“Like father, like son”: Testing folk beliefs about heredity in the arena of assisted reproduction.

“The apple doesn’t fall far from the tree”. “Chip off the old block”. “Cut from the same cloth”. “Black cat, black kitten”. “Chickens don’t make ducks”. “He didn’t lick it off the stones”. “It’s not from the wind she got it”. “She comes by it honestly”.
Every culture seems to have its own phrases describing the power of heredity – not just for physical traits, but also for behavioural ones. (Those last three are peculiar to Ireland, I think). This folk wisdom, accumulated from centuries of observation of human behaviour, seems to reflect a widespread belief that genetic effects on behaviour and personality are strong, indeed dominant over effects of upbringing.
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Of course, folk wisdom can be wrong. And old folk sayings may not reflect current thinking – perhaps people’s opinions on the subject have changed. Indeed, if you were to take academic discourse on the subject as a barometer of views of the general public, y…

What are the Laws of Biology?

The reductionist perspective on biology is that it all boils down to physics eventually. That anything that is happening in a living organism can be fully accounted for by an explanation at the level of matter in motion – atoms and molecules moving, exerting forces on each other, bumping into each other, exchanging energy with each other. And, from one vantage point, that is absolutely true – there’s no magic in there, no mystical vital essence – it’s clearly all physical stuff controlled by physical laws.
But that perspective does not provide a sufficient explanation of life. While living things obey the laws of physics, one cannot deduce either their existence or their behaviour from those laws alone. There are some other factors at work – higher-order principles of design and architecture of complex systems, especially ones that are either designed or evolved to produce purposeful behaviour. Living systems are for something – ultimately, they are for replicating themselves, but the…

Debunking the male-female brain mosaic

There is no such thing as a male brain, or a female brain. Instead, our brains are all really a mosaic of male and female parts – we all have an “intersex” brain. This is the claim made by psychologist Daphna Joel and colleagues, based mostly on a 2015 neuroimaging study in humans, but also some previous work in rodents. This idea – especially the catchy phrasing – has caught the public imagination and it has been widely covered in the media. Indeed, a recent editorial in Scientific American, entitled “The New Science of Sex and Gender”, cited this study as support for the view that “To varying extents, many of us are biological hybrids on a male-female continuum”. But what do the data actually show? I will argue below that the interpretation of a male-female mosaic is conceptually mistaken and based on a straw-man argument. I’ve discussed these findings and their interpretation before, as an illustration of how the same data can be used to support diametrically opposite viewpoints. He…

The genetics of educational attainment

A recently announced paper reports the results of an enormous genome-wide association study for educational attainment. The authors found 74 regions of the genome where there are common variants that show statistically significant association with this trait. Here are my thoughts on what this study found, what it didn’t find and what those positive and negative results might mean.

First, it was a huge effort by a lot of people who should be congratulated for working together to carry out this analysis on such a huge scale. It is an interesting question and a worthwhile effort, in my view. The trait they measure, time spent in education, is an important one and has been shown to be moderately heritable. One large study estimated the heritability at ~40%, meaning of the variance in this trait, in the sample studied, around that much was found to be attributable to genetic differences between people. (For reasons I can’t figure out, the current study cites that paper, but gives a figure …

Schema formation in synaesthesia

The following is an extract (just the text, not the figures) from a paper I wrote for the proceedings of the V International Conference Synesthesia: Science and Art. Alcalà la Real de Jaén. España. 16–19th May 2015. 
Many of the ideas were also developed in a paper with my colleague Fiona Newell, on Multisensory Integration and Cross-Modal Learning in Synaesthesia: a Unifying Model.

Psychologists use the term “schema” to refer to the information or knowledge that makes up our concept of an object. It includes all the attributes that the object has, such as the shapes of a letter and the sounds it can make, the shape of a numeral and the value it represents, or the face of a person and their name and everything you know about them. In many cases, those attributes are represented across very different brain areas (such as those conveying visual or auditory information, for example). With experience, the representations of the different attributes of an object become linked togethe…