Exaptation: Academic mentees' career pathway to be independent and impactful

In science, mentees often follow their mentors' career paths, but exceptional mentees frequently break from this routine, sometimes even outperforming their mentors. However, the pathways to independence for these excellent mentees and their interactions with mentors remain unclear. We analyzed the careers of over 500,000 mentees in Chemistry, Neuroscience, and Physics over the past 60 years to examine the strategies mentees employ in selecting research topics relative to their mentors, how these strategies evolve, and their resulting impact. Utilizing co-citation network analysis and a topic-specific impact allocation algorithm, we mapped the topic territory for each mentor-mentee pair and quantified their academic impact accrued within the topic. Our findings reveal mentees tend to engage with their mentors' less-dominated topics and explore new topics at the same time, and through this exaptive process, they begin to progressively establish their own research territories. This trend is particularly pronounced among those who outperform their mentors. Moreover, we identified an inverted U-shaped curve between the extent of topic divergence and the mentees' long-term impact, suggesting a moderate divergence from the mentors' research focus optimizes the mentees' academic impact. Finally, along the path to independence, increased coauthorship with mentors impedes the mentees' impact, whereas extending their collaboration networks with the mentors' former collaborators proves beneficial. These findings fill a crucial gap in understanding how mentees' research topic selection strategies affect academic success and offer valuable guidance for early-career researchers on pursuing independent research paths.