Doing things that are costly isn’t the only way to reliably signal. In this case the rabbit reliably communicates awareness of the fox’s presence. It cannot be fake because the rabbit must look in the right direction. The fact that it’s prey is not unaware of its presence is always going to be useful to a fox. It will still attempt to chase aware rabbits some times but the exchange of information will help both creatures in their decision making.
This is an equilibrium that all else being equal will be stable. Speed will still be selected for for exactly the same reason that it always was.
Just to elaborate (for clarity’s sake), by standing up and looking directly at the fox, the rabbit is changing the fox’s expected utility calculation. If the rabbit doesn’t see the fox, the fox will have the advantage of surprise and be able to close some of the distance between itself and the rabbit before the rabbit begins to run. This makes the chase less costly to the fox. If the rabbit does see the fox, when the fox begins the attack the rabbit will see it and be able to react immediately, neutralizing any surprise advantage the fox has. So if the fox knows that the rabbit knows that the fox is nearby, the fox may well not attack because of the amount of extra energy it would take to capture the rabbit.
The rabbit standing up and staring at the fox is an effective signal of awareness of the fox because it is difficult to fake (costliness is only one way that a signal can be difficult to fake). The rabbit can stand up and stare in a random direction if it wants to, but the probability of a rabbit doing that and being able to randomly stare directly at the fox is pretty slim. So if the fox sees the rabbit staring at it, then the fox can be pretty certain that the rabbit knows where the fox is at.
So ‘noticing the fox’ signals that the rabbit notices the fox and will run when it sees the fox beginning to chase. The fox uses the signal thus: “If the rabbit notices me it gets a headstart. With such a head start, and the fact that the rabbit runs at a certain minimum speed, I would not be able to catch it”.
Even though the reliability of the signal is independent of the running, its effectiveness/usefulness depends on the rabbit’s speed.
Once we have the free riding rabbits placing resources into noticing and away from running, foxes will realize this, and they will chase even when they have been noticed. So now noticing does not prevent the fox from chasing anymore, so there is less pressure on even fast rabbits to signal it.
And then the signaling collapses?
I admit to being quite confused over this. Waiting for someone to clear it all up!
Once we have the free riding rabbits placing resources into noticing and away from running
Placing emphasis on ‘noticing vs running’ is just confusing you. Noticing helps the rabbit run just as much as it helps it look in the right direction.
And then the signaling collapses?
No. Silas was just wrong. If average rabbit speed become slower then there will be a commensurate change in the threshold at which foxes chase rabbits even when they have been spotted. It will remain useful to show the fox that it has been spotted in all cases in which about 200ms of extra head start is worth sacrificing so that a chase may potentially be avoided.
If you are still confused, consider a situation in which rabbits and foxes always become aware of each other’s presence at a distance of precisely 250m. Would anyone suggest that rabbits would freeload and not bother to be fast themselves in that circumstance? No. In the ‘rabbits standing up’ situation the rabbits will still want to be fast for precisely the same reason. All standing up does is force the mutually acknowledged awareness.
Placing emphasis on ‘noticing vs running’ is just confusing you. Noticing helps the rabbit run just as much as it helps it look in the right direction.
Sorry I wasn’t being clear, previously I had always meant noticing==‘showing the fox you have noticed it’.
If average rabbit speed become slower then there will be a commensurate change in the threshold at which foxes chase rabbits even when they have been spotted.
What threshold? I’m guessing other factors such as the fox’s independent assessment of the rabbit’s speed?
It will remain useful to show the fox that it has been spotted in all cases in which about 200ms of extra head start is worth sacrificing so that a chase may potentially be avoided.
I didnt consider the fact that signaling having noticed required that sacrifice. Does it affect the analysis?
consider a situation in which rabbits and foxes always become aware of each other’s presence at a distance of precisely 250m. Would anyone suggest that rabbits would freeload and not bother to be fast themselves in that circumstance?
What threshold? I’m guessing other factors such as the fox’s independent assessment of the rabbit’s speed?
If the average rabbit becomes slower then the average fox will be more likely to estimate that a given rabbit chase is successful.
I didnt consider the fact that signaling having noticed required that sacrifice. Does it affect the analysis?
Not particularly. We haven’t been quantising anyway and it reasonable to consider the overhead here negligible for our purposes. ′
I don’t understand this part.
You don’t particularly need to. Just observe that rabbits running fast to avoid foxes is a stable equilibrium. Further understand that nothing in this scenario changes the fact that running fast is a stable equilibrium. The whole ‘signalling makes the equilibrium unstable’ idea is a total red herring, a recipe for confusion.
Hypothesis: most rabbits which are in good enough shape to notice are also in good enough shape to escape.
There simply aren’t enough old? sick? rabbits to freeload to make the system break down.
Anyone know whether inexperienced foxes chase noticing rabbits? If so, this make freeloading a risky enough strategy that it wouldn’t be commonly used.
Standing on your hind legs—which is the behaviour under discussion—is costly to rabbits—since it increases the chance of being observed by predators—so they can’t do it all the time.
However, that is not really the point. The signal is not: “look how fast I can run”—it is “look how much of a head my family and I have—given that I can see you now”.
Not all the time of course. I was refering to SilasBarta’s observation that this might not be a stable equilibrium. Because noticing the fox and turning to it is much cheaper than being able to run fast enough such that the fox will not catch you once you notice it. A good noticer but bad runner can take advantage of the good noticer/good runner’s signal and free ride off it. The fox wouldn’t care if you were a good noticer if you weren’t also a good runner, since it can still catch you once you have noticed it.
Maybe. Rabbits go to ground. Escape is not too tricky if they have time to reach their burrow. Running speed is probably a relatively small factor compared to how far away the fox is when the rabbit sees it.
