Brain and Behavior
developingintelligence | April 11, 2007Very early in the history of artificial intelligence research, it was apparent that cognitive agents needed to be able to maximize reward by changing their behavior. But this leads to a "credit-assignment" problem: how does the agent know which of its actions led to the reward? An early solution was to select the behavior with the maximal predicted rewards, and to later adjust the likelihood of that behavior according to whether it ultimately led to the anticipated reward. These "temporal-difference" errors in reward prediction were first implemented in a 1950's checker-playing program,…
clock | April 10, 2007Some Bottlenose Dolphins Don't Coerce Females To Mate:
Mating strategies are straightforward in bottlenose dolphins, or are they? Much of the work carried on male-female relationships in that species to date show that males tend to coerce females who are left with little choice about with whom to mate. This explains the complex relationships we observe in male bottlenose dolphins, which are only paralleled by human social strategies: the formation of alliances and alliances of alliances, also called coalitions. These alliances and coalitions are then used to out-compete other male bands to…
neurontic | April 8, 2007
Welcome to Encephalon, the blog carnival for brain geeks and those who love them. We got a heap of submissions this time around, so let's dive right in:
The Brain: An Owner's Manual
First up, Alvaro over at Sharp Brains discusses how aging brains may be affecting the legal profession, and urges us to keep our own memory problems in perspective in "Baby Boomers, Healthy Aging and Job Performance."
If you're still convinced that your brain is putt-putting along like an old jalopy, it might be time to read up on the "three easy and quick mental exercises that everyone should be doing daily…
cortex | April 8, 2007A friend of mine (who happens to be Ph.D student in economics) sent me a skeptical email regarding a recent article that sought to measure marginal utility:
I'm really not convinced that marginal utility can be so easily correlated with activity in the midbrain. I think one of the virtues of the economic definition of marginal utility is that it's ultimately vague in definition. Depending on the context it can be happiness or money or satisfaction or whatever that person wants. I'm not sure it benefits from a strict neuroscientific definition.
I understand the skepticism. But I think there is…
clock | April 5, 2007Remember "Ask the ScienceBlogger" series? Well, it's back. And it is somewhat different now. Instead of putting the question out for everyone to respond to (or not) at their own leisure, this time one particular SB blog will be charged with answering the question, and others are free to chime in if they wish so afterwards.
The first question is out of the box now:
What's the difference between psychology and neuroscience? Is psychology still relevant as we learn more about the brain and how it works?
And Dave and Greta Munger of Cognitive Daily were charged with answering it. They did the…
cortex | April 5, 2007Marginal utility can be measured. According to new research out of Wolfram Schultz's lab, poor people are much quicker learners than rich people when playing a Pavlovian paradigm for small amounts of money. (Poor people took about 12 trials to figure out the game, while rich people took about 35 trials.) This behavior was then confirmed with fMRI. Sure enough, rich people demonstrated less dopaminergic midbrain activity than poor people in response to the experimental paradigm. They were bored by the pocket change. Here's the abstract:
A basic tenet of microeconomics suggests that the…
retrospectacle | April 5, 2007A parasite called Toxoplasma gondii has a unique mechanism to help it spread: "tricking" rats into delighting in the smell of its predator, cats. This is an important adaptation since this parasite can only sexually reproduce in the gut of cats, so the parasite needs to get the infected rats into the cats' gut. Yeah, the cat eats the rat, and the parasite lives happily ever after.
Normally rats have a strong aversion to the scent of cat urine, but infected rats completely lose their aversion to cat pee but retain all their other fears and phobias.
"Toxoplasma affects fear of cat odors with…
cortex | April 5, 2007Dave and Greta Munger have posted an excellent reply to the following question:
What's the difference between psychology and neuroscience? Is psychology still relevant as we learn more about the brain and how it works?
You have to be a pretty staunch reductionist to believe that neuroscience makes psychology obsolete. After all, according to scientific materialism, neuroscience is ultimately just a subset of quantum mechanics. So should we all become physicists? Of course not. While our different levels of inquiry are obviously interconnected, they are also autonomous. As Dave points out,…
developingintelligence | April 5, 2007"To understand ourselves, we must embrace the alien." - PZ Meyers
One difficulty in understanding consciousness is the fact that we know of only one species that certainly possesses it: humans. A new article by Jennifer Mather suggests that octopi may also possess consciousness, despite the vastly different architecture of their brain. If two very different neural architectures can both support forms of advanced cognition, then the similarities between them may help clarify the computational requirements for intelligent behavior.
Octopus brains are striking different from those in primates…
clock | April 5, 2007
Want To Monitor Climate Change? P-p-p-pick Up A Penguin!:
We are used to hearing about the effects of climate change in terms of unusual animal behaviour, such as altering patterns of fish and bird migration. However, scientists at the University of Birmingham are trying out an alternative bio-indicator -- the king penguin -- to investigate whether they can be used to monitor the effects of climate change.
