> From: "Young, Mark" <MYOUNG92@psy.soton.ac.uk>
> Date: Thu, 11 May 1995 19:08:38 GMT
>
> There are experiments (eg. Underwood, 1965; Roediger & McDermott, in
> press) in which false recognition of a word list has been induced by
> implicit associative responses. That is, an early word on the list
> might be intended to provoke an associate in your mind, but this will
> be done implicitly. Later on you claim to recognise this associate,
> even though it wasn't actually presented.
A good example, on the one hand, of the kinds of tricks the brain plays
on you in filling in the gaps -- if it sounds familiar, you must have
heard it -- and, on the other hand, it shows how many ways degraded
information can be resuscitated retrospectively. Is it hindsight,
reconstruction? invention? This will come up next wek when we discuss
Dennett & Knisbourne's Orwellian vs. Stalinesque memories...
> If we're all actually conscious and "running our own show", surely
> under these conditions we wouldn't succumb to these false
> recognitions, as it makes us look like spanners.
Well, since the other-minds barrier is impenetrable, no one can know
FOR SURE what experience a person has or has not had except that
person. Maybe the association was so vivid it would have been
indistinguishable from a real perception. Especially from hindsight.
Certainly no one is an authority on that except the subject (that's why
it's called "subjective" or "1st-person" experience)...
> Also, I can't help feeling that the people who say a measure of
> consciousness just isn't sensitive enough if it finds implicit
> learning, are really just trying to move the goalposts. Surely the
> fact that people aren't reporting "awareness" on a questionnaire is
> exactly the point? Does consciousness not imply subjectivity?
That was Richard's Popperian point too, and I agree. And consciousness
IS subjectivity. And Descartes was right that a subject cannot be wrong
about what SEEMS to be going on. As to what is REALLY going on (i.e.,
did you really hear that, or did you just seem to), who's to say? I
could forget, or misremember. What seems to be happening now may or may
not be the same as what will seem to have been happening a moment ago,
a moment from now. Stay tuned for Orwell and Stalin next week. S.H.
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Dennett, Daniel C.; Kinsbourne, Marcel. Time and the observer: The
where and when of consciousness in the brain.
Behavioral & Brain Sciences, 1992 Jun, v15 (n2):183-247.
<b>ABSTRACT:</b> Compared the ways in which the Cartesian Theater model
(CTM) and the Multiple Drafts model (MDM) of consciousness treat
subjective timing. According to CTM, there is a place in the brain
where discriminations in all modalities are put into registration and
presented for subjective judgment. The timing of events is thought to
determine subjective order. According to the MDM, discriminations are
distributed in space and time in the brain. These events are thought to
have temporal properties, but those properties do not determine
subjective order because there is no single, definitive stream of
consciousness, only a parallel stream of conflicting and continuously
revised contents. MDM does a better job of explaining such puzzling
phenomena as backwards referral in time and gradual apparent motion
phenomena involving abrupt color change. 29 comments follow, and the
authors respond.
Libet, Benjamin. Unconscious cerebral initiative and the role of
conscious will in voluntary action. Behavioral & Brain Sciences, 1985
Dec, v8 (n4):529-566.
<b>ABSTRACT:</b> Studied unconscious cerebral initiative and the role
of conscio us will in voluntary action (VOA), by measuring
electromyogram (EMG) changes in a muscle after finger or wrist flexing.
Data indicate that VOAs can be initiated by unconscious cerebral
processes before conscious intention appears, but that conscious
control over the actual motor performance of the acts remains possible.
VOAs are preceded by electrophysiological "readiness potentials" (RPs).
The negative RP shift for unplanned spontaneous acts was used to
indicate the minimum onset times for the cerebral activity preceding a
fully endogenous VOA. Subjects' initial awareness of intending or
wanting to move occurred at -200 msec. The final decision to act could
still be consciously controlled during the 150 msec remaining after the
specific conscious intention appeared. Subjects could veto motor
performance during a 100-200 msec period before a prearranged time to
act. Commentary by 24 other authors and the author's own reply are
provided.
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