{"id":422,"date":"2007-05-17T13:24:33","date_gmt":"2007-05-17T13:24:33","guid":{"rendered":"http:\/\/scientopia.org\/blogs\/goodmath\/2007\/05\/17\/free-will-and-fruit-fly-behavior\/"},"modified":"2007-05-17T13:24:33","modified_gmt":"2007-05-17T13:24:33","slug":"free-will-and-fruit-fly-behavior","status":"publish","type":"post","link":"http:\/\/www.goodmath.org\/blog\/2007\/05\/17\/free-will-and-fruit-fly-behavior\/","title":{"rendered":"Free Will and Fruit Fly Behavior"},"content":{"rendered":"

I’ve been seeing articles popping up all over the place about a recent
\nPLOS article called Order in Spontaneous Behavior<\/a>. The majority of
\nthe articles seem to have been following the lead of the Discovery Institute, which claims that the article demonstrates the existence of free will, which they argue is inconsistent with naturalism and darwinism.<\/p>\n

<\/p>\n

The thing is, the paper says nothing of the sort<\/em>.<\/p>\n

The paper did a very interesting study on the behavior of fruit-flies. They basically tethered fruit flies inside of a small cylindrical apparatus, which basically amounts to
\na little tiny sensory-deprivation tank. Then they did a series of tests to measure the flies turning behavior over time in the absence of any kind of stimulus.<\/p>\n

The resulting data basically amounted to the time periods between turns: the fly flies straight for a while, then turns, then flies straight, then turns, etc. The data consists primarily of the sequence of time periods between turns.<\/p>\n

With that data, they proceeded to do a number of really fascinating mathematical analyses to try to understand the random\/non-random elements of the turning behaviors.
\nThe most common theories about insect brains (or in fact, animal brains in general) would suggest that they would have found two components that contributed to the behavior: a deterministic one, and a random one.<\/p>\n

That’s not<\/em> what they found. The simplest statement of what they found is: the
\nturning behavior of a fly in a sensory deprivation tank does not<\/em> match a simple
\ngaussian random process; nor does it match a simple combination of a deterministic process
\nwith a simple gaussian random process.<\/p>\n

Studying the data a bit more, they were able to find something that looked<\/em> suspiciously like a Levy distribution – which is a form of power-law distribution. So they proceeded to test that – and again<\/em> found that a random process didn’t match their observations even using a power-law distribution.<\/p>\n

They proceed through several other possible models and analyses, including some
\ninteresting tests of non-linear chaotic systems – and find a kind of fractal structure to the data, but beyond that, pretty much fail to find any simple random model that really captures their observations. <\/p>\n

So what does all that really mean? The papers authors do a great job of stating it
\nclearly:<\/p>\n

\nWe show
\nhere that random noise cannot be the sole source of behavioral
\nvariability. In addition to the inevitable noise component, we
\ndetected a nonlinear signature suggesting deterministic endoge-
\nnous processes (i.e., an initiator) involved in generating behavioral
\nvariability. It is this combination of chance and necessity that
\nrenders individual behavior so notoriously unpredictable. The
\nconsequences of this result are profound and may seem
\ncontradictory at first: despite being largely deterministic, this
\ninitiator falsifies the notion of behavioral determinism. By virtue of
\nits sensitivity to initial conditions, the initiator renders genuine
\nspontaneity (”voluntariness” [30]) a biological trait even in flies.\n<\/p><\/blockquote>\n

That quote is the source of all of the endless babble around the net about this – because it refers to an “initiator” and to the idea of “spontaneity” or “voluntariness”. The thing is, read in context, the “initiator” is not<\/em> what bozos like the DI guys claim it is. They’re talking about something in the flies brain that is neither
\na perfectly deterministic process like a computer program, nor the result of random stimulus. There is something complex in the interactions of a fly’s brain that isn’t simply deterministic, nor simply random. But it does<\/em> exhibit a great degree of order and structure – it’s behavior shows the hallmarks of a non-linear dynamic system.<\/p>\n

Basically, this means that simple models of animals brains, even applied to relatively
\nsimple scenarios, don’t work very well. Assuming that an animal brain will produce behaviors that consist of the combination of some deterministic behavior with some simple random input is, apparently, incorrect. The behavior of an animal is more complicated than that. How complicated? We’re not sure. The basic simple models of randomness – gaussian systems, power-law systems, non-linear chaotic systems – all do not produce a behavior with the complex traits that we see in the data collected for this experiment. But the data is also not consistent with any simple deterministic system. So there’s something complex going on.<\/p>\n

This does not<\/em> mean that the fly has some kind of “spirit” which is deciding
\n“Hey, I think I’ll twitch now”. Nor does it mean that the behavior of the fly
\ncannot<\/em> be modeled by any deterministic process with some kind of random input. In
\nfact, the data suggests exactly the opposite: the strong fractal structure shown for the
\ndata suggests that there is some combination of complex deterministic structure and
\nrandomness. Just that it’s not the kind of very simple one that we might have expected from
\nsomething as a simple as a fly.<\/p>\n","protected":false},"excerpt":{"rendered":"

I’ve been seeing articles popping up all over the place about a recent PLOS article called Order in Spontaneous Behavior. The majority of the articles seem to have been following the lead of the Discovery Institute, which claims that the article demonstrates the existence of free will, which they argue is inconsistent with naturalism and […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[24],"tags":[],"class_list":["post-422","post","type-post","status-publish","format-standard","hentry","category-goodmath"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p4lzZS-6O","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"_links":{"self":[{"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/posts\/422","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/comments?post=422"}],"version-history":[{"count":0,"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/posts\/422\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/media?parent=422"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/categories?post=422"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.goodmath.org\/blog\/wp-json\/wp\/v2\/tags?post=422"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}