developingintelligence | April 17, 2007Your body's bilateral symmetry statistically predicts your health, probability of schizotypy and depression, number of sexual partners, and resting metabolic rate (particularly if you are male). Bodily symmetry may reflect "developmental stability" - i.e., influences like disease, mutation and stress may cause a developmental divergence from DNA's symmetric blueprint. Not only do individuals differ in their environmental exposure to these things, but also in their sensitivity to them: a recent Intelligence article claims that "some individuals grow adaptive phenotypes under almost any…
developingintelligence | April 16, 2007Among nature's most impressive feats of engineering is the remarkably flexible and self-optimizing quality of human cognition. People seem to dynamically determine whether speed or accuracy is of utmost importance in a certain task, or whether they should continue with a current approach or begin anew with another, or whether they should rely on logic or intuition to solve a certain problem. A topic of intense research in cognitive neuroscience is how cognition can be made so flexible.
One possibility proposed by by Brown, Reynolds & Braver is that cognitive control is multi-faceted, in…
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,…
developingintelligence | April 10, 2007Right now, you're blind at one particular part of your visual field - because you have no photoreceptors at the location on your retina where the optic nerve begins its journey to visual cortex. Normally, you're unaware of this blind spot because of perceptual "filling-in" - a mechanism by which your brain actively fabricates the perceptual data it's missing.
But this isn't the only case where cognition manufactures perception. In the case of the Kanizsa triangle, you will sense the presence of a full triangle although none truly exists. In other words, your brain has fabricated "illusory…
developingintelligence | April 9, 2007Given a fixed amount of computational power in designing an intelligent system, there is a necessary tradeoff between how many resources are devoted solely to the current task, and how many resources are devoted to monitoring for information that may be important but is not necessarily relevant to the current task. If more resources are dedicated to the current task, it may be accomplished more quickly - but at the same time, this setting may make it more difficult to reorient and switch to a different task. On the other hand, if more resources are dedicated to monitoring or reorienting,…
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…
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…
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…
developingintelligence | April 2, 2007Everyone does something they later regret. Can you ever intentionally forget that you did it? The idea of memory repression has rarely been considered within scientific psychology, but the processes involved in intentional forgetting (also covered last week) are the focus of a recent article by Michael Anderson.
In his article, Anderson argues that the "cognitive control" required to suppress an unwanted memory is fundamentally similar to the processes involved in overcoming a habitual or "prepotent" response in favor of a weaker response. A simple example might be naming the ink color of…
developingintelligence | March 29, 2007Recent highlights from the best in brain-blogging:
Is our sense of morality localized to the ventromedial prefrontal cortex?
More reasons for caution when beginning sentences with the phrase; "Only humans are cognitively capable of ......."
Are wild monkeys in a stone-age of their own?
Spatial memory in single-celled organisms.
Continuing debate about the correlation between intelligence and gross indices of brain size.
More reasons to think that glia are not merely "support cells" after all.
So, what is a brain "area" anyway?
More neurons is better, right? Not true, at least in terms of…
developingintelligence | March 27, 2007"A good metaphor is something even the police should keep an eye on." - G.C. Lichtenberg
Although the brain-computer metaphor has served cognitive psychology well, research in cognitive neuroscience has revealed many important differences between brains and computers. Appreciating these differences may be crucial to understanding the mechanisms of neural information processing, and ultimately for the creation of artificial intelligence. Below, I review the most important of these differences (and the consequences to cognitive psychology of failing to recognize them): similar ground is…
developingintelligence | March 23, 2007The past continuously besets our ability to act flexibly in the future; habits grow strong, automaticity takes over and the mind wanders. Before you know it, you've forgotten to stop for milk on your regular commute, neglected to go to your dentist appointment, or merely "lost track" of what you were doing. These kinds of things are often studied in cognitive control laboratories, usually in the context of a task where there is particularly strong "proactive interference" from previous habits (for example, the habit to read color-words instead of naming ink-colors in the Stroop task).
