This dissertation comprises four papers that explore critical psychological processes—memory and decision-making—within legal contexts, with a focus on vulnerable populations in our contemporary, global, post-COVID world.The first paper investigates how culture, socioeconomic status (SES), and parenting styles influence children’s eyewitness memory and suggestibility. Drawing on ecological systems theory, this transnational study examines how these sociocultural factors shape children’s testimonial capacities, providing important cross-cultural insights into the reliability of child witnesses. The second paper addresses pressing concerns raised by the COVID-19 pandemic, which led to increased reports of child maltreatment and necessitated a shift toward virtual investigations and courtrooms. Using a mock crime and misinformation paradigm with eighty 8-year-olds interviewed either face-to-face or via tele-forensic interviewing (tele-FI) under the NICHD-Revised protocol, this study finds that tele-FI elicits significantly more accurate recall and lower suggestibility. These findings suggest tele-FI may not only serve as a viable alternative to in-person interviews but could also enhance the reliability of children’s testimonies in forensic and investigative contexts. The third paper turns to the broader scientific landscape shaped by the pandemic. As online developmental science became the new norm, this study surveyed thirty-four developmental researchers about their experiences, insights, and recommendations. Through thematic analysis and exploratory text mining, the paper reveals largely positive attitudes toward online research, though challenges such as academic precarity, structural inequality, and adaptive expertise remain. Broader discussions emerged on caregiver influence, children’s suggestibility, webcam-induced self-monitoring, and evolving notions of diversity. The synthesis suggests that online developmental science has reached a point of no return, urging the field to adopt a new mindset for the post-pandemic era. Finally, the fourth paper explores competency for execution (CFE), analyzing the characteristics of the twenty-eight successful Ford claimants in the U.S. compared to general death row and homicide cases. Findings highlight unique demographic and case profiles, systemic psycho-legal deficiencies, and striking state-level variations. While limited by small sample size, this study provides foundational data to better understand the complexities of CFE decisions. Collectively, these papers underscore the importance of integrating psychological science with legal practice to protect vulnerable individuals and inform policy.