In 2017, at a Nato summit meeting, then-US president Donald Trump and still-president Emmanuel Macron of France “enjoyed” a protracted handshake. You can watch it on YouTube. Is there a bit of arm twisting? Some white knuckles?
Both presidents were asked about it later. “He loves holding my hand,” said Trump. Macron disclosed that the whole thing was intentional, “to show that we won’t make small concessions, even symbolic ones”. Leaders the world over were reportedly practising for their turn.
It all sounds a little alpha male to me. How did they manage during Covid? You can’t do that stuff over Zoom.
Some 20 years ago, William Chaplin and colleagues at the University of Alabama published a delightful study looking at the first impressions we get from a handshake and, importantly, whether there’s any truth to those first impressions.
If you want to replicate this research, the first thing you need to do is train up four research assistants to consistently rate a handshake on theoretically important dimensions such as vigour, eye contact, texture and dryness (really) and, of course, strength. Next, you invite prospective participants to take part in a study that’ll involve four separate personality questionnaires. In they come to the testing room and in comes Assistant One. Hello, handshake and pleased to meet you, here’s your survey, then a thanks and a parting handshake. In comes Assistant Two, handshake and repeat.
At the end, you have one participant who has shaken hands twice with each of the four assistants for a total of eight handshakes frantically scored for strength, dryness etc. Chaplin and co reported that ratings for duration, eye contact, grip (from incomplete to full), strength and vigour hang together to make a firmness index.
People who displayed a firmer grip were generally perceived more positively by the raters as being more extroverted, agreeable, open, conscientious and emotionally stable. And at least some of these appear to be the case when we look at handshakers’ personality. Firm handshakes go with greater extroversion, openness and emotional stability.
As I’ve written previously, grip strength is also an indicator of physical health and is associated with better psychological wellbeing (because it’s associated with physical health). Recent research suggests there may be dynamic cognitive benefits to squeezing things as well.
Cue Shelby Bachman, Sumedha Attanti, and Mara Mather from the University of Southern California. “Come into our lab,” they say, “we’re going to test your working memory.” Working memory is a short-term memory store for holding temporarily important things.
Everyone sits down for a series of working memory tests alternating with a control or “grip protocol” task. Between memory tasks, all participants are told “right” and “left” and have to either turn the relevant hand (boring control condition) or squeeze a ball for 18 seconds with the target hand (exciting experimental condition), each followed by a 30-second pause before the next test.
Sure enough, the hand-squeezers outperform the hand-turners – they weren’t any more accurate at the working memory task, but were significantly faster.
But why? Essentially, we think more quickly when we’re experiencing physiological arousal that isn’t so arousing as to be stressful. This makes sense in evolutionary adaptive terms – faster thinking for things like how to get out of a heart-pumping situation.
In fact, Shelby reports the 18-second squeeze is the Goldilocks spot in pilot tests, increasing arousal as measured by salivary alpha-amylase more effectively than a three-minute squeeze. Salivary amylase is an enzyme we produce to help process our food and, yes, participants don’t just get to squeeze a ball but they also spit into a vial. When our nervous systems are a bit more excited, we produce more of this enzyme.
As interesting as I think this is, I haven’t addressed the most pressing issue: how small are Donald Trump’s hands?
