Chris Chatham
developingintelligence
Posts by this author
February 6, 2007
Humans are notoriously finicky decision makers, and new research is beginning to elucidate the neural networks that are responsible. For example, we are exquisitely sensitive to framing effects regardless of whether two decisions have mathematically equivalent value - a previous post reviews how…
February 5, 2007
What cognitive processes make up consciousness? One way of answering this question is to identify conscious processes as those involved in controlled but not in automatic behaviors. For example, if you see a bright dot appear in your field of vision, your eyes will automatically orient to that…
February 3, 2007
My favorites from the last two weeks in brain blogging:
First off, a new blog: Robots Will Take Over!
Neural networks in silicon, and progress in brain-computer interfaces.
Lifestyle improvements, brought to you by your friends at DARPA
Is machine learning really any different from statistics? (…
February 2, 2007
To the extent that the cognitive sciences actually consider the brain, the focus is clearly on neurons. Even the name of the field "neuroscience" suggests that neurons take the center stage. However, neurons are vastly outnumbered by glia, a different type of cell that is now known to be…
February 1, 2007
Yesterday I reviewed evidence showing that set switching (e.g., your ability to suddenly switch behaviors) and rule representation (your ability to represent rules in a game, for example), may be distinct processes, at least insofar as they may show distinct developmental trajectories and rely on…
January 31, 2007
Normal children - and adult patients with frontal damage - frequently have difficulty changing their responses to stimuli when the correct response changes. This difficulty is often considered an inability to switch between rules, but might result not so much from an inability to switch as from an…
January 30, 2007
If a large object were to suddenly disappear from your field of view, you might expect that you would notice its disappearance. However, change detection research has demonstrated that we have a surprisingly poor ability to detect even large changes to a visual scene (see here and here for…
January 29, 2007
If presented with a novel and a familiar object, infants strongly prefer to touch and look at novel objects. However, if these objects are then obscured - in the dark, or by an occluding screen - infants tend to reach more in the direction of the familiar objects. Some argue that the familiar…
January 26, 2007
Yesterday I reviewed several detailed architectural asymmetries between the right and left hemispheres, but presented little information on asymmetries in long-range connectivity. Recent advances in a form of magnetic resonance imaging called "diffusion tensor MRI" have made possible whole-brain…
January 25, 2007
In their 2003 Trends in Neurosciences article, Hutsler & Galuske refer to the well-known history of hemispheric asymmetry research as too focused on large-scale morphological differences, at the expense of microanatomical and connectivity differences. An understanding of these more detailed…
January 24, 2007
"Imagine that the U.S. is preparing for the outbreak of an unusual Asian disease, which is expected to kill 600 people. Two alternative programs to combat the disease have been proposed." The first program will save 200 people. The second program has a 33% probability of saving all 600 people,…
January 23, 2007
Although grammar is usually considered the "uniquely human" aspect of language, and the capacity to use primitive symbols is thought to be common among primates, high-level cognition is nonetheless strongly impacted by the use of symbols. For example, symbols can help in putative inhibition tasks…
January 22, 2007
Gyorgy Buzsaki, author of "Rhythms of the Brain," agreed to answer 10 questions posed by me and amnestic at GNXP. Covers computational modeling, 1/f noise, cortical homogeneity, and much more.
A steeper forgetting curve among those with a college education?
Imaging the neural representation of…
January 19, 2007
Although even the youngest infants have some ability to remember the past, this ability increases in both its reliability and its "temporal extent" with age. Such differences could result from changes in any of memory's constituent processes, including encoding, consolidation, or retrieval.…
January 18, 2007
The media is currently blowing up with reports that a 27-year-old woman who disappeared in the forests of Cambodia has now been found, 18-20 years later (reports vary). She was spotted on January 13th by a villager who saw a "jungle person, sneaking in to steal his rice," and was subsequentely…
January 18, 2007
Yesterday I outlined a few reasons to think that we may not actually forget all of our earliest memories; instead, they may merely be mislabeled due to a failure of source monitoring. According to a 2002 article by Drummey and Newcombe, a similar problem may underlie childhood amnesia - the…
January 17, 2007
Freud famously suggested that infantile amnesia is an active suppression of early traumatic memories. However, a review of the modern cognitive literature suggests that at least in some ways, infantile amnesia may actually be a myth.
Perhaps the most intuitive explanation of infantile amnesia is…
January 16, 2007
Suppose that "memory task A" shows marked improvement at 5 months, but "memory task B" doesn't show marked improvement until 9 months. Before we can make inferences about the development of memory, we need to understand how tasks A and B differentially strain the developing cognitive system.
Along…
January 15, 2007
Enjoy the holiday with some nice reading from Encephalon 14: Mixing Memory has posted the new issue.
January 13, 2007
Recent highlights from the brain blogosphere:
Can crossword puzzles help prevent senile dementia?
The current state of the brain fitness movement: as evaluated by the New York Times.
Spindle neurons evolved very recently - are they also the source of frontal dementia?
A new form of pharmacological…
January 12, 2007
The cognitive science of hemispheric asymmetry has long been marred by drastic over-simplification. The left/right distinction has been associated with dichotomies like rational vs. emotional, specific vs. holistic, and analytical vs. synthetic. Such differences are much more graded than…
January 11, 2007
As enigmatic as prefrontal function seems to be, the anterior portions of prefrontal cortex (aPFC) are even more mysterious. This results partly from the fact that aPFC is particularly difficult to access and study electrophysiologically in nonhuman primates, as Ramnani and Owen note in their 2004…
January 10, 2007
As described in yesterday's post, many theories have been proposed on the possible functional organization of prefrontal cortex (PFC). Although it's clear that this region plays a large role in human intelligence, it is unclear exactly "how" it does so. Nonetheless at least some general…
January 9, 2007
Although much progress has been made since neurologist Richard Restack called the brain one of science's last frontiers, the functions of some brain areas remain mysterious. Foremost among these is prefrontal cortex (PFC), a region that is much reduced in size in most other primates, is among the…
January 8, 2007
In a few places throughout the second edition of his landmark book, Mark Johnson suggests that the field of developmental cognitive neuroscience has matured from infancy to toddlerhood. This book, then, is a sort of biography, from the field's theoretical ancestry in 17th century debates between "…
January 7, 2007
Highlights from recent brain blogging:
Top 5 Robots of 2006 - the top 5 that we know about, that is. #1 gives you a taste of the current state of robotics.
Along those lines, this video about a few precautions we should all take.
The Neurophilosopher covers augmented cognition by DARPA, and a…
January 4, 2007
There are many theories of how human behavior came to differ so profoundly from that of even our closest primate relatives - language, recursion, theory of mind, and enhanced working memory are just a few of the "critical components" that have been proposed as enabling human intelligence. A very…
January 3, 2007
The prefrontal cortex is a major recipient of subcortical dopaminergic projections. Accordingly, almost all of the behavioral tasks that are known to critically depend on the prefrontal cortex are sensitive to dopamine levels. A curious exception is the Self Ordered Pointing task (SOPT), in…
January 2, 2007
It seem reasonable that evolution might select for adaptive behaviors by increasing the relative size of particular brain regions that support those behaviors; for example, bats might have an enlarged auditory cortex since they navigate with echolocation. To some extent this does happen, but such…