technology review martin giles and marybell lopez this week on "frontier." ♪ ♪ >>> good morning, everyonem scott mcgrew. in the history of my life this is going to be an artifact. it is a roll of tums. take it off the shelf and no cashier and the store knows who i am, what i collected and the cost of the item is charged to my account. well, i feel fine. it was small and really inexpensive and i wanted to try out the content. i'm not sure my future grandchildren will be impressed. this may not turn out to be a family heirloom because in the future most stores will probably be cashierless and it will be krishna matakuri. he runs the technology replacing checkout and martin giles of m.i.t. technology review. i was amazed. it felt a little like shoplifting. i'm sure most people have that experience, as well. how does it work? how did the machine know i had taken it off the shelf and left? >> let me answer that question first by telling you how it all started. this was about four years ago when my wife and i just moved back from south africa after a stint there and she -- we just had our baby

technology review martin giles and marybell lopez this week on "frontier." ♪ ♪ >>> good morning, everyonery of my life this is going to be an artifact. it is a