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Was: More Psychology Disguised as Physiology. Now: Psychology: the Secret of Life

“Researcher examines how brain perceives shades of gray” the headline (italics added)

From Psypost:

…but the actual study was on how people perceive shades of grey (or gray, depending on which language you’re writing in).

I intended this to be a minor moan about mislabelling interesting psychological research, but it developed into a discussion of the nature of Life and Meaning itself (sort of): see the bit after BUT… below.

This is about the interesting perceptual problem that we see white things as being white, even in rather dim light, when they’re reflecting thousands of times less light than they do in bright light, and also very much less light than is reflected from black things in bright light, which still look really black, even though they’re actually reflecting lots of light back to us. We must be working to some kind of baseline – ‘what’s the grey level brightness here?’ – or maybe ratio – ‘I’ll see the brightest thing here as white, and anything 100 times less bright as black’ – or something, but I don’t think that’s been worked out.
The study referred to here is testing out the ‘ratio’ explanation, by asking people to estimate levels of brightness over a checkerboard with a very great range of levels of brightness.

Sarah Allred, an assistant professor of psychology at Rutgers–Camden […] conducted the research with Alan L. Gilchrist, a professor of psychology at Rutgers–Newark, and professor David H. Brainard and post-doctoral fellow Ana Radonjic, both of the University of Pennsylvania. Their research will be published in the journal Current Biology. [No further reference given]
Participants were asked to look at a 5×5 checkerboard composed of grayscale squares with random intensities spanning the 10,000-to-1 range. They were asked to report what shades of gray a target square looked like by selecting a match from a standardized gray scale.
If the visual system relied only on ratios to determine surface lightness, then the ratio of checkerboard intensities the participants reported should have had the same ratio as that of the black and white samples on the reflectance scale, about 100-to-1.
Instead, the researchers found that this ratio could be as much as 50 times higher, more than 5,000-to-1.

Sounds like good evidence against the ratio model, which is interesting, because it’s probably the most obvious explanation for how we do this. I’d be tempted to follow this up and find out more (it’s also interesting for a photographer, because understanding the difference between how we appreciate tones and contrast and how the much more ‘objective’ system of the camera sensor/digital representation/monitor or paper output system does it would help in getting things to look the way we want them to look, in spite of the fact that the world of light is wilder and more varied than either our eyes or the digital systems can really cope with. Playing around with all the sliders and controls in Photoshop can help to give some ideas of what the issues are).


…you may guess what I’m going to say next. Why is this represented as brain research, rather than people research? The researcher is quoted as saying:

She continues, “In addition, even though we used behavioral rather than physiological measures, our results provide insight into the neural mechanisms that must underlie the behavioral results.”

“even though we used behavioural rather than physiological measures”?! Good grief.  Yes the neural mechanisms are (probably equally) interesting, and understanding them will extend our understanding of the, apparently less valuable, behavioural processes – but isn’t the only* reason we want to find out about the brain processes because the behaviour/experience is interesting/puzzling/maybe practically important? If we didn’t have all those puzzles of consciousness and complex behaviour, would anyone give a toss about the brain processes?

Now I’ve got going on this, I could take it further: what’s the root cause here? What’s driving the evolution and development of our brains? There can’t be evolutionary selection of brains: it’s not the tissue, or even the wiring (it’s not really wiring, of course, but that’s our late-20th century metaphor for whatever weird things are going on in there) which is selected: it’s actions in the world, which result in survival for long enough, and then success in mating, to produce viable, adaptive offspring – in other words, behavioural and psychological things.

Now, brain processes may limit the range of adaptation possible: in Terry Pratchett’s books, trolls are fick because their silicon-based nervous systems don’t run as fast as carbon-based ones at Ankh-Morpork temperatures (any real-life examples?), and physiological changes may give behavioural advantages which pay off in evolutionarily useful behaviour – like trichromatic vision in primates, which is said to give us better ability to distinguish between ripe and unripe fruits (and therefore allows better nutrition) than the crappy old two-colour system allowed – but the physiology is only important, and only selected for, as it’s mediated through behaviour.

