Piper reads about someone described as adventurous and extroverted. She then judges that this person is more likely to be a lawyer who enjoys hiking than a lawyer who does not. The best explanation for Piper's error is that she is basing her judgment on

the representative heuristic.

Explanation:

While confronted with confusion people often attempt to make a decision, by relying on a mental shortcut described as heuristic representatives. Heuristics are used we make quick decisions using past experiences. While these shortcuts may accelerate the process of decision making, it may also result in faulty choices and stereotypes. As per the question, Piper used heuristic to quickly judges the person.