No abstract

Four experiments investigated the conditions contributing to sensorimotor alignment effects (i.e., the advantage for spatial judgments from imagined perspectives aligned with the body). Through virtual reality technology, participants learned object locations around a room (learning room) and made spatial judgments from imagined perspectives aligned or misaligned with their actual facing direction. Sensorimotor alignment effects were found when testing occurred in the learning room but not after walking 3 m into a neighboring (novel) room. Sensorimotor alignment effects returned after returning to the learning room or after providing participants with egocentric imagery instructions in the novel room. Additionally, visual and spatial similarities between the test and learning environments were independently sufficient to cause sensorimotor alignment effects. Memory alignment effects, independent from sensorimotor alignment effects, occurred in all testing conditions. Results are interpreted in the context of two-system spatial memory theories positing separate representations to account for sensorimotor and memory alignment effects.Keywords: spatial memory, spatial updating, sensorimotor interference, perspective taking, alignment effectAn everyday task such as providing a friend with directions to one's home can entail imagining the friend's perspective and telling him or her whether to turn left or right at intersections. The ease with which a person can reason from a perspective and/or location other than one's own has been shown to depend on at least three factors: the perspectives one experienced when learning the imagined space (Diwadkar & McNamara, 1997;Shelton & McNamara, 1997), the structure of the space itself (McNamara, Rump & Werner, 2003;Mou & McNamara, 2002;Shelton & McNamara, 2001;Werner & Schmidt, 1999), and the position and orientation of the person's body during recall (May, 2004;Mou, McNamara, Valiquette, & Rump, 2004;Presson & Montello, 1994;Rieser, 1989). Reasoning about space is often easier from perspectives aligned rather than misaligned with salient reference frames (e.g., environmental reference frames or the body's reference frame). This empirical result is termed an alignment effect. Herein, we distinguish between two kinds of alignment effects. We refer to the advantage of responding from imagined perspectives that are aligned rather than misaligned with the body during retrieval as a sensorimotor alignment effect. As an example, the reader is invited to close his or her eyes and imagine the immediate surrounds from his or her current location and orientation in the environment. The reader is then asked to try to imagine how things would look if he or she were to rotate in place 180°. The increased difficulty after imagined rotation is an example of a sensorimotor alignment effect. Additionally, we refer to the advantage of reasoning from a perspective aligned rather than misaligned with the reference frames used to encode an environment in long-term memory as a memory alignment effe...

Underperception of egocentric distance in virtual reality has been a persistent concern for almost 20 years. Modern head-mounted displays (HMDs) appear to have begun to ameliorate underperception. The current study examined several aspects of perceived space in the HTC Vive. Blind-walking distance judgments, verbal distance judgments, and size judgments were measured in two distinct virtual environments (VEs)—a high-quality replica of a real classroom and an empty grass field—as well as the real classroom upon which the classroom VE was modeled. A brief walking interaction was also examined as an intervention for improving anticipated underperception in the VEs. Results from the Vive were compared to existing data using two older HMDs (nVisor SX111 and ST50). Blind-walking judgments were more accurate in the Vive compared to the older displays, and did not differ substantially from the real world nor across VEs. Size judgments were more accurate in the classroom VE than the grass VE and in the Vive compared to the older displays. Verbal judgments were significantly smaller in the classroom VE compared to the real classroom and did not significantly differ across VEs. Blind-walking and size judgments were more accurate after walking interaction, but verbal judgments were unaffected. The results indicate that underperception of distance in the HTC Vive is less than in older displays but has not yet been completely resolved. With more accurate space perception afforded by modern HMDs, alternative methods for improving judgments of perceived space—such as walking interaction—may no longer be necessary.

The role of environmental geometry in maintaining spatial orientation was measured in immersive virtual reality using a spatial updating task (requiring maintenance of orientation during locomotion) within rooms varying in rotational symmetry (the number of room orientations providing the same perspective). Spatial updating was equally good in trapezoidal, rectangular and square rooms (1-fold, two-fold and four-fold rotationally symmetric, respectively) but worse in a circular room (∞-fold rotationally symmetric). This contrasts with reorientation performance, which was incrementally impaired by increasing rotational symmetry. Spatial updating performance in a shape-changing room (containing visible corners and flat surfaces, but changing its shape over time) was no better than performance in a circular room, indicating that superior spatial updating performance in angular environments was due to remembered room shape, rather than improved self-motion perception in the presence of visible corners and flat surfaces.

Recent findings from spatial cognition and cognitive neuroscience suggest that different types of mental representations could mediate the off-line retrieval of spatial relations from memory and the on-line guidance of motor actions in space. As a result, a number of models proposing multiple systems of spatial memory have been recently formulated. In the present article we review these models and we evaluate their postulates based on available experimental evidence. Furthermore, we discuss how a multiple-system model can apply to situations in which people reason about their immediate surroundings or non-immediate environments by incorporating a model of sensorimotor facilitation/interference. This model draws heavily on previous accounts of sensorimotor interference and takes into account findings from the stimulus-response compatibility literature.