Sorry, that sentence was unclear- they have previous studies dealing with trolley-like problems and previous studies dealing with 5-HTTLPR’s relation to things like fear recognition and strength of perceived rewards and punishments. They don’t, as far as I know, have studies dealing with the relationship between 5-HTTLPR and trolley-like problems until now.
Sorry, that sentence was unclear- they have previous studies dealing with trolley-like problems and previous studies dealing with 5-HTTLPR’s relation to things like fear recognition and strength of perceived rewards and punishments. They don’t, as far as I know, have studies dealing with the relationship between 5-HTTLPR and trolley-like problems until now.