What should be the attention span of a 4year old at a time?

minimum 5 minutes to 7 minutes...

i agree with doctor shilpitha. As i have taught this age group. 5-7 mins max they could concentrate.  U have to be very creative or exptessive if u r teaching something  to them or doing a read aloud. 

Dear Rhituparna, I agree. About 5 - 7 minutes of consistent attention is what he or she should be developing. Hope this helps.