How did consciousness evolve? - with Nicholas Humphrey

Find out how consciousness is generated in the human brain - and discover the evidence suggesting some animals are also sentient.

Join renowned psychologist and philosopher Nicholas Humphrey as he presents his theory of 'phenomenal consciousness', in full for the first time.

Weaving together leading-edge science and personal breakthrough experiences, Nicholas provides a comprehensive look at the evolution of consciousness. He discusses discovering blindsight in monkeys, hanging out with mountain gorillas in Rwanda, to becoming a leading philosopher of the mind; all leading to a scientific understanding of consciousness and his theory as to how conscious feeling is generated in the human brain.

This theory also provides the foundation for Nicholas' controversial opinion - in contrast to broad scientific opinion - that phenomenal consciousness is only present in warm-blooded creatures such as mammals and birds, and not invertebrates like octopuses and bees, despite their known intelligence.

This lecture was recorded at the Ri on 21 June 2023.

00:00 Intro
03:20 Blind sight – seeing without a visual cortex
09:51 The difference between sensation and perception
11:37 Can consciousness be physically found in the brain?
16:58 How did natural selection lead to sensations?
22:28 How did this lead to consciousness in the human brain?
24:58 What is the point of phenomenal consciousness?
28:14 How human sentience led to theory of mind
30:17 Could animals also be sentient?
33:32 Body temperature and its effect on brain speed
34:45 Evidence for sentience in the animal kingdom
40:40 Mammals and birds show sentience – what about octopuses?
42:25 Can machines ever reach consciousness?
45:05 Could there be sentient aliens?
46:42 The extinction of consciousness on Earth

Nicholas Keynes Humphrey is an English neuropsychologist based in Cambridge, known for his work on evolution of primate intelligence and consciousness. He has been lecturer in psychology at Oxford, assistant director of the Subdepartment of Animal Behaviour at Cambridge, senior research fellow at Cambridge, professor of psychology at the New School for Social Research, New York, and school professor at the London School of Economics.

Humphrey played a significant role in the anti-nuclear movement in the late 1970s and delivered the BBC Bronowski memorial lecture titled "Four Minutes to Midnight" in 1981.

He has written 10 books and received several honours, including the Martin Luther King Memorial Prize, the Pufendorf Medal and the British Psychological Society's book award. He is the only scientist to have edited the literary journal Granta.

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[jmoney]

I am in awe of the positive energy in this comment section. Nothing like the typical YouTube experience. Lots of great conversations and interesting thoughts, creating fascinating dialogues.

[earthbound]

Oh my. I've lived 72 yrs and never considered that sentience could be described in this way. This lecture was incredibly absorbing, as if something I have never imagined was being revealed for me to ponder. In particular I have never heard of blind sight and the video of Helen the monkey was fascinating. Thank you Mr Humphrey.

[alexstjohn]

He doesn't quite say this but I wonder if it's what he means. In order to reason across the world and past experiences the mind has to build a simulation of the future based on it's experience with past events AND it has to have a simulation of "self" to place in that simulation in order to make plans to benefit "self". So "self-awareness" is the act of creating a model of yourself to include in your simulation of reality in order to predict how your choices may help or harm "self".

[jpvandijk]

The whole lecture is a sublime work of art.

[davidhess]

My cat is conscious, but it's self centered. I don't think she considers my feelings much, if at all. With her it's all me, me, me, meow!

[DerekHowden]

it wasn't that long ago we in the west didn't think that animals had any human qualities and now we know better. I was moving a picture on my wall and behind it was a spider with ten or so tiny little dots that were baby spiders. As soon as i had introduced light the parent spider hastily started to reach out and gather the babies up. I think nature by its very nature has a sense of its environment and relationships it has and is not only found in mammals and birds but through out life and that it doesnt need consciousness to sense itself and it's environment. For us, consciousness is something that happens after our sense of being as in we sense and are aware of a sudden noise that wakes us but it takes a while for consciousness to be fully aware to what is going on.

[geoffbanks]

May be the only talk on Consciousness worth listening to!

