developingintelligence | May 8, 2008Does 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 memory with equal resolution, regardless of the number of items stored. Authors Zhang & Luck first showed that subjects are equally accurate in reporting the color of a memorized item regardless of the number of other items being maintained in memory. Specifically, when subjects were asked to…
developingintelligence | May 7, 2008Complex 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 shown the effect is really due to the slowness of your slowest reaction times on such simple tasks. Known as the "worst performance rule," this can be revealed through various RT distribution decomposition techniques (e.g., "binning" of reaction times or ex-gaussian analysis).
A particular class of…
developingintelligence | April 10, 2008Peter 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 appeal to some philosophers, temporal limitations in neural processing are both critical for neuronal function and well accepted in both neuroscience and psychometrics. At the biological level, the membrane capacitance of neurons is important for regulating the firing rate of neurons, which itself has…
developingintelligence | March 4, 2008Almost 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 finds a special role for juvenile exercise in guarding against obesity throughout the lifespan.
Patterson & Levin review several reasons for why it's so difficult to lose weight. First, caloric restriction is associated with subsequent "compensatory" increases in food intake, in both humans…
developingintelligence | February 25, 2008How 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 algorithms must exist - how else could the brain disentangle mere correlations from true causation?
Temporal precedence helps to some extent - and does seem to play a large role in Hebbian learning (e.g., spike-timing dependent plasticity). But the smell of rain does not actually cause rain -…
developingintelligence | February 14, 2008Well, 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 else is performing these illusions on you (to reduce proprioceptive feedback):
The Aristotle: an object touched with crossed fingers will sometimes be identified as two objects (try it on your nose)
Comb: With a comb and a pencil, lay your index finger along the ends of the comb's teeth; use the pencil…
developingintelligence | February 11, 2008Caffeine 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 (owing to its lipid solubility) although it can take up to 45 minutes for full ingestion through the gastro-intestinal tract. Under normal conditions, this remains stable for around 1 hour before gradually clearing in the following 3-4 hours (depending on a variety of factors).
A landmark 2004 study…
developingintelligence | February 5, 2008We 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 have previously shown that spontaneous gesture during speech contains a form of implicit knowledge - knowledge that cannot be verbally reported, but nonetheless affects performance. Similar phenomena are known as knowledge-action dissociations; for example, in Piagetian conservation tasks, children…
developingintelligence | February 4, 2008When 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, a variety of mental processes seem to undergo rapid development, including task-switching, theory of mind, linguistic generalization, and an understanding of time. Previous work by Lagatutta and colleagues showed that up to 39% of 3 year olds could attribute sadness in a story's character to that…
developingintelligence | January 31, 2008Phil 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, Threshold, "Offset," "Output," and "Structure" (not sure about those latter three). The connectivity was determined by hand.
Phil states that the sculpture is not intelligent, but rather "some kind of squid baby."
Neural networks have great potential for contributing to the arts. For example, JP…
developingintelligence | January 19, 2008UPDATE: 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 (an expert on machine-effects in elections) as well.
At bottom is a disagreement over how to infer causality in observational data, and how to diagnose the functional form of a data set.
The good news is two-fold: there may not be a large "Diebold effect" when nonlinear methods are used, and reason…
developingintelligence | January 17, 2008Update: 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 regression to predict the presence of Diebold machines based on Clinton Campaign presence, median age, % holding bachelor's degrees, percapita income, and population density are themselves correlated with the residuals of a regression to predict Clinton's votes based on the same predictors (R=.306,…
developingintelligence | January 17, 2008Update: 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 at the mainstream media (e.g. this discussion of a red herring issue) - but also at some usually-thoughtful corners of the internet, including our very own Scienceblogs.
Mark at GoodMathBadMath, whom I eminently respect, has contributed trivial high-school anecdotes and parroted the essentially-…
developingintelligence | January 15, 2008UPDATES: 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 to show an advantage to Hillary conferred by the use of Diebold machines.
However, there was an easy explanation: towns with Diebold machines are more urban on average, and Hillary was always thought to have more support in urban areas. So, like many others, I was supremely irritated by the lack of…
developingintelligence | January 11, 2008One 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 behavioral measures of memory span. Impressively, the location of this "memory filter" is the globus pallidus, as predicted by a computational network model of cortex, but in contrast to that model, it shows functional correlations with parietal in addition to frontal areas. This work has immediate…
developingintelligence | January 11, 2008Josh 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 reflection" leads me to a different belief, as discussed here).
developingintelligence | January 10, 2008A 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 neuropsychological tests.
Vygotskian theory posits that children need to "learn to learn" - by mastering a set of mental tools which bootstrap their mental abilities, the same way that physical tools can extend physical abilities. The consequent "mental exercise" may strengthen the mind just like…
developingintelligence | January 8, 2008Mick 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 waveforms are sensitive to the "grammar" and "meaning" of musical harmonies, respectively.
What waveforms would you look for in this system?
Related Posts:Meaning From Melody: Music as LanguageHarmony in Grammar: Music as LanguageDynamic Gating in Long-Term Memory (and the N400)The Attentional…
developingintelligence | January 7, 2008A 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 is merely coactivated whenever motion is perceived. Such distinctions are both particularly important and particularly difficult to achieve in domains thought to be uniquely human: we cannot simply lesion human brains and observe the consequences as we can with animals trained to perform lower-…
developingintelligence | January 4, 2008A 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?
Tabloid language in Nature Neuroscience?
Frontal Cortex discusses a new book on electroconvulsive therapy (but I disagree this is a contrarian perspective - ECT has always been known to be highly effective).
PsychCentral discusses the collected videos of a guy who's documenting his ongoing…