【正确答案】 1、N    

【答案解析】[题眼] Laughter is a kind of semiverbalized social exnression of pleasure，developing earlier than speech．
[定位] 第5段第5句：Probably at about the salne time speech evolved，laughter originated too，as a kind of semiverbalized social expression of pleasure．
[解析] 题目中的earlierthan与原文中的about the same time不一致，所以答案是N。