Evolution

Our visual system predicts the future

I am reading John Coates’s thus far excellent The Hour Between Dog and Wolf: How Risk Taking Transforms Us, Body and Mind. There are many highlights and interesting pieces, the below being one of them.

First, we do not see in real-time:

When light hits out retina, the photons must be translated into a chemical signal, and then into an electrical signal that can be carried along nerve fibers. The electrical signal must then travel to the very back of the brain, to an area called the visual cortex, and then project forward again, along two separate pathways, one processing the identity of the objects we see, the “what” stream, as some researchers call it, and the other processing the location and motion of the objects, the “where” stream. These streams must then combine to form a unified image, and only then does this stream emerge into conscious awareness. The whole process is a surprisingly slow one, taking … up to one tenth of a second. Such a delay, though brief, leaves us constantly one step behind events.

So how does our body deal with this problem? How could you catch a ball or dodge a projectile if your vision is behind time?

[T]he brains visual circuits have devised an ingenious way of helping us. The brain anticipates the actual location of the object, and moves the visual image we end up seeing to this hypothetical new location. In other words, your visual system fast forwards what you see.

Very cool concept, but how would you show this?

Neuroscientists … have recorded the visual fast-forwarding by means of an experiment investigating what is called the “flash-lag effect.” In this experiment a person is shown an object, say a blue circle, with another circle inside it, a yellow one. The small yellow circle flashes on and off, so what you see is a blue circle with a yellow circle blinking inside it. Then the blue circle with the yellow one inside starts moving around your computer screen. What you should see is a moving blue circle with a blinking yellow one inside it. But you do not. Instead you see a blue circle moving around the screen with a blinking yellow circle trailing about a quarter of an inch behind it. What is going on is this: while the blue circle is moving, your brain advances the image to its anticipated actual location, given the one-tenth-of-a-second time lag between viewing it and being aware of it. But the yellow circle, blinking on and off, cannot be anticipated, so it is not advanced. It thus appears to be left behind by the fast-forwarded blue circle.

A quick scan of the Wikipedia page on the flash-lag effect suggests there are a few competing explanations, but it’s an interesting idea all the same. It would explain that feeling of disbelief when a batter swings at and misses a ball that moves unexpectedly in the air. They would have seen it in precisely the place they swung.

The below video provides a visual illustration.

A week of links

Links this week:

  1. Why idiots succeed.
  2. Rory Sutherland on social norms.
  3. Economics incentives versus nudge (pdf). Don’t forget that basic economic mechanisms can work.
  4. We’re related to our friends.
  5. Are there really trillion dollar bills on the sidewalk?
  6. A bash of the Myers-Briggs test. Personally, I’m a fan of the big five plus g. On g, the heritability of chimp IQ.
  7. Talent versus practice. Talent wins this one.
  8. Throwing away money on brain science.

A week of links

Links this week (or closer to a month):

  1. It’s reigning men. How our convict past explains our glass ceiling.
  2. Rory Sutherland on measurebation.
  3. The genetics of investment biases (ungated version). HT: Tyler Cowen.  Basically another confirmation of the three laws of behaviour genetics.
  4. Rats regret bad decisions.
  5. Matt Ridley on fat.
  6. Pulling apart the research on the destructiveness of female hurricanes – Paul Frijters and Andrew Gelman.
  7. Sendhil Mullainathan on the limits to big data.

Genes and socioeconomic aggregates

In April, a Conference on Genetics and Behaviour was held by the Human Capital and Economic Opportunity Global Working Group at the University of Chicago.

The videos for the conference are now up, so as I watch through them, I’ll post links and some brief thoughts. The first session, with videos linked below, was on Genes and Socioeconomic Aggregates. The video and audio are average at times, and you might want to get the slides (links provided where available) as they are hard to read in the video at times. However, there are some good bits in all of the presentations.

Gregory Cochran: Genetics and Society (slides)

Cochran laid out some ideas that should be in the minds of economists, although he does not focus much attention on selling the ideas. Unfortunately, the questions at the end got derailed by epigenetics (my views approximate Cochran’s). One interesting argument by Cochran is that human environments tend be variable, as, in a Malthusian world, good times (when people breed like mad) tend to be followed by bad (too many people) which tend to be followed by good (people died in the bad). As a result, epigenetic transmission based on the current environment may be a poor strategy.

When Cochran posted this video on his blog, some interesting discussion followed in the comments – they are worth checking out.

Enrico Spolaore: Ancestry and the Diffusion of Economic Development: Facts and Questions (slides)

Spolaore touches on his work concerning genetic distance and the diffusion of development (I have posted about it here, here and here). He is extending this work to look at the diffusion of fertility reduction from France (where the demographic transition first occurred), and is getting similar results.

Steven Durlauf: Two Remarks on the Inference of “Macro” Genetic Effects (slides)

I did not get much from Durlauf’s presentation, although some of the questions were interesting. Steve Hsu deflates the “it’s all too hard” message when he points out that animal breeding is now using genetic data.

Henry Harpending: Some Quantitative Genetics Approaches

Harpending discusses his work on how assortative mating can mimic strong selection. I sense this presentation might be difficult to follow if you aren’t familiar with his work (a link to that is here). Not much value in the question session, which gets derailed by issues concerning scaling when estimating heritability.

Aldo Rustichini: Determinants of Inequality and Intergenerational Mobility (slides)

A tough presentation to follow – you need to use the slides to have a chance of getting across it – and not recommended for those not mathematically inclined. The highlight is Greg Cochran trying not to jump out of his chair between the 7 and 8 minute mark due to some comments about heritability. Cochran also deflates the idea that there is a high level of false paternity in humans – for more on that, check out this post by Razib Khan.

