Final answer:
User Experience (UX) is the field of software development that deals with the user's interaction with the software, aiming to create a positive experience. Human-software interactions and usability are key to UX design, and software development is part of the tertiary economic sector.
Step-by-step explanation:
The area of software development that focuses on the user's reaction to and interaction with the software product is known as User Experience (UX). UX aims to improve the overall experience of a user when interacting with the software by making it more usable, accessible, and enjoyable. Aspects of UX design include ease of use, functionality, and how users feel as they navigate through the product. A human factors psychologist researching in this area would study human-software interactions to optimize the design and support the decision-making processes of workers. In the context of evaluating software, quality assurance processes also involve usability tests to ensure that the design meets users' needs. Software development is part of the tertiary sector of the economy, which is focused on service industries and includes information technology services.