Spring 2008 Class #21: Consciousness and Theory of Mind; Free Will

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EEB 210

Spring 2008
Class #21: Consciousness and Theory of Mind; free will

The word ‘consciousness’ first appears early in the 17th century, rapidly followed by ‘self-conscious’ and ‘self-consciousness’. The word has its Latin root in conscio, formed by the coalescence of cum (meaning ‘with’) and scio (meaning ‘know’). The word consciousness has come to have 3 principal meanings:

1)Consciousness as a waking state, as opposed to sleep or coma for example: i.e., After a lucid interval, the injured soldier lapsed into unconsciousness

2)Consciousness as experience---that is, to be conscious, or aware, of something: i.e., I became conscious of a feeling of dread, and an overpowering smell of burning rubber.

3)Consciousness as mind---anything that we believe, hope, fear, intend, expect, desire, etc. Thus, we might accurately say that ‘the prime minister is conscious of the funding crisis in the health service’ even at a time when his immediate thoughts are otherwise occupied: i.e., I am conscious that I may be straining your patience.

Part played by language in thought process---Many problems almost impossible to solve without thinking in words or even writing down information as it accumulates---think about multiplying two 5-digit numbers

Plato’s analogy of many birds in a cage, grouped in flocks, singly, etc.---but now that you have all the birds, how do you get the ones you want?---Analogy to how one strings together appropriate thoughts or pieces of information during the reasoning (problem solving) process

Consider a ‘game’ like “The Prisoners’ Dilemma”: Two suspects in a crime investigation are being separately interrogated by the police. Each is told that (1) if both confess they will each receive a 3-year prison term. If neither confesses, they will each receive a 2-year prison term. If one confesses and the other maintains his innocence, the one that confesses will go to prison for 1 year and the other will be sent to prison for 5 years. What will the suspects do? The answer depends to a large degree on their degree of trust in each other. In general, the safest strategy may be to confess, since the other suspect is likely to ‘defect’ and confess as he assesses the same situation.

Animals have evolved to deal with situations like this that occur in nature---that is, by responding to situations in which cooperation with another individual would lead to some benefit, but where there is a risk of defection by the other individual that would lead to high cost. In such situations, animals often fail to cooperate with each other, but they do so at an unconscious level. Humans have the ability to resolve such situations through reasoning, because we are able to ‘play out’ fairly complex scenarios in our minds.

Sherlock Holmes was very adept at deducing many things about a person just by seeing the way the individual walks, what his/her hands look like, etc. Thus, at some level, the author Sir Arthur Conan Doyle recognized the principle of theory of mind in humans.

Sigmund Freud’s theories regarding the workings of the ‘unconscious’ mind.

The concept of qualia---what perceptions ‘feel like’

Benjamin Libet’s experiments regarding the relation between consciousness and voluntary acts have led to considerable controversy regarding how and when one becomes conscious of an event:

1. in 1960s, Libet performed experiments in humans that suggested that about 500 msec (0.5 sec) of continuous neural activity in somatosensory cortex is required for achieving consciousness of a sensory stimulus

1. however, we seem to become conscious of peripheral sensory stimuli (i.e., touch, sight, etc.) almost immediately; this presents a paradox---why do we seem to be living in real time if 500 msec of cerebral cortical stimulation is required for achieving consciousness of cortical stimulation?

1. further experimental results obtained by Libet in an attempt to answer this question led him to the conclusion that the delay required for the brain to achieve consciousness is real, but that the brain’s consciousness of sensations is automatically referred back in time by about 500 msec

1. the experiment that led Libet to this conclusion was one in which subjects were given electrical stimulation directly to somatosensory cortex, followed after a small time lag by peripheral stimulation---the subject was asked to say which of the stimuli was perceived first---if peripheral stimulation was given less than 500 msec after the beginning of direct cortical stimulation, subjects consistently reported that they became conscious of the peripheral stimulation first

Free will

Later studies of Libet raised doubt about the role of conscious will in performance of voluntary actions

1. readiness potential (RP) can be detected from electrodes placed on scalp prior to performance of voluntary actions

1. Libet asked subjects to perform simple actions and he recorded the times of (a) the RP that preceded the action, (b) the subject’s report of when he/she decided to perform the act (consciousness of a decision), and (c) the actual beginning of the act as indicated by recording muscle potentials

1. RP preceded the beginning of the act by about 550 msec and conscious decision to perform the act preceded the act by only about 200 msec

1. thus, there was a surprising gap of about 350 msec between the onset of the RP and the time of the conscious decision

There are some controversial aspects of this study that have led to much debate over interpretation: recording of the time of RP and muscle potentials is simple and unambiguous, but recording the time of conscious decision is not, since it requires verbal reporting by the subject