Is poverty genetic?

Quamrul Ashraf has pointed me to an episode of Through the Wormhole with Morgan Freeman titled “Is Poverty Genetic?”

The official version of the video is below (payment required?), although it is blocked in Australia (Australians lead the world in digital piracy, despite being willing to pay for content. This sort of thing is why). Below that is another version I managed to find on YouTube – so go for it.

The good: The coverage of Ashraf’s work with Oded Galor on genetic diversity and economic development (my posts on their work are here), experiments on capuchin monkeys’ sense of fairness, and our sense of shame.

The so-so: The opening piece on Eric Turkheimer’s research on the heritability of IQ was OK, but when tied into the next section on differences in brain development, it goes a bit awry. A few concepts that would have helped – IQ heritability increases with age, differences that emerge after birth can be genetic, and genes shape their environment.

The not so good: Kin selection being spun as sacrifice for the benefit of the species. The overall conclusion.

Not sure: The econophysics of poverty.

A week of links

Links this week:

  1. Some economist bashing – first from Mark Buchanan, who wonders why economists wheel out “whacky” versions of what they know in public debate, and second, from Tim Harford, on an astonishing record of complete failure.
  2. Herb Gintis reviews Complexity and the Art of Public Policy: Solving Society’s Problems from the Bottom Up (HT: Arnold Kling)
  3. We can’t ignore the evidence: genes affect social mobility.
  4. The costs of climate change – some corrections.
  5. Steven Pinker on writing.

A week of links

Links this week:

  1. A conversation with Rory Sutherland. Many good pieces, but my favourite line:

Certainly there’s a problem with numbers in that there are sophisticated things in life that we all understand perfectly well when verbally described. Should psychology be constrained by math? I mean, who has the better understanding of human behavior—Shakespeare or Eugene Fama? If you make mathematical expression a barrier to entry, to any kind of theory, you are undoubtedly limiting yourselves.

  1. Another article taking a shot at the idea that “all calories are equal”.
  2. A not so glowing review of the latest book in the Freakonomics franchise – Think Like a Freak. Noah Smith also takes a shot.
  3. H. Allen Orr reviews Nicholas Wade’s A Troublesome Inheritance: Genes, Race and Human History.
  4. Two good pieces on the mess that is copyright protection – an extended riff on barriers to innovation and the ridiculous length of copyright terms.

Doubling down

First, from Andrew Leigh, discussing Gregory Clark’s work showing that low social mobility persists across countries and policy environments:

How do we break the pattern? Part of the answer must lie in a fair tax system, a targeted social welfare system, effective early childhood programs, and getting great teachers in front of disadvantaged classrooms. We need banks willing to take a chance on funding an outsider, and it doesn’t hurt to maintain a healthy Aussie scepticism about inherited privilege.

As an aside, it appears Leigh (with Mike Pottenger) is finding the same low mobility in Australia as Clark has found elsewhere.

In contrast, from Arnold Kling:

For libertarians, the implications of Clark’s finding of strong heritability of social status are ambiguous. On the one hand, his findings argue against extensive efforts at social engineering that try to achieve parity across groups. … Attempts to engineer different outcomes tend to produce perverse results. …

On the other hand, his findings argue against the need to create strong incentives to succeed. If some people are genetically oriented toward success, then they do not need lower tax rates to spur them on. Such people would be expected to succeed regardless. The ideal society implicit in Clark’s view is one in which the role of government is to ameliorate, rather than attempt to fix, the unequal distribution of incomes.

Kling’s approach to Clark’s argument seems preferable to doubling down on measures that don’t appear to increase social mobility. That is, of course, if increased social mobility is what we should be chasing.

A week of links

Links this week:

  1. There are plenty of reviews of Nicholas Wade’s new book, A Troublesome Inheritance: Genes, Race and Human HistoryRobert VerBruggen‘s is one of the more interesting. We’ll be throwing a lot of social science under the bus if we apply Andrew Gelman’s filter more generally. Greg Cochran points to some errors and Razib offers a perspective.
  2. Gelman again, this time on poor research in evolutionary psychology. I agree with both him and Pinker here.
  3. A review of Think Like a Freak. From the excerpts I have seen, it seems that Levitt and Dubner are running into the same problem as a lot of the behavioural economics literature – there are only so many “funky” stories to go around.
  4. Can a single gene explain 3 per cent of the variation in IQ? I don’t think so, but interesting none the less.

Becker on evolution and economics

Gary Becker was one of the first economists to seriously contemplate the role that evolutionary biology could play in economics. In 1976, he wrote:

I have argued that both economics and sociobiology would gain from combining the analytical techniques of economists with the techniques in population genetics, entomology, and other biological foundations of sociobiology. The preferences taken as given by economists and vaguely attributed to “human nature” or something similar – the emphasis on self-interest, altruism toward kin, social distinction, and other enduring aspects of preferences – may be largely explained by the selection over time of traits having greater genetic fitness and survival value.

Over the last two days, a couple of people have classed him as the greatest social scientist of the last 50 years. I am happy to grant the title of greatest economist over that period, but I’ll reserve the social scientist title. Becker broke down a lot of barriers in other fields, but I am not sure that many of his applications will outlast approaches grounded in biology. In the long-run, E.O. Wilson and his groundbreaking work starting with Sociobiology might be the more important piece.

In the meantime, below are links to some posts over the last few years I have written about Becker’s work:

  1. Rotten kids and altruism.
  2. Altruists and the knowledge problem.
  3. Consumption and fitness.
  4. Deriving the demand for children.
  5. The evolution of happiness.