THE ASSOCIATION OF IDEAS 31 



of my careful definition some readers have persisted in taking 

 it in one of its several other meanings, and have therefore misun- 

 derstood me. 



The original presentation is bound up with the discussion of 

 the nature of the "image" which is now largely a matter of his- 

 torical interest: the hypothesis may however be entirely sep- 

 arated from the old "image" problem without detriment. 



Figure 1 has been redrawn with minor changes. A pictorial 

 improvement might be made by representing neurons and synap- 

 ses (Watson, Behavior, p. 274, has so modified my original 

 figure), but the result would be no more true to life than the dia- 

 grams given, and may well await the accumulation of more defi- 

 nite information concerning the number of neurons enchained in 

 typical reaction arcs, and the details of their arrangement in the 

 series. Figure 2 has been redrawn in a different way, avoiding 

 the specification of a definite time order of the original reactions. 



The topic of the original paper (Images and Ideas) was con- 

 tinued in a paper on Thought-content and Feeling, published in 

 the Psychological Review, 1916, xxiii, 49-70, and the latter paper 

 should be read in the light of the present one, as it was intended 

 to be in the light of the first one. 



In the second part of this paper, in addition to more complete 

 illustration of the hypothesis set forth in the first part, the sup- 

 plementary hypothesis of "short-circuiting," which I briefly 

 stated my Outline of Psychobiology (p. 125, 2d edition, 1917), 

 is developed. This supplement removes the obvious objections 

 to the original unqualified hypothesis, and brings it into close 

 agreement with the fact so far observed. 



Seven years ago 1 1 began to tell my students that the conven- 

 tional doctrine of "mental images" is, in my estimation, largely 

 fiction, and to direct their attention to a simpler and more empiri- 

 cal analysis of the process and content in imagination. Two 

 years ago 2 1 published a brief text-book in which I expressed this 



In 1907. 

 In 1912. 



