INTRODUCTION: The present study examined long-term retention and transfer of knowledge and skills, as well as the effect of cognitive load on retention and transfer, using a sample of astronaut candidates and two comparison groups. The first comparison group, recruited from Johnson Space Center, was similar in age, education, and general health to the astronaut candidate group; the second comparison group included university undergraduate students.METHODS:This study employed two different tasks-a simple perceptual-motor task involving data entry and a complex memory updating task requiring both prospective and retrospective memory. Subjects completed multiple sessions involving both tasks over a 500-d period, with test sessions involving transfer and/or a cognitive load manipulation. For the perceptual-motor task, transfer involved changes to the stimuli that increased intrinsic cognitive load or changes to the required motoric procedures. For the memory updating task, extraneous cognitive load was increased by the addition of a concurrent secondary task.RESULTS:For both the perceptual-motor and memory updating tasks, astronaut candidates and candidate-like subjects performed more accurately, with greater speed, and were less impacted by increased cognitive load than undergraduate students. Despite the generally superior performance of astronaut candidates and candidate-like subjects, they were more likely to experience negative transfer on the perceptual-motor task, whereas undergraduate students demonstrated positive transfer.DISCUSSION:Candidate-like subjects provided a more accurate approximation of astronaut candidate performance than did undergraduate students, especially with regard to negative transfer effects and cognitive load.Kole JA, Barshi I, Healy AF, Schneider VI. Astronaut candidate, candidate-like, and undergraduate subjects compared on retention and transfer. Aerosp Med Hum Perform. 2023; 94(12):902-910.