On the difference between perception and sensation

Nicholas Humphrey at London Book Fair 2012
During my visit to the London Book Fair, I interviewed Nicholas Humphrey for the BookBaby eBook release of the 20th anniversary edition of his great work A History of the Mind.

In this clip, he discusses the phenomenon of blindsight as evidence of there being different internal pathways of sensation and perception. For Nick, perception is time-independent judgment of what’s “out there” in the world, and sensation is sensation involves the subject’s own interaction with stimuli, an active process which is an emotion-laden and which accrues through time.

An experiment showed him the reality of the distinction. The visual cortex in the back of a monkey’s brain was removed, but while the monkey believed she couldn’t see, she managed quite well visually, picking up objects and navigating through the world, although she had to be continually persuaded to do it. Some humans with damage to their visual cortex have “blindsight” as well – they will say they’re blind and feel no visual sensations, but if you ask them questions, they have access to a fair amount of visual information.

Humphrey’s conclusion is that information alone is not enough to create the feeling, the joy, the sense of presence and involvement in the act of “seeing.” These blindsight patients are lacking the dimension of sensation and cannot react internally to the stimuli’s qualities with emotional bodily expression. And that expression – that active response – is the basis for the “qualia of sensation,” the qualities we value so much when talking about consciousness.

Here’s the clip:

It’s a joy to be releasing the 20th anniversary edition of Nicholas Humphrey’s A History of the Mind through BookBaby.  I had the great pleasure of writing the forward for the book and interviewing him at the London Book Fair this year.

It’s available on Amazon, Apple, B&N –




– and dozens of other retailers.  Get it!


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