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When in history did our reward system develop, in order to ensure human reproduction? And what drives lower animals to reproduce?
Instinct
The reward is the survival of the lineage. but do animals know this as well? Do they have some kind of consciousness that they (well, actually not them, just their offspring) will "survive" if they manage to reproduce, or is it rather an instinctive, unconscious attraction towards the other sex, which has nothing to do with their brain? Animals with a neurological circuit do need some kind of stimulus to get them to reproduce, but that stimulus is built instinctively into their genes and/or brain, but if so, where exactly?
Reward
Neurological systems underlying reward seeking behaviour are widespread in the animal kingdom, from worms, to molluscs, to arthropods to vertebrates. In most cases, these reward pathways are mediated by biogenic amines, specifically, dopamine in worms, molluscs and vertebrates (including humans) and octopamine in arthropods. Thus, these reward systems are phylogenetically ancient, long predating mammals, in fact probably going back to at least the Cambrian era. But, are biogenic amines in all these cases also inherently related with reproduction? It is indeed well-known that dopamine/octopamine is present as a neurotransmitter in the nervous systems of lower animals, but does the act of reproduction in these cases also affect the increase of dopamine activity? Has this been measured? I'm questioning this correlation because dopamine is also known to have a rather neutral function, which has nothing to do with sexual arousal, since it is also used in the basal ganglia, where it motivates physical movement of the limbs (and can lead to Parkinson's disease in humans). A given neurotransmitter can signal in multiple functions, but what determines the function is the pattern of connections, not the signalling molecule itself.
Natural selection
There has always been a reward system, called "natural selection". It's where the fittest compete for food and mates, win, and survive. Generally, animals are driven to reproduce by a general primal urge to do so. But what is this "drive"? And where is located? All animals have different neurological circuits compared to humans, yet they all seem to have the same desire to reproduce, so where does this drive to sexually reproduce come from? Is it merely a physical attraction towards the other sex, or a neurological/genetic message which ensures an animal's survival?
Instinct
The reward is the survival of the lineage. but do animals know this as well? Do they have some kind of consciousness that they (well, actually not them, just their offspring) will "survive" if they manage to reproduce, or is it rather an instinctive, unconscious attraction towards the other sex, which has nothing to do with their brain? Animals with a neurological circuit do need some kind of stimulus to get them to reproduce, but that stimulus is built instinctively into their genes and/or brain, but if so, where exactly?
Reward
Neurological systems underlying reward seeking behaviour are widespread in the animal kingdom, from worms, to molluscs, to arthropods to vertebrates. In most cases, these reward pathways are mediated by biogenic amines, specifically, dopamine in worms, molluscs and vertebrates (including humans) and octopamine in arthropods. Thus, these reward systems are phylogenetically ancient, long predating mammals, in fact probably going back to at least the Cambrian era. But, are biogenic amines in all these cases also inherently related with reproduction? It is indeed well-known that dopamine/octopamine is present as a neurotransmitter in the nervous systems of lower animals, but does the act of reproduction in these cases also affect the increase of dopamine activity? Has this been measured? I'm questioning this correlation because dopamine is also known to have a rather neutral function, which has nothing to do with sexual arousal, since it is also used in the basal ganglia, where it motivates physical movement of the limbs (and can lead to Parkinson's disease in humans). A given neurotransmitter can signal in multiple functions, but what determines the function is the pattern of connections, not the signalling molecule itself.
Natural selection
There has always been a reward system, called "natural selection". It's where the fittest compete for food and mates, win, and survive. Generally, animals are driven to reproduce by a general primal urge to do so. But what is this "drive"? And where is located? All animals have different neurological circuits compared to humans, yet they all seem to have the same desire to reproduce, so where does this drive to sexually reproduce come from? Is it merely a physical attraction towards the other sex, or a neurological/genetic message which ensures an animal's survival?