How are thrill seekers beneficial to the species? The only benefits I see are stupid people dying so there's less of em for the species
Thrill seekers are more likely to act, and as such has increased chances of discovering food/new sources of food/new place to live than those that do not.
In the same way, aggressive behavior has increased chance to survive during periods of starvation. However, a calm benevolent personality has increased chances of survival during periods with normal or plenty of food.
Each personality comes with downsides and upsides. A calm personality who share with others, are more likely receive help in return. If, for example, they share of their food to those that does not have food, they are more likely to receive food from the individuals they shared it with, when they do not have food. If they take care of sick individuals, they are more likely to receive help in return. However, they usually are lower-ranked in social groups, and as such as less chance of reproducing in a rank-based social environment.
The aggressive type is more likely to get what he want, and is more likely to be the alpha in a group, and as such has a greater chance of spreading his genes. However, as he is more likely to get in to fights with other males, odds are he will either get killed prematurely, or be excluded from the group to live on his own, which greatly reduces his chances of survival.
Thrill seeker is closely related to the aggressive personality, but it doesn't have to be. In the human world, a lot of criminals are thrill seekers with a aggressive personality.
Purely evolutionary, thrill seekers and aggressive types are likely the individuals with the greatest chance of spreading their genes. Especially as they are more likely to sleep around and "cheat".
Almost every single personality type has its pros and cons. Some are more important than others during certain times, which is why different personalities exist - to increase the chance of the species surviving. If every individual in a species had the same personality, it would likely be the one to fit the environment best. However, if the conditions change, then this species is as good as dead, as it will have a hard time adapting to the new environment. Personalities are an important part of a species survival.
I do not believe mental disorders resulting in a psychopathic mass murderer has an evolutionary purpose. But then again, that is usually the result of how they were raised and what influences and experiences they had as a kid. Dogs for example aren't really born as aggressive dogs, but they can become psychopathic mass murderers depending on how you choose to raise it and which experiences you provide it with.
