Thursday, December 13, 2012

Speed of Perception

Neurobiologist Semir Zeki, author of Inner Vision  has shown that different features of the visual world are processed in different specialized areas of the brain. 

Distinct regions in the back of the brain are employed to resolve color, edges, form, and motion. After a period of time, these separate components of vision are reconstituted into a single unified experience, called a percept.

But this parallel processing happens at different speeds. According to Zeki, color is perceived before form, and form before motion. There's a 60 to 80 millisecond lag between color and motion. That lag is not an issue with still images or with film scenes with very little motion.

But if you have a scene with a lot of different bright colors moving around at a rapid rate, the lag could be an issue. In that case, as Zeki puts it, "the brain does not seem capable of binding together what happens in real time." Eighty milliseconds translates to two frames in a 24-frame-per-second film, and four frames in a film running at 48 frames per second.

I wonder if that's why so many action sequences in modern films are composed in monochromatic colors? Just a hunch.
Brain diagram from  Inner Vision: An Exploration of Art and the Brain by Semir Zeki, published by Oxford University Press, 1999

Stills from the Hobbit, courtesy Warner Brothers


Tom Hart said...

I wonder if that lag has something to do with the quesiness that some are apparently reporting when viewing The Hobbit, which is shot at 48 frames per second.

James Gurney said...

Tom, I may not get to see the 48 fps version because I don't think it's showing around my little town. But I suspect the faster frame rate would help rather than hurt the queasiness factor. To me it seems like just another creative tool that filmmakers can choose to use or not. When people say it has a "daytime TV" look, I assume it's just because of the associations people bring to the experience, not to anything intrinsic in the technique.

Max West said...

It makes sense in context, James. The first thing I usually notice is color. I'm more likely to notice a neon green shirt, a pink car, Las Vegas lights, and so on rather than the other characteristics in appearance.

That probably works in art as well like when the viewers are drawn to brighter or primary colors (red, blue, yellow).

armel said...

My guess is monochromatic look comes from compositing live action elements with CG, matte paintings, etc. It's easier to blend different elements when they're all monochromatic. The "Matrix" monochrome look is everywhere, these days.

Ravi Gupta said...

Hi sir ,

I have been reading your blog for some time and I have learned a lot through it. Your posts are quite informative and helpful.

Yesterday, I was doing an color piece for my self and I could not differentiate for myself that if it was a sunrise or sunset. So I decided to tweak it a little for myself, and do a different version of the same. Right now I think there is not much of difference between a sunset and sunrise.

If you could share your view on same or do a post on your blog explaining the difference between two, it will be great.


James Gurney said...

Ravi, yes, there are slight differences. In general, sunsets are more orange-hued from the dust kicked up in the afternoon, and sunrises are slightly pinker because of the more settled air.

Ravi Gupta said...

Thank you so much. This surely helps.