Effort in Machine Translation Post-Editing: The Role of Translation Expertise and Individual Cognitive Differences

Abstract

Machine translation post-editing (MTPE) has become an integral component of contemporary translation workflows. While technological advances are often assumed to reduce human effort, research suggests that effort in MTPE is complex and multidimensional. This dissertation investigates the relationship between expertise, effort, accuracy, and individual cognitive differences in MTPE, addressing three research questions: (1) to what extent expertise serves as a valid indicator of cognitive, temporal, and technical/linguistic effort in MTPE; (2) how expertise relates to objective and self-reported effort and post-editing (PE) accuracy; and (3) whether individual cognitive difference scores predict effort during MTPE. A mixed-methods experimental design was employed with 21 participants grouped as experienced translators, inexperienced translators, and field experts. Participants post-edited three legal texts that had been machine-translated from English into Turkish. Data were collected through keylogging using Translog-II, capturing total task duration, mean pause duration, total pause duration, pause percentage, pauses per word, text production and elimination, and user and production events per minute indicators. PE accuracy, post-task questionnaires, and retrospective think-aloud protocols were also collected. Additionally, individual cognitive differences were examined using executive function tests administered in the PEBL, measuring cognitive flexibility, inhibition, and working memory. The findings demonstrate that experienced translators often invested more temporal, cognitive, and technical/linguistic effort than the other groups, reflecting deliberate monitoring, revision, and quality control strategies. At the same time, expertise emerged as the strongest predictor of PE accuracy. Cognitive flexibility was found to meaningfully predict how effort was managed during MTPE, while inhibition and working memory showed more limited and selective effects. Consequently, the results indicate that effort in MTPE is shaped by expertise and cognitive profiles rather than being automatically reduced by technology, underscoring the continued centrality of expert human translators in achieving high-quality PE outcomes.