Now finally, as regards the apparent failure of the change in _SSW_ to
lengthen the second interval, for which we are seeking to account; the
comparatively great loss of time occurring where the change of
attitude would naturally be most difficult (that is, where it is
complicated with a change of attention from a strong stimulation to
the higher key of a weak stimulation) is sufficient to explain why
with most subjects the lengthening effect upon the second interval is
more than neutralized. The individual differences mentioned in the
preceding paragraph as affecting the relation of the two factors
determining the constant error, enter here of course to modify the
judgments and cause disagreement among the results for different
subjects.

Briefly stated, the most important points upon which this discussion
hinges are thus the following: We have shown--

1. That the introduction of either a local difference or a
difference of intensity in the tactual stimulations limiting
an interval has, in general, the effect of causing the
interval to appear longer than it otherwise would appear.

2. That the apparent exceptions to the above rule are, (_a_)
that the _increase_ of the local difference in the first
interval, the stimulated areas remaining unchanged, produces a
slight _decrease_ in the subjective lengthening of the
interval, and (_b_) that in certain cases a difference in
intensity of the stimulations limiting the second interval
apparently causes the interval to seem shorter than it
otherwise would.