basically this is from james barker and it basically illustrates that we're all born with approximately the same number of sweat glands and in that zero to three age if you're in a warm climate you develop the capacity to use them more. if you're in a colder climate, you don't. and then ever after, if you are somewhere else, can you cool yourself down if you are raised in that hotter environment. people think there are many other capacities of human development that might be malleable in this way. there is starting to be a large body of literature that ties certain stimuli at different points in development to these later in life capacities. there is a huge literature about the fetal hypothesis. this goes through different types of stimuli. nutritional insults that might happen. infectious disease, maternal stress. i don't have time go into the details, but i love the details. but all of these are sort of mounted on a really rigorous platform of trying to find out when there is a group that is a treatment group and control group. so you're not just saying, is it bad for your mom to be i