A word I like to throw around (especially when someone believes something different than what I believe) is epistemology. That’s the branch of philosophy that deals with the theory of knowledge, or how it is that we know what we know. When I think about epistemology I tend to think about the operation of my prefrontal cortex, as it carries out the so-called “executive function” of my brain: The evaluation of information gathered by the senses (these days, often via the distance-shrinking “perception engine” of the Internet), the use of logic, the rational weighing of evidence, and so on. There is also bias, including the predisposition to believe certain things because they match my a priori belief (see confirmation bias), but here I assume we’re still talking mostly about the prefrontal cortex.

But there is another aspect of knowledge that I too-frequently ignore. That’s the feeling of truth, the sense of certainty that accompanies knowing something. Here I suspect we’re moving beyond the prefrontal cortex into evolutionarily older structures. Where does that feeling come from?

An interesting disorder that may shed some light on this is prosopagnosia, or “face blindness”, in which a person has an inability to recognize faces, even if their ability to perceive the specific differences between one person’s face and another’s remains intact. Even more interesting (at least to me) is the somewhat-related disorder called the Capgras delusion, in which a person becomes convinced that someone they know well (like a close relative or loved one) has been replaced by an identical-looking stranger. In an NPR story from earlier this year (Seeing Impostors: When Loved Ones Suddenly Aren’t), Jad Abumrad and Robert Krulwich spoke with neuroscientist V.S. Ramachandran about a possible explanation for the Capgras delusion:

According to Ramachandran, when we see someone we know, a part of our brain called the fusiform gyrus identifies the face: “That looks like mom!” That message is then sent to the amygdala, the part of our brains that activates the emotions we associate with that person. In patients experiencing Capgras, Ramachandran says, the connection between visual recognition and emotional recognition is severed. Thus the patient is left with a convincing face — “That looks like mom!” — but none of the accompanying feelings about his mother.

Ramachandran holds that we are so dependent on our emotional reactions to the world around us, that the emotional feeling “that’s not my mother” wins out over the visual perception that it is. The compromise worked out by the brain is that your mother was somehow replaced, and this impostor is part of a malevolent scheme.

I see this as tying in with Justin Barrett’s notion of a Hyperactive Agency Detection Device. The idea is that humans have evolved to experience a deep-rooted, powerful sense of “agency” when perceiving certain kinds of phenomena, and (this is important) to do so even in cases when there is no agent. As just one example, in evolutionary terms it may have been beneficial for us to believe that that rustle in the bushes was a large, hungry predator stalking us, rather than the wind, and to believe that viscerally, on an emotional level, rather than treating it as a passing supposition that we might or might not be bothered to act upon. The energy our ancestors wasted by overreacting to windblown leaves was more than made up for, the theory goes, by the survival benefit conferred by being hyperalert to actual threats.

Having evolved this generalized mechanism for “knowing” things that are not necessarily so, we now experience all kinds of interesting consequences: A propensity to believe that the universe was created specifically for us by an imaginary, omnipotent being or beings. A belief that intelligent aliens from other worlds are kidnapping people, taking them aboard invisible spaceships, and subjecting them to anal probes. A belief that some dramatic, emotionally traumatic event (the assassination of John F. Kennedy, the 9/11 attacks) must have been the result of a conspiracy in which our own government was complicit. For a significant subset of the population, these and other conspiracy theories are not merely things that they suspect. They are things that they know.

Jonah Lehrer blogged yesterday about a recent study examining the role of a brain structure called the insula in mediating between physical sensations (like the feeling of warmth or cold one receives from holding a hot or cold object) and a willingness to extend trust to a trading partner: Trust and temperature. I especially liked this part:

We like to see ourselves as Promethean creatures, mostly liberated from this sack of meat we have to carry around for support. (John Updike, as usual, said it best: “We think we are what we think when in truth we are upright bags of tripe.”) But what the insula and these studies of embodied cognition demonstrate is that our mind is impossibly intertwined with carnal changes we can’t explain or comprehend.

I know what I know because my rational mind has analyzed facts and evidence, sure. But that’s not the whole story. The sensations delivered to me by my body — by chemical cues, sensations of warmth and cold, and the murky actions of older, deeper mechanisms that reach me as visceral emotions — play a large part. Perhaps the major part.

I just know it.

I’m interested in how the Internet serves to amplify human perceptions, to the point where we can instantly google up the information to prove or disprove factual assertions. Surely, this will have ushered in a brave new era of enlightened thought and rationality.

Or not. It turns out that the net is just as happy to serve up confirmatory swill to feed into our confirmation bias, and help us organize with like-minded loons to disseminate The Truth about lizard people or faked moon landings or geocentrism or whatever. More here and here.