Scientists Directly Control Brain Cell Activity With Light:
Every thought, feeling and action originates from the electrical signals emitted by diverse brain cells enmeshed in a tangle of…
ksharpe | April 4, 2007Starting today, ScienceBlogs is introducing a new-and-improved feature that allows you, dear reader, to tap into the brain-power and expertise of the ScienceBlogs collective mind—all to answer your most burning questions about matters scientific.
Every couple of weeks, a ScienceBlogs blogger will craft a succinct, specific answer to a question from his or her area of expertise. The answer will be linked from the ScienceBlogs main page, and it's our hope that response and commentary and even more questions will flow freely after.
The kick-off question for the series is inspired by modern…
dmunger | April 4, 2007Cognitive Daily has been chosen to respond to the first question in a newly revised feature on ScienceBlogs: Ask a ScienceBlogger. Readers can submit questions, and they'll be answered by an expert in the field of inquiry (even though it's posted under Dave's name, Dave and Greta worked together on this one). Then, hopefully, discussion among the various ScienceBlogs will ensue. This week's question:
What's the difference between psychology and neuroscience? Is psychology still relevant as we learn more about the brain and how it works?
The main difference between psychology and neuroscience…
developingintelligence | April 4, 2007"Instead of trying to produce a programme to simulate the adult mind, why not rather try to produce one which simulates the child's?" - Alan Turing (Computing Machinery, p456)
One of the defining features of childhood cognition is "behaving without thinking." Not surprisingly, developmental cognitive psychology has latched onto the idea of impulse control - and other processes putatively requiring inhibition - as a central explanatory construct, playing a role in attention deficit disorder, post-traumatic stress disorder and everything in between (including developmental trends in normal…
omnibrain | April 4, 2007This topic usually falls into the realm of ESP and parapsychology but there is no reason that it has to. For starters check out this snippet from a Wired article:
"It was slightly strange at first," Wächter says, "though on the bike, it was great." He started to become more aware of the peregrinations he had to make while trying to reach a destination. "I finally understood just how much roads actually wind," he says. He learned to deal with the stares he got in the library, his belt humming like a distant chain saw. Deep into the experiment, Wächter says, "I suddenly realized that my…
developingintelligence | April 3, 2007How does the brain exert flexible control over behavior? One idea is that high-level areas of the brain self-organize representations that lead to reward in a certain task, in a sense by "programming" or "executing" a pattern of activity that controls activity in more posterior and domain-specific regions (i.e., sensory or motor cortex). This portrays prefrontal cortex as a kind of field-programmable gate array, which can be dynamically reconfigured on the basis of dopaminergic reward signals, so as to perform different computations at will.
Concrete evidence for this view is provided by…
loom | April 3, 2007Reports are coming out this morning on a new study on one of the Loom's favorite organisms: Toxoplasma gondii, the single-celled parasite that lives in roughly half of all people on Earth and has the ability to alter the behavior of its host. I reported on the research last June in the New York Times, when the Stanford researchers reported their results at a scientific conference. It's nice to finally get the results on paper, though.
The study is a fine example of an underappreciated part of science: replication. In 2000 British researchers carried out a study in which they put healthy and…
omnibrain | March 29, 2007
There's an interesting debate happening at I believe, Cognitive Science, this year. Jerry Fodor has come out with a full force denial of evolutionary psychology and in the process has managed to piss off Daniel Dennett who has responded with a very nasty paper of his own.
I'll give you a couple snippets of the exciting debate as well as the papers concerned.
Fodor:
This started out to be a paper about why I am so down on Evolutionary Psychology (EP), a topic I've addressed in print before. (see Fodor, 19xx; 19xx). But, as I went along, it began to seem that really the paper was about what…
purepedantry | March 29, 2007This is interesting. Researchers at Columbia have established that restricting neurogenesis in the hippocampus improves working memory:
New research from Columbia University Medical Center may explain why people who are able to easily and accurately recall historical dates or long-ago events, may have a harder time with word recall or remembering the day's current events. They may have too much memory -- making it harder to filter out information and increasing the time it takes for new short-term memories to be processed and stored.
Published in the Proceedings of the National Academy of…
mixingmemory | March 27, 2007Research on the role of emotion/intuition in moral judgments is really heating up. For decades (millennia, even), moral judgment was thought to be a conscious, principle-based process, but over the last few years, researchers have been showing that emotion and intuition, both of which operate automatically and unconsciously for the most part, play a much larger role than most philosophers and psychologists had previously been willing to admit. In this context, two recent papers by roughly the same group of people have presented some really interesting findings which, if you ask me (and if you…
dmunger | March 26, 2007A rat's brain has millions of neurons, each with up to 10,000 connections to other neurons. This "simple" animal's neural network is mind-bogglingly complex. Yet a Swiss laboratory has achieved remarkable success duplicating a vast region of a rat's brain using a supercomputer. They still have a ways to go, however. The computer currently has 10,000 microprocessors, each representing a single neuron in the rat's brain. To duplicate the entire brain they'll need a computer 2,000 times bigger. Their ultimate goal is even more ambitious: to create a model of the human brain, with its hundred…