July 15 Parenting Tips Laughter is Learning! There is no funny business here, laughter has proven to be a vital part of child development for our little ones. One of babies’ first instincts are to smile. By 8-10 weeks babies can smile in response to stimuli and soon after they begin laughing spontaneously. This laughter shifts to a response to their environment by about 3 months old. Smiling and laughing are some of the very earliest forms of engaging with others and connecting in a social form.