.

For if the activity of the mind itself be more energetic, or takes its
attention more, than the connecting word, which is wanted; it will not
perceive the slighter link of this lost word; as who listens to a feeble
sound, must be very silent and motionless; so that in this case the very
vigour of the mind itself seems to prevent it from regaining the lost
catenation, as well as the too great exertion in endeavouring to regain it,
according to the tenth preceding article.

We frequently experience, when we are doubtful about the spelling of a
word, that the greater voluntary exertion we use, that is the more
intensely we think about it, the further are we from regaining the lost
association between the letters of it, but which readily recurs when we
have become careless about it. In the same manner, after having for an hour
laboured to recollect the name of some absent person, it shall seem,
particularly after sleep, to come into the mind as it were spontaneously;
that is the word we are in search of, was joined to the preceding one by
association; this association being dissevered, we endeavour to recover it
by volition; this very action of the mind strikes our attention more, than
the faint link of association, and we find it impossible by this means to
retrieve the lost word. After sleep, when volition is entirely suspended,
the mind becomes capable of perceiving the fainter link of association, and
the word is regained.

On this circumstance depends the impediment of speech before mentioned; the
first syllable of a word is causable by volition, but the remainder of it
is in common conversation introduced by its associations with this first
syllable acquired by long habit. Hence when the mind of the stammerer is
vehemently employed on some idea of ambition of shining, or fear of not
succeeding, the associations of the motions of the muscles of articulation
with each other become dissevered by this greater exertion, and he
endeavours in vain by voluntary efforts to rejoin the broken association.
For this purpose he continues to repeat the first syllable, which is
causable by volition, and strives in vain, by various distortions of
countenance, to produce the next links, which are subject to association.
See Class IV. 3. 1. 1.

11. After our accomplished musician has acquired great variety of tunes and
songs, so that some of them begin to cease to be easily recollected, she
finds progressive trains of musical note