In The Journal of Physiology, special issue on The Physiology of Evolution, edited by Denis Noble

The Creativity of Cells: Aneural Irrational Cognition
V. N. Alexander

In “On Having no Head: Cognition throughout Biological Systems” (2016), František Baluška and Michael Levin review the literature on aneural cognition in single-celled organisms, plants, and animal tissue, all of which exhibit abilities for memory, learning, decision-making, and goal-direction. “Cognition,” they argue, need not involve neurons per se.  Cells of all kinds appear to be capable of intelligent behavior that emerges from dynamical networks that propagate signals and alter connections in response to the environment—very like neuronal activity. In fact, as Baluška and Levin conclude, neural tissue seems to have merely improved upon ancient mechanisms used by all living systems generally.

This paper extends the exploration of the mechanisms of cognition by considering whether or not aneural cells may be capable of irrational cognition, making associations based on coincidental similarities and circumstantial factors.If aneural cells do harness such semiosic qualities, as with higher-level creativity, this might be how they are able to overcome old algorithms and invent tools for new situations.

I will look at three examples of irrational learning in aneural systems in terms of semiotics: (1) generalisation in the immune system, based on viral molecular mimicry, whereby immune cells attack the self, which seems to be an overgeneralisation of an icon sign based on mere similarity, not identity, (2) the classical conditioning of pea plants to trope toward wind as a sign of light, which seems to be an association of an index sign based on mere temporal proximity, and (3) a pharmaceutical intervention to prevent pregnancy, using a conjugate to encrypt self with non-self, which seems to be an example of symbol use.

We identify irrational cognition easily when it leads to ‘wrong’ outcomes, but, if it occurs, it may also lead to favourable outcomes and ‘creative’ solutions.

As Dietrich and Kanso (2010; 822) note, “Creativity is a cornerstone of what makes us human, yet the neural mechanisms underlying creative thinking are poorly understood.” In this paper, I have tried to describe new learning in terms of semiosic processes that involve physical similarities of signs and the physical proximity of signs and/or signal pathways (such that they can associate with or interfere with each other).