SilasBarta comments on Link: Strong Inference - Less Wrong

9 Post author: Daniel_Burfoot 23 May 2010 02:49AM

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Comment author: SilasBarta 23 May 2010 04:40:55AM 12 points [-]

Okay, but my suggestion is that this mode of empirical verification just isn't good enough. People have been using this obvious method for decades, and we still can't solve face detection (face recognition is presumably much harder than mere detection). This implies we need a non-obvious method of empirical evaluation.

Okay, but non-"whatever scientists are currently doing" is not an epistemology! You need to say what specific alternate you believe would be better, and you haven't done so. Instead, you've just made broad, sweeping generalizations about how foolish most scientists are, while constantly delaying the revelation of the superior method you think they should be using.

Please, please, just get to the point.

As for facial recognition, the error was in believing that it should be simple to explain what we're doing to a blank slate. Our evolutionary history includes billions of years of friend-or-foe, kin-or-nonkin identification, which means the algorithm that analyzes images for faces will be labyrinthine and involve a bunch of hammered-together pieces. But I don't see anything you've proposed that would lead to a faster solution of this problem; just casual dismissals that everyone's doing it wrong because they use fancy math that just can't be right.

FWIW, the best way to reverse-engineer a kind of cognition is to see what it gets wrong so you know what heuristics it's using. For facial recognition, that means optical illusions regarding faces. For example, look at this.

The bottom two images are the same, but flipped. Yet one face looks thinner than the other. There's a clue worth looking at.

The top two images are upside-down pictures of Margaret Thatcher that don't seem all that different, but when you flip it over to see them right-side up on your photo-viewing tool (and consider this your WARNING), one looks hideously deformed. There's another clue to look at.

Now, how would I have known to do that from the new, great epistemology you're proposing?

Comment author: JanetK 23 May 2010 02:44:26PM 3 points [-]

How right you are about the special nature of face recognition. Another clue is the difficulty of describing a face in words so that another person can picture it. We use aspects of the face that do not register in consciousness to make the identification. Still another clue is that false faces 'pop out' in our vision. Cracks in pavement, clouds in the sky, anything vaguely like a face can pop out as a face. And again, faces are the first things that babies take an interest in. Their eyes will fasten on a plate with a simple happy face (two dots and a line) drawn on it. It is certainly not ordinary every day vision.

Comment author: saturn 23 May 2010 03:40:47PM 0 points [-]

Can you easily read upside down?

I'm asking because neither of the upside-down face illusions seem to "work" for me. (I was immediately startled by the deformed version of Margaret Thatcher.)

Comment author: SilasBarta 23 May 2010 05:14:10PM 1 point [-]

Can you easily read upside down?

Yes, pretty easily (just checked).

I'm asking because neither of the upside-down face illusions seem to "work" for me. (I was immediately startled by the deformed version of Margaret Thatcher.)

So the deformed Thatcher picture wasn't any more startling upon turning the image over? Well, you may have some unusual aspects to your visual cognition. Try it with some more faces and see if the same thing comes up.

Comment author: NancyLebovitz 23 May 2010 09:00:07AM 0 points [-]

Another possibility would be to look at visual recognition systems in other species.