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Nov 24 2010

On free will-12: How about quick decisions?

(For previous posts in this series, see here.)

The 2008 research findings of Soon et. al., gave the surprising result that when we are allowed time to make decisions, our subconscious neural networks make the decisions up to ten seconds before we are consciously aware of it.

Of course, there are many situations in which we act without seeming to make any conscious decisions at all. If an object is suddenly thrown at us, we may duck, dodge, deflect, hit, or catch it, the ‘choice’ seemingly being made in much less than a second. In such cases, the action seems involuntary and we assign it to instinct, which is just another name for the unconscious neural activity of our brains. The instinct to duck when an object is directed at our head or to withdraw our hands from a hot object is due to the neural system having developed shortcuts because of its obvious survival value and has been selected for over a long time in our evolutionary history. The part of the brain that codes instincts must necessarily act very quickly to give commands to the motor brain in response to stimuli from the environment. Certain stimuli trigger a stimulus-action connection that bypasses those sections of the brain that indulge in time-consuming activities such as processing information and making judgments.

It is almost impossible to avoid, for example, even flinching when an object comes close to our eyes. Some people can do so after much practice, suggesting that they have over time developed new neural networks that can override their original instinct to create a new instinct that responds this way to specific stimuli.

But what about the case of (say) a tennis player who, seeing the ball come directly towards her over the net, seems to consciously choose in an instant whether to hit a forehand or backhand, return the ball cross-court or down the line, hit it short or deep? In this case, there seems to be a conscious decision being made and carried out, though the time available is a fraction of a second. It is such things that give us such a firm conviction that there is some part of us that is freely and consciously deciding things. How can we explain such decisions in the absence of free will?

I have not yet been able to track down studies on this particular question of brain activity for quick responses, so what I am going to suggest is pure speculation on my part, starting from the assumption that there is no free will.

The only way I can think of to explain how the tennis player’s responds is that when the ball is hit to her, the E (environment) part of the Genetics (G)-Environment (E)-Stochastic (S) model of the brain is triggered, which sets in motion a predetermined response. The unconscious neural network that decides what command to give the motor brain also sends a signal to our conscious thoughts/will that arrives there a fraction of an instant before the motor action is carried out. The fact that the conscious thought occurs before the action gives us the sense that the former caused the latter, when in actual fact both are the products of unconscious neural network activity in response to external stimuli.

This model might suggest that a tennis player will do the same thing in each situation, making their play highly predictable. In fact, there is considerable predictability in the way that athletes respond to game situations. There is a huge industry in professional sports devoted to analyzing individual players to detect patterns of their play so that their opponents can predict what the player will do in a response to a given situation and devise countermeasures.

But an expert tennis player does seem on occasion to be able to vary her shots to catch her opponent off-guard by doing the unexpected. This could be due to the fact that the stimuli they are responding to, though they may appear to be identical at a coarse level of observation, are not really exactly the same and thus cause different responses due to tiny variations. It may also be the case that there is a unpredictable element in the workings of the neural network (what I have referred to as stochastic processes) that sometimes cause her to go cross-court one time, and down the line the next, with the appropriate conscious thought being created just before the act takes place.

If this is the case, then that means that all the time when we think we are making quick decisions and acting on them, such as when we are driving, making conversation, playing sports, and so on, we are actually responding instinctively, the only difference from pure instinct (such as ducking to avoid an object coming towards our head) is that there is enough elapsed time between the decision made by our subconscious brain and the action for the subconscious brain to send a signal to our conscious brain just before the action is taken, giving us the illusion of being in control and consciously making decisions.

The part of the brain that makes quick decisions acts very much like instinct in terms of both the speed of the response and the involuntary nature of the act, except that ‘true’ instinctive responses have been hardwired into our brains over a long period of evolutionary time and we acquire them via our genes, while these quick decision responses are due to neural networks that we create over our own lifetimes and are unique to us.

Studies show that to become really competent at any skill or profession or sport (such as tennis), it takes about ten years of sustained practice. Perhaps that is how long it takes for a brain to develop the full range of synapses that enables it to respond with a range of subtle and sophisticated reactions to a wide variety of external stimuli. It is this variety of responses that gives us the illusion that we are making deliberate choices about how to respond to the current situation, rather than simply reacting based on our past experiences.

For example, when we learn to drive, we have to pay attention to road signs, to other cars and pedestrians, and be aware of the need, before changing lanes, to check the read view mirror, the side mirror, look over the shoulder for the blind spot, signal, then turn the wheel, and so on. For the novice driver, keeping all these things in the conscious mind makes driving nerve wracking, and every decision seems to take ages. I remember when learning to drive that I was mentally exhausted at the end of even a short practice session. But after much experience, we do all these things quickly and ‘without thinking’ which means that we have developed the appropriate neural networks that spring into action and provides the appropriate pre-determined response depending on the need.

It is not that we are not thinking about driving (or playing tennis) but have developed our own neural networks that enable us to think at a higher conceptual level, rather than at the level of the individual steps. So when we drive, the higher conceptual category of ‘change lanes’ triggers those neural networks that carry out all the required actions automatically. This may also explain why it is so hard to change the way we are used to doing things and the importance of developing good habits early.

Next in the series: Dealing with the consequences of not having free will

1 comment

  1. 1
    healthphysicist

    I really see no need to make a distintion between quick and slow decisions.

    Neuronal action potentials operate in the millisecond range. Some are constantly emitting action potentials at rates of 10-100 per second.

    http://en.wikipedia.org/wiki/Action_potential

    When the environment is moving faster than the action potentials we are incapable of making a decision…ie, when the ball is travelling too fast, the tennis player’s mind can’t address it, and the ball whizzes by, before the player can respond.

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