13 September 2008

The Mind Is A Hungry Hunter

The human mind/brain is the most complex and powerful multi-purpose machine known to itself. Using powerful new imaging tools, cognitive scientists are untangling the back and forth workings of the brain in ways impossible until recently.
Last year Drs. Peter J. Freed and J. John Mann, publishing in The American Journal of Psychiatry, reported on the literature of sadness and the brain. In 22 studies, brain scans were performed on nondepressed but sad volunteers. Sadness was mostly induced (subjects were shown sad pictures or films, asked to remember a sad event), although, in a couple of studies, subjects had recently experienced a loss. In the aggregate, sadness appeared to cause altered activity in more than 70 different brain regions. The amygdala and hippocampus both show up on this list, as do the front part of the brain (prefrontal cortex) and the anterior cingulate cortex. A structure called the insula (which means "island") also appears here—it is a small region of cortex beneath the temporal lobes that registers body perceptions and taste.

The authors believe this complicated picture makes sense. The brain regions on their list process conflict, pain, social isolation, memory, reward, attention, body sensations, decision making and emotional displays, all of which can contribute to feeling sad. Sadness triggers also vary—for example, the memory of a personal loss; a friend stressing over a work conflict; seeing a desolate film.

In the brain, happiness is as widely distributed as sadness. _SadBrainHappyBrain
The relationship between the brain's abstract mental stores, and more mundane processes such as looking for car keys, may be closer than you would ever guess.
Lead author Thomas Hills worked with Todd and fellow IU cognitive scientist Robert Goldstone in designing experiments to explore the search processes their study participants used in both spatial and abstract settings. The studies revolved around two search modes -- exploitation, where seekers stay with a place or task until they have gotten appreciable benefit from it, and exploration, where seekers move quickly from one place or one task to another, looking for a new set of resources to exploit. They then examined whether an initial search, in this case for resources in space, primed the mode used in the subsequent, more abstract search.

"We asked the question -- are the same mechanisms that let simpler organisms search in space for food related to how we search for things in our mind, for concepts or ideas?" Todd said. "Our conclusion is that they seem to be linked at some level, which is what our priming experiment suggests."
Even an everyday phenomenon such as human memory is far more complex than most of us realise.
In a recent experiment, people who viewed pictures of thousands of objects over five hours were able to remember astonishing details afterward about most of the objects.

Though previous studies have never measured such astounding feats of memory, it may be simply because no one really tried.

"People had never tested whether people could remember this much detail about this many objects," said researcher Timothy Brady, a cognitive neuroscientist at MIT. "Nobody actually pushed it this far." _Source
The mind is always searching for something--always hungry, like a hunter. Understanding how the brain goes about its endless parallel searching, combined with an endless parallel pattern matching process, will give cognitive scientists powerful new theoretical platforms from which to work.

New discoveries about how the mind generates "plausible fictions" in anticipation of various possible events, is an essential part of the puzzle of cognition. Central to all of these simultaneous and distant-but-related events, is the factor of "timing." As an asynchronous set of massively parallel modular processors, the human brains multiple parts must work together in a "real time" that is unique to that particular brain.

Within the details of all of these generalities, lies the incredible complexity of the stimulus to sensation to perception to cognition to response cycle. A deeper study of these issues helps to explain Al Fin's current pessimism concerning the near to intermediate term prospects of downloading human consciousness into a machine. That part of the singularity will have to wait.

The goal of human cognitive simulation by machines has a far more favourable prognosis. That should only take a decade or two, compared to the likely many many decades required for the goal of downloading. But the idea that a machine with human-level cognition would necessarily soon lead to a machine with superhuman-level cognition is on shaky ground. I prefer finding ways of making humans themselves better cognitive machines.

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