What Birds Know About Fractal Geometry

sciencehabit writes "In a new study, researchers find that a single number that describes the complexity of feather patterns on bird chests, a parameter called the fractal dimension, is linked to whether a bird has a strong immune system or is malnourished. When scientists restricted the food of red-legged partridges, the patterns on their chests had a lower fractal dimension than those sported by their well-fed colleagues. The food-restricted birds, on average, weighed 13% less than their well-fed colleagues and had weaker immune systems, which makes fractal dimension an easily recognizable sign of a potential mate's health and vitality, the researchers contend."

Comments

Call it what you will

[CuteSteveJobs]

'Fractal dimension' seems like a cool buzzword which will make it easier to get research noticed, so call it what you will, but a the color of birds feathers except for blues are determined by their diet. Blue is determined structurally. The pattern is determined by proteins following genetically-laid out patterns, same as like stripes or spots on other animals. There is some logic that birds with good diets would have 'better' patterns as determined by their prospective mates.

http://www.smithsonianmag.com/science-nature/Why-Are-Some-Feathers-Blue.html
http://www.birds.cornell.edu/AllAboutBirds/studying/feathers/color/document_view

Re:Call it what you will

[craigminah]

The title is misleading...the birds like the pattern and know nothing about fractals. Reminds me of the story of a mathematician's dog who "knew calculus" because of the way it waited for a ball to bounce off a wall. It didn't know calculus, it just learned what happens when a ball is tossed against a wall. To know calculus or fractal geometry would mean you'd do some form of calculations and be aware of the interrelationships of the variables within...neither the birds nor the dogs did any such thing.

People at nightclubs simply like or dislike the way someone acts/looks to determine if they want to "mate" with them...no math there but a story will come out saying men and women at nightclubs perform complex trig to find mates.

Re:Call it what you will

[fuzzyfuzzyfungus]

What? The world has come to this? Instead of how intelligent, strong, or attractive we are, the primary factor is socio-economic status?

Wow, I bet that realisation causes more than a few suicides.

At the level described in TFA(malnutrition leading to visible differences in development persisting into maturity) or similar(doesn't sound like they tested it; but parasite load and certain sorts of environmental pressures probably have the same effect) there really isn't a terribly strong separation of physical factors and socio-economic status(to the degree that birds have that). At the knife-edge-of-subsistence level, the fact that intelligence, strength, and attractiveness are paid for in calories and nutrient distributions really tightens the connection between personal virtues and economic status.

More Slashdot Pundit FAIL

[Required Snark]

Fractal dimension is not a set of buzzwords, but a useful concept in both mathematics and technology. http://en.wikipedia.org/wiki/Fractal

Fractals have many uses http://en.wikipedia.org/wiki/Fractal#Applications_in_technology It is a perfectly reasonable hypothesis that birds recognize the fractal dimension of plumage in their own species. Conflating this with "being able to compute a fractal" is ignorant. Some birds are known to get information about magnetic fields through their visual channel. This does not mean they are solving Maxwell's equations.

It is possible to extract fractal dimension information from images. Typing in "fractal dimension image detection" into Google Scholar results in over 25000 references. If academics have figured out how to do this then evolution may also embody these concepts.

Posting on Slashdot is an opportunity to share knowledge and learn things. Unfortunately far to many people who post here show that they are ignorant and arrogant. I call them the Slashdot Pundits.

Just because you know one thing does not mean that things you haven't heard of are wrong. With Google and the like, it's easy to fact check. On this topic so far all we have seen is woefully uninformed people criticizing academics and making fools of themselves. I would think that shear embarrassment would tend to eliminate this kind of drivel, but I guess if you are stupid enough to make such uninformed statements, you are also incapable of understanding how bad it makes you look.

Re:More Slashdot Pundit FAIL

[fuzzyfuzzyfungus]

There is, arguably, a meaningful distinction between 'knowing' something(in the sense of being able to use that something in conscious cogitation) and 'knowing' something in the sense of 'exhibiting behavior that could not be accomplished without possessing some similarly capable mechanism; but not necessarily possessing any conscious knowledge, or even consciousness at all'.

It's an open question(that the paper isn't really interested in attacking) whether birds 'know' anything about fractal dimension in the first sense, or what if anything they know at all in that sense; but there is a much stronger case to be made that they do exhibit behavior that could only be accomplished with access to the results of such a computation, even if the processing is a total black-box. Much the same is true of humans: you don't need to take physics to play catch(and, indeed, even those who have generally don't start using conscious calculation to catch falling objects); but our ability to catch objects is pretty hard to explain without positing that we have some mechanism that gives us access(and rather fast access, no less) to good approximations of answers to certain classes of physics problems.