The Principles of Psychology, Volume 1 · William James
FOOTNOTES:
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 in W.'s experiments), it carries on the two processes 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 insufficient, 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 rhythmical experiences.
In reaction-time experiments, for example, when, in a regularly recurring series, the stimulus is once in a while omitted, the observer sometimes reacts as if it came. Here, as Wundt somewhere observes, we catch ourselves acting merely because our inward preparation is complete. The 'fixing' of the index is a sort of action; so that my interpretation tallies with facts recognized elsewhere; but Wundt's explanation (if I understand it) of the experiments requires us to believe that an observer like v. Tschisch shall steadily and without exception get an hallucination of a bell-stroke before the latter occurs, and _not hear the real bell-stroke afterwards_. I doubt whether this is possible, and I can think of no analogue to it in the rest of our experience. The whole subject deserves to be gone over again. To Wundt is due the highest credit for his patience in working out the facts. His explanation of them in his earlier work (Vorlesungen üb. Menschen und Thierseele, i, 37-42, 365-371) consisted merely in the appeal to the unity of consciousness, and may be considered quite crude. [338] Note that the permanent interests are themselves grounded in certain objects and relations in which our interest is immediate and instinctive. [339] Herbart: Psychologie als Wissenschaft, § 128. [340] Sir W. Hamilton. Metaphysics, lecture xiv. [341] Mental Physiol., § 124. The oft-cited case of soldiers not perceiving that they are wounded is of an analogous sort.
This harmonizes very well with the German popular expression _den Kopf zusammennehmen_, etc., etc. In a former illness, in which I could not endure the slightest effort of continuous thought, and had no theoretical bias on this question, the muscles of the scalp, especially those of the occiput, assumed a fairly morbid degree of sensibility whenever I tried to _think_." (_Ibid._ pp. 490-491.) In an early writing by Professor Mach, after speaking of the way in which by attention we decompose complex musical sounds into their elements, this investigator continues: "It is more than a figure of speech when one says that we 'search' among the sounds. This hearkening search is very observably a bodily activity, just like attentive looking in the case of the eye. If, obeying the drift of physiology, we understand by attention nothing mystical, but a bodily disposition, it is most natural to seek it in the variable tension of the muscles of the ear. Just so, what common men call attentive looking reduces itself mainly to accommodating and setting of the optic axes.... According to this, it seems to me a very plausible view that quite generally Attention has its seat in the mechanism of the body. If nervous work is being done through certain channels, that by itself is a mechanical ground for other channels being closed." (Wien. Sitzungsberichte, Math. Naturw., xlviii, 2, 297. 1863.) [361] Physiol. Optik, p. 741. [362] Hermann's Handbuch, iii, i, 548. [363] Helmholtz: Tonempfindungen, 3d ed. 85-9 (Engl. tr., 2d ed. 50, 51; see also pp. 60-1). [364] Physiol. Psych., ii, 209. [365] Physiol. Optik, 741.
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