468 



In so short a period of time we cannot divide onr attention 

 among several weak, stininli so as to perceive all of tliem willi the 

 Siiine distinctness. Now when such weak stimnii are presented in 

 i-apid snccessioii, we may expect tiie same; also wlien they follow 

 each other at short intervals, we cannot perceive all of tliem and 

 we. must make a selection, in onr experimentation we also observed 

 that it is exactly series of weak anti obscure stimuli that ai'e best 

 adapted to subjective rhytlimisation. 



Now, ivhy is this acceiituatioii regahtr f 



A periodically recurring stimulus is easy U) perceive; we are 

 l)eforehand predisposed to the iuipi'cssion, as we know when it is 

 coining. When for instance of a series of stimuli we cleaily apprehend 

 llu! first and the third, we are better prepared for the fifth and the 

 seventh. We may change this accommodation at will every moment 

 so thai we apprehend a 3- instead of a 2-rhythm, or we may sub- 

 stitute a rising for a falling rhythm. 



The foregoing offeis an explanation for other familiar features of 

 subjective rhytlimisation. 



The quicker the rate of succesion of stimuli the larger will be 

 the groups in which they are included. We endeavour to apprehend 

 well as many stimuli as is possible, the slower the movement the 

 larger will be the number of stimuli we pei'ceive distinctly. When 

 the rate of succession increases a 2-rliytlim is changed into a 3-rhythm, 

 i\ 3-rliylhm becomes a 4-rhythm, etc. 



It is also e\ ident that the rate of the movement must not exceed 

 certain bounds. When the pauses between two stimuli are too long, 

 all our attention may be directed to every separate stimulus, tlie 

 percei)tion of evei-y stimulus attains its maximal intensity, so that no 

 rhytlimisation will occur. When the pauses are too short, we cannot 

 single out any stimulus, they run together into a vague entity. 



It is also clear now that a sensation of relaxation (a pleasurable 

 relief) is aroused when, after being constrained to intently follow 

 a series of stimuli, we perceive them rhythmically, because of the 

 much smaller demand upon our attention. 



Ill experimenting it will be noted that the observer's aptitnde for 

 the rhythmic perception of a series of stimuli is ever increasing. 

 Ultimately a certain rhythm will stick to him, it has so to say 

 become an obsession. 



It is just the same with special series of regular stimuli, which 

 conlinually affect us in every-day life, such as the ticking of a 

 clock, in which every one recognizes a rhythm, without being alile 

 to lireak away from it. 



