Thread by @feross

🤯 Just read a fascinating paper called "The Surprising Creativity of Digital Evolution"

🤣 It's a bunch of HILARIOUS anecdotes showing how Artificial Life systems often produce SUPER surprising and SHOCKINGLY ridiculous results. 😲

👇 THREAD

😜 "Selection Gone Wild"

"It is often functionally simpler for evolution to just exploit loopholes in the quantitative measure than it is to achieve the actual desired outcome"

🙄 "Evolution had discovered another cheat: "somersaulting without jumping at all. ... At the start of the simulation, the individual 'kicks' the foot of its pole off the ground, and begins falling head-first, somersaulting its foot"

"Doing so created a large gap between the ground and the 'lowest point', thus securing a high fitness score without having to learn the intended skill of jumping"

Campbell's Law: well-intentioned metrics become corrupted by direct pressure to optimize them. True in humans too 😅

"Evolution often uncovers clever loopholes in human-written tests, sometimes achieving optimal fitness in unforeseen ways"

😇 "It entirely short-circuited the buggy program, having it always return an empty list, exploiting the technicality that it was scored as being in order"

😏 Why learn when you can oscillate?

"One common trick that digital evolution can learn to exploit is recognizing subtle patterns ... providing a simple escape hatch to solve a task..."

"The networks seemed to learn associations *without even receiving the necessary stimuli*"

🤨 Digital organisms can also learn to play dumb to avoid being killed off. Sound like sci-fi fiction? Not so! This is real. ☹️

😵🤥 "The organisms ... appeared to not replicate at all, in effect 'playing dead' in front of what amounted to a predator."

🤨 "Edge cases, bugs, or minor flaws in the implemented laws of physics are sometimes amplified and exploited by evolution"

💥 "With faster motion, integration errors could accumulate, and some creatures learned to exploit that bug by quickly twitching small body parts."

😳 "Fitness functions often do not include implicit knowledge held by experts, thus allowing for solutions that experts consider so ridiculous, undesirable, or unexpected that they did not think to exclude or penalize such solutions when originally designing the fitness function"

Here's a case where researchers took a robot arm and *intentionally disabled* it's gripper arm. They thought with it's arm crippled it wouldn't be able to move the box on the table very much. WRONG! 😰

It figured out how to grab the box and move it around with no problems! 😱

"Surprisingly, MAP-Elites found ways to hit the box with the gripper in *just* the right way, to force the gripper to open so that it gripped the box firmly. Once holding the box, the gripper could move to a broad range of positions, exceeding experimenters' expectations"

😲 Here's another intentionally crippled robot figuring out how to bypass the restriction.

😫 "The simulated robot, tasked with walking fast without touching any of its feet to the ground, flips over and walks on it's elbows"

Researchers assumed that preventing the robot from touching its feet to the ground would prevent it from walking. NOT TRUE!

Sometimes *impossibly compact solutions* were evolved.

"Evolution had learned to leverage some type of subtle electromagnetic coupling, something that a human designer would not have considered (or perhaps even know how to leverage)"

The fastest route is not always a straight line.

"While the evolved robots successfully drove towards the light source, they often did so in unusual and unintuitive ways. Some backed up into the light while facing the dark. Others used light-sensitive eccentric spinning" 🤔

Evolution can also produce surprisingly good art – table designs and dance music.

"The outputs were not valued because they were decent attempts by computers to produce artistic creations, but were instead judged as valuable strictly on their own merits."

💻🎶 In 2000, researchers used evolution to produce popular music.

🕺 "Clubgoers had no idea that key pieces of the tracks they were dancing to were authored by computers"

Universal Music secretly distributed it because the CEO thought no one would buy computer-generated music

🤩 An art museum accepted and displayed evolved art produced by "innovation engines"

👩‍🎤 "Interestingly, the images have diverse aesthetic styles, and bear resemblance to abstract 'concept art' pieces that reflect intelligent statements about their theme"

🦒 This one is REALLY FUN.

💪 Evolution of muscles and bones!

🐆 🦓 🐈 "Evolution generated locomotion strategies unexpectedly convergent with those of biological creatures"

"The gait in the top figure is similar to the crawling of an inchworm, requiring evolution to discover from scratch the benefit of complementary (opposing) muscle groups, similar to such muscle pairs in humans, e.g. biceps and triceps—and also to place them in a functional way"

🤔 What happens when you let natural selection run in a digital medium?

"The surprisingly large palette of emergent behaviors included parasitism, immunity to parasitism, circumvention of immunity, hyper-parasitism, obligate sociality, cheaters exploiting social cooperation..."

😯 Even digital creatures end up with vestigal organs (organs that no longer have a purpose)

🤨 "They sometimes contained small body parts whose function was not immediately obvious, yet they seemed to be carefully placed on the creature's body"

"Analysis of the 'fin' and its evolution demonstrated that its persistence was a consequence of a specific limitation of the evolutionary algorithm"

Here's what the small top fin looks like in practice (doing nothing):

Digital creatures also evolved genome duplication, just like nature!

"[The] organisms resulted from an unanticipated situation, which was triggered when organisms had an odd number of instructions in their genome, and a mutations then introduced a second 'copy' instruction"

Another amazing behavior: Costly genes hiding from natural selection! Super cool!

"The 'public good secretion' genes that survived increase in cost were frequently overlapping with crucial metabolic genes, meaning that they were physically encoded using the same DNA base pairs"

😅 Conclusion tweet!

"A persistent misunderstanding is that digital evolution cannot meaningfully inform biology because 'it is only a simulation'"

"The diversity and abundance of examples suggest that surprise in digital evolution is common, rather than a rare exception"

📖 Read the full paper here:

The Surprising Creativity of Digital Evolution: A Collection of Anecdotes from the Evolutionary Computation and Artificial Life Research Communities
arxiv.org/abs/1803.03453

I hope this was a fun read for you! ❤️