On the (Mis) Understanding of the "this" Reference

The paper presents research conducted with high school (HS) students (N= 86) learning object-oriented programming (OOP) and computer science HS teachers (N= 48). The focus was on students' and teachers' understanding of the this reference. Proper conceptualization of this indicates an understanding of objects in general and of the current object, and it involves various aspects of programming variants. Students' preferences as to the use of the this reference were also examined. Findings revealed a lack of understanding of both the implication and the implementation of this; only 45% of the students expressed understanding of when we must use this; only 60% expressed understanding of when not to use this, and only 24% expressed clear understanding in their definition of this. Even correct answers do not necessarily indicate conceptual understanding, rather a repetition of definitions or programming habits, or a reliance on operative aspects of the implementation. The teachers expressed a considerable lack of clarity in accurately characterizing the correctness of students' answers.