Physical gestures for abstract concepts: Inclusive design with primary metaphors

Designers in inclusive design are challenged to create interactive products that cater for a wide range of prior experiences and cognitive abilities of their users. But suitable design guidance for this task is rare. This paper proposes the theory of primary metaphor and explores its validity as a source of design guidance. Primary metaphor theory describes how basic mental representations of physical sensorimotor experiences are extended to understand abstract domains. As primary metaphors are subconscious mental representations that are highly automated, they should be robustly available to people with differing levels of cognitive ability. Their proposed universality should make them accessible to people with differing levels of prior experience with technology. These predictions were tested for 12 primary metaphors that predict relations between spatial gestures and abstract interactive content. In an empirical study, 65 participants from two age groups (young and old) were asked to produce two-dimensional touch and three-dimensional free-form gestures in response to given abstract keywords and spatial dimensions of movements. The results show that across age groups in 92% of all cases users choose gestures that confirmed the predictions of the theory. Although the two age groups differed in their cognitive abilities and prior experience with technology, overall they did not differ in the amount of metaphor-congruent gestures they made. As predicted, only small or zero correlations of metaphor-congruent gestures with prior experience or cognitive ability could be found. The results provide a promising step toward inclusive design guidelines for gesture interaction with abstract content on mobile multitouch devices.