Tuesday, April 23, 2013

Social Priming: In Theory


You are walking into a room. There is a man sitting behind a table. You sit down across from him. The man sits higher than you, which makes you feel relatively powerless. But he gives you a mug of hot coffee. The warm mug makes you like the man a little more. You warm to him so to speak. He asks you about your relationship with your significant other. You lean on the table. It is wobbly, so you say that your relationship is very stable. You take a sip from the coffee. It is bitter. Now you think the man is a jerk for having asked you about your personal life. Then the man hands you the test. It is attached to a heavy clipboard, which makes you think the test is important. You’re probably not going to do well, because the cover sheet is red. But wait—what a relief!—on the first page is a picture of Einstein! Now you are going to ace the test. If only there wasn’t that lingering smell of the cleaning fluid that was used to sanitize the room. It makes you want to clean the crumbs, which must have been left by a previous test-taker, from the tabletop. You need to focus. Fortunately, there is a ray of sunlight coming through the window. It leaves a bright spot on the floor. At last you can concentrate on the test. The final question of the test asks you to form a sentence that includes the words gray, Florida, bingo, and pension. You leave the room, walking slowly…

These are just some findings that have been reported in the literature (well, most of them are; I made one up, guess which one) on social priming. But I don’t want to focus on the findings themselves in this post. What I want to do is find out what the theory behind them is. The picture suggested by social priming research is that we are constantly bombarded with a cacophony of cues in all sensory domains that push our behavior around in various ways. This cannot be true.

In a 2006 paper, John Bargh, by all accounts the major player in the area of social priming, arrived at very much the same conclusion. What have we been priming all these years?, he asks. To address the cacophony problem, Bargh suggests that all cues are not created equal. Cues related to goals trump other cues. For example (this is my example, not his), you may be walking slowly out of the room after having just formed a sentence that includes gray, Florida, bingo, and pension but as soon as someone yells FIRE!, you are bound to make a dash for the nearest exit. Your self-preservation goal has trumped whatever priming you may have received from the sentence-unscrambling task.

This makes sense. Bargh also provides a useful overview of the history of priming. Although priming is a concept from cognitive psychology, Bargh is right in criticizing classical cognitive science in its treatment of priming. Classical cognitive science has mostly been interested in priming words. For example, you recognize the word doctor faster after having just seen nurse than after having just seen bread.  Although this has provided useful insights into the organization of memory, inference generation, false memories, speech errors, and so on, there is no clear behavioral component. The behavior on the subject’s part is limited to pressing a button. Bargh does not think this counts as real behavior. And who can blame him? His goal is to examine how priming affects not just thinking but also action, a goal that has also been adopted in contemporary cognitive psychology and cognitive neuroscience.

Bargh observes another difference between classical cognitive psychology and social cognition. The classical priming experiment examines words as primes and as targets (the recognition of a word is often the dependent measure). In social cognition complex conceptual structures are primed that have action components associated with them. Whereas a classical priming experiment may want to investigate whether gray primes old, a social priming experiment wants to know whether priming with gray and old will influence the speed of subsequent action. Despite its strong points, the Bargh article is rather low on specifics regarding the mechanisms of priming and the representations that are involved.

Enter a recent Psychological Review paper by Stroeber and Thagard. They provide a computational model of social priming. A key concept in their model is constraint satisfaction. To illustrate this, let me introduce you to your long-lost cousin Lars from Sweden. He used to live on a small island in the middle of a lake that is frozen over much of the year. His close relatives live in villages all around the lake. Did I tell you he died? How sad, you just learned you had a lost relative and now you find out he’s already dead. Among Lars’ possessions was a very expensive grand piano, which is coveted by all of his relatives. They’ve put the piano on the ice and are now each trying to push the valuable musical instrument to their side of the lake. Bj√∂rn and Bennie are very interested in the piano but being musicians, they are not very strong and they cannot get the piano to move in their preferred direction (if only they had Agneta and Frida to help them!). Their cousin Knut is a hockey player and is pushing the piano in a different direction. Other relatives are pushing in yet other directions. Which way will the piano go? It is basically the sum of all the force vectors. Because people will not be able to apply constant force, the piano’s path will not be a straight line—until the weakest relatives get tired. And then, slowly but surely, the piano will move in the direction of Knut’s log cabin.

That’s how constraint satisfaction works. Each relative constrains the path of the piano just like each cue constrains the course of action. Some cues will be stronger than others. And some cues will have longer-lasting effects than others. The system handles the cacophony of cues through constraint satisfaction. Sometimes a cue is so strong that it wins out immediately over all the others, as in the case when someone yells FIRE!. The cousin-Lars-analogy of this would be if someone donned an Iron Man suit and then started pushing the piano. The others might as well give up right away.

In line with Bargh’s notion of priming, the model assumes that primed concepts activate holistic representations of situations, which have psychological, cultural, and biological components. These layers mutually constrain each other. The way in which they do this is acquired during socialization. Because concepts have affective meanings, they can generate responses automatically. Affective meanings are organized in culturally-shared structures (meaning that responses will be similar across individuals). Members of a culture will try to maintain these structures, which produces a set of constraints.

