**6.3 Discussion**

Using real surfaces with a clearly-demarcated axis of haptic exploration, we sought to extend the bisection method used by Durgin, Li and Hajnal (2010) to the haptic domain. Our results are consistent with a close correspondence between visual and haptic spatial biases in the perception of orientation. The haptic results are also quite similar to the average perceived horizontal/vertical bisection point (31°) measured by Durgin and Li (2011a) for perceived gaze declination. In other words, across a variety of modalities (proprioception of gaze declination, visual perception of 3D surface orientation in depth and haptic perception of 3D surface orientation in depth) the perceived bisection point between horizontal and vertical is very close to 30° from horizontal.
