What Is the Simplest Organism Capable of Emotion?

[Secan]

<moderator moved to General Discussion>
What is the simplest organism with emotion?

Can it occur without any nervous system?

 

[Helios]

I'd say crabs

 

[BillTre]

How do you define emotion?

Wikipedia says:

Emotions are biological states associated with the nervous system[1][2][3] brought on by neurophysiological changes variously associated with thoughts, feelings, behavioural responses, and a degree of pleasure or displeasure.[4][5] There is currently no scientific consensus on a definition. Emotions are often intertwined with mood, temperament, personality, disposition, creativity[6][7] and motivation.[8]

Indicating a connection to nervous system function.
However, since there is no agreed upon definition, it is more difficult to answer your question.
Conceivably, any nervous system could be claimed to have emotions if it can undertake different behaviors at different times.

 

[Ygggdrasil]

If you take a very broad view that emotions are just physiological responses to certain neurotransmitter molecules, then bacteria have shown to be responsive to human neurotransmitter molecules (indeed, bacteria synthesize about 95% of the body's serotonin, which is an important neurotransmitter, so one could say that they are involved in producing emotion as well).

 

[madness]

We could get more precise about this by defining emotion. One of the most interesting theories of emotion (in my view) is the interoceptive theory (https://www.fil.ion.ucl.ac.uk/~karl/Interoceptive inference emotion and the embodied self..pdf). This theory says that emotion is the brain inferring the body's internal physiological state, in the same way the brain infers the state of the external world (i.e., perception). Most (maybe all?) living organisms do this to some extent, but the complexity of the internal model and inference process vary hugely from bacteria to primates.

I once went to a talk by the author of this paper (https://www.pnas.org/content/113/18/4900?_e_pi_=7,PAGE_ID10,5279993613), who claimed (both in the talk and paper) that insects are conscious precisely because they have an internal model of the external world and their influence on it. That's probably a controversial claim, but if you take that to be true then I think you would have to concede that they also have emotions, at least according to the interoceptive theory.

Edit: I should mention that the interoceptive theory was first proposed by William James, the father of Psychology https://en.wikipedia.org/wiki/James–Lange_theory. The link I gave above is forwarding a modern Bayesian predictive coding version of the theory.

 

[BillTre]

I once went to a talk by the author of this paper (https://www.pnas.org/content/113/18/4900?_e_pi_=7,PAGE_ID10,5279993613), who claimed (both in the talk and paper) that insects are conscious precisely because they have an internal model of the external world and their influence on it. That's probably a controversial claim, but if you take that to be true then I think you would have to concede that they also have emotions, at least according to the interoceptive theory.

Although I personally like the idea of consciousness involving the a personal identity navigating an internal model of their environment, as well as the idea that several animals could have consciousness, I still think it is pretty difficult to provide any proof of this consciousness to people. One can legitimately argue that everyone other than yourself is not conscious (I have no proof of your conscious experience).
I would however argue that consciousness and emotion are not necessarily connected, depending on how one might define consciousness. Personally I would accept emotional states, defined by behavioral changes, which could but do not require conscious involvement.
In this way, an emotional response such as a fight or flight response would result in an overall redirection of an animal's behavior, throwing the animal into using a different set of behaviors in response to a given set of environmental stimuli. Its a different set of responses to similar inputs. They could be reflexes, but a different set of reflexive actions determined by the emotional state of the animal.

Even more out there:
I have heard in a few podcasts, another involvement of internalization of of the external environment.
An organism evolved to its environment could be said to carry within it a "model of its external world" in its adaptation to meet the challenges of its environment (sadly, could not fiind any real references on this). So, is an organism in a non-neurological manner have some kind of consciousness?
I tend to restrict my consideration of consciousness to neural functioning, but that's not based on much more than my opinion.

 

[madness]

Although I personally like the idea of consciousness involving the a personal identity navigating an internal model of their environment, as well as the idea that several animals could have consciousness, I still think it is pretty difficult to provide any proof of this consciousness to people. One can legitimately argue that everyone other than yourself is not conscious (I have no proof of your conscious experience).
I would however argue that consciousness and emotion are not necessarily connected, depending on how one might define consciousness. Personally I would accept emotional states, defined by behavioral changes, which could but do not require conscious involvement.
In this way, an emotional response such as a fight or flight response would result in an overall redirection of an animal's behavior, throwing the animal into using a different set of behaviors in response to a given set of environmental stimuli. Its a different set of responses to similar inputs. They could be reflexes, but a different set of reflexive actions determined by the emotional state of the animal.

