A Minimal Developmental Model Can Increase Evolvability in Soft Robots
This addresses the challenge of isolating developmental mechanisms in evolutionary robotics, though it is incremental as it builds on existing theories with a simplified model.
The study tackled the problem of how development aids evolution in robots by introducing a minimal developmental model where robot bodies change over their lifetime without environmental influence, and found that this model increases evolvability by allowing evolution to explore a larger range of body plans, with heterochronic mutations stabilizing these plans in descendants.
Different subsystems of organisms adapt over many time scales, such as rapid changes in the nervous system (learning), slower morphological and neurological change over the lifetime of the organism (postnatal development), and change over many generations (evolution). Much work has focused on instantiating learning or evolution in robots, but relatively little on development. Although many theories have been forwarded as to how development can aid evolution, it is difficult to isolate each such proposed mechanism. Thus, here we introduce a minimal yet embodied model of development: the body of the robot changes over its lifetime, yet growth is not influenced by the environment. We show that even this simple developmental model confers evolvability because it allows evolution to sweep over a larger range of body plans than an equivalent non-developmental system, and subsequent heterochronic mutations 'lock in' this body plan in more morphologically-static descendants. Future work will involve gradually complexifying the developmental model to determine when and how such added complexity increases evolvability.