Biopsychology is often considered as a challenging course for first-year Psychology students. Data from the BINUS Psychology Department in 2020 shows that learning outcomes in Biopsychology of first-year students have not been optimal. Therefore, intervention is needed to improve learning outcomes of students through self-regulated learning, especially in the online learning context. This study aims to find an overview of perception about Biology of students and the effectiveness of Differentiated Instruction (DI) implementation to improve self-regulated learning. Biology was chosen due to its relatedness to Biopsychology. Partial results from 216 first-year psychology students showed that most (92.12%) were familiar with Biology. Moreover, this study showed that most participants (77.77%) perceived Biology as an interesting but challenging subject to learn. Furthermore, from 216 participants, 36 participants completed the mental effort (ME) and judgement of learning (JOL) questionnaire (within five online sessions). Paired sample t-test analysis showed no significant difference in ME and JOL in online sessions before and during DI intervention, indicating that the implementation of our intervention did not lead to higher effort or confidence during learning. We speculated that a more elaborate DI intervention is needed to improve ME and JOL of first-year students, which lead to optimal learning.