Comparing the effect of embodiment on distributed information processing in plants and ants

Abstract

Information processing is an essential part of biology, and is often distributed across multiple entities, such as cells in a tissue or ants in a colony. However, not only the computation steps themselves matter, but also the context in which they occur. An important example is embodiment: the influence of body shape and properties on information processing. Since a few years, research explicitly distinguishes between solid brains, consisting of sessile parts, and liquid brains with motile parts. Previous research separately examined plants and ant colonies as solid or liquid brains, respectively. This literature review directly compared these two systems to investigate how their solid or liquid embodiment shapes their distributed information processing. Key results were: there is a solid-liquid brain spectrum, which corresponds to computations using structure or movement, respectively. Developing networks must balance construction cost against transport speed within embodiment constraints. Local communication suffices for system-wide information integration and complex computations, but long-distance communication methods add signal robustness, quick responses due to shortcuts through 3D space, and enable interaction with neighbouring plants or colonies. Computational output typically modifies input of subsequent information processes, often through proprioception. Contrary to the dominant perspectives in the plant cognition debate, this research showed the existence and importance of whole-plant emergent processes, but started from the plant embodiment instead of forcing plants into a neural animal mould. In this way, new research questions arise, such as how communication delay and signal integration are affected when growth adds plant organs and increases inter-organ distance.