Mismatch theory

Mismatch theory is an evolutionarily informed concept. The essence of mismatch theory is that organisms possess traits (including behavioral, emotional, and biological) that have been passed down through generations, preserved by natural selection because of their adaptive function in a given environment. However, the given environment of the evolutionary period is quite unlike the current environment. Therefore, traits that were at one time adaptive in a certain environment, are now "mismatched" to the environment that the trait is currently present in.