 22, C 17) for a short than for a long word, and for a word in the native than in a foreign language (B 14, C 9). It will be noticed that the perception-time is only slightly longer for a word than for a single letter; we do not therefore perceive separately the letters of which a word is composed, but the word as a whole. The application of this to teaching children to read is evident ; I have already in connexion with other experiments called attention to it. The only other perception-time we have to consider is for a picture. It takes, we may suppose, about the same time to recognise the picture of a tree as it takes to see the tree itself ; this is consequently a process nearly always going on in the brain. I had carefully drawn twenty-six pictures of common objects, tree, hand, ship, etc., about one square cm. in size, the method of de- termining the perception-time being as before. We thus find that the perception-time for a picture, and we may assume for the objects we are continually seeing in our daily life, was 96<T for B, 117 for C, about the same as for a colour and shorter than for a letter or word. (To be concluded.) TABLES XXII.-XXVIII.