“Oh yeah, that’s right!” — investigating social memory

Much has been written about how strongly we are influenced by the opinions of others, especially when we find ourselves on the minority end of an idea — or a memory.

The July 1 issue of Science published “Following the Crowd: Brain Substrates of Long-Term Memory Conformity,” a study of social influence on memory by Micah Edelson et al.

In line with several other investigations reviewed here recently, “Following the Crowd” combines an experimental observation with empirical data of brain activity. As I’ve written before, this is the kind of social psychology research that I find most convincing, since it relies more heavily on physical measurement than do those studies which manage merely to attempt an explanation of observed behaviours.

As the authors note, while the influence of social pressure on memory is well known, with many instances of subjects who abandon true memories in favour of false ones, “the underlying neurobiology of this process is unknown.”

The authors distinguish “private conformity,” in which an individual’s sincere memory undergoes long-term changes, from “public conformity,” in which an individual “goes along” with the crowd in the short term, without altering what he or she really believes. While these two memory events may be indistinguishable behaviourally, the current study demonstrates that “they reflect different cognitive processes.”

In the study, target participants who had previously correctly recalled the details of a video which they had viewed with four others were shown the fabricated “false” answers of the four others with whom they had viewed the video and were retested on their recall. Still later, target subjects were told that their co-viewers’ answers had been generated randomly. The subjects were then tested one more time.

This testing and retesting process was further clarified through a variety of control and elimination procedures (the details are in the original article but aren’t reported here) to maximize confidence that only data relevant to the investigative target was included.

Using fMRI scans, the study showed that brain regions associated with memory and social cognition demonstrated “a particular brain signature of enhanced amygdala activity and enhanced amygdala-hippocampus  connectivity [that] predicted long-lasting but not temporary memory alterations.” In other words, this active brain signature was present when private conformity was occurring, but not when merely public conformity prevailed.

As in the fairness study reported here recently, the amygdala plays a central role in social influence on memory:

The amygdala plays a key role in social and  emotional processing and modulates memory related  hippocampal activity. It is strategically  placed for this function, having rich  anatomical connections with the hippocampal  complex (the anterior hippocampus in particular)  as well as with neocortical areas.  The amygdala is thus a prime candidate for  mediating social effects on memory, most likely  involving its interactions with other brain regions.

In their conclusion, the researchers caution: “Altering memory in response to group influence  may produce untoward effects. For example, social influence such as false propaganda can deleteriously affect individuals’ memory in political campaigns and commercial advertising and impede justice by influencing eyewitness  testimony.”

However, they speculate that “memory  conformity may also serve an adaptive purpose,  because social learning is often more efficient  and accurate than individual learning. For  this reason, humans may be predisposed to trust  the judgment of the group, even when it stands  in opposition to their own original beliefs.”

It’s worth noting that the “what” and the “how” can be described with considerable confidence, thanks to the empirical nature of the study. The “why,” however, remains tentative and speculative.

Relatedly, the researchers point out several times in their article that purely observational study cannot distinguish effectively between momentary social conformity and actual, persistent memory changes. In either case, the subjects’ overt behaviour is observationally identical.

Of course, this limitation is not restricted to the study immediately at hand. It’s a general limitation of observation, interview, and self-reporting methodologies. It’s precisely for this reason that an empirical approach, involving neurobiology in the investigations of cognitive psychology, holds the key to real understanding.

If this view is considered “reductionism,” then so be it. Without a kind of reductionism, there’s no science. What else is the scientific method but the practice of a systematic and necessary brand of reductionism?

This isn’t an ontological reductionism, note, but a methodological one. Without the methodological reductionism in the scientific method, there’s no science.

I’m feeling rather frisky today, even feisty, so I’ll end with an even balder statement:

… And without science, there’s no knowledge.

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