Thursday, 22 October 2009

The Secret You: A Review

I watched "The Secret You", a Horizon programme which attempted to investigate the perpetual question "Who am I?" from the point of view of science rather than philosophy.

Of course, one thing the programme rather glossed over was that while the results of experiments into a "sense of self" can be puzzling, and suggest that it is more complex, they have to be interpreted, and this element of interpretation was not really considered strongly. But more of that later.

This was the "blurb" for the programme from the BBC website:

"With the help of a hammer-wielding scientist, Jennifer Aniston and a general anesthetic, Professor Marcus du Sautoy goes in search of answers to one of science's greatest mysteries: how do we know who we are? While the thoughts that make us feel as though we know ourselves are easy to experience, they are notoriously difficult to explain. So, in order to find out where they come from, Marcus subjects himself to a series of probing experiments. He learns at what age our self-awareness emerges and whether other species share this trait. Next, he has his mind scrambled by a cutting-edge experiment in anaesthesia. Having survived that ordeal, Marcus is given an out-of-body experience in a bid to locate his true self. And in Hollywood, he learns how celebrities are helping scientists understand the microscopic activities of our brain. Finally, he takes part in a mind-reading experiment that both helps explain and radically alters his understanding of who he is. "

The age of self-awareness was given by the experiment of a "mirror test" (1) which has been around for some time. It is described here:

"Mirror self-recognition (MSR) as a test for 'knowing oneself' was introduced in 1970 by Gordon Gallup when he revealed that chimpanzees can recognize a colored spot placed on a part of their body, only visible with the help of a mirror, is in fact NOT on another animal, but on the monkey looking into the mirror."(2)

A child was illustrated recognising itself, and then du Sautoy went on to say that only humans and four great apes recognised themselves. But in fact this finding has been replicated in elephants - once the mirrors were large enough in 2006, and dolphins even earlier. In 2008, there was even a study on "Mirror-Induced Behavior in the Magpie" (2) which showed that a few, but not all magpies would replicate noticing the spot and trying to remove it when they saw themselves in a mirror.

But interpretation is still important - "there is debate as to the value of the test as applied to animals who rely primarily on senses other than vision"; in particular, Marc Bekoff (3) worked on the basis that dogs recognition might be more acutely based on smell than vision, and has developed work on self-recognition using dog urine. As he notes in an article in Psychology Today:

"Many animals know such facts as "this is my tail," "this is my territory," "this is my bone or my piece of elk," "this is my mate," and "this is my urine." Their sense of "mine-ness" or "body-ness" is their sense of "self."(4)

"How do animals differentiate themselves from others? Many studies of self-awareness have used mirrors to assess how visual cues are used. They've been effective for captive primates, dolphins and elephants. Although mirror-like visual images are absent in most field situations, it's possible that individuals learn something about themselves from their reflections in water. But we also need to know more about the role of senses other than vision in studies of self-awareness because some animals for example, rodents who can distinguish among individuals don't seem to respond to visual images. Odors and sounds are very important in the worlds of many animals. Many mammals differentiate between their own and others' urine and glandular secretions, and many birds know their own and others' songs. Moving Jethro's "yellow snow" from place to place allowed me to learn that Jethro made fine discriminations between his own and others' urine . Perhaps a sense of self relies on a composite signal that results from integrating information from different senses."(4)

Of course our world is dominated by sight, and so it is natural for us to devise tests that work with a primacy of sight (perhaps why an overlooked omission in the Bible is a description of what people look like). But it was a pity that Horizon not only ignored the elephant and dolphin, but also did not consider how self-recognition be tested in other ways. Incidentally, no one has come up with a test for self-recognition in a blind person, yet blind people clearly have a sense of self. People with autism also have problems with facial recognition, and mirror tests with autistic people have produced mixed results.

Another experiment looked at the research of Libet. This can be easily described as follows, and du Sautoy duly became an experimental subject following very much the pattern described below.

