Answer:
Social referencing
Step-by-step explanation:
Social referencing is the behavioral attitude which infants use to respond or behave behaviors towards any thing, human, and situations. Social referencing is the mechanisms by which a child tries understand the environment around them.
Social referencing happens when any child observes the facial expressions of other known person to understand how to behave in any unknown situation.
When Justin was not able to recognize Frank, he needed hints how to respond to him, hence, Justin, looks at his mother to whom a child is most closed, to see what is her response. Thus he is using social referencing to make a judgement about his uncle.