A new study suggests that physically stepping backwards may be associated with gains in the ability to deal with problematic situations. As newly reported in Psychological Science (hat tip to Hannah) by Koch, Holland, Hengstler & Knippenberg, people were better able to resolve interference in laboratory “Stroop” task after stepping backwards, relative to stepping to the side or forwards. The authors argue that stepping backwards is typically associated with problematic situations, which characteristically require cognitive control (the set of capacities which enable us to control our behavior and focus on important features of the environment). Koch et al conclude that stepping backwards allows one to more strongly engage these control processes!
The authors demonstrated this fascinating effect by testing 38 subjects on laptop-based Stroop task (in which subjects must name the colors of words while NOT reading the words themselves – e.g., RED). The laptop was mounted on a mobile cart, and subjects were asked to take a step in one of four possible directions (backwards, forwards, left or right) before 12 words were presented in sequence. These “blocks” of trials consisted of equal numbers of incongruent (RED), congruent (RED), and “neutral” trials in which non-color words were used (LOT). Each subject saw a total of 8 blocks, and verbal reaction times were measured by the onset time of the voice on trials that were both correct and within 2.5 standard deviations of their median reaction times.
The results showed a clear effect of stepping backwards – subjects were remarkably faster to name the ink color of incongruent color-words (RED) when they had stepped backwards, relative to forwards or sideways! Moreover, there were no differences on the neutral or congruent trial types, although there was perhaps a trend towards longer reaction times on congruent trials when subjects had stepped backwards. Both effects are consistent with the idea that stepping backwards allowed subjects to better attend to color (or to better suppress word-reading, depending on your interpretation of what’s involved in this task).
This work is remarkable not only for demonstrating how a very concrete and simple bodily experience can influence even the highest levels of cognitive processing (in this case, the so-called “cognitive control” processes that enable focused attention), but also because performance on the Stroop task is notoriously difficult to improve. Previous work indicates that meditation might improve performance on this task, but it requires months of training and yields only small or inconsistent effects. In contrast, more targeted “cognitive” training has shown no or very inconsistent effects on Stroop performance, even when that training is successful at improving performance on other tasks.
There’s always the possibility that findings like this just reflect a very (un?)lucky set of researchers (that is, a Type I error), but I find this a little unlikely in this particular case. In particular, the trend towards increased reaction times for congruent trials when subjects had stepped backwards is very suggestive – and very consistent with the significant results found for the incongruent trials. Focusing on the important color features helps in incongruent trials, but could hurt you in congruent trials (where reading the word would actually give you the correct answer). If the influence of stepping backwards were actually random, and the significant improvement in reaction times on incongruent trials just a result of random chance, one wouldn’t expect to see any evidence of the opposite effect on congruent trials. On the other hand…
I do wonder a bit about the “mobile cart” setup used here. One trivial technique for improving performance on the Stroop task is to blur your vision – by crossing your eyes or “diffusing” your spatial attention. By doing this, you are less likely to read the word, and thus more likely to be able to name the ink color rapidly in incongruent trials. If stepping backwards is associated with the spreading of spatial attention (as seems reasonable – to make sure you don’t fall over!) or simply with less acute vision than stepping to the side or forwards (as also seems reasonable – vision is probably better for objects that approach or stay the same than for those that at least momentarily recede), these effects could be just another demonstration of the well-known sensitivity of the Stroop task to vision and spatial attention. Unfortunately, the short-report format used here does not allow for much detail in the methods section, and so the relevant details for ruling out this alternative were not provided in the paper.