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elements] will tend to show is that their responses . . . will tend to diminish.
When the stimulus is repeated monotonously, the phenomenon is well known
under the name of “habituation.” We can also recognise, in everyday experi-
ence, a tendency for what is at first interesting and evocative to become later
boring and uninspiring. Whether the extreme unresponsiveness of melancholia
is really an exaggeration of this process is unknown, but the possibility deserves
consideration. What makes the possibility specially interesting is that the theory
of such statistical systems makes it quite clear that any complex network that
has progressed to a non-responding state can, in general, be made responsive
again by administering to it any large and random disturbance. The theory also
makes clear that such a disturbance will necessarily disturb severely the sys-
tem's memory: the parallel with E. C. T.'s effect on memory is obvious. Whether,
however, E. C. T. acts in essentially this way is a question for the future.
This passage is remarkable in at least two ways. First, it does not belong
in Ashby's essay at all. If taken seriously, it undercuts the entire rationale for
the biochemical investigations reported there. Second, and more important
in the present context, it makes an explicit connection between Ashby's cy-
bernetics and his work on DAMS on the one hand, and his interest in ECT
and its functioning on the other, and we can return to DAMS here.
39
A journal
entry of 25 August 1951 records that “while working with DAMS I found I was
unconsciously expecting it to 'run down,' then I realised what was happening,
& that my expectation was not unreasonable, was a new idea in fact.” Then
follows the first discussion of “habituation” in DAMS (though Ashby does not
use the word here): “there is therefore a tendency for the neons to change
their average 'readiness' from 'more' to 'less.' ” And Ashby immediately moves
from this observation to a consideration of the antidotes to habituation: “After
this initial reserve of changeable neons has been used up the system's pos-
sibilities are more restricted. The only way to restore the possibilities is to
switch the set off, or perhaps to put in some other change quite different
from those used during the routine. This fact can obviously be generalised to
a principle.” As just mentioned, there was a stock equation in the cybernetics
of this period between switching off a machine and sleep therapy for mental
illness, though Ashby does not comment on this in his note. However, there
then follows a quick sketch of the argument that in its response to a new and
different input, DAMS will regain its prehabituation sensitivity to the old one,
after which Ashby concludes: “Summary: A multistable system tends to lose
reactivity, which will often be restored by applying some strong, but unre-
