Placebos and Evolution: A Theory

A few weeks ago, Nicholas Humphrey, the renowned British psychologist, emailed me with some of his thoughts on placebos and self healing.

Humphrey is one of the few researchers who dare to go beyond the IF and the HOW questions of placebo healing and delve into the WHY. Specifically, if humans are endowed with varied and powerful self-healing resources, why are these effects so conditional and reliable for some while nonexistent for others, and why do we seem to need "permission" from some third party (be it a pill, a doctor, or a sign from the heavens) to trigger our endogenous healing potential?

Over the years, Humphrey has put together a theory about all this -- an evolutionary tale, a story of ancient, cognitive reflexes, protective and essential in our cave days but overly-cautious in the modern world, coaxed with a bit of trickery. Along with the neurologist and evolutionary psychologist John Skoyles, Humphrey wrote a concise version of this theory in the September 2012 issue of Current Biology titled, "The Evolutionary Psychology of Healing: A Human Success Story."

It's a fascinating theory that Humphrey also describes in a podcast interview (his bit starts at 15:14). Before I offer my layman's summary, it's worth noting that Humphrey's family tree includes both the economist John Maynard Keynes and, most pertinent for this post, the physiologist A.V. Hill. It was Hill who first postulated the idea that there must be some kind of protective mechanism a "governor" either incorporated in the heart muscle or in the brain that could regulating fatigue in an exercising body to prevent us from exerting ourselves to death. The idea was largely ignored until the 1990s when the South African exercise physiologist Tim Noakes picked up and expanded on the concept, and began giving this "central governor" more empirical support. Accordingly, the central governor protects us by inducing fatigue, slowing us down, conserving our resources, based on an ongoing, forward-looking analysis of how much gas we have left in the tank and how much farther it is to the finish line.

Humphrey first points out that the benefits of our self-healing mechanisms (our immune systems, our natural wound healing, even our protective pain and our toxin-killing fevers) also have costs in terms of consuming energy and nutrients, and the opportunity costs of a day in bed. He proposes that in our cave days, these costs could loom very large indeed, and that a self-healing "governor" would take them into account and possibly hold the self-healing mechanisms back until the coast was clear, the days were warmer, and resources such as food were easier to come by.

The self-healing governor, though hardwired, could learn things, Humphrey says. It could learn about medicine, for instance, and become more generous and optimistic with healing resources under its spell, both the "directly curative" treatments and the "mumbo-jumbo" of rituals and snake oil. Nevertheless, the governor remained essentially conservative, stuck in evolutionary time, unaware that (at least in the developed world) we lived in a context of abundant resources where day-to-day survival was much less of an iffy proposition.

Enter the placebo -- a bit of a ruse that might have been catastrophic in our hardscrabble history but today is what Humphreys and Skoyles dub, "a dose of contrived optimism" that fits the reality of our world and can, "restore confidence in the wisdom of self-cure."

Voting For A Face

Want an election crystal ball? Take a look at the candidates’ faces. Really? Well, a few years ago, Princeton psychologist Alex Todorov and colleagues, had people glance at hundreds of headshots of rival U.S. congressional and Senate candidates (whom they didn’t recognize) from recent elections. The participants rated how “competent” each candidate looked. Matched with actual election outcomes, the more competent-looking candidate won about 70 percent of the time. Not only that, a face’s “competence” advantage correlated positively with the margin of victory.

By statistically analyzing the measurements of many faces, Todorov and his team isolated what makes faces look more or less competent. Much of it relates to perceived “facial maturity” and attractiveness, but it’s easier to show than tell how this works. Check out this video from the lab’s website in which a face that is neutral in competence morphs to highly competent and then to utterly incompetent before returning to neutral:

Todorov’s findings have been repeatedly replicated, controlling for gender, age, race, incumbency, and a few other possible explanations. The results hold when the subjects are from a different country or a different culture than the candidates. They hold when the subjects are children from one country judging the faces of candidates from another. These are true snap judgments. Their correlation with election results doesn’t fade even when glances are as brief as one tenth of a second.

What’s going on? Our brains seem to have specialized neural circuits devoted to face perception. Researchers suggest that humans have a well-honed and automatic response to faces, one deeply rooted in our evolution, helping us read each other’s intentions and tell friend from foe, a particularly important skill back in our cave days.

Into this basic neural machinery, we feed our various cultural stereotypes, a process that University of Toronto psychologist Nicholas Rule calls, “cultural tuning.”  In one of Rule’s studies, Japanese and American “voters” saw the same traits in the faces of candidates from each other’s countries. Instead of competence, these subjects judged “warmth” (a mix of likeability and trustworthiness) and “power” (a mix of dominance and facial maturity). Despite agreeing on these traits, however, subjects could only predict the election winners among same-culture candidates. Americans tended to choose the more powerful faces while the Japanese favored those with more warmth.

