During the asymptomatic phase of Alzheimer's disease (AD), identifying cognitive processes that distinguish it from age-related changes will facilitate better treatment. We characterized changes in context-free memory processes in normal aging males and females from 15-110 years old. 681,428 subjects, aged 15-110 years old (Figure 1), were screened for subjective or medical record evidence of cognitive impairment (CI) or dementia. The MCI Screen, which assesses context-free working and episodic memory, metamemory, semantic judgment, and context-rich episodic memory, was used to objectively identify CI. We used correspondence analysis to optimally scale the item responses of the context free memory sub-tasks. These optimally scaled sub-task scores were summarized by 5-year age groups (except for 90-110 year-olds) and by gender (Figures 2-4). To examine gender-specific, nonlinear effects of aging upon context-free memory, we performed polynomial regression of the Memory Performance Index (MPI: an optimally scaled summary measure of serial position and retrieval effects of the immediate and delayed free recall trials) vs. age, by gender, before and after removing outliers (Figures 5, 6). We used the minimum covariance determinant estimator (MCD) plus age-specific prevalence to remove outliers in each age-gender group. The gender-specific, optimally scaled scores showed that, from 30 to 110 years old, females performed better than males on all context-free memory sub-tasks. The MCD outlier method created an approximately normally distributed sample for all age-gender groups except for females from 90 to 99 years old. Polynomial regression of MPI vs. age showed that the 95% confidence bands of MPI vs. age were extremely narrow for both males and females from 15 to 85 years old, widened slightly from 85 to about 93 years old, then markedly increased from 93+ to 110 years old. Interestingly, mean MPI score increased from about 93 to 110 years old. By 30 years old, females have better memory than males for all context-free memory sub-processes. This finding suggests a fundamental, gender-specific change in memory performance favoring females after 30 years old. After 93 years old, mean context-free memory increases but its variability also increases markedly.