One step lower down
The team at Harvard found a break in ribosomal RNA that occurs only in octopuses. When the change was engineered into bacteria, the cells made fewer mistakes while building proteins and the risk of misfolded molecules forming toxic aggregates fell. Protein clumps in octopus tissue were both fewer and smaller than in squid.[1]
When we try to understand a mind, the place we are used to looking is how neurons connect to one another: circuits, networks, layers. What is examined here is one step lower. A neuron is a structure, and that structure is built out of proteins; if the ribosome assembling them makes mistakes, even the most elegant circuit diagram gets woven from the wrong material. What this study shows is that in that materials workshop there is a setting particular to octopuses.[1]
Timing and restraint
The timing is striking. The authors note that this change coincides with shallow-water octopuses settling into complex environments roughly 100 million years ago and their nervous systems expanding rapidly. Co-lead author Rishav Mitra measures his language carefully in drawing the link: the change "might help these neurons to work well".[1]
Why neurons in particular? In long-lived cells that build protein continuously, accumulated error costs more than it does in other tissue, and a more accurate ribosome pays off most there. But the same change could have been selected for a reason unconnected with neurons; tolerating warm or variable water also strains protein folding, and in that case any neural benefit is a by-product. The coincidence of timing does not tell us which of the two accounts is right.[1]
What knowing would take
The geneticist Eli Eisenberg sets the limit plainly: "more proof is needed to support the hypothesis that they contributed to the evolution of neural complexity or cognitive capacity." Testing this in humans would mean altering ribosomal RNA and measuring learning and problem-solving, which is described as highly challenging. Even so, what stands here is not small. Asking how a mind is built, we are used to looking upstairs, at thought itself; this finding carries the same question down to the basement and asks there how a molecule folds correctly. For now it is a hypothesis. But it is one that moves where the question sits.[1]