A…
developingintelligence | March 22, 2007Imagine you are invisible. Congratulations, you are now actually less likely to remember what you were doing a few minutes ago, and possibly a lot longer ago than that. At least, this is the basic finding from a 2002 article by Sahakyan & Kelley, who showed that when people are asked to forget something they'd learned, they may actually do this by rapidly changing their internal context in a way that is similar to what happens if, say, you're asked to imagine that you're invisible.
In the laboratory, this is usually studied in the "directed forgetting paradigm," in which subjects learn…
developingintelligence | March 21, 2007In the new issue of Seed, Douglas Hofstadter talks about "strange loops" - his term for patterns of level-crossing feedback inside some medium (such as neurons) - and their role in consciousness. Likewise, Gerald Edelman has talked about how a "reentrant dynamic core" of neural activity could tightly integrate large groups of neurons through positive feedback cycles. Similarly, many view interactions among neural oscillations as a candidate mechanism for the formation of consciousness - such oscillations can perform abstract computations (as in liquid state machines) and can interact with…
developingintelligence | March 20, 2007Imagine that you are about to pass to a teammate when he suddenly darts in another direction, in an attempt to get clear. With some difficulty, you will be able to modify your pass and correctly throw the ball to your teammate's new location. How is this process implemented in the brain? This scenario relies on quick processing of relevant perceptual information in order to modify or interrupt the ongoing motor commands, which itself requires a tight linkage between perception and action - yet another unsolved "binding problem" in cognitive neuroscience (as covered yesterday).
One form of…
developingintelligence | March 19, 2007Last week I discussed how central dopamine levels appear to correlate with how strongly actions are bound to particular visual features. I presented this as part of "the binding problem," but in fact the topic runs must deeper: cognitive neuroscience has yet to reveal the mechanisms by which the motor system "links up" with the perceptual system. This is the topic covered by Verleger et al's 2005 J. Psychophysiology article, which points not to dopamine, nor to multiplexed neural synchrony, but rather to the "P3b" component of scalp electrical activity as the "glue" that binds together…
developingintelligence | March 13, 2007Some theories suggest that color and shape information - processed in different parts of the brain - must be integrated by attention in order to give rise to a coherent visual experience (in other words, attention is thought to solve the "binding problem"). Although that explanation is probably not satisfying to many, no doubt mostly because attention itself is an ill-defined construct, at least it's a beginning in solving the binding problem. However, a recent article from Allen, Baddeley & Hitch argues that even this humble claim may be entirely wrong.
Allen et al. suggest that the…
developingintelligence | March 10, 2007Recent highlights from the best in brain blogging:
Online experiments at the Harvard Visual Cognition Lab!
Less invasive brain-computer interfacing, for video games.
Brain-computer interface implants: videos.
A new weapon in the Israeli arsenal: the VIPER robot.
The current state of the art in robotics, as reviewed by Cognitive Daily.
Guiding pigeons with remote controls.
Hunting by single-cell organisms: the slime mold.
Relatively complex reasoning revealed in rats (improved! now links to the correct page).
Mental representations in non-human animals: signs of animal intelligence?
Evolving…
developingintelligence | March 9, 2007"Simplicity is the ultimate sophistication." - Leonardo Da Vinci
"The aim of science is to seek the simplest explanation of complex facts. We are apt to fall into the error of thinking that the facts are simple because simplicity is the goal of our quest. The guiding motto in the life of every natural philosopher should be ``Seek simplicity and distrust it.'' - Alfred North Whitehead
No one ever said the brain was going to be simple - and this is precisely why there is a need to use simple tasks in cognitive neuroscience; even the "simplest" tasks may be subserved by bewildering complex…
developingintelligence | March 8, 2007The infamous "binding problem" concerns how a coherent subjective experience of the world can emerge from the widely-distributed processing of individual object characteristics (for example, object identity and object spatial locations appear to be processed by independent neural systems). It is clear that binding requires focused attention (at least, according to "Feature Integration Theory"), but the specific mechanism by which attention binds remains elusive. Partly because of this, Baddeley has even revised the standard model of working memory to include an "episodic buffer" for binding…