Chris Chatham
developingintelligence
Posts by this author
June 9, 2008
Working memory - the ability to hold information "in mind" in the face of environmental interference - has traditionally been associated with the prefrontal cortices (PFC), based primarily on data from monkeys. High resolution functional imaging (such as fMRI) have revealed that PFC is just one…
June 6, 2008
A variety of new cognitive neuroscience shows how our ability to ignore distractions - to "perceptually filter", in a sense - is based on a ventral attentional network, is related to working memory, and may be involved in putative inhibitory tasks.
First, a little background. In 2004, Vogel &…
May 27, 2008
In this poster, Bastos, Mullen and colleagues show that they can analyze electrical oscillations on the scalp of human subjects and predict how quickly they will respond in a simple target detection task. They do this by an interesting method known as the Steady State Visual Evoked Potential (…
May 23, 2008
The organization of the human prefrontal cortex (PFC) is a lasting mystery in cognitive neuroscience, but not for lack of answers - the issue is deciding among them, since all seem to characterize prefrontal function in very different but apparently equally-valid ways. If this mystery were…
May 22, 2008
"It has attained a certain mystique in the physical and biological sciences because it manages to be both rare and ubiquitous. Examples [...] are found in quasar luminosity, tide and river height, traffic flow, and human heartbeat..." (Gilden & Hannock)
Since the mid-90s, a small group of…
May 21, 2008
New research from Wharton and the Carlson School shows that a methodologically-appealing measure of impulsivity - hyperbolic discounting rate - may actually reflect a systematic "skew" in the way people perceive time.
Previous work has shown that people tend to decreasingly discount the…
May 14, 2008
In 2001, Yamamoto and Kitazawa showed that the perception of temporal order can be reversed when subjects cross their hands. Subjects closed their eyes and had their hands mechanically touched in quick succession (with stimuli separated in time by a variable amount - from 1500 ms to 0 ms).…
May 13, 2008
Your ability to control thought and behavior relative to your peers - a set of capacities known as "executive functions" - is almost entirely genetic in origin, according to a newly in-press paper from Friedman et al. Over 560 twins completed tests to measure fundamental components of these…
May 12, 2008
Time pervades our understanding of the world - we use it to coordinate our movements, to perceive motion, to plan our behaviors, and perhaps even to understand causality.
But it is an under-appreciated factor in cognition. Even in the domain of the well-understood visual system, few realize that…
May 9, 2008
Our ability to suppress unwanted thoughts and behaviors is thought to be related to a process known as "inhibition," whereby ventrolateral regions of prefrontal cortex (vlPFC) actively suppress inappropriate representations. A 2001 study by Sakagami et al. recorded firing data from neurons in the…
May 8, 2008
Does the resolution or precision of human memory change with its available capacity? In other words, can you remember fewer items with greater precision than you can remember more items?
Contradicting intuition, a new paper from yesterday's issue of Nature shows that all items are stored in…
May 7, 2008
Complex cognition can be predicted by remarkably simple tasks. For example, the speed with which you choose one of two possible responses can reliably predict IQ. Some theories propose that this relationship is due to differences in something called "processing speed," but more recent work has…
April 10, 2008
Peter Hankins has written an excellent commentary criticizing the "positive comparisons" I make after contrasting brains with computers.
Peter says:"... the concept of processing speed has no useful application in the brain rather than that it isn't fixed."
While this statement may intuitively…
March 4, 2008
Almost everyone tries to lose weight at some point, but we are remarkably bad at it; most people quickly return to their original weight after cessation of exercise or resumption of a normal diet. A review article by Patterson & Levin elucidates the pathways for this effect, and in the process…
February 25, 2008
How does the human brain construct intelligent behavior? Computational models have proposed several mechanisms to accomplish this: the most well known is "Hebbian learning," a process mathematically similar to both principal components analysis and Bayesian statistics. But other neural learning…
February 14, 2008
Well, it's not quite as erotic as it sounds, but they could break the ice on more than a few Valentine's dates. Hayward's new article in Brain Research Bulletin describes all known tactile illusions. Some can be tried easily at home, but can work better when your gaze is averted and if someone…
February 11, 2008
Caffeine is the most widely used stimulant in the world, but few use it to maximal advantage. Get optimally wired with these tips.
