Other MINDs

BY PETER GODFREY-SMITH

Three Sentence Summary

Octopus intelligence and large nervous system evolved independently of mammals and vertebrates, meaning they offer an insight into how these systems work and came into being. Their evolution show how mutations and adaptations can confer advantages and disadvantages, which necessitate further evolution so that they can effectively make use of these adaptations. This process of evolutionary feedback occurs at multiple levels, is likely the genesis of all life and plays a huge role in determining a lifespan of a species.

WHAT DID I THINK?

A wide-ranging book that touches on so many things: evolution, adaptation, ageing, death and sensory experience. With octopi at the centre of the story, Godfrey-Smith colourfully illustrates how evolutionary processes have been driven by a process of bio-feedback.

542 million years ago a creature likely accidentally hunted another starting an evolutionary arms race, with creatures evolving to become better hunters or to evade predators. This adaptations themselves led to other evolutionary developments (i.e. octopus needing to develop a nervous system to control their body). Godfrey-Smith compellingly argues that "the mind evolved in response to other minds."

It made me think about how humanity's dominance and our disconnect from nature means that the process of bio-feedback is less visible (i.e. how many species are going extinct because of the impact of humanity). But as with any system, even what seems invisible has to become visible and will likely do so rapidly (i.e. climate change cascades).

Another aspect I really enjoyed was Godfrey-Smith's explanation of why we age and die. Mutations which have negative impacts early on in life will be more efficiently "cleaned out" than ones that impact later on in life because of natural selection. Over time, these mutations that are harmful in older age will become more commonplace and it will look like we have been "programmed to decline."

How strongly I recommend it: 9/10

NOTES

Why study octopi?

• The last common ancestor of octopus and humans would have lived around 600 million years ago at a time when no organisms had made it to land. Likely to be some sort of "worm-ish"; from there life split into two categories that became many vertebrate and invertebrate.

• Insects and spider engage in complex behaviour - especially social - but still have small nervous system. In contrast, octopus with their large brains and complex nervous systems are "an island of mental complexity in the sea of invertebrate animals." Godfrey-Smith writes, "This is probably the closest we will come to meeting an intelligent alien."

• Octopus intelligence and large nervous system evolved independently of humans/mammals/vertebrates, meaning they offer an insight into how these systems work, came into being and might work differently. They are "a second expression of what was present before."

Communication in simple organisms

• Sensing abilities of a type in single-celled organisms: E coli has a sense of taste or smell. It can detect welcome/unwelcome chemicals around it.

• Birth of social behaviour: Example is quorum sensing. Bacteria living inside Hawaiian squid can produce and sense presence of a chemical. This means it can identify how many of the other bacteria are around. Only if there is critical mass, do they produce a chemical that cancels out squid's shadow, making it a more effective predator.

• These types of coordination and communication essential for transition to occur from single-celled organisms to multicellular organisms. Many cells acting in concert, with some cells submerging their individuality to become part of a "large joint venture."

• One of the ways this happens is via the nervous system, which is made up of neurons, which spray chemicals into gap between it and another neuron, which can trigger action.

• While fast, it requires a lot of energy. In our case, nearly a quarter of our calories.

• Original purpose of nervous system is to link perception and action. "A multitude of micro-actions must be shaped into a macro-action."

Cambrian Explosion

• Around 542 million years ago, there were changes to the Earth's chemistry and climate.

• A tiny sea creature sensed another creature and ate it, becoming the first predator. An evolutionary arms race began. Process of bio-feedback, as one organism evolved, it changed the environment for others.

• Predators and prey evolved more complex bodies to catch or elude other creatures. An extreme selection pressure was underway.

• "Bilaterian" animals, with a left and right side, best suited to mobility and complex behaviour that mobility enables. Nervous systems existed prior to bilaterians, but "this body created vast new possibilities for their use."

• Development of eyes allowed for more sensory input but again required processing engine.

• How did the nervous system come into being as we might recognise it? May have originated twice in same animal at two different places: a motion controlling brain marching up to the head where it met light-sensitive organs which become eyes.

Octopus Rising

• Early cephalopods rose in the sea and changed how they used certain feature. For example, once aloft their "foot" was no use for crawling so was used for grasping objects and eventually flowered into a cluster of tentacles.

• Octopus has almost no hard parts creating "a body of pure possibility". It let go of its skeleton and shell meaning it can squeeze through a hole the size of its eyeball.

• Measuring the intelligence of octopus is difficult not least because no part by part correspondence between their brains and ours. Most of the neurons in an octopus are found in their arms, not their brain.

• To understand animal intelligence one often looks at the social life of the animal. A complex social life usually gives rise to high intelligence. But octopus are in most cases are solitary.

• But controlling its body as it evolved (i.e. foot into tentacles) may have given rise to an unusual nervous system that allowed for a mixture of local and central control, which may have driven the growth of neurons. This evolution might have been responsible for capacities that arise as byproducts.

Integrating Experience

• As information comes in via our senses they are integrated into a single picture, but not all animals do this as much as we do. Many animals have eyes in the sides of the head not the front meaning they have separate visual fields.

• If we show something to only one side of the brain, does the other side get the information too?

• In pigeons this information was not being passed from one side to the other. They were blindfolded and taught to do a task with one eye. When forced to use the other eye they did not know how to.

• Mental fragmentation like this can be found in human who have had connections in their brain severed to help them deal with their epilepsy. In split-brain patient, left side of the brain speaks back while the right side of the brain controls the left hand which may disagree with their left side voice.

Why do we age (and die)?

• Cuttlefish live one or two years; depending on the type of octopus, they can live one to four years. What is the point of building a large nervous system and learning about the world if there is almost no time to put that information to you? Or simply put, why don't cephalopods live for a longer time? Why don’t we all live for a longer time?

• We often answer this question using the analogy of a car. The parts wear out. But if we are constantly replacing our cells, so in theory "there is no reason why it should ever stop running."

• Why do hummingbirds live till they are ten, rockfish till they are two hundred, bristlecone pines till they are thousands of years old, and octopuses until they are two?

• Late-acting mutations will be cleaned out less efficiently by natural selection than early-acting ones. Gene pool of population will contain lots of mutations that are harmful to long-lived individuals. Over time, they will become more common because these individuals live long enough to reproduce. It will appear that we have been "programmed to decline" or in Godfrey-Smith's words, "the population has begun to evolve ageing."

• These processes described as the Medwar-Williams theory by Godfrey-Smith.

• The lifespans of different animals are set by their risks of death from external causes, by how quickly they can reach reproductive age, and other features of their lifestyle and environment.

• Without their shell cephalopods much more vulnerable, so have to grow and become fertile quickly (i.e. in one season). But their vulnerability also meant they evolved camouflage and wiles. in Godfrey-Smith's words: "A cephalopod’s lifespan has been tuned by the continual risk of not making it to the next day. As a result, they have ended up with their unusual combination: a very large nervous system and a very short life."

• Exception to this rule shows the validity Medwar-Williams theory. There are octopus that live to sixteen years off the coast of Monterey coast. They are predated less because of the positioning of the den (shallower water) and they even lay their eggs out in open. Over time, their life span has expanded and behaviours changed because of the differences in the external environment.