Hartley has been interested in how experiences guide decision making and behaviors for as long as she can remember. In her high school AP Psychology class, she read a book by
Oliver Sacks and this was one pivotal moment in her decision to pursue a career in academic psychology. During her undergrad, she joined the lab of
John Gabrieli and worked under the mentorship of a graduate student in the lab, Noam Sobel. She conducted her undergraduate research in
Cognitive Neuroscience and became a co-author on three publications exploring human olfaction. Her work helped elucidate that the anterior
cerebellum plays a role in regulating sniff volume in relation to odour concentration and that the human brain is activated by odourants at undetectably low concentrations. After graduating from Stanford in 1999 with a Bachelors of Science, Hartley decided to pursue work in industry as a software engineer at a small artificial intelligence startup in New York City. Hartley later used this training in AI where she learned to think about the basic ingredients of intelligence, in her own independent research program. She worked under the mentorship of
Elizabeth A. Phelps studying Individual differences in the expression and control of conditioned fear. She found that the thickness of the ventromedial prefrontal cortex was correlated with fear-related arousal and that increased thickness of the posterior insula was correlated with larger conditioned responses during fear acquisition. Her article in the Proceedings of the
National Academy of Sciences showed that specific risk alleles in the human
serotonin transporter are associated with spontaneous fear recovery after extinction and heightened depression and anxiety. She worked under the mentorship of
B.J. Casey. She found that when stressors were controllable, fear extinction was improved and spontaneous recovery of fear associations was limited. Along with several collaborators, Hartley explored when anxiety-related treatments might be most effective throughout development. They found that lack of
synaptic plasticity in the prefrontal cortex in adolescent mice was associated with blunted fear extinction. == Career and research ==