Reverse education, where younger individuals teach older adults, has gained prominence but lacks comprehensive understanding regarding its dynamics and impacts. This study addresses this gap by exploring the cognitive processes of older adult learners who view young university students as their teachers. Through semi-structured interviews with 12 older adults learning to use smartphones, we identify and analyse 3 critical stages of their cognitive journey: pre-teaching, teaching interaction, and learning reflection. In the pre-teaching stage, older adults accept young students as teachers primarily due to the perceived authority of the educational institution. During the teaching interaction stage, they recognize the value of the younger generation's teaching abilities and emotional support. In the learning reflection stage, older adults emphasize the quality of their learning experience and personal growth when evaluating young students as teachers. Our findings provide a nuanced understanding of why older adult learners embrace reverse education, highlighting the importance of teaching competencies and emotional engagement. These insights have significant implications for enhancing reverse education practices and the professional development of educators in senior university settings.