Standing on your hind legs—which is the behaviour under discussion—is costly to rabbits—since it increases the chance of being observed by predators—so they can’t do it all the time.
Not only that, you can only look in one direction at a time. You do need to know where the fox is. The rabbit only loses a couple of hundred milliseconds if the fox decides to make a dash for it anyway.
Stotting is costly, hence reliable. ‘Noticing and turning to the fox’ is not.
Doing things that are costly isn’t the only way to reliably signal. In this case the rabbit reliably communicates awareness of the fox’s presence. It cannot be fake because the rabbit must look in the right direction. The fact that it’s prey is not unaware of its presence is always going to be useful to a fox. It will still attempt to chase aware rabbits some times but the exchange of information will help both creatures in their decision making.
This is an equilibrium that all else being equal will be stable. Speed will still be selected for for exactly the same reason that it always was.
Just to elaborate (for clarity’s sake), by standing up and looking directly at the fox, the rabbit is changing the fox’s expected utility calculation. If the rabbit doesn’t see the fox, the fox will have the advantage of surprise and be able to close some of the distance between itself and the rabbit before the rabbit begins to run. This makes the chase less costly to the fox. If the rabbit does see the fox, when the fox begins the attack the rabbit will see it and be able to react immediately, neutralizing any surprise advantage the fox has. So if the fox knows that the rabbit knows that the fox is nearby, the fox may well not attack because of the amount of extra energy it would take to capture the rabbit.
The rabbit standing up and staring at the fox is an effective signal of awareness of the fox because it is difficult to fake (costliness is only one way that a signal can be difficult to fake). The rabbit can stand up and stare in a random direction if it wants to, but the probability of a rabbit doing that and being able to randomly stare directly at the fox is pretty slim. So if the fox sees the rabbit staring at it, then the fox can be pretty certain that the rabbit knows where the fox is at.
Very clear. Thanks.
So ‘noticing the fox’ signals that the rabbit notices the fox and will run when it sees the fox beginning to chase. The fox uses the signal thus: “If the rabbit notices me it gets a headstart. With such a head start, and the fact that the rabbit runs at a certain minimum speed, I would not be able to catch it”.
Even though the reliability of the signal is independent of the running, its effectiveness/usefulness depends on the rabbit’s speed.
Once we have the free riding rabbits placing resources into noticing and away from running, foxes will realize this, and they will chase even when they have been noticed. So now noticing does not prevent the fox from chasing anymore, so there is less pressure on even fast rabbits to signal it.
And then the signaling collapses?
I admit to being quite confused over this. Waiting for someone to clear it all up!
Placing emphasis on ‘noticing vs running’ is just confusing you. Noticing helps the rabbit run just as much as it helps it look in the right direction.
No. Silas was just wrong. If average rabbit speed become slower then there will be a commensurate change in the threshold at which foxes chase rabbits even when they have been spotted. It will remain useful to show the fox that it has been spotted in all cases in which about 200ms of extra head start is worth sacrificing so that a chase may potentially be avoided.
If you are still confused, consider a situation in which rabbits and foxes always become aware of each other’s presence at a distance of precisely 250m. Would anyone suggest that rabbits would freeload and not bother to be fast themselves in that circumstance? No. In the ‘rabbits standing up’ situation the rabbits will still want to be fast for precisely the same reason. All standing up does is force the mutually acknowledged awareness.
Sorry I wasn’t being clear, previously I had always meant noticing==‘showing the fox you have noticed it’.
What threshold? I’m guessing other factors such as the fox’s independent assessment of the rabbit’s speed?
I didnt consider the fact that signaling having noticed required that sacrifice. Does it affect the analysis?
I don’t understand this part.
If the average rabbit becomes slower then the average fox will be more likely to estimate that a given rabbit chase is successful.
Not particularly. We haven’t been quantising anyway and it reasonable to consider the overhead here negligible for our purposes. ′
You don’t particularly need to. Just observe that rabbits running fast to avoid foxes is a stable equilibrium. Further understand that nothing in this scenario changes the fact that running fast is a stable equilibrium. The whole ‘signalling makes the equilibrium unstable’ idea is a total red herring, a recipe for confusion.
Hypothesis: most rabbits which are in good enough shape to notice are also in good enough shape to escape.
There simply aren’t enough old? sick? rabbits to freeload to make the system break down.
Anyone know whether inexperienced foxes chase noticing rabbits? If so, this make freeloading a risky enough strategy that it wouldn’t be commonly used.
I expected the devil would be in the details! But yeah, your hypothesis sounds plausible, and freeloading seems risky.
That correlation can not (and need not) be counted on to make the equilibrium stable over a large number of generations.
Standing on your hind legs—which is the behaviour under discussion—is costly to rabbits—since it increases the chance of being observed by predators—so they can’t do it all the time.
However, that is not really the point. The signal is not: “look how fast I can run”—it is “look how much of a head my family and I have—given that I can see you now”.
Not all the time of course. I was refering to SilasBarta’s observation that this might not be a stable equilibrium. Because noticing the fox and turning to it is much cheaper than being able to run fast enough such that the fox will not catch you once you notice it. A good noticer but bad runner can take advantage of the good noticer/good runner’s signal and free ride off it. The fox wouldn’t care if you were a good noticer if you weren’t also a good runner, since it can still catch you once you have noticed it.
Maybe. Rabbits go to ground. Escape is not too tricky if they have time to reach their burrow. Running speed is probably a relatively small factor compared to how far away the fox is when the rabbit sees it.
Yeah, running speed may not be such an important factor.
Not only that, you can only look in one direction at a time. You do need to know where the fox is. The rabbit only loses a couple of hundred milliseconds if the fox decides to make a dash for it anyway.