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Ryan Ditchfield, Ph.D.

Assistant Professor

Office Phone Email
S2 149 559.278.2812

Biographical Sketch

Navigating the criminal justice system requires people to make difficult decisions. Eyewitnesses must decide whether a presented suspect is the perpetrator or not, suspects must decide how to respond in police interviews, and police officers must decide how to interact with eyewitnesses, suspects, and other actors in the justice system. When these decisions are wrong, there can be serious consequences: misidentifications, false confessions, wrongful convictions, and loss of public trust in the justice system. 

As a legal psychologist and Assistant Professor in the Department of Criminology at Fresno State, Dr. Ditchfield investigates how individuals in the criminal justice system (e.g., eyewitnesses, criminal suspects, and police officers) make hard choices in high-stakes situations where those choices appear to have real consequences. By investigating decision making in a controlled, experimental environment, Dr. Ditchfield’s work provides insight into the psychological mechanisms that cause legal decision making errors. 

Dr. Ditchfield graduated from Fresno State in 2016 with degrees in Criminology and Political Science, and earned his masters and doctorate at Iowa State University in Social Psychology. He is also a member of the American Psychological Association and the American Psychology-Law Society. 


Ph.D., Social Psychology, Iowa State University, Ames, IA

M.S., Social Psychology, Iowa State University, Ames, IA

B.S., Criminology: Forensic Behavioral Science, California State University, Fresno, CA

B.A., Political Science, California State University, Fresno, CA


Smith, A. M., Smalarz, L., Ditchfield, R. E., & Ayala, N. T. (2021). Evaluating the claim that high confidence implies high accuracy in eyewitness identification. In press, Psychology, Public Policy and Law.


Ditchfield, R. E., Guyll, M., Madon, S., & Muñoz, J. E. (2021). Consequence activation affects eyewitness decision making bias. Under review, Behavioral Sciences and the Law.


Vallano, J., Guyll, M., Ditchfield, R. E., & Slapinski, K. (2021). An experimental examination of rapport and minimization within a criminal interview. Under review, Psychology, Public Policy and Law. 


Madon, S., More, C., & Ditchfield, R. E. (2019). Interrogations and confessions. In N. Brewer, & A. Douglass (Ed.), Improving the criminal justice system: Perspective from psychological science. Guilford Press.