What would it be like to see with your skin?

In the octopus's case there is a conductor, the central brain. But the players it conducts [the animal's limbs] are jazz players, inclined to improvisation, who will accept only so much direction. Or perhaps they are players who receive only rough, general instructions from the conductor, who trusts them to play something that works. [...]

Now we learn that an octopus can see with its skin. The skin is not only affected by light — something true of quite a few animals — but it responds by changing its own delicate, pixel-like color-controlling machinery.

What could it be like to see with your skin? There could be no focusing of an image. Only general changes and washes of light could be detected. We don't yet know whether the skin's sensing is communicated to the brain, or whether the information remains local. Both possibilities stretch the imagination. If the skin's sensing is carried to the brain, then the animal's visual sensitivity would extend in all directions, beyond where the eyes can reach. If the skin's sensing does not reach the brain, then each arm might see for itself, and keep what it sees to itself.

From Other Minds: The octopus and the evolution of intelligent life, by Peter Godfrey-Smith, 2016.

“She changed color beneath my touch.”

"The moment the lid was off, we reached for each other. She had already oozed from the far corner of her lair, where she had been hiding, to the top of the tank to investigate her visitor. Her eight arms boiled up, twisting, slippery, to meet mine. 

As we gazed into each other’s eyes, Athena encircled my arms with hers, latching on with first dozens, then hundreds of her sensitive, dexterous suckers. They felt like an alien’s kiss — at once a probe and a caress. Although she can taste with all of her skin, in the suckers both taste and touch are exquisitely developed. Athena was tasting me and feeling me at once, knowing my skin, and possibly the blood and bone beneath, in a way I could never fathom. When I stroked her soft head with my fingertips, she changed color beneath my touch, her ruby-flecked skin going white and smooth.

Athena was remarkably gentle with me — even as she began to transfer her grip from her smaller, outer suckers to the larger ones. She seemed to be slowly but steadily pulling me into her tank. Had it been big enough to accommodate my body, I would have gone in willingly."

— Adapted from Deep Intellect by Sy Montgomery, Orion Magazine, February 2015. Athena is a forty-pound, five-foot-long, two-and-a-half-year-old giant Pacific octopus in the New England Aquarium in Boston.