topics: |  cognitive | neuro-psychology | brain | subconscious

A paean to the unconscious that makes decisions instantaneously based on
signals that the conscious brain is completely unaware of.

Excerpts

From hunch to theory

Gamblers - given four deck of cards - A,B (red) and C,D (blue).  The red cards
   give high payoffs, but also have high costs.  The blue cards give slow
   payoffs, but are better in the long run.  By the 50th card, gamblers
   have a hunch that the blue cards are a better bet.  By the 80th card,
   they can tell you why.  The brain has formed a theory.

But the amazing finding is that when researchers put sensors on the palm to
measure sweat (skin conductance response or SCR) - the sweat glands under
the palm produce more sweat when we are hot, but also when under stress
(that's why we have "clammy hands" when stressed.)  They found that
the subjects were generating stress responses to the red deck as
early as the tenth card, forty cards before they could were able to say
that they had a hunch ... Right around this time, their behaviour also
started favouring the blue cards and taking fewer and fewer of the
reds... [p.9]

Antoine Bechara, Antonio Damasio et al 1997, Science: Deciding
    advantageously before knowing the advantageous strategy
    (see also Damasio's "Descartes' Error"). 

Excerpt from paper: 
    After sampling all four decks, and before encountering any losses,
    subjects preferred decks A and B and did not generate significant
    anticipatory SCRs. We called this period pre-punishment. After
    encountering a few losses in decks A or B (usually by card 10), normal
    participants began to generate anticipatory SCRs to decks A and B. Yet by
    card 20, all indicated that they did not have a clue about what was going
    on.  We called thisb period pre-hunch (Fig. 1). By about card 50, all
    normal participants began to express a “hunch” that decks A and B were
    riskier and all generated anticipatory SCRs whenever they pondered a
    choice from deck A or B. We called this period hunch.  By card 80, many
    normal participants expressed knowledge about why, in the long run, decks
    A and B were bad and decks C and D were good. We called this period
    conceptual. Seven of the 10 normal participants reached the conceptual
    period, during which they continued to avoid the bad decks, and continued
    to generate SCRs whenever they considered sampling again from the bad
    decks. Remarkably, the three normal participants who did not reach the
    conceptual period still made advantageous choices.

Main claim from abstract:
 	Deciding advantageously in a complex situation is thought to require
	overt reasoning on declarative knowledge, namely, on facts pertaining
	to premises, options for action, and outcomes of actions that embody
	the pertinent previous experience. An alternative possibility was
	investigated: that overt reasoning is preceded by a nonconscious
	biasing step that uses neural systems other than those that support
	declarative knowledge.... The results suggest that, in normal
	individuals, nonconscious biases guide behavior before conscious
	knowledge does. Without the help of such biases, overt knowledge may
	be insufficient to ensure advantageous behavior.

[The main purpose of this book is to outline the functioning of this rapid
decision learning system, which is the "Blink" of the title. ]

Deciding if a prof is good or bad

How long did it take you, when you were at college, to decide how good
a teacher your prof was?  a class? a week? a semester? Ambady gave
students three ten-second videos of a teacher - without sound - and
they could easily rate the teacher's [PUNCT] effectiveness.  They were
remarkably consistent even when she showed the students just two
seconds.  Comparing these snap decisions with student evaluations
after a full semester, remarkable agreement. [p.13]

[Nalini Ambady, Robert Rosenthal 1993 Half a minute: Predicting
 teacher evaluations from thin slices of nonverbal behaviour and
 physical attractiveness.  Journal of Personality and Social Psychology]

[Timothy Wilson: Strangers to Ourselves: Discovering the Adaptive Unconscious
 (Harvard U Press 2002) - "the psychologist who has thought extensively and
 has written the most accessible account of the computer inside our mind"]

Kouros - rare greek statue - experts had instantaneous reactions -
"something's wrong", "too fresh", "intuitive repulsion"... which on
prolonged further evaluation, turn out to be correct. [p.5-8]