One of the fundamental problems of studying the phenomenon of Consciousness is in defining it objectively. To define it, one has to make a replicable model of consciousness, using some universal aspect of animal behavior that can be measured independent of the internal state of the individual’s brain in a lab setting.
Neuroscientists have, long ago, concurred on the usefulness of measuring CONFIDENCE as a function of consciousness.
What is this?
Let me explain a bit:
A subject has to see the direction of movement of a blinking dot on a screen first. After seeing, he has to decide for sure which direction the movement occurred. Since the perception of movement and the decision on its direction can be “unconscious” as far as the brain is concerned. So, to make this unconscious perception a conscious and purposeful one, the subject is asked to make a finite choice – a sort of betting – on the direction of the motion of the blotch on the screen by means of selecting a number. For example, 1 to indicate pure guessing, 2 for some uncertainty and 3 for complete certainty. This procedure assumes that when the subject has little awareness of the dots’ direction of motion his confidence is low, whereas if he clearly “saw” the motion, his confidence is high.
Navindra Persaud of the University of Toronto and Peter McLeod and Alan Cowey of Oxford University took this to the next step, by adding a bit of “real” gambling (Nature Neuroscience January 2007). In their version, subjects first make a decision regarding whether they’ve perceived something and then must gamble either a small or a large amount of money on their confidence in this decision.
Their first experiment involved a patient code-named GY. This man has a rare acquired pathology called “blindsight”. His brain areas involved in the sense of vision were damaged in an accident. Now, his eyes “see” the blotch on the screen but since the visual areas of the brain never receive signals from the eyes, he doesn’t have the “conscious” feeling of having seen the blotch. But physiologically speaking, he does “see” the blotches. The phenomenon of “blindsight” gives scientists an opportunity to test the subjective “unconscious” feelings and make the patient convert them into “conscious” feelings. When asked to indicate the presence or absence of a faint, small grating on a computer screen, he does so correctly in 70 % of all trials, which is far above chance (50 %). Yet he fails to convert this superior performance into money when betting; he places a high bet on only about half (48 %) of his correct choices. When GY is consciously aware of the stimulus, he wagers high, much as we all would. His gambling thus seems to reflect his conscious awareness of his belief that he saw the blotch rather than his actual (unconscious) detection of the stimulus, suggesting that Gambling may provide a means to measure awareness.
The second experiment involves an artificial grammar task. In this task participants learn a small number of short letter sequences. They are then told that the sequences obeyed a simple rule (like for example, that every “x” is always followed by an “a”). But they are not told what the rule is. When shown a new sequence, subjects mostly determine correctly whether the new sequence follows the unknown rule. Yet very rarely can the subjects decipher why they believe a sequence does or does not obey the rule. The overall rate of correct classification is 81%.Yet subjects do not convert performance into money. High bets follow a correct choice 45 % of the time and follow a false choice 32 % of the time. In short, the subjects are usually right about whether the sequence follows the rule, but they lack enough confidence to bet on it.In the final experiment, the Iowa gambling task subjects pick the top card from one of four decks. Each card wins or loses the subject a certain amount of money. Two of the four decks have a net positive yield and two a negative yield, which the subjects don’t know. Subjects place a low or a high bet on the chosen card before it is revealed and lose or win accordingly. The outcome of the experiment is that they usually turn over at least 30 cards on those decks before they gain the confidence to bet aggressively on the results. That is, they wait for a certain time before they can believe in their own knowledge of the nature of the decks.
But whenever the subjects were questioned about their knowledge of the “rule” of the card game, the subjects increasingly started aggressive betting. The questioning gave them a way to ponder on their own knowledge and how it could be turned advantageous. This demonstrates that if subjects learn to trust their gut they can do better.
The wagering techniques used by Persaud, McLeod and Cowey rely on people’s instinct for reaping a profit. This method is a far better one in reliably measuring consciousness b’coz it doesn’t alter the instinct. Rather, it simply assesses how one converts the unconscious perception into a purposeful, conscious, action.