ABSTRACT: Rapid actions to persons holding weapons were simulated using desktop virtual reality. Subjects responded to simulated (a) criminals, by pointing the computer's mouse at them and left-clicking (simulated shooting), (b) fellow police officers, by pressing the spacebar (safety signal), and (c) citizens, by inaction. In one of two tasks Black males holding guns were police officers while White
males holding guns were criminals. In the other, Whites with guns were police and Blacks with guns were criminals. In both tasks Blacks or Whites holding harmless objects were citizens. Signal detection analyses revealed two race effects that led to Blacks being incorrectly shot at more than Whites: a perceptual sensitivity effect (when held by Blacks guns were less distinguishable from harmless objects) and a response bias effect (objects held by Blacks were more likely to be treated as guns).