When will my 5 week old baby know who i am & start to have preferences of who he likes?

Approx. 8-12 weeks: Babies recognize mothers body odor and voice first. They start developing memory of this stimulus and recognizing it as familiar by 8-12 weeks.

Your infant has: Already developed a preference for smelling your nipple pads, if you're nursing, & "knows" your voice. Procedural memory (remembering what it means when you settle in to nurse or when he sees a bottle) begins at 5 mos., leading to stranger anxiety @ 6 mos., when he recognizes strangers vs. Non-strangers. Customize the aap's healthy child app, also on aap.Org, for anticipatory guidance.