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Our future, our universe, and other weighty topics


Wednesday, May 4, 2016

Neuroscience or Pretentious Prattle?

Normally Scientific American has some fairly intelligent articles, although it occasionally gives us goofy drivel that insults the intelligence of anyone who managed to progress beyond elementary school. An example is a recent article entitled “What Neuroscience Says About Free Will.”

The author suggests an absurd hypothesis: “Perhaps in the very moments that we experience a choice, our minds are rewriting history, fooling us into thinking that this choice—that was actually completed after its consequences were subconsciously perceived—was a choice that we had made all along.” Subconscious “rewriting history” in just a moment of time? Get real.

The author then describes an experiment he did apparently designed to support this idea. The experiment is described as follows:

Participants were repeatedly presented with five white circles in random locations on a computer monitor and were asked to quickly choose one of the circles in their head before one lit up red. If a circle turned red so fast that they didn’t feel like they were able to complete their choice, participants could indicate that they ran out of time. Otherwise, they indicated whether they had chosen the red circle (before it turned red) or had chosen a different circle. Unbeknownst to participants, the circle that lit up red on each trial of the experiment was selected completely randomly by our computer script. Hence, if participants were truly completing their choices when they claimed to be completing them—before one of the circles turned red—they should have chosen the red circle on approximately 1 in 5 trials. Yet participants’ reported performance deviated unrealistically far from this 20% probability, exceeding 30% when a circle turned red especially quickly.

The author suggests absurdly that this little test suggests something about free will – that “it might be nothing more than a trick the brain plays on itself.” The experiment suggests nothing at all about free will. The experiment simply tells us minor stuff about human performance and memory that we already knew.

Here are some basic facts about human performance and memory that are rather well known:
  1. When they don't have much motivation, people may perform poorly on tests that require concentration.
  2. People may perform poorly on boring tests.
  3. People may perform poorly on tests that ask them to do something they have never tried to do.
  4. People remember fairly well interesting or important things (such as a human face), but may have a poor remembrance of abstract things such as the position of white circles on a computer screen.
  5. People have a good memory for important choices, but don't remember well meaningless choices such as which of 5 white circles on a computer screen they chose in their minds.
  6. Performance tends to deteriorate when things are sped up so that things are appearing on the test screen “especially quickly.”

The fact that performance tends to degrade unpredictably when humans interface with a machine that is sped up “especially quickly” has been known since as least the 1950's, when it was demonstrated in this hilarious scene from the “I Love Lucy” television show starring Lucille Ball.



Given all these things, it is predictable that you would get exactly the results reported, even if free will is perfectly real, and even if there is nothing at all like “the mind tricking itself.”

Now given these facts, imagine you are some college student who has signed up for some test like the test described. You know that no matter how poorly you perform, you will get the same reward (which may be an hourly wage or perhaps some academic credit). So when the test speeds up, are you going to concentrate very hard, trying real hard to remember where those boring little white circles were on the screen? Knowing that it makes no difference whether you try hard, you will be just as likely to not try very hard (perhaps while the test is running, you'll be daydreaming or thinking about that pretty woman you saw last night). So when you see some little red circles popping up at a faster rate, there's a good chance that you'll just kind of “flip a coin” in your mind as to whether or not you specify that was the position that you previously chose in your mind. Knowing that the experimenter can't know which white circle you chose in your mind, you may be thinking to yourself, “No one will ever know.” Given a certain fraction of slacker subjects who are just lazily taking this kind of approach to the test, we would expect exactly the results reported.

Even if we imagine no such slacker subjects, the results reported could be plausibly explained by simply imagining that humans don't do very well at remembering meaningless choices they have made, and don't remember well the positions of meaningless things. In fact, we're not even very good at remembering the position of meaningful things. If you ask someone to bring up an image of Brad Pitt, and then close the image, and then ask that person on which fourth of the computer screen Brad's head was located, there is maybe a 25% chance they'll give the wrong answer. The fact that there was an option in the test for specifying “I didn't have time to choose” means very little, because subjects would have a psychological aversion for selecting an option which might tend to identify them as slow-minded (a kind “I'm a slow dummy” button).

The author's laughable suggestion that the predictable result of the experiment is an example of neuroscience telling us something about free will (that free will is an illusion) is just an example of pretentious glory hunger. Entirely lacking in such grandiose implications, the trivial experiment is so unsurprising that it deserves nothing but a yawn. The experiment is also not an example of neuroscience, which the Merriam Webster dictionary tells us is “ a branch (as neurophysiology) of the life sciences that deals with the anatomy, physiology, biochemistry, or molecular biology of nerves and nervous tissue and especially with their relation to behavior and learning.” Doing little experiments like this (without monitoring of the brain) is not neuroscience, but mere garden-variety psychology experimentation. Psychology experimentation is soft science, and it should not be sold as hard science. 

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The lesson we can learn here is that we should not assume scientists are always reliable interpreters of the data they collect. They very often are not. Given a choice between interpreting some data in a plausible way, and between interpreting the data in some implausible way that matches his philosophical biases, a scientist may choose the latter.