As a social cognitive psychologist, I am interested in how people act towards individuals from different social groups, as defined by things like race, gender, and attractiveness. My research focuses on social questions like “Does the race of a suspect influence an officer’s decision to use lethal force?” and “Are attractive but unqualified job candidates more likely to be hired than unattractive but qualified candidates?” To answer these questions, I analyze behavior across multiple areas (social, cognitive) with multiple methods (experimental studies, secondary data analysis, and computational modeling).
I am also concerned with increasing the reproducibility of psychological science. This concern manifests in my own research, as well as my work on meta-science and replication. Read below for a description of my ongoing research projects.
Police Use of Force
Recent shootings of unarmed Black men have raised questions about police use of lethal force. Why do officers and civilians mistakenly shoot unarmed people, and what roles do civilian race, officer expertise, and prior information play in this decision?
I answer these questions using several different methods, including secondary data analysis of actual police shootings and simulated shooting tasks in the laboratory. In the former approach, I compile information about police shootings of civilians from police departments, independent databases, and news reports. I have used this research to test for racial disparities in different types of fatal shootings.
In my lab approach to studying use of force, police and civilians see immersive videos of people carrying weapons or not and must make decisions about whether to shoot or not using a modified Glock handgun. I have used this approach to show how police expertise and dispatch information reduce racial bias the decision to shoot.
Process Modeling
Cognitive models provide a framework for formally testing process-level accounts of behavior, especially when competing accounts predict the same behavior but for different reasons. My research often studies psychological processes using the drift diffusion model (DDM; see below). This model describes decisions as a process where people may start with a prior bias (β) to favor an option (e.g., to shoot or not shoot, to hire or not hire). They then repeatedly sample information from the environment (δ) until they meet a threshold (α), triggering a decision. The DDM quantifies these parts of the decision process, and I have used it to test how they are influenced by factors like race and attractiveness.
The drift diffusion model.
As one example, laboratory tasks of shooting decisions show civilians are more likely to shoot unarmed Black men than unarmed White men. But how does race impact the decision process? Perhaps people are biased to shoot Black men whether they are armed or not (a prior bias). Or perhaps objects seem more dangerous when held by Black than White men (an information bias). DDM analyses revealed officers showed a prior bias to shoot Black men, rather than race biasing the decision as information was collected.
This approach is also instrumental in developing tailored interventions to reduce biases. In one ongoing project, I used the DDM to identify how attractiveness impacts hiring decisions. The model revealed the preference for attractive candidates was due to people showing both a prior bias to favor attractive candidates, and treating candidates’ looks as relevant information. I used this data to test two interventions that eliminated each source of bias (showing candidate faces after their qualifications, and making participants aware of their biases, respectively).
I have also used cognitive modeling to study attraction within the dating app “Tinder.” In this app, people see pictures of others and decide if they want to talk to them. Men are faster and more likely to “swipe right” on female users (i.e., agree to talk to them). The DDM reveals this is not because men show a prior bias to simply swipe right more than women, but because men find female users more compelling than women find male users. I am currently using the DDM to disentangle why knowing that a user likes you increases the chances of swiping right on them. Is it because people simply like those that like them or does it give the user rose-tinted glasses, making the person actually seem more attractive?
Meta-Science
I am committed to increasing research standards and reproducibility in psychological science. Materials and data from all my work may be found here. I have also contributed to several large-scale projects on reproducibility, including the Reproducibility Project and Many Labs 3. In addition, I have also contributed to the discipline by conducting high-powered replications of embodiment research. This work has focused on the role of physical states on cleanliness and physical posture on power.
Recent embodiment work has proposed that states like cleanliness might unintentionally influence moral judgments. However, there is debate about whether these states exacerbate or attenuate the severity of moral judgments. To test these accounts, I have conducted direct replications and extensions (i.e., tests of moderators) of well-cited studies in this area. My work demonstrates that these effects are small at best and have generated considerable discussion about how to interpret replication studies and psychological evidence.
Top: “Powerless” poses; Bottom: “Powerful” poses
Work on expansive “power” poses (see images above) has captured much public attention because of their potential real-world benefits for achieving desired goals. However, this work suffers from a critical issue: in studies individuals are not made aware of the true function of the power pose, whereas in the real world they must know the function of the pose in order to deliberately use it. My colleagues and I tested the role of awareness in a direct replication of the seminal power pose study for a special issue on power poses. Our results did not support the premise that power poses have behavioral benefits and point to a need to refine existing theories on power poses.
David J. Johnson 