Not all gestures are created equal: the effects of typical and atypical iconic gestures on narrative comprehension

Observing hand gestures during learning consistently benefits learners across a variety of tasks. How observation of gestures benefits learning, however, is yet unanswered, and cannot be answered without further understanding which types of gestures aid learning. Specifically, the effects of observing varying types of iconic gestures are yet to be established. Across two studies we examined the role that observing different types of iconic hand gestures has in assisting adult narrative comprehension. Some iconic hand gestures (typical gestures) were produced more frequently than others (atypical gestures). Crucially, observing these different types of gestures during a narrative comprehension task did not provide equal benefit for comprehension. Rather, observing typical gestures significantly enhanced narrative comprehension beyond observing atypical gestures or no gestures. We argue that iconic gestures may be split into separate categories of typical and atypical gestures, which in turn have differential effects on narrative comprehension.