Understanding how shared expectations can shape reality: an examination of the underlying mechanisms in the accumulation of perceptual bias effects

摘要

This research examined the underlying mechanisms in the accumulation of perceptual bias effects within the context of a criminal investigation. Biased assimilation processes, including the tendency to seek, interpret, and remember information in a manner consistent with one\u27s expectation, and perceived consensus were proposed as potential mediators of accumulation. Two experiments tested this proposition by manipulating perceivers\u27 expectations about a fabricated target\u27s guilt and their interaction with another person. Results from Experiment 1 indicated that perceptual bias effects accumulated across those perceivers who reported having similar beliefs with another person\u27s written statement. These perceivers reported more extreme beliefs about the suspect\u27s guilt in a direction consistent with their initial expectation than those who either did not perceive consensus with another person\u27s written statement or who were not exposed to information from another person. There was no evidence to indicate biased seeking tendencies mediated this effect; however, there was support for biased interpretation and some support for biased recall tendencies as mediators of accumulation. In contrast to Experiment 1, the results from Experiment 2 indicated that perceptual bias effects were not accumulating across perceivers. Perceivers who worked in pairs did not report more extreme beliefs about the suspect\u27s guilt than those who worked alone. Although perceivers\u27 sought, interpreted, and remembered information in a manner consistent with their expectations, they did not do so to a greater extent when working with someone who shared their beliefs about the suspect\u27s guilt than when working alone. In addition, the majority of perceivers perceived consensus even in situations in which they worked with someone who was given a dissimilar expectation about the suspect\u27s guilt. The inconsistent findings across the two experiments are discussed in regards to differences in methodology. The findings are also discussed in regards to their implications for understanding how and when expectations can shape social reality and for understanding factors that may contribute to errors within the criminal justice system.