You forgot to say that this question is about the article "The Flight from Conversation" by Sherry Turkle.
Answer:
The author's purpose is to exemplify what she is talking about, providing a basis for her argument and simplifying it so that the reader has an extended understanding of the subject spoken.
Step-by-step explanation:
In paragraph 9 the author is arguing about how the success of current communication, with the use of devices, is due to the fact that we manage to control our relationship with the people with whom we communicate, in this case, we can keep away from them, but not much; and, close to them, but not much. To extend the reader's understanding and provide a basis for this argument, the author alludes to the Goldilocks effect, which is an effect that refers to the children's intention to like things that are neither too much nor too complex, but rather in right measure, in the same way as we establish our current communication.