What caused the initial emergence of cooperative strategies in environments of PD-type?
I’d think that cooperative strategies emerge in non-PD-type situations, where individual defection is strictly worse than cooperation (e.g. hunting large prey in packs). When the environment changes toward PD-type (e.g. shortage of large prey means not every pack member is fed), some individuals evolve to defect. However, having too many of them results in reduced benefit for everyone, so the defection mutation never spreads too widely (e.g. a pack where everyone starts to defect by fighting and possibly killing others for food share soon becomes too small to hunt effectively). Instead of straight up defection, other mutations provide more fitness without significant detriment (e.g. pack hierarchy with the strongest thriving and the weakest dying out).
The summary you quoted seems to imply something like this. I am not familiar with the actual research on the topic, however, feel free to summarize.
Group selectionism alert. The “we are optimized for effectively playing the iterated prisoner’s dilemma” argument, AKA “people will remember you being a jackass”, sounds much more plausible.
I made no argument that cooperation emerges in the PD environment, quite the opposite. I argued that, once it emerged in a non-PD environment, it does not necessarily die out in a PD environment. No group selection required.
Group selection effects are significant when the individuals of the group have a very high genetic similarity, making it overlap with kin selection. Typical examples are the cells in the body of a multicellular organisms or eusocial organisms in a hive. In groups made of mildly related individuals, like those produced by mammalian sexual reproduction (e.g. a wolf pack, a human tribe), individual selection will typically overwhelm group selection barring extreme selective pressures.
Social mammals of species which exhibit non-kin altruistic cooperation all have the ability to detect and punish defectors. One-shot PD scenarios are rare, while iterated PD scenarios are much more common in social environments, creating a selective pressure to evolve tit-for-tat strategies.
I’d think that cooperative strategies emerge in non-PD-type situations, where individual defection is strictly worse than cooperation (e.g. hunting large prey in packs). When the environment changes toward PD-type (e.g. shortage of large prey means not every pack member is fed), some individuals evolve to defect. However, having too many of them results in reduced benefit for everyone, so the defection mutation never spreads too widely (e.g. a pack where everyone starts to defect by fighting and possibly killing others for food share soon becomes too small to hunt effectively). Instead of straight up defection, other mutations provide more fitness without significant detriment (e.g. pack hierarchy with the strongest thriving and the weakest dying out).
The summary you quoted seems to imply something like this. I am not familiar with the actual research on the topic, however, feel free to summarize.
Group selectionism alert. The “we are optimized for effectively playing the iterated prisoner’s dilemma” argument, AKA “people will remember you being a jackass”, sounds much more plausible.
I made no argument that cooperation emerges in the PD environment, quite the opposite. I argued that, once it emerged in a non-PD environment, it does not necessarily die out in a PD environment. No group selection required.
That’s a group selection argument.
Group selection effects are significant when the individuals of the group have a very high genetic similarity, making it overlap with kin selection. Typical examples are the cells in the body of a multicellular organisms or eusocial organisms in a hive.
In groups made of mildly related individuals, like those produced by mammalian sexual reproduction (e.g. a wolf pack, a human tribe), individual selection will typically overwhelm group selection barring extreme selective pressures.
Social mammals of species which exhibit non-kin altruistic cooperation all have the ability to detect and punish defectors. One-shot PD scenarios are rare, while iterated PD scenarios are much more common in social environments, creating a selective pressure to evolve tit-for-tat strategies.