"Put simply, Libet's research, which has been repeated and refined by other neuroscientists, seemed to show that the part of the subject's brain associated with a physical action, for example, pressing a button, showed activity significantly earlier (a few tenths of a second) than the subject became aware of making the decision to act. This research seemed to show that the idea of conscious choice is often an illusion. Whilst we do make conscious decisions which involve forward planning, our day to day actions are automatic. The sense we have of making conscious choices reflect the deep seated need of human beings to make meaning, but it is an illusion."(5)

I knew something I'd read in New Scientist in January this year had re-assessed Libet's research, and eventually I managed to track this down. Neuroscientists Judy Trevena and Jeff Miller questioned Libet's work.

"Their research involved replicating Libet's experiment but with an important modification. While Libet asked his subjects to press buttons, the New Zealand team allowed subjects to choose whether or not to press. Trevena and Miller then found that the brain activity identified by Libet (so called Readiness Potential) occurred after the subjects had been prompted and before they were aware of making a choice - whether or not they then decided to press the button. In other words, it is not that the automatic brain 'decides' to act before the conscious brain but that it creates a readiness to act which only gets turned into action by conscious intervention. Furthermore ,Trevena and Miller claim to show that the brain activity specifically associated with 'deciding' to act takes place after the conscious awareness of that decision." (5)

As another article commented:

"Scientists have quoted the [Libet] experiment as evidence that free will is an illusion - a conclusion that was always controversial, particularly as there is no proof the RP represents a decision to move. To contradict the interpretation, Jeff Miller and Judy Trevena of the University of Otago in Dunedin, New Zealand, attempted to tease apart what prompts the RP using a similar experiment, with a key twist, reports New Scientist. Just like Libet, they used scalp electrodes, but instead of letting their volunteers decide when to move, the duo asked them to wait for an audio tone before deciding whether to tap a key. Had Libet's interpretation been correct, the RP should have been greater after the tone when a person chose to tap the key, said Miller. But they noticed that while there was an RP before volunteers made their decision to move, the signal was the same whether or not they elected to tap. Miller concluded that the RP might merely be a sign that the brain is paying attention and does not indicate that a decision has been made. The researchers also failed to find evidence of subconscious decision-making in a second experiment. This time they asked volunteers to press a key after the tone, but to decide on the spot whether to use their left or right hand. As movement in the right limbs is related to the brain signals in the left hemisphere and vice versa, they reasoned that if an unconscious process is driving this decision, where it occurs in the brain should depend on which hand is chosen. But they found no such correlation. (ANI)(6,7)

The importance of Miller and Trevena is not just that it shows that Libet's experiment did not give the whole picture - it also demonstrates a key facet of science which was hammered home again and again by the philosopher of science, Karl Popper, that while repetitions are needed, they are not sufficient to confirm a theory. All the sightings of white swans in the world cannot prove that all swans are white; one black swan is all it takes to upset the theory.

Although this was news earlier this year, Horizon did not mention Miller and Trevena's experiment, which is another example of poor research, which was a pity because it was an engaging and entertaining programme. But the 2006 programme by evolutionary development psychologist Armand Leroi - "What makes us Human", was much better, perhaps because Leroi was talking about his own field of study, and was cautious about how TV can oversimplify and deceive - notably he once said ""left to their own devices, TV producers simply cannot be trusted to tell the truth"!

Leroi, incidentally, showed an elephant recognising itself in a mirror, and noted that early results had been inconclusive simple because the mirrors had been too small - another example of how unexamined human bias can distort experimental results.

In the case of both mirror repetition tests, and the Libet experiment, it is clear that by conflating interpretation of an experiment with the results of that experiment to create a presentation of "scientific fact", Horizon is guilty of doing precisely that, and I think a little more philosophy of science, and a broadening of how experiments can be interpreted, would have produced a better programme. The out of date research also didn't help matters.

(3) The cognitive animal: empirical and theoretical perspectives on animal cognition By Marc Bekoff, Colin Allen, Gordon M. Burghardt

1 comment:

Nick Palmer said...

A long time ago I discovered that, when breathing normally, my nostrils flare a few tenths before I inhale. Breathing consciously gives the same effect. However, in those few tenths of a second, one can make a decision whether to inhale or not - regardless of whether one does or not, the nostrils still flare.

Tell Horizon to contact me if they need any clarification instead of all those scientists!