So how does this cause behavior? Priming activates neural populations that act as “semantic pointers” to underlying sensorimotor and emotional representations. This is the biological component of the model. The idea is very much in the vein of Damasio’s convergence zones.

So the model is an account of how a simple prime in one modality may give rise to a range of responses, some purely cognitive, some emotional, and some behavioral.

I realize that I’m not doing the model much justice in this brief description but my point is that it apparently is possible to come up with a plausible model of social priming that is relatively detailed in parts and is consistent with current models of memory and action.


It is of course ironic that the model has been developed to explain findings that have proven so difficult to replicate and have raised so much controversy. Nevertheless, the model provides an interesting and rather detailed account of how social priming works in theory. Now it would be interesting to see if it can generate novel predictions that can be tested in rigorous experiments.

12 comments:

  1. You've made me curious to read the new psych review paper. I got a chance to talk to Thagard several times a few years ago while I was doing a post-doc at Waterloo, he's a really interesting guy and I think constraint satisfaction is a very useful way of looking at a lot of social reasoning. (Thagard and I wrote a short chapter together that's coming out soon on how constraint satisfaction can help explain both paranoia and irrational exuberance though self-reinforcing feedback loops.)

    I think one thing that I'd add on priming, which makes your introductory paragraph sound so absurd (intentionally, obviously), is that it seems to me that priming only makes much difference when whatever is being primed is relevant to the person at the time.

    For example (assuming all these examples are true, for the moment), if I smell cleaning fluid, it might make me a little more likely to clean up crumbs if there are some in front of me, but I wouldn't go looking for them in another room. If my chair is wobbly, I won't spontaneously attribute that to my relationship (which one even?) -- but if I'm specifically asked, and I try to retrieve my feelings about it, only then will the wobbliness potential come into the equation. This is one reason why we're not constantly overwhelmed by primes pushing us in a thousand different directions.

    One thing that seems important to me to separate in the priming literature may be an artifact of the current scientific culture. Namely, I think that the difficult-to-replicate priming effects are the ones that are purposely surprising and difficult to find. (This also means that they are, given the current state of the science, more vulnerable to false positives.)

    I feel quite confident that we are strongly primed all the time, but by very strong primes. However, these strong primes are often confounded with other things (for example, if I smell french fries and 10 minutes later I want to go to McDonalds, it could be because I explicitly made the decision to go).

    But more importantly, they are also not as interesting and therefore less likely to get publish or generate attention. And so the publications that we see are these carefully designed minimal primes -- I don't think that means that behavioral priming itself is hard to find. If the man sitting across the table from you reminds you of your best friend growing up, you're probably more likely to comply with his requests than if he reminds you of someone you don't like. The warm cup of coffee in your hand may help too, but it has a much more challenging path.

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    1. Excellent comment. I agree 100%. It anticipates my next post.

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  2. Recommend you read Loersch & Payne's model: Loersch, C., & Payne, B.K. (2011). The situated inference model: An integrative account of the effects of primes on perception, behavior, and motivation. Perspectives on Psychological Science, 6, 234-252.

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    1. Thanks for the tip. I discuss this article in my next post.

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  4. Since I'm autistic, I'm hyper-alert to all the sensory cues you mention. It seems to me that most autistic people live a bimodal existence; either easily distracted/flustered by an overload of sensory input, or totally focused on the task at hand, completely excluding all extraneous inputs. I'd be interested to know (assuming you are able to construct the tests you mention) if the results would be markedly different for neuroexceptional people (including not just autism but also related profiles like bipolar, schizophrenia, and dyslexia).

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  5. Always think there might be big individual difference in social priming (among normal people as well), if there is a thing called social priming anyway.

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  6. Autism is normal, just not typical. Of course there are large individual variations in just about everything. In doing controlled studies, the question is always whether there are differences in the means of the distributions of whatever is being measured.

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  7. Great post. Wouldn't the constraints model predict precisely that priming effects be difficult to replicate? If primes represent the culturally learned affective component of concept all pushing among one another than they should be highly subject to individual and cultural differences. Precisely at what level of specificity is an interesting question. Will white college students prime differently than black urban workers? Will Danes prime differently from Swedes? At some level what we are talking about here is the relationship between learning and conscious perception; should we be surprised that some labs can find big effects here and others can't? Small shifts in experimenter-experimentee relations, cultural setting, etc would all have a huge impact on the actual effect if the constraints model is correct.

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    1. Good points. To my mind, the strongest constraint would still be the subjects' knowledge and experience regarding the task at hand. These may or may not be nudged a little bit by social primes (at least of the type we're talking about here. See my next post for a discussion of stronger primes). Let's suppose for a moment the walking-speed finding is true. Then I would think that people would walk out of the lab slightly slower than at their usual speed. I'd expect normal walking speed to predict far more of the variance than priming condition.

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    2. I think one of the reasons priming effects are so difficult to replicate is that such priming effects involve something like a conspiracy of the weak: Multiple sources of weak constraints conspire to eventually produce a detectable effect, but each constraint in and of itself is so weak that it fails to register. That would also account for the observed variability in obtaining such effects.

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    3. "Conspiracy of the weak" is a nice way to put it. All the more surprising that some studies report strong effects.

      In my next post, I make the point that much stronger primes may be needed.

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