To identify digital biomarkers associated with cognitive function, we analyzed human-computer interaction from 7 days of smartphone use in 27 subjects (ages 18-34) who received a gold standard neuropsychological assessment. For several neuropsychological constructs (working memory, memory, executive function, language, and intelligence), we found a family of digital biomarkers that predicted test scores with high correlations ( < 10). These preliminary results suggest that passive measures from smartphone use could be a continuous ecological surrogate for laboratory-based neuropsychological assessment.