Deception about study purpose does not affect participant behavior

The use of deception in research is divisive along disciplinary lines. Whereas psychologists argue that deception may be necessary to obtain unbiased measures, economists hold that deception can generate suspicion of researchers, invalidating measures and ‘poisoning’ the participant pool for others. However, experimental studies on the effects of deception, notably false-purpose deception—the most common form of experimental deception—are scarce. Challenges with participant attrition and avoiding confounds with a form of deception in which two related studies are presented as unrelated likely explain this scarcity. Here, we avoid these issues, testing within an experiment to what extent false-purpose deception affects honesty. We deploy two commonly used incentivized measures of honesty and unethical behavior: coin-flip and die-roll tasks. Across two pre-registered studies with over 2000 crowdsourced participants, we found that false-purpose deception did not affect honesty in either task, even when we deliberately provoked suspicion of deception. Past experience of deception also had no bearing on honesty. However, incentivized measures of norms indicated that many participants had reservations about researcher use of false-purpose deception in general—often considered the least concerning form of deception. Together, these findings suggest that while false-purpose deception is not fundamentally problematic in the context of measuring honesty, it should only be used as a method of last resort. Our results motivate further experimental research to study the causal effects of other forms of deception, and other potential spillovers.