**6. Experiment 2: Horizontal/vertical bisection point for surface orientation in depth assessed by dynamic touch with the tip of the index finger**

To avoid verbal biases, Durgin, Li and Hajnal (2010) used a bisection task in which they presented surface visually and asked participants to indicate whether the surface was closer to vertical or to horizontal. They reported a mean visual bisection of point of 34° from horizontal. That is, a surface of 34° was equally likely to be judged closer to vertical as it was to be judged closer to horizontal. In fact the cubic fit to their verbal data predicted that the 45° point would have been at 36.3° in the visual case, and it seems likely that verbal reports tend to slightly underestimate the magnitude of the actual spatial bias (see also Durgin & Li, 2011a, 2011b). The present experiment simply replicated the bisection procedure of Durgin, Li and Hajnal for the haptic case.
