Cost of Beauty book

In “The Evolution of Beauty”, Richard O. Prum argues that many of the ornaments present in animals need not have an adaptationist purpose (as is the common held belief), but can be the result of the aesthetic choice of the females.

This web app is inspired by that idea. It creates a set of male and female Things that can mate and reproduce.


Males try to seduce females, and females select the most attractive male. Males have to catch up to the females (before they die) in order to reproduce.


Descent with moodification

When new Things are born after mating, they inherit a mixture of their parents’ “genetic code”. This code encodes certain traits: the Thing’s size, growth duration, length of life, speed, the number of children it will have, its color, and sex.

Genetic code

Aesthetic preferences

Females prefer colorful things, but being colorful can be expensive: it can reduce the length of life of the male, making it more difficult to reach a female in time to mate. How expensive is beauty?

Expensive beauty

If you set it to something high, the Things aren’t very colorful.

Low colour things

Mid-level beauty

If you set it to a medium setting, you get fall-like colours: not too colorful, not too grey.

Medium colour things


To simulate overpopulation, if the number of Things pass a certain threshold, many of them get wiped out. This can often result in interesting resulting colours. In this example with low beauty cost, after a major wipeout, mostly bright green Things survived.


Parting notes

This is an initial exploration into the idea of leveraging the tension between adaptationist and aesthetic evolution for generating digital art. Through an extremely simple mechanism we have been able to showcase a playful and varied set of “living paintings”, which we hope will encourage other digital artists to incorporate these ideas into their craft.

Parting video

If you want to read more, you can check out my white paper for more details.

Here is the original tweet.


I am not a biologist nor claim to really understand what’s happening, so please forgive me if my interpretation is completely wrong!