1) Consume in small, frequent amounts.
Between 20-200mg per hour may be an optimal dose for cognitive function.
Caffeine crosses the blood-brain barrier quickly (…
February 5, 2008
We often assume that true understanding is conveyed through spoken speech rather than gesture, but new research shows that "talking with your hands" can not only reveal different information than spoken language, it can be both more correct and yield better learning.
Goldin-Meadow and colleagues…
February 4, 2008
When do we learn to imagine the future, and how is that capacity based on imagining the past? How does this kind of "mental time travel" develop? Lagatutta's recent article in Child Development tracks the development of this impressive feat, thought by some to be uniquely human.
At 3 years of age…
January 31, 2008
Phil Stearns has constructed a 45 "neuron" network of electronic parts which responds to lights and tones with a (rather cute) squealing sound. A picture of the components for this strange device:
Each "neuron" consisted of analog electronics corresponding to each of 6 functions: Input, Summing,…
January 19, 2008
UPDATE: Diebold effect explained?
Marc has an excellent summary of a flurry of Diebold-related discussions between me, "T", Marc, and Sean.
Sean also has a network model of the apparent Diebold effect.
I think we'll soon hear from Brian Mingus (who's running a meta-classifier) and Steve Freeman (…
January 17, 2008
Update: Diebold Effect explained.
Here's a unique approach to understanding the Diebold effect: S.Walker has dealt with a potential multicolinearity problem between predictors by taking the principal components of a variety of demographic variables.
My brief rejoinder: the residuals of a logistic…
January 17, 2008
Update: Diebold effect explained.
Jon Stewart famously accused the Crossfire co-hosts as "hurting America" by imitating the style and appearance of political debate to disguise partisan hackery and vacuous strawman arguments.
In the case of the recent NH primary, the same criticism can be leveled…
January 15, 2008
UPDATES: Diebold effect explained. (previous: 1, 2, 3, 4 5 6 (a nonlinear approach) 7)
In contrast to exit pre-election polls, the final vote tally from the NH democratic primary shows a surprise victory for Hillary Clinton. People quickly noticed an anomaly in the voting tallies which seemed…
January 11, 2008
One of the bottlenecks in human memory capacity is its "filtering efficiency" - irrelevant information in memory only detracts from an already-constrained memory span. New work by McNab & Klingberg images the neural structure directly responsible for such filtering, and shows it can predict…
January 11, 2008
Josh Hartshorne, coauthor of a the Hartshorne & Ullman study I've discussed before, has a new blog that's already filled with interesting posts.
What is to blame for psychology's awful PR?
Does workforce diversity improve productivity?
Why languages can't be learned (though my own "careful…
January 10, 2008
A new educational system called "Tools of the Mind" teaches not facts and figures, but rather focuses on cognitive skills in structured play. In the largest and most compelling study yet, exposure to this curriculum in the classroom drastically improves performance on a variety of psychometric and…
January 8, 2008
Mick Grierson has created a real-time EEG-based brain-computer interface for music synthesis. You can watch a video here.
We've been designing experiments to test how classic ERPs (P300/600, N400, etc) may emerge from user interactions with this system, given previous demonstrations that those…
January 7, 2008
A continuing challenge in cognitive neuroscience is determining which neural structures are actually responsible for certain thoughts and behaviors. For example, fMRI and other neuroimaging techniques cannot tell us if a certain region of visual cortex is necessary for perceiving motion, or if it…
January 4, 2008
A downright amazing post on cognitive dissonance at Mind Hacks.
Gesturing unlocks children's math skills.
An entertaining review of new work on inner speech.
A new case of simultagnosia (the inability to see more than one object at a time).
Repressed memories: a "culture-bound" syndrome?…