Although I don't disagree with what you're saying, I think you might be missing the point of what I said. My point was that, according to the James-Lange/interoceptive theory of emotion, emotion means having an internal model of the physiological state of the body. Similarly, according to the paper I linked, consciousness means having an internal model of the external world. If you accept those two theories, then emotion most definitely is connected to consciousness. However you are free to reject either of those theories, and I don't necessarily accept them. Apparently most neuroscientists do accept the interoceptive theory of emotion (or at least believe that interoception plays a role in emotion). The theory that consciousness is equivalent to having an internal model of the world is probably the more contentious of the two.

It's also worth emphasising that we don't need to accept the theory that an internal model is sufficient for consciousness in order to make the claim about emotion. All we need is to accept the James-Lange/interoceptive theory of emotion and accept the fact that insects have an internal model of their body. Again, debatable but less contentious that invoking consciousness in the discussion.

I tend to restrict my consideration of consciousness to neural functioning, but that's not based on much more than my opinion.

I certainly wouldn't take that point of view, and I think it's becoming a minority perspective these days. The only two people I can think of who believe(d) that are Francis Crick and John Searle.

 

[Secan]

Although I don't disagree with what you're saying, I think you might be missing the point of what I said. My point was that, according to the James-Lange/interoceptive theory of emotion, emotion means having an internal model of the physiological state of the body. Similarly, according to the paper I linked, consciousness means having an internal model of the external world. If you accept those two theories, then emotion most definitely is connected to consciousness. However you are free to reject either of those theories, and I don't necessarily accept them. Apparently most neuroscientists do accept the interoceptive theory of emotion (or at least believe that interoception plays a role in emotion). The theory that consciousness is equivalent to having an internal model of the world is probably the more contentious of the two.

It's also worth emphasising that we don't need to accept the theory that an internal model is sufficient for consciousness in order to make the claim about emotion. All we need is to accept the James-Lange/interoceptive theory of emotion and accept the fact that insects have an internal model of their body. Again, debatable but less contentious that invoking consciousness in the discussion.
I certainly wouldn't take that point of view, and I think it's becoming a minority perspective these days. The only two people I can think of who believe(d) that are Francis Crick and John Searle.

Damasio hasnt written a book for years. His topics were similar to it.

What is the current latest book for the brain and emotion?

Also is there any attempt to integrate emotion to AI? Is it not they have mapped the brain of a fly and trying to simulate the brain? What thinking machines have been proposed that have emotions?

 

[Laroxe]

I have to agree with the earlier response, really its all down to how we define emotion, the term seems to cover a lot of very different phenomenon. At the most basic level emotions represent responses to significant events that are capable of triggering distinctive bodily changes and behaviours. Most people have considered emotions to be a biological state so there is a physiological reaction to some environmental stimulus, this stimulus results in an evaluation which motivates action. At this level we know that a number of single celled animals are sensitive to particular chemical cues in their environment, some represent food and motivate movement towards the source, others represent a threat and motivate withdrawal.

I suspect when it comes to definitions that its better to think of emotions as representing a range of reactions that can occur at different levels of sophistication in different animals.

It seems many of the ideas represent the work of people attempting to describe human emotion and this inevitably involves conscious awareness, only humans can describe their experiences.

However even in describing emotions as feelings, what is really described is the awareness of an emotion, its the conscious result of an emotion. I would argue that while our nervous system might be a cause of emotion and that emotion clearly impacts on our nervous system they are not necessarily interdependent. Its only certain parts of the range of things we call emotion that require more complex processing that require a nervous system and I think that the complexity of the nervous system will inevitably impact on the range and experience of emotional states.

Its not really surprising that emotion fell out of favour as a subject to study and its only recently that more work is being published but with a much more focussed approach to specific states.

 

[madness]

Damasio hasnt written a book for years. His topics were similar to it.

What is the current latest book for the brain and emotion?

I'm not really sure about that. There aren't many books studying emotion from a theoretical perspective but probably plenty looking at it from other perspectives (e.g., Frans de Waal looking at emotion in the animal kingdom).

Also is there any attempt to integrate emotion to AI? Is it not they have mapped the brain of a fly and trying to simulate the brain? What thinking machines have been proposed that have emotions?

I don't know of many. There has been an explosion of research into Reinforcement Learning in AI, which uses reward and punishment for learning (see Google DeepMind for examples). This same Reinforcement Learning is used by neuroscientists to study emotion, and there is now an emergent field called Computatational Psychiatry which uses Reinforcement Learning to study mental health disorders (for example, see here starting around 34.30 minutes ).

