Wiser, Michael J., Emily L. Dolson, Anya Vostinar, Richard E. Lenski, and Charles Ofria. “The Boundedness Illusion: Asymptotic projections from early evolution underestimate evolutionary potential.” PeerJ Preprints 6 (2018): e27246v2.
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Open-ended evolution researchers seek to create systems that continually produce new evolutionary outcomes, attempting to reflect the power and diversity of evolution in nature. The specific metrics used (novelty, complexity, diversity, etc) vary by researcher, but the holy grail would be a system where any of these can accumulate indefinitely. Of course, one challenge that we face in reaching this goal is even recognizing if we have succeeded. To determine the evolutionary potential of a system, we must conduct finite experiments; based on their results we can predict how we would expect evolution to progress were it to continue. Here we examine how such predictions might be made and how accurate they might be. We focus on predicting fitness; this metric is often easy to calculate, and correlated with increases in traits like novelty and complexity. For each run in a simple digital evolution experiment, we find the best fit to measured values of fitness, and demonstrate that projecting this fit out usually predicts that fitness will be constrained by an asymptote. Upon extending the experiment, however, we see that fitness often far exceeds this asymptote, belying the boundedness that it implies. Extending past a premature end point allows us to see beyond this “boundedness illusion”