The Role of Verbal and Nonverbal Communication in a Two-Person, Cooperative Manipulation Task

—Motivated by the differences between human and robot teams, we investigated the role of verbal communication between human teammates as they work together to move a large object to a series of target locations. Only one member of the group was told the target sequence by the experimenters; while the second teammate had no target knowledge. The two experimental conditions we compared were: Haptic-Verbal (teammates are allowed to talk) and Haptic Only (no talking allowed). The team's trajectory was recorded and evaluated. In addition, participants completed a NASA TLX-style post-experimental survey which gauges workload along 6 different dimensions. In our initial experiment we found no significant difference in performance when verbal communication was added. In a follow up experiment, using a different manipulation task, we did find that the addition of verbal communication significantly improved performance and reduced the perceived workload. In both experiments, for the haptic-only condition, we found that a remarkable number of groups independently improvised common haptic communication protocols (CHIPs). We speculate that such protocols can be substituted for verbal communication; and that the performance difference between verbal and non-verbal communication may relate to how easy it is to distinguish the CHIPs from motions required for task completion.