In this essay we document moderate continuity in mental development beginning in infancy and extending into childhood. Psychological opinion in the past has tended to favor discontinuity theories of cognitive development from infancy. In recent years, however, the foundations on which discontinuity positions were originally established have themselves come under question and new findings grounded in new assessment procedures have appeared, necessitating revision of opinion on this significant psychological and developmental issue. Our essay has several aims. We first review briefly the bases for contemporary discontinuity theories of mental development. Second, we present current findings that support the alternative proposition of continuity: Recent research demonstrates that infants who more efficiently encode visual stimuli or more efficiently recollect visual or auditory stimuli tend to perform more proficiently on traditional psychometric assessments of intelligence and language during childhood. Third, we scrutinize the assessment methods from which these continuity results derive. Fourth, we offer several models that help to explain the continuity findings. Fifth, we discuss critically the origins and the maintenance of continuity in mental development as it is coming to be conceptualized currently. Finally, we reflect on implications of continuity for the future of infant assessments specifically and for theories of early mental development generally.