ATTENTION. 415 



the single bell-stroke makes the ripening of the perception 

 slower, and the index is seen too late. So, at least, do I 

 understand the explanations which Herren Wundt and v. 

 Tschisch give.* 



* Physiol. Psych., 2d ed. ii. 373-4; 3d ed. ii. 339; Philosophische 

 Studien, ii. 621 ff. — I know that I am stupid, but I confess I tiud these 

 theoretical statements, especially Wundt's, a little hazy. Herr v. Tschisch 

 considers it impossible that the perception of the index's position should 

 come in too late, and says it demands no particular attention (p. 622). It 

 Beams, however, that this can hardly be the case. Both observers speak of 

 the difficulty of seeing the index at the right moment. The case is quite 

 different from that of distributing the attention impartially over simulta- 

 neous momentary sensations. The bell or other signal gives a momentary 

 sensation, the index a continuous one, of motion. To note any one position 

 of the latter is to interrupt this sensation of motion and to substitute an 

 entirely different percept — one, namely, of position — for it, during a time 

 however brief. This involves a sudden change in the manner of attending 

 to the revolutions of the index; which change ought to take place n-jither 

 ooner nor later than the momentary impression, and fix the index as it is 

 then and there visible. Now this is not a case of simply getting two sen- 

 sations at once and so feeling them — which would be an harmonious act; 

 but of stopping one and changing it into another, whilst we simultaneously 

 get a third. Two of these acts are discrepant, and the whole three rather 

 interfere with each other. It becomes hard to ' fix ' the Index at the very 

 instant that we catch the momentary impression; so we fall into a way of 

 fixing it either at the last possible moment before, or at the first possible 

 moment after, the impression comes. 



This at least seems to me the more probable state of affairs. If we fix 

 the index before the impression really comes, that means that we perceive 

 it too late But why do we fix it before when the impressions come slow 

 and simple, and after when they come rapid and complex? And why 

 under certain conditions is there no displacement at all? The answer 

 which suggests itself is that when there is just enough leisure between the 

 impressions for the attention to adapt itself comfortably both to them and 

 to the index (one second iuW.'s experiments), it carries on the two pro- 

 cesses at once; when the leisure is excessive, the attention, following its 

 own laws of ripening, and being ready to note the index before the other 

 impression comes, notes it then, since that is the moment of easiest action, 

 whilst the impression, which comes a moment later, interferes with noting 

 it again ; and finally, that when the leisure is insuflicient, the momentary 

 impressions, being the more fixed data, are attended to first, and the index 

 is fixed a little later on. The noting of the index at too early a moment 

 would be the noting of a real fact, with its analogue in many other rhyth- 

 mical experiences. In reaction-time experiments, for example, when, in a 

 regularly recurring series, the stimulus is once in a while omitted, the ob- 

 server sometimes reacts as if it came. Here, as Wundt somewhere observes, 

 we catch ourselves acting merely because our inward preparation is com- 

 plete. The 'fixing' of the index is a sort of action; so that my interpre- 



