This is very true, and it's a big problem for research in general, not just for these studies. Essentially, it's difficult to find research subjects that are representative of the general population, and college students are over represented because they are such a convenient population to study. Here is an interesting article on the subject if you'd like to read about it. I think it's still a relevant finding, but I would hope that the results of these studies would be different with more mature participants, as you say.
This is very true, and it's a big problem for research in general, not just for these studies. Essentially, it's difficult to find research subjects that are representative of the general population, and college students are over represented because they are such a convenient population to study. Here is an interesting article on the subject if you'd like to read about it. I think it's still a relevant finding, but I would hope that the results of these studies would be different with more mature participants, as you say.