Over New Year's I had a brief discussion with a condensed-matter physicist who proclaimed that 1) "some developmental research is amazingly bad" and that 2) "they think they can tell what a baby has learned from what direction it looks," topping it all off with 3) "you guys don't even know what learning is!" I won't argue with the first point (there are bad researchers in every field, even condensed matter physics), and I'm too lazy to bother with the third (although the 2000 Nobel prize committee might disagree), but the second point - on the technique of preferential looking - I just can't…

Play is more often simply observed than studied scientifically - play behaviors occur unpredictably and, when they do occur, are highly chaotic, making it very difficult to study them in the laboratory. Despite these challenges, new work is beginning to make play accessible from a rigorous scientific framework. For example, a recent article by Schulz & Bonawitz takes Piaget's notion of play as a mechanism for understanding causal relationships and recasts it into a testable prediction: children should be more likely to play with an object about which they have incomplete or confounded…

Originally posted on 12/16 2006: The term "executive function" is frequently used but infrequently defined. In attempting to experimentally define executive functions in terms of their relationship to age, reasoning and perceptual speed, Timothy Salthouse reviewed the variety of verbal definitions given to construct of "executive function." Although these differ in terminology and emphasis, they are clearly addressing a similar concept: "Executive functions cover a variety of skills that allow one to organize behavior in a purposeful, coordinated manner, and to reflect on or analyze the…

If you encounter a difficult situation, you may be extra careful afterwards, even in a different or unrelated situation. This intuitive statement has recently been confirmed in a laboratory task, and extended to show that such carry-over "conflict adaptation" effects may affect the speed with which you approach subsequent tasks very differently from how it affects the probability of making a mistake. A task often used to look at conflict is the flanker task: when subjects must respond to an arrow symbol that is surrounded by other arrow symbols, responses will be faster when the surrounding…

Is there a basic "computational unit" of the neocortex? In contrast to subcortical regions, neocortical architecture seems fairly regular and matrix-like - leading to it's other name, "isocortex." While there are many contenders for the title of the "canonical circuit" or "cortical algorithm", few would dispute that cortical columns are a fundamental organizational principle of cortex. Or wouldn't they? In their new Neuron article, Douglas & Martin's argue that the cortical column is a poor contender for identifying the cortex's "canonical circuit." They describe how the anatomical…

How does memory help to accomplish moment-to-moment goal-directed action? Classic accounts, such as Baddeley's working memory model, suggest that there are separate storage and processing ("executive") mechanisms, whereas newer accounts (proposed by a variety of researchers) propose that storage and processing are intertwined in the form of maintained goal or context representations. According to these newer theories, individual differences in the strength of goal representations can more or less efficiently "bias" perception and behavior, particularly in cases where habit or environmental…

Your IQ can be reliably predicted by simple reaction time tasks - perhaps even more reliably than with much more complex cognitive tasks. This surprising psychometric fact has led to the belief in human "processing speed." In the same way that a computer with a faster microprocessor might carry out more computations, with potentially less demand on memory, the idea is that brains with better neuronal efficiency also manifest both higher IQ and proportionately faster reaction times even in simple tasks. To me, this story always seemed "too good to be true" - or perhaps merely "too simple to…

A lot of good brain blogging lately; some beautiful drawings from the era of phrenology, some crazy kids high on scopolamine, James Flynn's current thoughts on intelligence, and more... Who has better graphics? It's a close call between the phrenology of old and today's fMRI. Beware the No2 Pencil - even low levels of lead exposure can lead to cognitive decline. Getting high on scopolamine is not a good idea, but videos of it are pretty entertaining. Mind, the time-machine: video proof (at the bottom) that hippocampus travels to places you haven't been yet. The speed of thought in memory…

The world wide web can be understood as a giant matrix of associations (links) between various nodes (web pages). At an abstract level, this is similar to human memory, consisting of a matrix of associations (learned relationships, or neuronal connections) between various nodes (memories, or the distributed representations constituting them). In the new issue of Psych. Science, Griffiths et al. ask whether Google's famously accurate and fast PageRank algorithm for internet search might behave similarly to the brain's algorithm - whatever that might be - for searching human memory. About…

The ability to actively maintain more information in memory, known as "working memory," seems to benefit performance in a variety of tasks. One idea is that these tasks require controlled attention, allowing for better control over behavior. But there's a serious problem with this explanation: maybe this doesn't reflect improved control so much as superior motivation. In other words, maybe subjects with higher working memory are the only ones who care, and everyone else is just goofing off! Thankfully, there are some cases where additional working memory has no benefit - or can even be a…

