nd that quickly succeeding equal or very similar
impressions have a tendency to inhibit each other or to fuse with
each other. Where such an inhibition occurs, we probably ought to
suppose that the perception of the first impression exhausts the
psychical disposition for this particular mental experience. The
psychophysical apparatus becomes for a moment unable to arouse the
same impression once more.

The above described new experiments suggest to me that this inhibition
of equal or similar impressions is found unequally developed in
different individuals. They possess a different tendency to temporary
exhaustion of psychophysical dispositions. There are evidently persons
who after they have received an impression are unable immediately to
seize the same impression again. Their attention and their whole inner
attitude fails. But there are evidently other persons for whom, on the
contrary, the experience of an impression is a kind of inner
preparation for arousing the same or a similar impression. In their
case the psychophysical dispositions become stimulated and excited,
and therefore favor the repetition. If, as in our experiments, the
task is simply to judge the existence of equal or similar impressions
without any strain of attention, the one group of persons must
underestimate the number of the equal impressions because many words
are simply inhibited in their minds and remain neglected, the other
groups of persons must from their mental dispositions overestimate the
number of similar words. From here we have to take one step more. If
these two groups of persons have to perform a task in which it is
necessary that not a single member of a series of repetitions be
overlooked, it is clear that the two groups must react in a very
different way. Now a perfect perception of every single member is
forced on them. Those who grasp equal impressions easily, and who are
prepared beforehand for every new repetition by their inner
dispositions, will follow the series without strain and will
experience the repetition itself with true satisfaction. On the other
hand, those in whom every impression inhibits the readiness to receive
a repetition, and whose inner energy for the same experience is
exhausted, must feel it as a painful and fatiguing effort if they are
obliged to turn their attention to one member after another in a
uniform series. This mental torture is evidently the displeasure which
such individuals call the disli