 

[Mr Green T]

Emotion needs an observer to verify it is not just a reaction impulse and to define the emotion. You don't need life at all to be registering observational decisions. Strictly speaking you can give anything observational emotion and it would be hard to logically argue against it, if you follow a consistent and rigorous method.

I find the charm quark very charming myself.

 

[madness]

Emotion needs an observer to verify it is not just a reaction impulse and to define the emotion. You don't need life at all to be registering observational decisions. Strictly speaking you can give anything observational emotion and it would be hard to logically argue against it, if you follow a consistent and rigorous method.

I find the charm quark very charming myself.

There is some debate about this in the field of neuroscience. For example, we often study fear in mice by the fact that they exhibit "freezing behaviours" (they freeze when a tone is played that was previously paired with an electric shock for example). Some argue that we are actually studying "fear-like behaviours" and should only call them such. But when you pair this "freezing behaviour" with measurements of activation in their amygdala, and compare both neural and behavioural factors across species, and apply the concept of homology in biology (https://en.wikipedia.org/wiki/Homology_(biology)), I don't think there is any problem in applying the concept of emotions to other species. Frans de Waal is an ardent proponent of this perspective (https://en.wikipedia.org/wiki/Frans_de_Waal).

 

[Cato]

Those are profound questions. What is necessary in order for something to have emotions is an aspect of the question of what is necessary in order for something to be conscious – the defining feature of consciousness is the ability to have subjective experience, and emotion is one type of subjective experience. The question of how exactly consciousness arises in the universe has been called by some as the greatest unanswered scientific question. The Hard Problem of Consciousness asks how atoms, which do not possesses the property of consciousness, can be combined into brains which do possesses consciousness.

Answers fall into four categories:

• Materialism – The one fundamental substance in the universe is matter. Matter does not possesses the property of consciousness. However, consciousness is a property which can emerge from certain large and complex configurations of nonconscious matter.
• Substance Dualism – There are two fundamental substances in the universe: 1) nonconscious matter, and 2) some type of conscious substance. The combination of the two produces consciousness in brains.
• Modified Materialism/Panpsychism – The one fundamental substance in the universe is matter. But consciousness is in fact one of the fundamental properties of matter. The amount and organizations of conscious matter in brains produces the consciousness that we experience.
• Idealism – The one fundamental substance in the universe is consciousness. Matter arises from consciousness.

These four positions are all at first glance possible. Each has its supporters and detractors. None has been proven or disproven to the satisfaction of all reasonable people. The answer to your questions depends on which of these views you hold.

Materialism says that a reasonably large and complex nervous system is necessary for something to be consciousness. But materialism cannot draw the line exactly between what does and does not have consciousness. Still, single cell organisms or organisms of any size without a nervous system would most likely not be conscious. All the answers given above are explanations within the materialist framework.

Substance dualism might possibly allow simple organisms like bacteria, or even inanimate objects such as rocks, to be conscious. It is unclear what if any lines might be drawn in this case.

Panpsychism would say that, since all matter possesses consciousness, certainly simple organisms without a nervous system are to some degree conscious.

Idealism would say that the question does not make any sense.

My own view (clearly debatable) is that Materialism is close to being provably false – it seems to me that there exists no way for the property of consciousness to arise from any combination of matter which does not possesses it in the first place.

I am open to one or more of the other three options.

 

[madness]

Those are profound questions. What is necessary in order for something to have emotions is an aspect of the question of what is necessary in order for something to be conscious – the defining feature of consciousness is the ability to have subjective experience, and emotion is one type of subjective experience. The question of how exactly consciousness arises in the universe has been called by some as the greatest unanswered scientific question. The Hard Problem of Consciousness asks how atoms, which do not possesses the property of consciousness, can be combined into brains which do possesses consciousness.

Answers fall into four categories:

• Materialism – The one fundamental substance in the universe is matter. Matter does not possesses the property of consciousness. However, consciousness is a property which can emerge from certain large and complex configurations of nonconscious matter.
• Substance Dualism – There are two fundamental substances in the universe: 1) nonconscious matter, and 2) some type of conscious substance. The combination of the two produces consciousness in brains.
• Modified Materialism/Panpsychism – The one fundamental substance in the universe is matter. But consciousness is in fact one of the fundamental properties of matter. The amount and organizations of conscious matter in brains produces the consciousness that we experience.
• Idealism – The one fundamental substance in the universe is consciousness. Matter arises from consciousness.

These four positions are all at first glance possible. Each has its supporters and detractors. None has been proven or disproven to the satisfaction of all reasonable people. The answer to your questions depends on which of these views you hold.

