The evolutionary psychology of war

Nothing too shocking here for students of evolutionary psychology but it’s always interesting to see real world examples of how our shared behavior. There is a new book by Sebastian Junger called War, in which he recounts how men do not fight for larger ideological goals (eg. “a safer Iraq”, “finding Bin Laden”) but instead they can overcome fears because “they’re more concerned about their brothers than what happens to themselves individually”. Here’s Junger on Good Morning America:
http://abcnews.go.com/assets/player/walt2.6/flash/SFP_Walt.swf

After the jump some more from Junger and a nice talk from Robert Sapolsky about similar behaviors in chimps.

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When Will We Be Able to Build Brains Like Ours?

When Will We Be Able to Build Brains Like Ours? – by Terry Sejnowski – scientificamerican.com

Terry Sejnowski discusses the recent ‘catfight’ that erupted between Dharmenda Modha of IBM and Henry Markram of the EPFL over claims from Modha that his group had successfully modeled the brain of a cat.

Dr. Sejnowski provides a summary of the quest to describe the nervous system using computational models and introduces a central question: What level of abstraction is appropriate?

“Looking at the same neuron, physicists and engineers tend to see the simplicity whereas biologists tend to see the complexity. The problem with simplified models is that they may be throwing away the baby with the bathwater. The problem with biophysical models is that the number of details is nearly infinite and much of it is unknown. How much brain function is lost by using simplified neurons and circuits?”

Despite the differing approaches, both Modha and Markram say we’ll have a model human brain by 2019. Sejnowski claims that these will be impoverished brain models, “at best these simulations will resemble a baby brain, or perhaps a psychotic one”, but he does remain hopeful in his closing remarks:

“And gradually, as it increasingly mimics the workings of our brains, the world around us will become smarter and more efficient. As this cognitive infrastructure evolves, it may someday even reach a point where it will rival our brains in power and sophistication. Intelligence will inherit the earth.”

Submitted By: Dan Knudsen

Bayesian truth serum

Neville told me about this neat article from ’04. It presents a way to offer rewards to people taking a poll in such a way so as to motivate them to be honest, with no prior information about what the distribution of correct answers is. Apparently, previous such techniques are based on the idea of rewarding people for agreeing with other people’s answers. This new thing about this technique for calculating the reward is that it provides people with an incentive to tell their true opinion even if they know that they hold a minority viewpoint.

Drazen Prelec. A Bayesian Truth Serum for Subjective Data. Science 15 October 2004: Vol. 306. no. 5695, pp. 462 – 466. DOI: 10.1126/science.1102081

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The truth about TTX!

If the Fish Liver Can’t Kill, Is It Really a Delicacy? [NYT, login]

Amazing. It looks like TTX (tetrodotoxin, a potent voltage-gated sodium channel blocker well-known to electrophysiologists) is not made by the pufferfish (which I had always assumed), rather it is from the bacteria/food consumed by the fish.

Decades earlier, another Japanese scientist had identified fugu’s poison as tetrodotoxin, a neurotoxin that leaves victims mentally aware while they suffer paralysis and, in the worst cases, die of heart failure or suffocation. There is no known antidote.

Researchers surmised that fugu probably got the toxin by eating other animals that carried tetrodotoxin-laden bacteria, developing immunity over time — though scientists then did not rule out the possibility that fugu produced the toxin on its own.

By this year, Mr. Noguchi had tested more than 7,000 fugu in seven prefectures in Japan that had been given only feed free of the tetrodotoxin-laden bacteria. Not one was poisonous.

“When it wasn’t known where fugu’s poison came from, the mystery made for better conversation,” Mr. Noguchi said. “So, in effect, we took the romance out of fugu.”

Aside from the interesting science, it appears there is also a small Japanese “industry” (de-ttx? detox?) seriously affected by TTX-free fugu. More after the jump Continue reading

Where are we with this whole free will thing?

Haim Sompolinsky has written an excellent book chapter on the scientific view of free will and choice, pulling in good ideas from physics and neuroscience along with contemporary philosophical commentary.

I think this chapter might be helpful for neuroscientists outside of the lab. Often a dinner table discussion has moved to the idea of “quantum consciousness” or “quantum free will”. Often, someone will mention Roger Penrose, who has become something of a poster boy for this idea that quantum indeterminacy (eg. Heisenberg’s uncertainty principle) is one possible way that free will is really free. And then, people look around and say, “Well, you’re a neuroscientist. Do we have free will?” (And that’s when I take another big drink or bite while I figure out something semi-coherent to say.)

Sompolinsky does a nice job of evaluating such claims (in the end, he says we cannot rule out the possibility that the brain is an indeterministic system but it seems unlikely) and provides nice scientific insight. In his view, it is far more likely that the brain’s apparent randomness (eg. individual cell spike rasters vary across repeated presentations of the same stimulus) is more simply explained by thermal noise (think of varying channel gating properties) and chaotic brain dynamics. (Recall, a chaotic system is still deterministic; it simply exhibits aperiodic behavior due to exquisite sensitivity to initial conditions. It is difficult to predict the long-term behavior of chaotic systems. The more we know the initial conditions in detail, the better our prediction.) On the other hand, he argues that the relevant length and time scales for neurons (micrometers and milliseconds) are far larger by many orders of magnitude than those of quantum noise. Chaos might amplify such quantum events, but this is far from being the simplest, most parsimonious explanation. Given the current level of neuroscience understanding, this is almost idle speculation. Regardless of the (in)determinacy of the world, Sompolinsky effectively argues against any non-physical, purely mental (ie. dualistic) agent of causation.

Thus, in sum, the world and our brains might not be determined but, even given that, there’s no reason to believe we have any causative ability to change things in the sense of traditional free will. These observations seem right on the mark to me. I hope they bring some insight for others. Or at least a way to fend off the dinner-table-free-will-conversation barrage of questions.

Levels of analysis

Salon features an interview today with Steve Pinker and Rebecca Goldstein:

Proud atheists: Steven Pinker, Rebecca Goldstein interview | Salon Books

After reiterating the physicalist view of the mind, the article ends with this quote from Pinker (reminiscent of Marr’s levels of analysis):

[…] But just by looking at the brain itself, will you ever be able to understand the creative mind?

PINKER: I suspect not. In fact, the reason I’m not a neurobiologist but a cognitive psychologist is that I think looking at brain tissue is often the wrong level of analysis. You have to look at a higher level of organization. For the same reason that a movie critic doesn’t focus a magnifying glass on the little microscopic pits in a DVD, even though a movie is nothing but a pattern of pits in a DVD. I think there’s a lot of insight that you’ll gain about the human mind by looking at the whole human behaving, thinking and reporting on his own consciousness. And that might be true of creativity as well. It may be that the historian, the cognitive psychologist and the biographer working together will give us more insight than someone looking at neurons and brain chemistry.

I think the analogy with the DVD is disingenuous. In the case of the DVD, we know precisely how the low-level pits are combined to form the high-level representation (the movie). The system is not mysterious. To be fair, Pinker doesn’t say that neurobiology is always the wrong level of analysis. Maybe he would have been correct 50 or 100 years ago, but I think it’s clear now that neurobiology is on the path to providing a complete synthesis (certainly, with the help of cognitive psychology) that cannot be achieved without it.