An Investigation into the Cause of Orientation-Sensitivity in Haptic Object Recognition

Abstract

Object orientation influences visual and haptic recognition differently. This could be caused by the two modalities accessing different object representations or it could be due to differences in how each modality acquires information. These two alternatives were investigated using sequential haptic matching tasks. Matches presented the same object twice. Mismatches presented two similarly-shaped objects. Objects were either both placed at the same orientation or were rotated 90° in depth from each other. Experiment 1 manipulated exploration time to test if longer durations weakened orientation-sensitivity by allowing orientation-invariant representations to be extracted. This hypothesis was not supported. Experiment 2 investigated whether the same-orientation advantage resulted from general spatial or motor action cueing rather than the involvement of orientation-specific object representations. To distinguish between these two possibilities, people did a secondary task interleaved within the matching task. They reported the orientation of a fork or spoon which was presented in between the first and second objects. The main axis of the fork/spoon was the same as that of the final object, equating spatial and motor cueing across the same-orientation and orientation-change conditions. Nevertheless, matching remained orientation-sensitive. Together these results suggest that there are separate visual and haptic stored, orientation-specific perceptual representations of objects.

Haptic Object Recognition is View-Independent in Early Blind but not Sighted People

“…In this study, we compared early blind and sighted control participants to test whether visual experience affects haptic view-dependence. As predicted, the sighted group was haptically view-dependent, replicating previous findings (Craddock & Lawson, 2008; Lacey et al., 2007; Lawson, 2011; Newell et al., 2001), but the early blind group was view-independent. There was no overall difference between blind and sighted participants—this may reflect the fact that the novel objects used here were equally unfamiliar to both groups but is also in line with previous studies (e.g., Norman & Bartholomew, 2011) given that our blind group was predominantly congenitally blind.…”

“…Therefore, one might assume that haptic object recognition would be unaffected by a change in orientation, that is, it would be view-independent. However, a number of studies have shown that haptic recognition of 3-D objects is significantly impaired if the objects are rotated between encoding and recognition phases and is, therefore, view-dependent (Craddock & Lawson, 2008; Lacey, Peters, & Sathian, 2007; Lawson, 2011; Newell, Ernst, Tjan, & Bülthoff, 2001; reviewed by Lacey & Sathian, 2014). For unfamiliar objects, view-dependence characterizes both visual and haptic recognition (Lacey et al., 2007; Newell et al., 2001).…”

The puzzle of cross‐modal shape experience

“…Orientation-dependent haptic recognition has been documented in several other studies as well (Newell et al, 2001;Lacey et al, 2009;Lawson, 2009Lawson, , 2011. Thus, the haptic system plausibly forms representations of shape in perceiver-centered reference frames.…”

Visuo-haptic multisensory object recognition, categorization, and representation

“…During haptic exploration, the hands can contact an object from different sides simultaneously: intuitively, therefore, one might expect information about several different “views” to be acquired at the same time and that haptic recognition would be view-independent. However, numerous studies have now shown that this intuition is not correct and that haptic object recognition is also view-dependent (Newell et al, 2001; Lacey et al, 2007, 2009b; Ueda and Saiki, 2007, 2012; Craddock and Lawson, 2008, 2010; Lawson, 2009, 2011). The factors underlying haptic view-dependence are not currently known: even unlimited exploration time and orientation cuing do not reduce view-dependence (Lawson, 2011).…”