Well, I'd think that even a limited problem solving ability would have survival value.

Once developed, it may lead to social standing within the community, too, but that would derive from the implications for survival.

Females could select for that. Then a problem-solving ability may become more pronounced, just as my dog's interest in chasing sticks is the result of developmental rather than mutational changes.

At a minimum, later individuals of that species could be better at problem-solving than earlier. When the next big mutation came along, they could take it with 'em.

Or not. I don't know. I'm an example of development only going so far. And my willingness to type, especially late at night, has far exceeded my problem-solving development.

Bodes ill for sexual selection, now that I think about it. Maybe scent could serve as an attractant. Hope so. I'd have a better chance. My odor is stronger than my intellect.

Regards.