three stimulations is capable of reversing the direction of the
constant error, an intensity change in a given direction changing the
error from positive to negative for some subjects, and from negative
to positive for others.


III. INTERPRETATION OF RESULTS.


We may say provisionally that the _change_ from a tactual stimulation
of one kind to a tactual stimulation of another kind tends to lengthen
subjectively the interval which the two limit. If we apply the same
generalization to the other sensorial realms, we discover that it
agrees with the general results obtained by Meumann[15] in
investigating the effects of intensity changes upon auditory time, and
also with the results obtained by Schumann[16] in investigations with
stimulations addressed alternately to one ear and to the other.
Meumann reports also that the change from stimulation of one sense to
stimulation of another subjectively lengthens the corresponding
interval.

[15] _op. cit._ (II.), S. 289-297.

[16] _op. cit._, S. 67.

What, then, are the factors, introduced by the change, which produce
this lengthening effect? The results of introspection on the part of
some of the subjects of our experiments furnish the clue which may
enable us to construct a working hypothesis.