The scientific controversy over social priming - the (claimed) ability of incidental exposure to stimuli to 'prime' or evoke complex behaviors - has been rumbling for the past few years. Will it ever end? In this post I'll propose one way in which I think it could be resolved. 'Social priming' is a fascinating concept. A paradigmatic example of a social priming effect is the claim that solving word puzzles involving words such as 'old' and 'elderly' makes people walk slower, presumably because these words 'prime' the concept of old age, which stereotypically means slow movement.
Social priming has been around for over 20 years. The current controversy dates back a few years; the rise of social priming doubts began, I think, in 2012, a year in which a group of researchers could not replicate the old people-slow walking effect, leading to some acrimonious blog posts by John Bargh, who had originally reported that effect in 1996. 2012 was also the year in which Diederik Stapel was found to have committed academic fraud on a massive scale, many of the studies that he fabricated involved social priming. Social priming is not the only area of psychology involved in the 'replication crisis', but it's fair to say that this is where it has been most acute. And yet, as far as I can see, this debate has not achieved much. The battle-lines are well defined and I don't see many people who have changed their minds in either direction. Each new study is embraced by people who already agree with its conclusions, and written off by those who disagree. At times the debate has led to heated personal attacks. Is there a better way? I think there is. Rather than a tug-of-war in which believers and skeptics are pulling from different sides, someone should organize a collaborative team, involving leading representatives of both parties: an adversarial collaboration. This alliance should then aim to carry out the largest ever study of social priming effects, with the goal of a definitive answer, one way or the other. The proponents would be asked to select a handful of social priming effects that they consider the most likely to replicate. They would also be asked to name (within reason) the methodological parameters that they consider important to success. The skeptics would participate in these discussions, and then everyone would decide upon the protocol. All of the methods and data analysis plans would then be publicly preregistered, to prevent p-hacking by either side. The actual data collection would then be done jointly by the believers and skeptics (perhaps spread over multiple labs). All data would be sent to a central repository. Any unforeseen problems arising would be resolved by a joint decision of both sides. Finally, once all of the data was collected, the results would be made public and analyzed in accordance with the agreed-upon plan. Before embarking on data collection for the study, all of the researchers would be asked to state that they have confidence that the planned study is scientifically valid, and that it will be a fair and genuine test of the social priming hypothesis. In this way, the involved researchers would be committing themselves to accept, or at least not lightly reject, the results that they would be about to help collect. Perhaps this statement of intent would be the most important part of the project, because it would make it more difficult for the 'losing' side to write off the study as poorly designed. This is also why it's important that both believers and skeptics are represented in the planning and execution of the study. The fact that the protocol and data were all posted publicly would also help increase the credibility of the results. As to how one could organize such a thing, that's another question. But it would be a sensible use of resources. Lots of money has been spent, and continues to be spent, funding social priming research; it would be a waste if the whole line of research just petered out eventually without any truly convincing results ever emerging. Whether or not social priming exists is a very interesting question. No amount of small experiments will provide a definitive answer: there have been hundreds already, and look where we are. A large, carefully controlled, and collaborative study is needed.