On SAGE Insight: The importance and prevalence of experimenter effects in the field of psychology

Article title: The Role of Experimenter Belief in Social Priming

From Psychological Science
Association for Psychological Science

Priming, the act of influencing another’s behavior via indirect cues, is a common experimental manipulation in social psychology. In many social psychological priming paradigms, an experimenter asks participants to perform a task that primes, or activates, a particular concept, such as age or social power. Although priming appears to be one way of influencing behavior, the subtle social cues people exchange in face-to-face interactions also have powerful effects. Indeed, the beliefs and stereotypes that people bring to interactions shape both the behaviors they produce and their interaction partners’ responses. In research settings, experimenters’ expectations may have the insidious effect of confounding task results. Indeed, research shows that when experimenters are motivated to find significant effects, they are more likely to do so.

This paper suggests that experimenter effects may play an important role in shaping research findings when experimenters are not double blind to participant condition. Authors show that the mechanism for this effect is that experimenters alter their behaviour depending on what task condition they believe a participant will experience. This paper is a wake-up call for the field of psychology about the importance and prevalence of experimenter effects.


Research suggests that stimuli that prime social concepts can fundamentally alter people’s behavior. However, most researchers who conduct priming studies fail to explicitly report double-blind procedures. Because experimenter expectations may influence participant behavior, we asked whether a short pre-experiment interaction between participants and experimenters would contribute to priming effects when experimenters were not blind to participant condition. An initial double-blind experiment failed to demonstrate the expected effects of a social prime on executive cognition. To determine whether double-blind procedures caused this result, we independently manipulated participants’ exposure to a prime and experimenters’ belief about which prime participants received. Across four experiments, we found that experimenter belief, rather than prime condition, altered participant behavior. Experimenter belief also altered participants’ perceptions of their experimenter, suggesting that differences in experimenter behavior across conditions caused the effect. Findings reinforce double-blind designs as experimental best practice and suggest that people’s prior beliefs have important consequences for shaping behavior with an interaction partner.

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Article details
The Role of Experimenter Belief in Social Priming
Thandiwe S. E. Gilder, Erin A. Heerey
First Published January 29, 2018
DOI: 10.1177/0956797617737128
From Psychological Science

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