On Subconscious Action

from reference 1


The subconscious components of our minds are more powerful than many admit, or feel comfortable admitting. As we go about our lives, our subconsciousness learns about aspects of our existence that might otherwise clutter our thoughts with a distracting chatter of activity: what pressure must I apply to the coffee cup in order for it to remain in my grasp, what route must I take through the throng of commuters in Penn-station to avoid colliding with others, has my blood-sugar dropped below the threshold where I experience hunger, et cetera. In fact, to some extent, the subconscious mind has access to information that the conscious mind does not, as in the muscle tension and blood-sugar examples. Understanding how these abilities are segregated between conscious and unconscious, and to what extent that question even makes sense to ask at both a behavioral and neurophysiological level are of fundamental interest to the understanding of consciousness and human neurological function in general.

A recent study speaks to this topic by probing the extent to which the subconscious can learn about the association between briefly presented visual cues and a monetary reward¹. Specifically, Chris Frith & colleagues had subjects play a game where the ability to win money in a given turn of the game was predicted by a visual cue which was presented too briefly to be consciously perceived (see instructions below²). The results of this study suggest that humans are reliably able to subconsciously learn the rewarding value of these visual cues. Importantly, in a control experiment, the researchers demonstrated that the subjects were unable to discriminate between the stimuli without the monetary reward/punishment scheme.

Given the abilities of humans (sketched above) to relegate processing to the subconscious, this finding isn't that surprising. However, this paper demonstrates the importance of feedback (reward or punishment) for instructing the subconscious. Furthermore, the fact that something as arbitrary as the conscious perception of promised financial reward can serve as the feed-back signal suggests a fundamental role for this type of learning that isn't limited to certain acts, but might underlie the learning abilities of humans in general.

References/Notes:
1. Pessiglione M, Petrovic P, Daunizeau J, Palminteri S, Dolan RJ, Frith CD. Subliminal instrumental conditioning demonstrated in the human brain. Neuron, 59(4): 561-567, 2008.

2. "The aim of the game is to win money, by guessing the outcome of a button press.

At the beginning of each trial you must orient your gaze towards the central cross and pay attention to the
masked cue. You will not be able to perceive the cue which is hidden behind the mask.

When the interrogation dot appears you have 3 seconds to make your choice between
- holding the button down
- leaving the button up
If you change your mind you can still release or press the button until the 3 seconds have elapsed.

‘GO!’ will be written in yellow if, at the end of the 3 seconds delay, the button is being pressed.

Then we will display the outcome of your choice. Not pressing the button is safe: you will always get a
neutral outcome (£0). Pressing the button is of interest but risky: you can equally win £1, get nil (£0) or
lose £1. This depends on which cue was hidden behind the mask.

There is no logical rule to find in this game. If you never press the button, or if you press it every trial,
your overall payoff will be nil. To win money you must guess if the ongoing trial is a winning or a losing
trial. Your choices should be improved trial after trial by your unconscious emotional reactions. Just
follow your gut feelings and you will win, and avoid losing, a lot of pounds! "