Sunday, February 28, 2010

How looking away prevents pedestrian collisions

One day a friend and I were briskly strolling along a mall corridor, engaged in conversation, until something quite hilarious happened. A burly gentleman was quickly approaching my friend's direct line of trajectory. She and this man had to make either one of two choices; move to the left or to the right to avoid a disastrous collision. Simple, no? And so I thought. With about a foot between them, my tiny-sized friend and this large stranger began this seemingly unending, and surprisingly well-coordinated dance (or if you're an avid sports fan, picture Spud Webb desperately trying to drive on Shaq) one mirroring the others' movements, swaying back and forth, side to side. Both were a bit confused as to which direction to settle on, and for an estimated 5 seconds I stood there in utter disbelief, witnessing this extremely awkward, yet ridiculously entertaining situation.

How do we avoid catastrophes like this from happening on a daily basis? And if navigating through a mall corridor without incident is THAT difficult, how does the multitude of pedestrians in somewhere like Manhattan manage to avoid such annoying or, in my friend's case, embarrassing encounters? Inattention and "mind-blindness", an inability to develop an awareness of what is in the mind of another human, would seem to be the main culprits. However, there's bit more to it than that and it involves eye gazing.

Thursday, February 25, 2010

The power of prediction reduces activation in the primary visual cortex

Prediction is an invaluable skill for navigating through complex environments. Somehow the brain generates predictions about perceptual inputs it's likely to receive using contextual information from recent memory. Statistical regularities are learned (e.g. movement and attack patterns of Mega Man bosses) and lead to less activation in corresponding brain areas. The brain is truly a miserly organ. "Why put in more work than I have to when I know what's gonna happen next", says the brain.

Alink and colleagues over at the Max Planck Institute in Germany decided to check out what's really going on in the brain when it's making visual predictions.

Using fMRI, the team tested whether predictability reduced responses in the human visual cortex as put forth in Rao and Ballard's 1999 model of predictive coding. They assessed the theoretical claim by looking at the response of V1 (primary visual cortex) when detecting predictive and non-predictive motions.

Tuesday, February 23, 2010

A young Stephen Hawking

I discovered this picture online of a young Stephen Hawking with his first wife Jane. When asked why she would marry a man with a 3 year life expectancy she answered,"those were the days of atomic gloom and doom, so we all had a rather short life expectancy."

more on Stephen Hawking

Saturday, February 13, 2010

DSM-V Draft

Finally, the draft of the DSM-V is out! They've made a few substantial changes such as the tacked on dimensional component to Axis I disorders. Although it hasn't fully moved from categorical to dimensional I suppose it's still a work in progress.

Mindhacks has written up a good summation of the key alterations. The link to the DSM-V draft can be found HERE. Explore and enjoy!