- There is more to gesture than meets the eye: Visual attention to gesture’s referents cannot account for its facilitative effects during math instruction (Miriam Novack, Elizabeth Wakefield, Eliza Congdon, Steven Franconeri, Susan Goldin-Meadow): Earlier work has shown that gestures can help kids learn math concepts, but this work explores one possible explanation for why this is so: that gestures attract and focus visual attention. To test this, kids watched a video in which someone explained how to do a mathematical equivalence problem (a problem like 5 + 6 + 3 = __ + 3. For some kids, the explainer gestured by pointing to relevant parts of the problem as she explained; for others, she just explained (using the exact same speech as for the gesture-receiving kids). The researchers used eye tracking while the kids watched the videos and found that those who watched the video with gestures looked more to the problem (and less at the speaker) than who watched the video sans gesture. More importantly, those who watched the gesture video did better on a posttest than those who didn’t. The main caveat was that the kids’ eye patterns did not predict their posttest performance; in other words, looking more at the problem and less at the speaker while learning may have contributed to better understanding of the math principle, but not significantly; other mechanisms must also be underlying gesture’s effect on learning.
But in case you started to think that gestures are a magic learning bullet:
- Effects of Gesture on Analogical Problem Solving: When the Hands Lead You Astray (Autumn Hostetter, Mareike Wieth, Keith Moreno, Jeffrey Washington): There’s a pretty famous problem for cognitive science tests studying people’s analogical abilities, referred to as Duncker’s radiation problem: A person has a tumor and needs radiation. A strong beam will be too strong and will kill healthy skin. A weak beam won’t be strong enough to kill the tumor. What to do? The reason this problem is used as a test of analogical reading is that participants are presented a different story – an army wants to attack a fortress (and the fortress is at the intersection of a bunch of roads), but there are mines placed on the roads leading up to it, so the whole army can’t pass down one road at a time. Yet if they only send a small portion of the army down a road, the attack will be too weak. The solve this by splitting up and all converging on the fortress at the same time. Now can you solve the radiation problem? Even though the solution is analogous (target the tumor with weak rays coming from different directions) people (college undergrads) usually still struggle. It’s a testament to how hard analogical reasoning is.
But that’s just background leading to the current study, where the researchers asked: if people gesture while retelling the fortress story, will they have more success on the radiation problem? To test this, they had one group of participants that they explicitly told to gesture, one group that they told not to gesture, and a final group that they didn’t instruct at all regarding gestures. They found that the gesturers in fact did worse than non-gesturers, and after analyzing the things that people actually talked about in the different conditions, discovered that when people gestured, they tended to talk more about concrete details of the situation – for example, the roads and the fortress – and this focus on the perceptual features of the fortress story actually inhibited their ability to apply the analogical relations of that story to the radiation case.
Taking this study into consideration with the previous one, it’s clear that gesture is not all good or all bad; there are lots of nuances of a situation that need to be taken into account and lots of open questions ripe for research.
- tDCS to premotor cortex changes action verb understanding: Complementary effects of inhibitory and excitatory stimulation (Tom Gijssels, Daniel Casasanto): We know the premotor cortex is involved when we execute actions, and there’s quite a bit of debate about to what extent it’s involved in using language about actions. They used transcranial direct current stimulation – a method that provides a small electrical current to a targeted area of the brain – over the premotor cortex (PMC) to test for its involvement in processing action verbs (specifically, seeing a word or a non-word and indicating whether it’s a real English word). People who received PMC inhibitory stimulation (which decreases the likelihood of the PMC neurons firing) were more accurate for their responses about action verbs, while those who received PMC excitatory stimulation (increasing the likelihood of the PMC neurons firing). This at first seems paradoxical – inhibiting the motor area helps performance and exciting it hurts, but there are some potential explanations for this finding. One that seems intriguing to me is that since the PMC is also responsible for motor movements, inhibiting the area helped people suppress the inappropriate motor action (for example, actually grabbing if they read the verb grab), and as a consequence facilitated their performance on the word task; excitatory stimulation over the same area had the opposite effect. Again, this study makes it clear that something cool is going on in the parts of our brain responsible for motor actions when we encounter language about actions… but as always, more research is needed.
- Tacos for dinner. After three days of long, stimulating conference days, the veggie tacos at El Vez were so good that they make the conference highlight list.
For every cool project I heard about, there were undoubtedly many more that I didn’t get to see. Luckily, the proceedings are published online, giving us the printed version of all the work presented at the conference. Already looking forward to next year’s event in London!