The Field That Waited a Century

In 1906 the American zoologist Herbert Spencer Jennings spent long hours watching a single-celled organism shaped like a trumpet. Stentor roeselii is attached to its perch by a holdfast, and Jennings irritated it — gently, repeatedly — to see what it would do. It bent away; if that failed it reversed its cilia; if that failed it contracted; and if all else failed it let go and swam off to start life somewhere else. A repertoire, worked through in order, in an organism with no nervous system to hold one. Jennings’s observation was dismissed for fifty years on the strength of a replication attempt that used the wrong species and the wrong stimulus.

He was not the last to be dismissed. In the 1950s Beatrice Gelber reported conditioning in Paramecium — single cells learning to associate a wire with food. Behaviourist orthodoxy explained her results away, and her name with them; a re-examination in 2021 concluded the dismissals were flawed and the experiments deserve re-running.

Evidence kept arriving from people who weren’t asking anyone’s permission to collect it. Microbiologists worked out, receptor by receptor, how a swimming bacterium compares the present moment against a chemical record of a few seconds ago. And in 2000 Toshiyuki Nakagaki showed that a slime mould — a single vast cell with no neurons at all — solves a maze by shortest path. Given oat flakes laid out as the stations of greater Tokyo, its successor experiment re-drew the commuter rail network overnight, about as efficient and fault-tolerant as the one the engineers had built. Nakagaki’s reward was two Ig Nobel prizes — the award for research that makes people laugh, then think.

What the results lacked was not quality but a home. Each sat in its own discipline as a curiosity — remarkable behaviour, wrong kind of organism. Supplying it took an unusual route into the academy: Pamela Lyon came to philosophy of biology after a career as an investigative journalist, and in 2006, as a mature-age doctoral student, she named the habit that kept the results homeless. Cognitive science had always worked anthropogenically — start from human cognition, take it as the paradigm, and grade every other creature by how much of our kind of thinking it approximates. On that footing the orphaned results could never be more than curiosities: each one scored against a standard it was never going to meet. Lyon proposed the inversion — the biogenic approach: start from what living systems demonstrably do, and work upward, asking psychological questions as if they were biological questions. In 2015 she made it concrete with what she called the cognitive cell, reading a bacterium’s signalling machinery capacity by capacity — sensing, evaluating, retaining, adjusting — as a genuine repertoire in miniature rather than a metaphor at the edge of the subject.

The name came around 2018 — basal cognition — and with the name, a field began assembling itself around the people who had been carrying the evidence separately. In 2021 it got its founding charter: a double theme issue of the Royal Society’s Philosophical Transactions, convened by Lyon with Fred Keijzer, Detlev Arendt and Michael Levin — whose lab was already the field’s experimental engine — gathering a hundred and fifteen years of orphaned evidence under one roof, together with a working definition to hold it: cognition as the suite of capacities by which organisms become familiar with their environment, value what they meet, exploit what helps and avoid what harms. A field born not from a single discovery but from a convening — the frame arriving last, long after the facts. And fittingly, the vindications had begun: in 2019 a Harvard team repeated Jennings’s experiment — carmine powder failed, plastic microbeads worked — and the trumpet cell ran through its repertoire exactly as described, one hundred and thirteen years on.

This post is part of the conversations series. See also the reference entry on Basal cognition.

Photo: allisonsaeng / Unsplash