This recent item from Chris Mooney tells an interesting story about the last time someone thought a revolutionary communications medium was going to usher in a new era of truth and rationality. It was Condorcet, back in 1794, talking about the Internet of his day: How the Printing Press Ensures Eternal Enlightenment (Or So They Thought in the 18th Century).

Sigh. Technology only gets you so far. The wetware remains a problem. PEBKAC, as we used to observe in tech support.

Apropos my recent obsession with science vs. its opposite on the Internet, I really liked this item from Greg Laden: Skeptics: How do you know what to “believe”?

“My car is not running right. I think the elves that make it run have tummy aches.”

And then the mechanic tries to explain that there are no elves in the car, but the person insists.

“You have not seen that there are no elves in the car. And besides when you open the hood the elves become invisible. Anyway, the elves have tummy aches. Fix the tummy aches.” And so on.

That is what many people who are not scientists sound like when they are talking about science.

From USA Today: Are celebrities crossing the line on medical advice?

In her book Mother Warriors, McCarthy, who declined to be interviewed for this story, says she learned about autism from “the university of Google.”

Explaining complex science – especially in the few minutes allotted on a TV program – is challenging, Carroll says. Audiences sympathize with McCarthy, who says she doesn’t need science because she observes her son, Evan, every day. “At home,” she writes, “Evan is my science.”

“How can you argue with that?” Carroll asks. “It’s her child. It’s her body. They win.”

This really gets to the heart of what worries me about what I’ve taken to calling “The Perception Engine.” We’ve entered an era in which the distance between a human mind and the confirming (or disconfirming) information that would support (or undercut) a pet theory is essentially zero. Just as previous generations amplified their muscle power with steam and the internal combustion engine, we’ve amplified our senses. How will we use this newfound power? Will there be a flowering of reason and understanding? Or will a thousand conspiracy theories bloom, as people give in to the lure of confirmation bias?

Both, it sounds like.

A man with a watch knows what time it is. A man with two is never sure. — Anonymous

I’m surrounded by conspiracies. There was an excellent Tank Riot podcast the other day: Conspiracies, Part 6, which was mostly about the JFK assassination and the Zapruder film in particular. One point that Viktor made (loosely paraphrased): In the olden days, when some public figure was assassinated we all read the news reports, which were mediated by a professional class of interpreters, and we more or less knew (or thought we knew) what time it was. With the Kennedy assassination, though, where we had a source of objective truth (the Zapruder film), it didn’t make things better; instead, it made things much, much worse, serving as the raw material for an endless parade of conspiracy theories.

Or Climategate (of course), which Kevin Drum had a nice item on today (Quote of the Day: Climate Denialism), where the eponymous quotation was of Al Gore (as interviewed by John Dickerson in Slate): “What in the Hell Do They Think Is Causing It?”

If the people that believed the moon landing was staged on a movie lot had access to unlimited money from large carbon polluters or some other special interest who wanted to confuse people into thinking that the moon landing didn’t take place, I’m sure we’d have a robust debate about it right now.

Or there were all those beautiful shots of what surely was an upper stage of a (Russian, presumably) rocket venting propellant over Norway:

…of which Phil Plait in his excellent Bad Astronomy blog had many interesting things to say (Awesomely bizarre light show freaks out Norway), but which prompted a set of blog comments the most memorable of which was this one by user Billy:

Sweden, Norway, Finland and Russia all denny [sic] having launched a rocket at that time. Also, for it to be a rocket the spiral is too symmetric. To me this looks like a vortex of a very strong energy force. Perhaps a temporary black hole because of some thing happening to the earth’s magnetic field? I’m 99.9% sure this was not man made; at least not with anything that I know of…

To the above: NO WAY is that a rocket.

See? He’s 99.9% sure. He’s quantified his level of certainty. He’s being scientific.

Sigh. What began with the JFK assassination has picked up steam since we got the Internet. If you’re willing to ignore conflicting data and focus only on finding confirmation for your a priori opinions, Google is perfectly happy to let you enclose yourself in a snuggie of comforting factoids. Meanwhile, real engineers and scientists, people who have to make rockets go up and governments recognize the catastrophe that climate denialists would inflict on our descendants, people who measure their ideas not against what they want to believe, but against what actually is, labor on.

Update: Russia comes clean: Yeah, it was an upper-stage failure of a submarine-launched missile. So, what do you think the chances are that Billy is hard at work recalibrating his estimates in light of this anomalous data? Yup, I agree: Somewhere around 0.1%.