Geoff Hinton has a new TiCS paper describing recent advances in algorithms used to train multilayered neural networks. First, a little background: neural networks of a sufficient size can calculate any mathematical function (an infamous proof among neural network modelers). Unfortunately, the tricky part is figuring out how to set the connections in that network to calculate those functions. This is where learning algorithms become necessary - unless you want to tweak each connection by hand until you get a working network (not a problem if you don't care how the brain works), then you…

Neuroesthetics seeks to identify the neural basis of aesthetic experience - how does the brain give rise to the perception of beauty? A new paper in Network indicates that artists consistently create works which contain the same statistical properties as natural scenes, even when the objects being depicted do not themselves contain such statistics when photographed. Redies, Hanisch, Blickhan and Denzler review previous work demonstrating that the "spatial frequencies" of natural scenes (essentially, their spatial complexity) follow a 1/f power spectrum, where increased spatial complexity is…

Asperger's disorder is a subtype of autism, characterized by deficits in social interaction, delays in nonverbal communication and possibly also deficits in nonverbal IQ (such as on a test known as Block Design). However, a new study in Brain and Cognition challenges this latter claim - with surprising results. Hayashi et al gave 17 children with Asperger's a test of fluid intelligence called the Raven's Progressive Matrices. Fluid intelligence is thought to reflect problem-solving ability, to show large individual differences, and to be a distinct construct from general intelligence ("g…

Speech recognition remains a daunting challenge for computer programmers partly because the continuous speech stream is highly under-determined. For example take coarticulation, which refers to the fact that the auditory frequencies corresponding to a given letter are strongly influenced by the letters both preceding and following it - sometimes interpreted to mean that there is no invariant set of purely auditory characteristics defining any given letter. Thus it's difficult to recover the words that a person is saying, since each part of that word is influenced by the words surrounding it…

Aging is associated with some slow but measurable forms of cognitive decline, but there is debate over the type of cognitive changes taking place. A recent study by Rush, Barch & Braver uses a series of interesting tasks to clarify the nature of this cognitive decline. The results seem to show that changes in "context processing" - the ability to internally represent environmental cues to control thought and action - but not inhibition or processing speed underlie aging-related decrements in cognitive function. The work has implications for our understanding of and interventions for…

A first-hand report of caloric vestibular stimulation - to treat Body Integrity Identity Disorder, in which patients often desire to have large parts of their bodies amputated. Ambien, a sleep drug recently discovered to awaken some people from comas is also linked to strange behavior: one woman paints her frontdoor - in her sleep. Altruism as an identifying characteristic of intelligence - "friendly intelligence," at least. Isaac Asimov asks "What Is Intelligence Anyway?" Brian Mingus asks if we'd recognize it if we saw it. Can you extract the "ball" from each image based on motion cues…

Trueswell & Kim's paper in the Journal of Memory and Language describes a phenomenon known as "fast priming," in which a reading task is momentarily interrupted by a brief presentation of a "prime" word, usually lasting around 30 to 40 ms. The reading task then continues, and although subjects are typically unaware of the presentation of this word (usually describing it merely as a "flicker") the processing of subsequent words are influenced by many characteristics of the prime word, including its meaning as well as its sonic and orthographic characteristics. Al Fin has an excellent…

When one object passes in front of another we know that the occluded object has not vanished, and yet representations in our visual cortex have been assumed not to reflect this information. Instead, such "object permanence" information has been thought to require active maintenance, perhaps with help from prefrontal regions, thus explaining why young children (with underdeveloped prefrontal cortices) often fail to show behavior that is consistent with knowledge of object permanence. A recent study by Hulme & Zeki elaborates this view by presenting 13 subjects in an fMRI scanner with…

Several high-profile studies have shown that bilingual children outperform their monolingual peers in terms of several cognitive abilities - including tests of verbal and nonverbal problem-solving, selective attention, flexibility (e.g., task-switching) and others. These studies have captured the public imagination and probably guided many moms to expose their kids to a second language. But a new article in Developmental Science suggests that these impressive results may be somewhat overblown: bilingual children may be likely to come from wealthier families than monolingual children (EDIT:…

Synaesthesia involves the inappropriate binding of one perception to another - for example, color-grapheme synaesthetes might perceive the letter "h" to be noticeably red, and are actually slower to identify the letter "h" when it is green than when it is red or gray. This "inappropriate binding" of color to other percepts can be disrupted in synaesthetes through transcranial magnetic stimulation of the parietal lobe. While interesting, this work does not say much about how binding is accomplished in normal subjects, where various colors and various shapes need to be regularly and…