Sickness behaviour – useful concept or psycho-humbug?

Woolie said:
Just reporting back on @Mij's article. The Maes one.

I'm not interested in what they have to say about ME right now. I'm interested in what they say about bodily responses to acute infection - whether there's evidence for a coordinated "sickness behaviour" response.

The review of what happens during actue infection is quite helpful. In contrast to the sickness behaviour idea, most of the studies they reference show that the various "behaviours" that accompany infection are NOT mediated by the brain. The mechanisms are mostly peripheral (e.g., cytokines interfere with mitochondrial activity, which leads to fatigue). Some changes involve the CNS - for example the systematic increasing in body temp seen in fever involves the hypothalamus. And the changes in heart rate and blood pressure involve the CNS signalling to the autonomic nervous system. Neither fever nor cardiovascular changes are "behaviours" strictly speaking, but I suppose they may contribute to the general shitty exhausted feeling that inclines you to want to rest.

So much for the centrally coordinated adaptive behavioural modification system. Not much support there.

The paper also reviews the ways in which the CNS might be involved in the whole bodily response to infection. A surprise to me was that the role of the CNS is largely in switching off the inflammation, not heightening it. They explain that peripheral inflammation can activate microglia and astrocytes in the brain via various routes (some cytokines, like TNFa, can cross the blood brain barrier efficiently; others operate more indirectly via the peripheral nervous system). In respnse, the brain up-regulates the production of glucocorticoids, which has an anti-inflammatory effect, and also initiates the release of catecholamines and acetylcholine, which also inhibit the production of proinflammatory cytokines (e.g. IL1, IL6 and TNFa), and also of T helper cells.

My conclusion:

  • Low-level brain structures coordinate some body-wide responses to infection (fever, heart rate changes). But most of the changes leading to "sickness behaviour" occur outside the central nervous system. They are things like cytokines interfering with mitochondrial function.

  • Sickness behaviour is not a useful concept. Its adds little, and is open to misinterpretation and abuse. A much clearer way to talk about behaviour changes that occur during an acute infection is simply to call them "behaviour changes that occur during an acute infection".

  • As for its relation to MECFS, I don't think that matters, if the concept itself is stupid.
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Pretty much then leads you back to the role of cytokines. It's interesting that the CNS turns off inflamation once the message is received. This happens also for some pain receptors. A bit like the brain says...yep got the message dealing with it.

As with most psychological theories, they tend to fall apart when you start talking at the molecular level.
 
chrisb said:
a mechanistic body, devoid of free will or personality might be thought of as displaying "sickness behaviour".
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What's this magical "free will" you think humans might have? Free will is a concept that I always have thought has never been placed on a solid conceptual footing in philosophy, psychology, and science in general.

One of the main problems I think in making progress in understanding free will (if it exists) is the fact that people find it comforting to believe that they do have free will, and would not like to contemplate a world in which there was no free will.

Thus belief in free will is akin to belief in God: just as any scientific analysis of the existence of God is clouded by an underlying psychological need many people have for God to exist (bias, in other words), likewise, scientific analysis of free will is clouded in a similar way, because many people are unable to face the idea that they may not have free will. So they assume they have free will, but without offering any evidence for it.

The way I like to look at free will is in more relative terms: there may or may not be such a thing as absolute free will, but some people may possess relatively more free will than others.

For example, if you are brought up in an environment in which only the crude base instincts dominate, such as for example the feral street gangs of young kids that many modern cities have, where base survival instincts like fear and aggression drive everyday reality, then you will have little free will, in the sense that you almost mechanistically follow these base instincts in your daily life, and are a slave to them. The behavioral portfolio is very limited, and in this sense such kids are not very free.

Whereas for people who have had a more fortunate upbringing, these same base instincts of fear and aggression exist in their psyche, but because through a better upbringing these people have cultivated many other aspects of their mind, as a result their minds have developed many more areas and interconnecting pathways, areas such as rationality, moral conscience, creativity, and so forth. Thus the outward behavioral responses of such people are far more complex and varied, because behavioral responses are the result of the mental interaction of all these pathways. In any situation they face, such people bring to bear so many more areas of mind — aspects of mind which may temper and counterpoise the base instincts.

And this is may be nature of free will: where mechanical instincts or any other drives are tempered and counterpoised by other aspects of the mind. That makes you feel as if you have more free will, because you know that you are not a slave to the base instincts and drives.

Another example of such free will is where you might feel a sexual or amorous attraction towards an individual, but that attraction is counterpoised by other aspects of your mind such as rationality and moral conscience, which remind you that you are married, and that acting on your base instinct of amorous attraction may risk your marriage.

But is that really free will in any absolute sense? If your rationality and moral conscience are just counterweights to your amorous instincts, your final behavioral decision is not really free, it's just a mechanical balance of two opposing forces: your amorous desires versus your rationality and moral conscience.

So where is the free will, if you behavior is just a mechanical balance of two opposing forces? In the absolute sense, it seems more deterministic than free.
 
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chrisb said:
"Behaviour" seems to be a very malleable word. Sometimes it seems to be used where others might use "symptom", but it seems to imply the possibility that the behaviour is possibly voluntary and could be altered by an act of will.
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Agreed. The brain is in many ways a central control system, but much of that control is going to be very low level, way below anything people have any ability to control manually. There must be many automated control mechanisms our brains are involved in, that in an evolutionary sense are likely very ancient; some probably from before we were even human.
 
chrisb said:
I do not think they possess it , but it is a commonly held belief.
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In terms of understanding how behavior can be modified or skewed in a particular direction by the sickness behavior response, the model of free will that I detailed above I think makes it easy to understand.

If you are feeling very tired and depressed because of the sickness behavior response, you are likely not going to go out for a night on the town; however, you still possess enough freedom to do so if you really wanted to. But the chances are that you won't because you feel so low. Thus the effects of sickness behavior don't fully override your free will, but they do certainly tend to skew your behavior in a certain way.
 
lansbergen said:
@Hip What is mind?
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You need a good mind to attempt to understand what mind might be, and I don't think any of us with brain fog have the clarity of thought to tackle these complex questions. I used to have a great interest in the philosophy of mind, but I cannot delve much into that field now, because unfortunately my thinking is too blurred.
 
Wow! I feel like I'm in the middle of reading Oliver Sacks or watching Monty Python, two of my favorite intellectual pastimes!

What’s rather interesting/confusing is how we sometimes ascribe human qualities to animals. Can’t think of the word. Does this mean we are as clueless of them as the psychobabblers toward us?

I don’t believe that for a moment. It was just a passing thought.

My cat IS human and I AM cat! :laugh:

Edit.
Anthropomorphism.
 
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barbc said:
What’s rather interesting/confusing is how we sometimes ascribe human qualities to animals. Can’t think of the word.
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anthropomorphism?
barbc said:
Does this mean we are as clueless of them as the psychobabblers toward us?I don’t believe that for a moment. My cat IS human and I AM cat! :laugh:
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I think we humans have a history of underestimating animals. All part of our overconfidence and arrogance. Animals are often the butt of overzealous theorists, and being unable to speak up for themselves, they are considered fair game (sound familiar?). Some of the bullshit science that has been bandied about re dogs is appalling and has harmed them greatly e.g., pack mentality, simplistic hierarchical society, they need to be shown "who's boss" or they'll take over, blah blah.

Apparently, all this is based on studies of incarcerated wolves with no particular pre-existing bonds. Natural wolf packs are incredibly cooperative and although there are individuals everyone looks up to (just as is the case with humans), they engage in rich rituals that strengthen their mutual bonds to one another. Just as humans do.

Sorry, I went on an off-topic rant...
 
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