A sinister attractor – why males are more likely to be left-handed

It seems an innocent enough question: why are males more frequently left-handed than females? But the answer is far from simple, and it reveals fundamental principles of how our psychological and behavioural traits are encoded in our genomes, how variability in those traits arise, and how development is channelled towards specific outcomes. It turns out that the explanation rests on an underlying difference between males and females that has far-reaching consequences for all kinds of traits, including neurodevelopmental disorders. A recent tweet from Abdel Abdellaoui showed data on rates of left-handedness obtained from the UK Biobank, and asked two questions: why is left-handedness more common in males and why are rates of reported left-handedness increasing over time? I don’t think the answer to the second question is known but I presume it has to do with the declining practice of forcing left-handers to write right-handed. This once common practice reflects a lon

Corvid consciousness – computation, cognition, or comprehension?

A really nice paper came out recently that claims to have discovere d a ne ural correlate of sensory consciousness in a corvid bird (the carrion crow). The authors use an elegant set up involving barely perceptible visual stimuli to distinguish the delivery of a stimulus and the s ubjective percept that it engenders. The experiment clearly demonstrates that crows can maintain an internal representation for a period of time before taking an action based on a rule that is subsequently presented to them. This kind of task has been used in primates to distinguish what happens in the brain when an animal consciously detects a stimulus versus when it doesn’t. But is this really a correlate of conscious subjective experience or simply a marker of ongoing neural activity that mediates working memory? What do we even mean by conscious subjective experience? Does maintaining an active neural state necessarily entail a mental state?   The experimental set up is really powerful. The authors t

Are bigger bits of brains better?

We scoff at the folly of phrenology – the simplistic idea that the size and shape of bumps on the skull could tell you something about a person’s character and psychological attributes. It was all the rage in the Victorian era (the early to mid-1800s) in the UK and the US especially, with practitioners armed with calipers claiming to measure all kinds of personal propensities, from Acquisitiveness and Combativeness to Benevolence and Wonder. The skull bumps were just a proxy, of course – the idea was that they reflected the size and shape of the underlying brain regions, which were what was really associated with various traits. It all seems a bit quaint and simplistic now (apart from the entrenched association with racism ), but while we may like to think we have moved on, a lot of modern human neuroscience is founded on the same premises.    - The first premise is that different mental functions or psychological traits can be localised to specific regions of the brain.   - T

Escaping Flatland - when determinism falls, it takes reductionism with it

For the reductionist, reality is flat. It may seem to comprise things in some kind of hierarchy of levels – atoms, molecules, cells, organs, organisms, populations, societies, economies, nations, worlds – but actually everything that happens at all those levels really derives from the interactions at the bottom. If you could calculate the outcome of all the low-level interactions in any system, you could predict its behaviour perfectly and there would be nothing left to explain . It’s turtles all the way down. Reductionism is related to determinism, though not in a straightforward way. There are different types of determinism , which are intertwined with reductionism to varying degrees. The reductive version of determinism claims that everything derives from the lowest level AND those interactions are completely deterministic with no randomness. There are things that seem random, to us, but that is only a statement about our ignorance, not about