So there you go – it’s psychology which got us where we are now; the physiology was just dragged along as a necessary underpinning. It’s about time we started misrepresenting brain research as psychology, just to make it sound important, not the other way round.

*OK, some nerds might be interested in it for its own sake, just like some people like to speculate about prime numbers – and that kind of interest can sometimes be useful in the long term.

I admit that some of the physiology can be adaptive in straightforwardly physiological ways: so the mutation which makes some people resistant to the malaria parasite clearly improves their ability to survive and reproduce without that effect being psychologically mediated or significant, but I don’t see that as applying to brain-based evolution.


2 responses to “Was: More Psychology Disguised as Physiology. Now: Psychology: the Secret of Life

  1. drdrew01 December 16, 2011 at 12:53 pm

    This is going to be a ramable but.

    I’m a bit of a fan of Alan Gilchrist. His book ‘Seeing Black and White’ (reviewed here: Dunn, A. K., (2007). It’s all black and white, isn’t it? The Psychologist, 20(10), 622) is a fantastic treatment of the problems of seeing in black and white. It’s part subject history, part warning, part theory, part evidence and all beautifully written by a man that’s spent his career on investigating the fundamental issue of light perception. All I want to say about that is that (a) Gilchrist has shown that despite more than 100 years of effort we are still not that much closer to understanding it, (b) this is partly because we have not been paying attention to our history and have reinvented the wheel and so the same old problems only to solve them in the same way, (c) it’s also because it’s really not very simple, and (d) as my old supervisor once said to me, ‘ You look at the phenomenon – and compare the behavioural/psychological with the physiology and all you get is miss-match’. Nothing ties up neatly and that’s the fun part right?

    Oh and as for the media and science communication, well it’s all a bit of a mare really isn’t it?

    This issue of distinguishing between physiological and psychological and behavioural in terms of what they mean and how they match is an interesting one and it relates to level of perspective I guess. For me, ‘we’ are biological entities in a social world. The physiology underpins our behaviour in the sense that it is the machine on which ‘we’ run and through which we engage with the social world. All of this is psychology. And the way I understand Psychology is (a) as a psychological being, (b) as a rational scientist, (c) an entity that is aware that (a), (b) and (c) don’t really fit together very well. The human condition is, in my view, a condition of contradiction.

    Evolution operates, me thinks, at the level of the individual primarily but it can (and arguably does) operate at the group level too (though this is now a more contentious issue). Culture also seems to evolve with both adaptive and maladaptive results. There’s a gene-culture interaction and it’s natural language that makes all the difference. As part of this our psychology has evolved too. But unlike diehard evolutionary psychologists would argue I don’t subscribe to a massive modularity hypothesis – a multi modular brain that evolved in the Pleistocene and hasn’t changed since (for good or ill). Sure there’s modularity (I give thee the sensory systems) but I think there’s generalised problem solving too.

    As a psychologist I think we are best equipped for understanding human behaviour/psychology operating at the proximal and developmental levels of Tinbergen’s 4 whys, but that doesn’t mean we shouldn’t borrow other methods from other approaches to (human) evolution and biological sciences. Nor should be afraid to look back and hypothesis when we are able. Importantly we can’t escape the biology and we shouldn’t ignore culture. So as I said before ‘we’ are biological entities in a social world but I’d also add that I can’t see how you get one without the other lest ‘we’ cease to exist.

    Anyhow, if you are interested in this line of rambling, then you might be interested in this book (I have just finished the 2nd edition, I read the first over the summer).

    Laland, K. N. & Brown, G. R. (2002). Sense and Nonsense: Evolutionary Perspectives on Human Behaviour (OUP) 2nd edition.

    (1st edition)
    (2) edition)

  2. Pingback: One of the foundation myths of modern psychology: “Brain Scans Show” « millerpsych

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