I thought I heard the theory that it was therapeutic. That it's a way of imparting vibration, say, to one's kittens, and no, really, vibration can be therapeutic.
Now, I like that theory, but it has the problem of being incongruous with the fact that cats purr when happy or content (Dent is proof that ignorance is bliss, no?) not when worried or concerned.
So I have an alternative hypothesis. I find it fascinating that it's affective, and it is about expressing contentment. Why would a species find it useful to communicate a sense of well-being?
Well, you could use such a thing for the same purpose for which we and other species use expressions of alarm and discontent for. By using it in reverse.
Animals across a wide variety of species evolved vocalizations (and other signaling) of alarm and distress to alert conspecifics. To alert the other members of the pack/herd/flock/troupe/pod to flee, or veer, or circle up to defend the young, or attack. In other words: it's coordinative communication, to elicit socially coherent behaviors.
The problem with this approach is that screaming when you see a predator may be good for your fellows, it's potentially really terrible for you, especially if the predator hadn't quite seen you yet but now knows exactly where you are.
Wouldn't it be neat if a species came up with the approach of making a more-or-less continuous quiet sound, that could fall silent when there was a threat? It would be a lot more discreet a way to signal one's pride – or one's cubs – that now would be an excellent time to shut up and hold still. A kind of deadman's switch – or warrant canary – for a threat alarm.
But the thing is, if a species evolved that, it would have a variety of additional interesting applications. Threat alarms generally do. If you develop the apparatus to make a really big noise that your fellows will recognize as a threat alarm, and it's wired into your HPA axis, well, it's just a half-step to the side to use that in contests for mates and territory. And that gets you aggression displays to conspecifics to contend for social dominance.
You could do it in reverse, too. If instead of an aggression signal, you have a contentment signal, then giving it means you're not contending for dominance, you're acquiescing to the social order as it stands.
[Whups, stopped in the middle of my thought.]
And that solves one of the great problems in being a social organism: how can one trust one's conspecifics enough to cooperate with them, when one is in competition with them for resources? I propose that having involuntary behaviors which betray one's interiority makes an individual more trustworthy. It betrays one's intentions, such that one can't perpetrate deceit. If one is going to attack the dominant member of one's social group in a contest for dominance, one will stop purring first.
[And for another thing!]
I would think this is a particularly hard problem for apex predators. Cooperating enough to say, hunt in packs, is beneficial because more tasty megafauna for everyone, but mighty tricky to pull off when, actually, everyone is a tiger. It's a prisoner's dilemma. Except what makes the prisoner's dilemma the prisoner's dilemma is the prisoners can't communicate, and can't know whether or not other members of the system will defect.
Purring is, I propose, a solution to the prisoner's dilemma: it prevents cats from defecting without warning. It makes cats able to trust cats, so they can tolerate one another's presence enough to cooperate.
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timeasmymeasure
no subject
Date: 2019-04-22 04:19 am (UTC)so... why evolve this weird vocal ability?
I thought I heard the theory that it was therapeutic. That it's a way of imparting vibration, say, to one's kittens, and no, really, vibration can be therapeutic.
Now, I like that theory, but it has the problem of being incongruous with the fact that cats purr when happy or content (Dent is proof that ignorance is bliss, no?) not when worried or concerned.
So I have an alternative hypothesis. I find it fascinating that it's affective, and it is about expressing contentment. Why would a species find it useful to communicate a sense of well-being?
Well, you could use such a thing for the same purpose for which we and other species use expressions of alarm and discontent for. By using it in reverse.
Animals across a wide variety of species evolved vocalizations (and other signaling) of alarm and distress to alert conspecifics. To alert the other members of the pack/herd/flock/troupe/pod to flee, or veer, or circle up to defend the young, or attack. In other words: it's coordinative communication, to elicit socially coherent behaviors.
The problem with this approach is that screaming when you see a predator may be good for your fellows, it's potentially really terrible for you, especially if the predator hadn't quite seen you yet but now knows exactly where you are.
Wouldn't it be neat if a species came up with the approach of making a more-or-less continuous quiet sound, that could fall silent when there was a threat? It would be a lot more discreet a way to signal one's pride – or one's cubs – that now would be an excellent time to shut up and hold still. A kind of deadman's switch – or warrant canary – for a threat alarm.
But the thing is, if a species evolved that, it would have a variety of additional interesting applications. Threat alarms generally do. If you develop the apparatus to make a really big noise that your fellows will recognize as a threat alarm, and it's wired into your HPA axis, well, it's just a half-step to the side to use that in contests for mates and territory. And that gets you aggression displays to conspecifics to contend for social dominance.
You could do it in reverse, too. If instead of an aggression signal, you have a contentment signal, then giving it means you're not contending for dominance, you're acquiescing to the social order as it stands.
[Whups, stopped in the middle of my thought.]
And that solves one of the great problems in being a social organism: how can one trust one's conspecifics enough to cooperate with them, when one is in competition with them for resources? I propose that having involuntary behaviors which betray one's interiority makes an individual more trustworthy. It betrays one's intentions, such that one can't perpetrate deceit. If one is going to attack the dominant member of one's social group in a contest for dominance, one will stop purring first.
[And for another thing!]
I would think this is a particularly hard problem for apex predators. Cooperating enough to say, hunt in packs, is beneficial because more tasty megafauna for everyone, but mighty tricky to pull off when, actually, everyone is a tiger. It's a prisoner's dilemma. Except what makes the prisoner's dilemma the prisoner's dilemma is the prisoners can't communicate, and can't know whether or not other members of the system will defect.
Purring is, I propose, a solution to the prisoner's dilemma: it prevents cats from defecting without warning. It makes cats able to trust cats, so they can tolerate one another's presence enough to cooperate.