[garychap]

This has to be the single most engaging and thought provoking RI lecture I've ever seen. Dare I venture that this lecture was quite _'phenomenal'_ ; )

[eyebrid]

I mostly agree but the conclusion that only the warm blooded have sentience falls short of the experience of many caretakers or people who have cold blooded pets who show affinity for specific people and play. Quite a few divers have encountered curious fish that befriended them and evidently like to play. The animal kingdom has a wide variety of social structures from strong communal bonds to solitary life, it seems more appropriate to assume sentience than not, with varying degrees of complexity.

[SteveSteve-didn]

Excellent. This guy articulates my intuition. Never understood these other overcomplicated theories of consciousness that never could provide any evidence. He delivers !

[ClayFarrisNaff]

If you'll pardon the pun, what a phenomenal lecture! Monumental is perhaps more apt, since this represents the culmination of a lifetime of curiosity, thought, experiment, and scholarship. I deeply embrace the concluding remarks (which resonate well with the conclusion of my book Free God Now about the Darwinian imperative to keep life going, especially conscious life, as it alone is capable of recognizing that life is good). Congratulations and thank you, Nicholas Humphrey.

[RetNemmoc]

I have long looked at consciousness as an emergent process of sorting out priorities between sensory inputs, based on recorded memory of past interactions. For example, running from danger could land you in the mouth of another danger, so if you survived this experience once, you begin evaluating possible outcomes in advance of the possibility of danger. Possible outcomes that could interfere with the goal of eating, and not being eaten. Like a game of pinball, you learn, iteratively, how to keep the ball rolling (keeping it alive) for as long as possible. The process of evaluating the interplay between senses (sensing the senses) is itself an evolved/emergent sensory function. It is the "you" that you perceive as you – the crosstalk between senses becomes sensible. 

I also think of language as being part of the same emergent ability, a further evolved sorting out process. Language is what allows for meaning, which allows for questions like "why and how am I 'me?" Science is a process we use for answering the how, but I don't see much in the way of useful possible outcomes of why, so I don't ask it much – my mind has enough perceiving and evaluating to do. Asking why (especially when it comes to inserting God and gods into the question) is a distracting whirlwind of looping unresolvable thoughts that yield nothing I need. "What for" is a more practical (and my preferred) form of the question of why.

[ScottLahteine]

9:00 — Perception (oddly) also relies on remembering the experience of perception. It sounds like blind sight is a potential memory issue, not just a sensory one. The apparent perception of the flow of time is similarly affected by a malfunctioning memory system.

[monkeyworship]

After having significant experience with psychedelics and it’s effect good and VERY bad, exploring consciousness is incredible and makes so much more sense.

[bebemegie]

Thank you so much for your research and dedication 🦋✌🏾💙🌺🌲 I feel we are all starting to evolve our sentience to understand the importance of all life and respecting is sentience. If you spend time in nature, with animals and try see their sentience/ life/ feelings it kinda becomes obvious. Much love to you all.

[maskddingo]

The feedback loop the presenter describes in the brain reminds me of things like static RAM and op-amps... both are used to do complex calculations in electronics via the use of feedback. The feedback eventually drives these devices into a stable state.

[rodcameron]

Wonderful lecture.
I am not overly satisfied with the implementation of a homunculus (proto-self as referred to in the lecture) to explain consciousness. That relegates the theory to a lot of talk about what consciousness does and not what consciousness is. It also succumbs to infinite regress, ultimately explaining nothing.
I did love the information relating processing speed of nerve cells at higher temperatures as a catalyst of the evolution of consciousness in some warm blooded mammals. That idea I had not heard before.
The later part of the lecture showing how consciousness could be detected by looking at the actions beings was really good. Very powerful. I would be interested in hearing his thoughts on mimicking systems such as AI.
I am endlessly fascinated by theories of consciousness. Good job! Wonderful lecture!

[glasperlinspiel]

Conscious is an epiphenomon of biology. In terms of information processing, it’s so simple that very simple creatures will be conscious. Sentience requires the socialization of consciousness.

[jessephillips]

This is the first time I've heard a scientist articulate my own view of consciousness. I was really moved by this. Thank you.

[cinemaipswich]

100 years ago, you were either asleep (unconscious) or awake (conscious). Since then science has appropriated the word to mean more. If it were a mouse, it is one type of consciousness, but if it is human it is another. Since then we have the word "sentience", which may evolve from "sapience". Add to this perception and sensation, and the lexicon becomes muddled.