possible, we mounted a go pro on 30-year-old alex roberts. >> i'm excited to shop. to be honest. >> to see what's going on inside her brain as she hits the stores. >> i love this. this is amazing. >> reporter: according to analysis provided by the facial tracking company in bezo, she is on a shopping high. her eyes are wide and alert, mouth slightly open. these are all signs that the pleasure center in her brain is lighting up which experts at the university of michigan say is comparable to the joy felt after having sex. they were also surprised to learn something else. >> there's this pain that's associated with spending. and to the best that we can tell, there seems to be this tradeoff, weighing of pleasure versus pain. >> reporter: was that the case for alex? >> i need a denim shirt. >> alex's quick tightening of the lips and scanning items indicate she's disappointed and feeling stress according to facial tracking experts.