Research in Progress
My research involves utilizing theoretical insights from the evolutionary sciences and methodology from psychology, neuroscience, endocrinology, immunology, behavioral ecology, and related fields, to untangle complex, often bidirectional relationships between human biology and behavior. I am interested in exploring these relationships at multiple levels of biological organization, from the population level, to the individual level, all the way down to the cellular level. Currently, I am working on projects covering sex differences in immune function, relationships between disgust and inflammation, as well as the impact of pre-existing conditions and other factors on individuals’ behavior and psychological health during the COVID-19 pandemic.
PhD in Experimental Psychology, Texas Christian University
BA in Psychology, University of Nebraska-Omaha
Mengelkoch, S., Gassen, J., Corrigan, E. K., & Hill, S. E. (2022). Exploring the links between personality and immune function. Personality and Individual Differences, 184, 111179.
Gassen, J., Nowak, T. J., Henderson, A. D., Weaver, S. P., Baker, E. J., & Muehlenbein, M. P. (2021). Unrealistic Optimism and Risk for COVID-19 Disease. Frontiers in Psychology, 12.
Muehlenbein, M. P., Dore, K. M., Gassen, J., Nguyen, V., Jolley, O. G., & Gallagher, C. (2021). Travel medicine meets conservation medicine in St. Kitts: Disinhibition, cognitive‐affective inconsistency, and disease risk among vacationers around green monkeys (Chlorocebus sabaeus). American Journal of Primatology, e23301.
Gassen, J., White, J. D., Peterman, J. L., Mengelkoch, S., Leyva, R. P. P., Prokosch, M. L., ... & Hill, S. E. (2021). Sex differences in the impact of childhood socioeconomic status on immune function. Scientific Reports, 11(1), 1-10.
White, J. D., Arefin, T. M., Pugliese, A., Lee, C. H., Gassen, J., Zhang, J., & Kaffman, A. (2020). Early life stress causes sex-specific changes in adult fronto-limbic connectivity that differentially drive learning. eLife, 9, e58301.
Leyva, R. P. P., Mengelkoch, S., Gassen, J., Ellis, B. J., Russell, E. M., & Hill, S. E. (2020). Low socioeconomic status and eating in the absence of hunger in children aged 3–14. Appetite, 154, 104755.
Gassen, J., Mengelkoch, S., Bradshaw, H. K., & Hill, S. E. (2020). Does the Punishment Fit the Crime (and Immune System)? A Potential Role for the Immune System in Regulating Punishment Sensitivity. Frontiers in Psychology, 11:1263. doi: 10.3389/fpsyg.2020.01263.
Gassen, J., Proffitt Leyva, R. P., Mengelkoch, S., White, J. D., Peterman, J. L., Prokosch, M. L., ... & Hill, S. E. (2019). Day length predicts investment in human immune function: Shorter days yield greater investment. Psychoneuroendocrinology, 107, 141-147.
Gassen, J., Prokosch, M. L., Eimerbrink, M. J., Proffitt Leyva, R. P., White, J. D., ... & Hill, S. E. (2019). Inflammation predicts decision-making characterized by impulsivity, present focus, and an inability to delay gratification. Scientific Reports, 9:4928. doi: https://doi.org/10.1038/s41598-019-41437-1.
Gassen, J., & Hill, S. E. (2019). Why the activities of the immune system matter for social and personality psychology (and not only for those who study health). Social and Personality Psychology Compass, 13(6). doi: https://doi.org/10.1111/spc3.12471.
Gassen, J., Makhanova, A., Maner, J. K., Plant, E. A., Eckel, L. A., ...& Hill, S. E. (2019). Experimentally-induced inflammation predicts present focus. Adaptive Human Behavior and Physiology, 1-16. doi: https://doi.org/10.1007/s40750-019-00110-7.
Gassen, J., Prokosch, M. L., Makhanova, A., Eimerbrink, M. J., White, J. D., Proffitt Leyva, R. P., ... & Hill, S.E. (2018). Behavioral immune system activity predicts downregulation of chronic basal inflammation. PLoS ONE, 13(9), e0203961
Gassen, J., Bradshaw, H. K., & Hill, S. E. (2018). Mating effort predicts human menstrual cycle frequency. Evolutionary Psychology, 16(4), 1474704918812124. doi: 10.1177/1474704918812124.
Prokosch, M. L., Gassen, J., Ackerman, J. M., & Hill, S. E. (2019). Caution in the time of cholera: Pathogen threats decrease risk tolerance. Evolutionary Behavioral Sciences, 13(4), 311–334.
Gassen, J., Bradshaw, H. K., Proffitt Leyva, R. P., & Hill, S. E. (2017). Predictability or controllability: Which matters more for the BCD (Commentary on Pepper & Nettle)? Behavioral and Brain Sciences, 40. doi:10.1017/S0140525X1700098X.