Are the subjects of Asch’s experiments conformists?

There is a handful of psychology works that have the burdensome honour of informing our view of human behaviour, usually with spectacular results that tend to satisfy some of our preconceptions on how this behaviour should look like. Two of them, the Stanford prison experiment (showing that stable adults quickly become sadist prison guards, given the right situational cues) and the Milgram experiment (showing that stable adults are willing to obey to an authority, in this case the experimenter, to the point of administering painful electric shocks to unknown confederates of the experimenter), while retaining fascination in the large public, tend to be considered cautiously by scientists, and have been recently criticised in mainstream or quasi-mainstream media (see, for example, here, here, and here).

Another one, the Asch experiment, seems to enjoy better health (but see here). The experiments show that subjects disregard their own information on a simple perceptual task (matching two lines of equal length) to conform to a majority of individuals (again, confederates of the experimenter) that give a clearly wrong answer. I can not resist to quote a website that provides the full text of an article of Asch, which, supposedly:

highlighted the fragility of the person in a mass society when he is confronted with the contrary opinion of a majority, and the tendency to conform even if this means to go against the person’s basic perceptions. This is a chilling text that should be carefully read and remembered whenever we think we are swayed by the mass, against our deepest feelings and convictions.

[Incidentally, it would be interesting to study whether (and why, in case) the idea that we are easily influenceable by others is so culturally attractive. I am not talking about mundane cultural transmission, which is of course important (and it is what I study in my professional life), but to phenomena like, for example, subliminal messages and advertising, and how they captivate people of various educational background, at least in my daily experience.]

Going back to Asch, I found again an unproblematized reference to the experiments in my flight reading of yesterday, topped with a bonus of a recent fMRI experiment showing that the brain area activated during the wrong response of the subjects was linked to spatial awareness, not to conscious decision making (i.e. “subjects were calling it like they saw it” – insert sarcastic face). So here is a post to try to make some clarity.

First, what is conformism?

Unfortunately, in this case, the scientific definition is as precise as the one we use in the common language, that is: not at all. This is a pity, because a quantitative and appropriate (at least for some usages) definition of conformism has been developed in the field of cultural evolution more than thirty years ago. In Culture and the Evolutionary Process, Robert Boyd and Pete Richerson define conformist frequency-dependent bias as requiring “naive individuals be disproportionally likely to acquire the more (or less) common variant” (pag. 206, italics in the original). The critical point here is obviously the “disproportionally” part. Imagine you enter in a Caffè, and, on 10 clients, 7 are drinking wine, and 3 coffee (I just travelled in the south of France). A conformist bias does not simply require that you will be more likely to drink wine, but that your probability to drink wine will be higher than 70%. Why is this important? As Boyd and Richerson note, “almost any time there is cultural transmission” (ibidem) you will be more likely to drink wine. In fact, if you choose absolutely randomly, you will have exactly the 70% of probability of choosing wine (imagine you are blindfolded and touch a client to decide what to order – do not do this in the south of France). So, conformism, if we use this precise definition, is not “do what the majority does”, because for “doing what the majority does” one does not need any bias, but simply copying at random.

When individuals are conformists, one can visualise the relationship between the frequency of a certain behaviour (say the wine drinking in the Caffè) and the probability to perform that behaviour (say to actually order wine) with a sigmoid line (see the red line in the graph above). The dotted black line is unbiased or random copying.

Now we can go back to Asch. In the classic set-up (see the various descriptions in Asch 1955), a subject is supposedly participating in an experiment involving a simple perceptual task. She is shown a card with a line (see figure below, left) and is then asked to match the line of the same length in a second card (see figure below, right). The twist is that there are other seven participants to the experiment and they are, unknowingly to the subject, instructed by the experimenter on how to respond to the test. Because of the way they are positioned in the room, the subject is always the last one to answer and can listen to what the others say. The confederates give the “true” answer for the first two trials, and then they start to give wrong, unanimous, answers for 12 of the 16 remaining trails, on which the subjects’ answers are actually tested.

What are the actual, not so chilling in fact, results? 25% of the subjects never defied to the majority opinion, and kept on, for all trials, to give the “correct” answer, impermeable to any social influence, while 5% of the subjects always gave the answer of the confederates. Over all subjects, and all trials, 36.8% of answers were influenced by the majority opinion.

In a variation of the experiment, interesting from our perspective, Asch replaced a confederate with a “true” participant (or instructed a confederate, this time, to give the correct answer) and found that “subjects answered incorrectly only one fourth as often as under the pressure of a unanimous majority” (Asch 1955), that is, slightly less than one in ten times.

What if we look at these results from the point of view of Boyd and Richerson’s definition of conformism? The plot below uses the same logic of the first one (i.e. plotting the frequency of a behaviour versus the probability of performing it) using the data from Asch’s experiments.

In the classic experiment, where all the seven confederates chose the wrong line, “only” 36.8% of the times subjects did the same, and, when 6 confederates chose the wrong line, only ~10% of the times. The red trend is then dotted as we do not have data, but the only alternative I can imagine is that the probability would drop to zero even sooner. One needs to conclude not only that subjects in the Asch experiment were not conformist, but they were not even particularly socially influenced (remember the dotted black trend represents unbiased, random, copying).

And here a xkcd, just because is the 10th of August.

Update 11.08.2015. Alex Mesoudi pointed me to Efferson et al. 2008, Evolution and Human Behavior (pdf here), see in particular section 3.3. They reach (ehm…7 years before me) similar conclusions, but discuss that “the joint effect of conflicting biases means that we cannot isolate the response to frequency information” and so, if I understand correctly, that we can not claim neither conformity nor absence of it for Asch’s results. This sounds sensible to me, but is there any real empirical data where we actually can isolate the response to frequency information?