It’s hard to gauge the accuracy of these competence judgments, of course, because a politician’s actual competence is nearly impossible to objectively measure, especially in the context of a campaign. Ideology is a bit easier to verify. Party affiliation and voting records are good clues. Can we tell whether a candidate will govern to the left or right of the political spectrum just by glancing at his or her face? The answer is debated. Importantly, though, many people think they can, and studies find significant agreement (if not necessarily truth) in face-based guesses about ideology.

In a handful of published studies, subjects are usually just a bit better than chance at guessing party affiliation. Exactly what they are seeing is murky. In Finland and Australia, more attractive candidates were judged to be more conservative. In England, subjects judging the faces of MPs inferred Labor from broad, toothy smiles and round faces, and Conservative from tighter smiles and more angular faces.

One study of American voters found them to be a bit better than chance (averaging 57 percent correct) at guessing the party affiliation of unknown politicians, controlling for gender. To control for age differences, researchers had people look at college yearbook photos of students identified as members of the college Republican or Democrat clubs. In this case, they averaged 62 percent correct. The faces judged as Republican tended to convey more “power” to subjects while those faces identified as Democrats correlated with more “warmth.”

According to a study published in September, looking more Republican than your opponent correlated with a significant increase in the candidate’s vote share in Republican-leaning states (and among Republican voters in hypothetical elections) even if the candidate was actually a Democrat! The researchers, led by Christopher Olivola, a former member of Todorov’s lab and now a research fellow at the University of Warwick (UK), expected to find a similar boost on the Democratic side, but they didn’t. As with previous studies, subjects viewing pairs of photographs were slightly better than chance at guessing political affiliation. Nevertheless, Olivola is skeptical that people really have an ability to accurately read political affiliation in faces beyond the obvious cues  (e.g. minorities are more likely Democrats).

By necessity, study participants don’t recognize the politicians they’re judging. In real elections, of course, most people vote along party lines or based on a passion for certain issues. And once they step into the voting booth, most have at least have an inkling about who’s running, and there are no photographs on the ballots (in America at least). This begs the question: Do these biases matter in real elections?

Absent a string of candidates undergoing plastic surgery, the best that researchers can do is isolate correlations. Last year, for instance, MIT political scientists surveyed people who intended to vote in elections contested by candidates whose faces were rated (by others) on their attractiveness and apparent competence. Woven into the survey were questions about TV habits and a sort-of quiz about the federal government and the basics of major issues. They found that uninformed voters (lowest quartile) who also watch a lot of TV (top quartile) seem to be particularly swayed by a candidate’s appearance. Specifically, candidates gained nearly 5 percent of vote share among these folks for every 10 percent increase in how appealing they looked (a mix of competence and attractiveness). How many of these people are leaving the TV long enough to find their way to polling places?

“I have sad news for you,” says Gabriel Lenz, one of the MIT researchers. “It’s probably more common than this survey suggests.” According to the 2008 American National Election Study, for example, 60 percent of eligible voters didn’t know which party controlled the most seats in Congress.

As it happens, researchers have compared Barack Obama and Mitt Romney’s face-based competence.  At the outset of the 2008 presidential primaries, when both men were relative unknowns to people outside the U.S., a group of researchers asked New Zealand high-school students to rate the competence of every politician vying for the nomination. On a ten-point scale of competence, Hillary Clinton ranked highest among the Democrats while Obama came in third (6.8). That outpaced the highest-rated Republican, John McCain (6.2) and Romney (6.1).

Of course, the number of voters who know next to nothing about candidates in an election as high profile as the contest for President of the United States shrinks considerably. Looking the part is likely to matter a lot more in the 435 elections for the House of Representatives and, to a lesser extent, the 33 Senate races that will be decided on November 6. 

“I think that by the time a candidate gets the presidential nomination from one of the major parties, they must have some basic level of competence,” says Todorov. “There is so much vetting. There are so many gatekeepers. People don’t just get there randomly.”

Listen!

Here are two audio snippets of me reading from Mind Over Mind. The first is from chapter 2 "In The Zone" and lasts about 5 minutes. The second is from chapter 4 "Accounting for Taste" and lasts about 4 minutes.

These audio excerpts were ripped from videos created by multimedia wizard Devin Hahn, who is in the process of creating a video trailer for the book. Thanks, Devin!


Hope you enjoy!