Incidental encoding of enclosure geometry does not require visual input: evidence from blindfolded adults

Abstract

Although spatial orientation with respect to the geometric properties of an environment appears to be an ability shared across various species, debate remains concerning potential similarities and differences with respect to the underlying mechanism(s). One prominent theoretical account of orientation with respect to the environment suggests that participants match visual memories to their current visual perception and navigate to reduce the discrepancy between the two. We tested whether visual input was necessary to incidentally encode the geometric properties of an environment, by training disoriented and blindfolded adult participants to search by touch for a target object hidden in one of four locations, marked by distinctive textural cues, located in the corners of a rectangular enclosure. Following training, we removed the distinctive textural cues and probed the extent to which the participants had learned the geometry of the enclosure. Even in the absence of vision and unique textural cues, search behavior was consistent with evidence for the encoding of enclosure geometry. A follow-up experiment in which participants were trained in a rectangular enclosure but were tested in a square enclosure provided converging evidence that search behavior was influenced by the geometric properties of the enclosure. Collectively, these results suggest that even in the absence of vision, participants incidentally encoded the geometric properties of the enclosure, indicating that visual input is not required to encode the geometric properties of an environment.

Spatial reorientation with a geometric array of auditory cues

“…For example, with visual impairments or under conditions of low environment visibility (e.g., under foggy conditions or at night), anecdotal experience suggests that reorientation can be accomplished using auditory (e.g., traffic noise), balance/kinesthetic (e.g., walking on a slant), or haptic (e.g., long cane) information. Recently, these experiences have been supported through systematic studies (reorientation using auditory cues: Nardi, Anzures, et al, 2019; kinesthetic cues from slope information: Nardi et al, 2011; and haptics: Sturz et al, 2014), but what we know about how these other sensory modalities support reorientation, compared to visually guided reorientation, is very limited. This knowledge is useful because it can be employed to design multimodal spatial displays to help everyday navigation and safe mobility (e.g., maps, crossing signals, exit localisation).…”

“…In a rectangular environment with a distinct textural cue in each corner, participants learned to associate the correct cue to the target corner. Furthermore, and crucially, even if not necessary for the task, they also extracted the geometric information from the environment so that, when the texture cues were removed, they were able to restrict searches to the two, opposite, geometrically correct corners (Sturz et al, 2014). We were interested in examining whether the incidental encoding of geometry would also occur with an auditory accessed environment.…”

Spatial reorientation with non-visual cues: Failure to spontaneously use auditory information

“…Our expectation was based on previous studies on visual-based reorientation, which overall reveal that a source of spatial information—especially a geometric cue—tends to be encoded even when not necessary or sufficient (e.g., Cheng, 1986; Cheng et al, 2013). This has been shown even with haptic cues (Sturz et al, 2014). In contrast, in Experiment 1, there was no evidence that the auditory information was encoded at all.…”

“…In a similar scenario but with visual cues, abundant evidence (Hermer & Spelke, 1996; Learmonth, Newcombe, & Huttenlocher, 2001; Vallortigara, Zanforlin, & Pasti, 1990; for a review, see Cheng & Newcombe, 2005) has shown that human and non-human animals tend to learn the target location with both sources of information and not with just the more informative one. Sturz and colleagues (2014) revealed that haptic-based reorientation followed the same pattern: participants learned both the target texture cue and the geometrically correct location, although the texture information alone would have sufficed.…”

“…Growing evidence supports the theory of functional equivalence (Bryant, 1997; Loomis, Klatzky, Avraamides, Lippa, & Golledge, 2007), according to which, despite different encoding modalities, many aspects of the spatial representation and behaviour are equivalent (Avraamides, Loomis, Klatzky, & Golledge, 2004; Giudice, Betty, & Loomis, 2011; Giudice, Klatzky, & Loomis, 2009; Levine, Jankovic, & Palij, 1982; Yamamoto & Shelton, 2005). For example, in a recent study on haptic-based reorientation (Sturz, Gaskin, & Roberts, 2014), blindfolded participants had to learn the location of a target object by exploring with their hands the corners of a rectangular enclosure. The target was hidden in one of the corners, and each corner had distinct textural cues.…”