My 8 week old smiles occasionally and will 'get in to' being played with but it takes quite a bit! He still seems happy to just sit and stare at things around him with quite a blank face. When will he become noticeably more in to people interacting with him?
3/4 months i would say, as WMMC. my DD really loved being played with by 6 months, i would say - before that it was fairly random, so something that got a big grin one day would leave her completely uninterested the next.
3 months was a big turning point - he was already a smiley baby but started to become much more 'interactive' then (i know, that makes him sound like a computer game!) and just got better and better really - now 6 months old and just a joy to be with, except at 3am
Because we are told babies start smiling at 6 weeks, I'd kind of expected DS to be more smiley and interactive at 2 mo than he actually was. As everyone has said 3/4 months sees a big change, as does 5/6 when they can hold objects and play with them. In the meantime keep singing .