Mind Hacks

Chapter 2. Seeing: Hacks 13–33

The puzzle that is vision lies in the chasm between the raw sensation gathered by the eye—light landing on our retinas—and our rich perception of color, objects, motion, shape, entire 3D scenes. In this chapter, we’ll fiddle about with some of the ways the brain makes this possible.

We’ll start with an overview of the visual system [[Hack #13]], the limits of your vision [[Hack #14]], and the active nature of visual perception [[Hack #15]].

There are constraints in vision we usually don’t notice, like the blind spot [[Hack #16]] and the 90 minutes of blindness we experience every day as vision deactivates while our pupils jump around [[Hack #17]]. We’ll have a look at both these and also at some of the shortcuts and tricks visual processing uses to make our lives easier: assuming the sun is overhead [[Hack #20] and [Hack #21]], jumping out of the way of rapidly expanding dark shapes [[Hack #32]] (a handy shortcut for faster processing if you need to dodge quickly), and tricks like the use of noisy neurons [[Hack #33]] to extract signal out of visual noise.

Along the way, we’ll take in how we perceive depth [[Hack #22] and [Hack #24]], and motion [[Hack #25] and [Hack #29]]. (That’s both the correct and false perception of motion, by the way.) We’ll finish off with a little optical illusion called the Rotating Snakes Illusion [[Hack #30]] that has all of us fooled. After all, sometimes it’s fun to be duped.

Hack #13. Understand Visual Processing

The visual ...