Measuring the unconscious mind By Epsos.de

Measuring the unconscious mind

People are unaware of much of the knowledge they possess, making it hard for psychologists to study this knowledge. We need ways to investigate the unconscious mind, and perhaps making use of people’s greediness is one of the ways to do this.

One of the goals (and some would say the most important goal) of psychology is to study the contents of the human mind. Normally, getting to know the contents of the mind requires interrogating people: what did you see? how do you feel? what did you think? While this may seem a straightforward way to investigate the mind, it is riddled with problems.

The problem we face when asking people what they think or believe is that people cannot always accurately describe such content. You may know the feeling that you have a hunch, or suspicion, that something is the case, but are not able to express it in words. And maybe you are even completely unaware of some of the knowledge that you have.

Researchers wanting to find out how conscious and unconscious knowledge are used prepared a card game in which participants could pick cards from one of four decks. Most of the time picking a card would result in winning money, but some cards would result in a penalty where the participant would lose money. However, the researchers rigged the game so that two of the decks would provide net winnings, whereas the other two would result in net losses.

As people were playing the game, they slowly started to avoid the two ‘bad’ decks. However, when they were asked if they understood the nature of the game most people could not say why they behaved the way they did, and instead reported having a ‘hunch’ or a ‘gut feeling’. It was not until the 80th card that they could explicitly identify the good and bad decks. Clearly, people have knowledge without being able to report it.

Apparently, by looking at behavior we can see evidence of unconscious knowledge. Some researchers have proposed yet other ways to study the unconscious mind. One of these methods assumes that offering people money makes them more willing to use their knowledge. This is how it works: you force people to make a choice and ask them to wager money on the correctness of their choice - a method known as post-decision wagering. If they are correct, they win money, if not, they lose money.

We decided to put this this method to the test, and flashed numbers on a computer screen for a split second. Then, we asked one group of people to wager money on whether or not they saw the numbers. Also, we asked another group of people to just indicate how clearly they saw these numbers, without betting any money. It turns out that people were more accurate in indicating that they saw these numbers if you asked them to wager money on it! Apparently, they have some knowledge that they only use when they can earn money. Maybe it’s time for universities to start paying students for passing exams...

Read more about this research in the publication 'Consciousness of targets during the attentional blink: A gradual or all-or-none dimension?' by Sander Nieuwenhuis and Roy de Kleijn, published in 2011 in Attention, Perception, & Psychophysics, 73, 364–373.


Rich Norman

The wagering of money does alter the distribution of attention, but it seems that this is an alteration in the attention paid to the uncomfortable task of interpreting the residual internal stimulus. The other day I got glasses, and had to pay attention to the ever more blurred letters. It was easier to give an answer of, "I do not know, it is too blurry." Here, an indistinct internal stimulus requires unpleasant amounts of effort to interpret. When cajoled by the doctor, I was able to interpret the letters! Money provides the additional incentive to interpret. This may be a factor, perceptual interpretive discomfort, in the graded nature of unconscious influence upon perception, should the idea prove out.

The notion of the unconscious is never used to my satisfaction these days. I love cognitive-neuroscience, but, no attention is paid to the real psychoanalytic unconscious. Neuro-Psychoanalysis seeks to unite depth-psychology and cognitive-neuroscience with worthy result, but, does so referring to subjects mainly with brain lesions, etc. Quantitative assessment of unconscious processes proper should be available with our current MEG and fMRI technology. I believe I have the method. A new paradigm of sorts...part physics, part psychology. I am looking for a lab to take interest. (I am outside of the academic system, but write in proper form). Quantitative diagnosis of mental illness and unconscious content. Do you have any suggestions?

Rich Norman www.richnorman.com

Roy de Kleijn

@ Alex: Yes it would. It's a fine line between accuracy and entertainment value.

@ Edward: Paying more attention does not seem to increase accuracy of T2 detection in an AB paradigm. In fact, instruction to pay less attention seems to decrease the attentional blink (see Olivers & Nieuwenhuis, 2006, JEP:HPP).

@ Marco: Risk-taking behavior as measured by the Columbia Card Task did not seem to correlate with accuracy or mean wagering amount (preliminary analyses). I agree with your idea of 'hunches' and intuition. Where in pure gambling these hunches might serve no purpose, in tasks such as this these hunches may actually reflect knowledge (or 'information' as you will ;-)

Marco L

Cool article! I think what the experiment most interestingly showcases is the grey area between conscious 'knowledge' and subconscious 'information' which has yet to manifest as actual knowledge.

Interesting herein is money as an incentive, whether it augments the role of 'gut feelings' in decision making, or simply raises attention, engagement, or the mental work one is willing to perform, might be open for debate.

Personally though, I think the first, this is why:
Money as an incentive might prime people into gambling-like behavior: Over confident, more daring to take risks and listen to hunches and gut feelings, especially in the absence of any other reliable method to base decisions on.

Where normally this gambling-attitude simply results in people losing money because actual gambling is sheer luck, in this experiment one would benefit greatly from being more open and trusting towards listening to their 'hunches' and intuition.

Personally I think that the morale of the story is: "Know when to trust your intuition". Learn to read and interpret those gut feelings! Many are closed to instinct and intuition, even though it's the source of all genius. Oh think of all the kinds of wonders that may lie dormant beneath this grey veil of subconsciousness!

(excuse me for the long comment, sog etc)

Edward Spruit

Cool study, but I think the results would be better explained by attributing the increase in performance in the 'money-wagering' group to an increase in task utility that urged the participants to be more engaged in the task (i.e. they payed more attention because there was more to gain), rather than a difference in access to unconscious knowledge.


Wait. Wouldn't a more accurate parallel be to ask students to wager money on the questions of the exams?

Getting paid would be worse:


Leuk blog! Wou dat ik betaald was voor elk gehaald tentamen...

Bruno Weijenborg

Interessant stuk, ik houd een oogje in het zeil ;)