The speaker mainly discusses________.

Culture can be defined as behavior that is learned and transmitted to members of a group. A child learns a particular behavior through observation as well as through positive and negative feedback from his/her family and peers. A minor point to remember is that this feedback can be overt or covert. Much covert feedback involves nonverbal cues that an outsider to that culture would not understand.

The cowbird is an unusual American bird, which builds no nest. Instead, a female lays an egg in the nest of another bird and leaves the chicks to be hatched and raised by the adopted parents. Usually, these adopted parents don’t seem to notice anything strange about the young cowbird. Even though it may be twice size of their own chicks.