magazine issue 4 2014 / Issue 20

Manipulating the body, measuring the body, and tinkering in the name of Psychology

• written by Thomas Schubert
• edited by Spike Lee

Manipulating thought and measuring the body

What can be done about this? It seems that one way out of this dilemma is to reverse the experiments. Instead of manipulating the body and measuring thought, researchers could manipulate what participants are thinking and feeling, and measure their bodily behaviour. If the mind is truly embodied, the effects should go both ways: Thinking and feeling should influence the body, even if no specific behavioural intention is executed.

Indeed that is what some researchers have been doing. Several properties of the living, breathing, moving human body have been measured in such studies.

Think back to the studies showing that inducing approach to objects results in liking them more. The obvious reversal would be to test whether we indeed spontaneously and quite unconsciously approach positive objects and avoid negative ones, even if we do not have to actually move around. Eerland and colleagues tested this by asking their participants to stand on a WII balance board – a component of the computer game platform that measures where you place your centre of gravity. Participants viewed strongly positive and negative pictures on a computer screen while standing on this platform. In the first second of just viewing, participants indeed swayed slightly forward towards positive pictures, but did not move much when seeing negative pictures (Eerland, Guadalupe, Franken, & Zwaan, 2012). Watch out how you sway the next time you see something (or somebody) really attractive.

Experimenters have also observed how our bodies react to words. For instance, Suzanne Oosterwijk and colleagues asked the participants in their study to generate words related to disappointment or pride (and also neutral words) (Oosterwijk, Rotteveel, Fischer, & Hess, 2009). Unbeknown to the participants, the researchers tracked their head postures. Participants wore head phones that were marked with a yellow patch, and they were filmed by a hidden camera. The researchers later painstakingly analysed the clips frame by frame tracking the position of the yellow patch. They found that while participants generated words of disappointment, their heads literally sank into despair, while they staid levelled and even initially rose a little when generating words of pride.

In a similar study, participants were asked to think about what their life had been like four years earlier, or to think about what their life would be like in four years (Miles, Nind, & Macrae, 2010). They were doing that while standing upright, blindfolded to facilitate vivid imagery, and with a motion tracking sensor attached to their leg above the knee. When thinking about the past, participants slightly leaned backward, but when thinking about the future, they slightly leaned forward. Presumably, the way we think about time is not completely abstract – we mentally represent it on a path through space, with the past behind us and the future in front. When we mentally travel in time, we physically try to move there as well.

In these three studies, participants had no real reason to move their bodies, but they did, and this movement was tracked by the researchers. In another type of experiments, participants get an instruction to move in a specific way, and it is studied how quickly and accurately they can do that. The trick is here that the correct movements are made easy or hard by other ideas that again come from embodied representations.

Here is an example experiment following this strategy (Zwaan & Taylor, 2006): Participants were presented with complete sentences and asked to judge whether these  made sense (some did not). In order to indicate their judgment, participants had to turn a rotating knob either to the left in one condition or to the right in another condition. Some sentences implied movement, for instance “He turned down the volume”, typically a counter-clockwise movement on many devices. By now you will probably guess what happened: Judging the correctness of this sentence was easier (and thus faster) when having to perform a counter-clockwise movement to do so, and the opposite occured for sentences implying clockwise movements. (This type of experiment has a long tradition, going back to the 90s, when Solarz (1960) built a system with mechanical levers participants had to push and pull.)

These were all examples involving movements, but measuring the body does not end there. Psychologists have studied various physiological processes for a long time: changes in heartbeat, breathing, sweating, hormonal changes, and movements of facial muscles, such as smiling and frowning (see Blascovich, 2014, for an overview). For instance, it is known that the temperature of the body and fingers change in certain patterns when emotions are experienced (Ekman, Levenson, & Friesen, 1983). Similarly, IJzerman and colleagues (2012) have recently found that when a person is excluded socially from a group, their finger temperature drops somewhat. They used a very precise industrial thermometer hooked up to a computer to measure finger temperature. Following an embodiment reasoning, the idea is that such physiological processes feed back into our feeling and thinking.