# A Minimal Developmental Model Can Increase Evolvability in Soft Robots

## TL;DR

This paper presents a simple developmental model for soft robots, demonstrating that even minimal development can enhance evolvability by allowing a broader exploration of body plans and facilitating beneficial mutations.

## Contribution

The study introduces a minimal embodied developmental model for robots and shows it increases evolvability compared to non-developmental systems.

## Key findings

- Developmental robots explore a larger range of body plans.
- Developmental changes can be 'locked in' by mutations.
- Minimal development improves evolvability.

## Abstract

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.