Materialism says that a reasonably large and complex nervous system is necessary for something to be consciousness. But materialism cannot draw the line exactly between what does and does not have consciousness. Still, single cell organisms or organisms of any size without a nervous system would most likely not be conscious. All the answers given above are explanations within the materialist framework.

Substance dualism might possibly allow simple organisms like bacteria, or even inanimate objects such as rocks, to be conscious. It is unclear what if any lines might be drawn in this case.

Panpsychism would say that, since all matter possesses consciousness, certainly simple organisms without a nervous system are to some degree conscious.

Idealism would say that the question does not make any sense.

My own view (clearly debatable) is that Materialism is close to being provably false – it seems to me that there exists no way for the property of consciousness to arise from any combination of matter which does not possesses it in the first place.

I am open to one or more of the other three options.

I'm not sure that you need to worry about consciousness when you study emotion. If you take David Chalmers classsic definition of the "hard problem" of consciousness, then everything that can be considered a biological "function" which can be explained via a biological "mechanism" is an "easy problem". Many phenomena appear to have an "easy" and a "hard" component, in the sense that although there is a function which can be explained by a mechanism, there is also an accompanying subjective experience which appears inexplicable via any material mechanism. We often focus on things like perception of colour when we talk about easy and hard problems of consciousness, but emotion also has a purely functional aspect and a subjective experiential aspect. So I believe we can study the "easy" problem of emotion, in the same way we study the "easy" problem of colour perception without worrying deeply about Inverted Qualia, Mary's Room and all the rest of it.

 

[jim mcnamara]

Okay. This thread went exactly as I was afraid it would. Philosophy. We have no staff to support Philosophy or Psychology topics in the science section. In order to allow the thread to progress it is moving to General Discussion.

DO NOT forget citations. We seem to be losing those along the way as well.

 

[symbolipoint]

Hey! Someone actually TRY to give an answer and explain why or give some kind of reference to support about your stated simplest organism having emotion. How low in complexity can we go? Mouse? Lizard? Guppy?

 

[madness]

Okay. This thread went exactly as I was afraid it would. Philosophy. We have no staff to support Philosophy or Psychology topics in the science section. In order to allow the thread to progress it is moving to General Discussion.

DO NOT forget citations. We seem to be losing those along the way as well.

In my defense I was trying to explain to the poster above why we don't need to worry about philosophical questions in order to study emotion scientificially. But I can see why you moved the thread, it has digressed from the science.

 

[madness]

Hey! Someone actually TRY to give an answer and explain why or give some kind of reference to support about your stated simplest organism having emotion. How low in complexity can we go? Mouse? Lizard? Guppy?

I did this in post 5 and 7. I explained that if you take a couple of published claims to be true, then you can ascribe emotion to insects.

In general you need to first choose a theory of emotion (and there are a lot of competing scientific theories on the subject https://en.wikipedia.org/wiki/Emotion#Theories), then look for scientific evidence that a particular organism satisfies the criteria of the theory. If you choose a different theory of emotion you will get a different answer to the one I gave.

 

[Buzz Bloom]

My own view (clearly debatable) is that Materialism is close to being provably false – it seems to me that there exists no way for the property of consciousness to arise from any combination of matter which does not possesses it in the first place.

Hi Cato:

I find myself completely comfortable with your Materialism category. I am guessing that the source of our two different views is related to the concept of emergence. The following link is a reasonable introduction to the concept, and there are also books about it.

https://www.britannica.com/science/emergence-science​

The focus of the above linked article is that life is made of stuff which is not alive. That is, life emerged from non-life. It is not an enormous step to progress from that to seeing conscious life as having component structures with properties that non-conscious life does not have.

Regards,
Buzz

 

[fresh_42]

What is the simplest organism with emotion?

What is an emotion?

We all stem from the same basic cells, even plants. Hence there is no a priori reason to assume that any organism does not have emotions. The question has to be: Can we prove that an organism has no emotions?

We denied emotions for all non humans in our history. That was clearly wrong.
We denied emotions for all non mammals in our history. That was also wrong.
We use this property as an excuse that we do not have to bother, which is a purely human point of view.

 

[Evo]

Damasio hasnt written a book for years. His topics were similar to it.

What is the current latest book for the brain and emotion?

Also is there any attempt to integrate emotion to AI? Is it not they have mapped the brain of a fly and trying to simulate the brain? What thinking machines have been proposed that have emotions?

These are unanswerable questions, so it goes into the realm of personal speculation. Your original post had many great answers, so this thread is now closed.

Thanks to all that participated!