A: An 8 month old may play alone with toys for long periods of time, so that pattern in itself is not necessarily abnormal. What I would want to know is this: does your son play with you at least several times a day, when you are feeding him and changing his clothes and engaging with him socially? It is normal for an 8 month old to have some solitary activities, but it is important that an 8 month old be responsive to parents AT TIMES. Looking you in the eye, playing and laughing together, staring at something that you are also staring at with mutual interest--these are indications that interpersonal relationships are developing well. Your son should be showing you clearly that he is attached to you, and that you can share a rich, casual, playful interaction together several times in the course of an ordinary day.
You might not be able to catch his attention at all times, if he is deeply studying some other toy or involved in his own ideas at that particular moment. But you and he should be intimately involved in a deep shared experience of looking, watching, laughing, and playing together at least some of the time, every day.
If you have some question about this, don't hesitate to ask your pediatrician to give you an opinion based upon experience with a large number of babies. If there is a problem, early professional intervention can help.