144 



SCIENCE. 



[Vol. XVI. No. 397 



to make the distinction on the basis of the after-image, and 

 thus signal the appreciation of it too soon; or, again, an 

 extreme desire not to re-act before the distinction is made 

 may delay re-action to an unusual length. Friederich's 

 investigations show for colors a simple re-action time of 175 ff, 

 and a "subjective distinction" time of 2670' (XXXIX.); 



the methods for comparative purposes; and, in addition, we 

 can vary the complexity of the distinction while leaving the 

 choice the same (and to a more limited extent can vary the 

 choice without the distinction), and thus can in many cases 

 distinguish whether an increased complexity of an adaptive 

 re-action is to be referred to an increase in the difficulty of 



Table of Complex Re-action Times.^ 



J Black and white-on-black 

 II White and a particular color. 



Ill White and a color. 



IViEed:blue or green:yellow. 



VjColors 



VI I Roman capital letters 



VlljShort English words, 



Vmlxong 



Character 



of Ex- 

 periment. 



IX Short German " 



Xi Pictures of objects 



XI Eed:blue or gre6n:yellow — 



XII: Pairs of short English words 



XIIl! " " colors 



XIV " " pictures 



XV Capital Roman letters. . . 

 XVI •' German letters. . 



XVII Short English words 



XVIII " German " 



XIX Colors 



XX Pictures of objects 



XXI Words in construction. . 



f Eight S 

 ■i left 



( hand. 

 Naming. 



Continu- 

 ous 

 series. 



XXIViSpoken words, "one," "two," 



"three," "four," "Ave" — Adaptive. 16 fingers. 

 XXV; " words, "lupus," "lupi," 



"lupo," "lupum," "lupe" 

 XXVISpokeu words, 3 groups of 5 



grammatical forms 



XXVII 

 XXVIII 



words, 5 categories. . 



XXX Direction of light. 



Incomplete. Finger. 



XXXIII Localize touch 



XXXIV Tones of different pitch ! " 



XXXT Tone and noise I " 



XXXVI Strong and weak touch ' " 



XXXVII Tones of different pitch " 



XXXVIII Strong and weak touch i " 



XXXIX White and black. ■ Subjected. 



XL White, black, red, green , " 



XLI One-place numbers . 

 XLII Three- place " 

 XLIII Five-place 



XLIV Sounds of different intensity 



XLV 

 XLVI 

 XLVII 



Visual impressions. 



LIL " 

 LIII 100 words.. 

 LIV 100 letters 



.Adaptive. 18-10 Angers 



. I Continuous. 



Naming. 



Krles : 

 Auerbach. 



{Friede- 

 rich's 3 sub 

 Jeets. 



Ttecher's 

 6 subjects. 



' Merkel's 10 

 . subjects. 



as 



249 1 146 



264 146 



306- 146 



3131 146 



326 146 



360 146 



375^ 146 



367 146 



3091 146 



340 I 146 



401 170 



438 170 

 437I 170 

 4241 170 

 526, 170 

 409: 170 

 439: ITO 

 6011 170 

 545 170 



138 



170 



No. of 

 Possible 

 Impres- 

 sions. 



161 132 



177 143 



176 142 



176 134 



202 158 



219 140; 



296 1761 4 



318 186' 9 



3971 186' 900 

 697i 186, Indefinite. 



164' 114' 



178 114 



194 114 



276 ISS' 



394 188: 



Ee-act to white-on-black. 

 React to color, varied 



amongst ten. 

 Ee-act to color, but need not 



distinguish same. 

 Ee-act to predesignated color 



German. 

 English, read 

 (right to left). 



Ich meiner mir mich wir. 



" Du deiner dir dich ihr. 

 Der des dem den die. 



" JVbwn, pronoun, adjective^ 

 number^ verb. 



" City^ river, animal, plant, 

 element. 



" Author, musician, natural- 

 ist, philosopher, statesman. 



Whether right or left spark 

 goes first. 



Whether in front or in back 



of fixation-point. 

 On middle finger or back of 



hand. 

 Ee act to higher. 



" strong. 

 " lower. 

 " weak. 



Any two of the numbers 1, 2, 

 3. 4, 6, and I , II., III., IV., 



four of the Nos. 1, 2, etc. 



the choice or to an increase in the difficulty of the distinc- 

 tion. 



1 Eoman numerals in the text refer to the corresponding experiments in this table. 



while Tigerstedt, and also Tischer, find only about half this 

 difference for nearly the same re-aetion. It seems wisest, 

 underthese circumstances, not to decide the relative shares of 

 the distinction and choice in the adaptive re-action, but to 

 study the combined time as a whole, and the influences by 

 which it is affected. We can thus utilize the results of all 



It is desirable to analyze more particularly the nature of 

 the difference between the simple re-action and the "sub- 

 jective," and between the simple and the incomplete. An 

 essential point relates to the mode of re-action, whether motor 



