Where you are affects what you can easily imagine: Environmental geometry elicits sensorimotor interference in remote perspective taking

Perceived spatial presence and body orientation affect the recall of out-of-sight places in an immersive sketching experiment

The orientation of sketch maps of remote but familiar city squares produced from memory has been shown to depend on the distance and airline direction from the production site to the remembered square (position-dependent recall, Röhrich et al. in PLoS One 9(11): e112793, 2014). Here, we present a virtual reality version of the original experiment and additionally study the role of body orientation. Three main points can be made: First, "immersive sketching" is a novel and useful paradigm in which subjects sketch maps live on paper while being immersed in virtual reality. Second, the original effect of position-dependent recall was confirmed, indicating that the sense of being present at a particular location, even if generated in a virtual environment, suffices to bias the imagery of distant places. Finally, the orientation of the produced sketch maps depended also on the body orientation of the subjects. At each production site, body orientation was controlled by varying the position of the live feed in the virtual environment, such that subjects had to turn towards the prescribed direction. Position-dependent recall is strongest if subjects are aligned with the airline direction to the target and virtually goes away if they turn in the opposite direction. We conclude that the representation of out-of-sight target places depends on both the current airline direction to the target and the body orientation.

A Smart Model of Imaginal Perspective Taking

The ability to judge spatial relations from perspectives that differ from one's current body orientation and location is important for many everyday activities. Despite considerable research on imaginal perspective taking, however, detailed computational accounts of the processes involved in this ability are missing. In this contribution, I introduce Smart (Spatial Memory Access by Reference Frame SelecTion) as a computational cognitive model of imaginal perspective taking processes. In assuming that imaginal perspective taking is governed by reference frame selection for memory access and subsequent motor activation, Smart is able to explain and simulate key findings on human imaginal perspective taking. In addition to providing novel insight into the mechanisms underlying imaginal perspective taking, Smart also has several implications for our view on spatial memory, more generally. In particular, Smart supports the idea that enduring spatial representations are essentially orientation-free and that spatial representations are best viewed as flexible combinations of representation structures and reference frames.

Alignment in spatial memory: Encoding of reference frames or of relations?

A common assumption about spatial memory is that it is organized along one or more reference directions such that access to memory is easier along directions aligned with the reference direction(s). This assumption rests to no small part on frequently replicated alignment effects arising in judgment of relative direction. In this contribution, we report an experiment designed to investigate a possible alternative explanation of alignment effects. By contrasting performance in a judgment of relative direction task with performance in an ego perspective taking task, we tested to what extent alignment effects arise from encoding of relations in addition to or instead of from organization along reference directions. Experimental results suggest little if any contribution of relation encoding on alignment effects, thus lending further support to the assumption of reference directions in spatial memory. Data from both tasks yielded the same alignment effects and provided evidence for a single direction being encoded in memory. Moreover, our results shed new light on and raise questions concerning differential sensorimotor and cognitive influence on spatial memory use. While both influence memory use, systematic bias seems to arise solely from reference directions, along which memory is organized.

Disentangling spatial conflicts in mental perspective taking

The present experiment was conducted to examine the cognitive processes underlying mental perspective taking in remembered environments. Participants learned a layout of everyday objects from multiple randomly chosen perspectives. They were then blindfolded and tested for their spatial knowledge by having them point to unseen object locations from imagined perspectives. The acoustic display of a first object name informed participants about the to-be-imagined position, a second object name about the to-be-imagined heading, before a third object name identified the target they should point to with a joystick. The choice of object triplets allowed for independent variation of head-direction disparity (HDD), i.e., the difference in heading direction between real and imagined perspective, and object direction disparity (ODD), i.e., the egocentric shift of target object direction between real and imagined perspectives. Results revealed a consistent pattern of monotonic increasing detrimental effects of HDD (0°, 60°, 120°, 180°) and ODD (0-45°, 46-90°, 91-135°, 136-180°). The independent variation of HDD and ODD disclosed a third source of extra processing costs that could be traced back to allocentric differences in target object direction (ODD_allo). A SOA-interval (1, 3, or 5 s) before target presentation allowed participants to save on overall pointing times and errors but did not allow them to reduce incremental costs from HDD, ODD_ego, or ODD_allo. The present results reveal that multiple overlapping spatial interference conflicts between real and imagined spatial perspectives are the most important source of additional processing costs in mental perspective taking in remembered environments.

Crossing boundaries: Global reorientation following transfer from the inside to the outside of an arena

In 2 spatial navigation experiments, human participants were asked to find a hidden goal (a WiFi signal) that was located in 1 of the right-angled corners of a kite-shaped (Experiment 1) or a cross-shaped (Experiment 2) virtual environment. Goal location was defined solely with respect to the geometry of the environment. Following this training, in a test conducted in extinction, participants were placed onto the outside of the same environments and asked to locate the WiFi signal. The results of both experiments revealed that participants spent more time searching in regions on the outside of the environments that were closest to where the WiFi signal was located during training. These results are difficult to explain in terms of analyses of spatial navigation and reorientation that emphasize the role of local representational encoding or view matching. Instead, we suggest that these results are better understood in terms of a global representation of the shape of the environment.

Thinking outside of the box II: Disrupting the cognitive map

A number of influential spatial learning theories posit that organisms encode a viewpoint independent (i.e. allocentric) representation of the global boundary shape of their environment in order to support spatial reorientation and place learning. In contrast to the trial and error learning mechanisms that support domain-general processes, a representation of the global-shape of the environment is thought to be encoded automatically as part of a cognitive map, and without interference from other spatial cues. To date, however, this core theoretical assumption has not been appropriately examined. This is because previous attempts to address this question have failed to employ tasks that fully dissociate reorientation based on an allocentric representation of global-shape from egocentric reorientation strategies. Here, we address this issue in two experiments. Participants were trained to navigate to a hidden goal on one side of a virtual arena (e.g. the inside) before being required to find the same point on the alternative side (e.g. the outside). At test, performing the correct search behaviour requires an allocentric representation of the global boundary-shape. Using established associative learning procedures of overshadowing and blocking, we find that search behaviour at test is disrupted when participants were able to form landmark-goal associations during training. These results demonstrate that encoding of an allocentric representation of boundary information is susceptible to interference from landmark cues, and is not acquired through special means. Instead, the results suggest that allocentric representations of environmental boundaries are acquired through the same kind of error-correction mechanisms that support domain-general non-spatial learning.

Virtual Orientation Overrides Physical Orientation to Define a Reference Frame in Spatial Updating

Previous studies showed that people could use either an egocentric or allocentric reference frame in spatial updating with body-based cues (i.e., physical body movements), but the adopted reference frame was anchored by the physical egocentric front when body-based cues were constrained. A recent study (He et al., 2018) showed that even without body-based cues, the orientation participants initially faced in the virtual environment (VE; initial heading) could be used to establish a reference frame, suggesting that the physical egocentric front could be overridden by a virtual orientation. In the current project, we aimed to: (a) replicate He et al.’s (2018) finding; (b) examine when the reference frame defined by the virtual initial heading was established; and (c) investigate the cognitive processes in establishing the initial heading as a reference frame. In four experiments, we were able to replicate the previous findings and found that the reference frame defined by the initial heading was established during spatial updating. More importantly, the reference frame defined by the initial heading was egocentric and participants did not need to know the orientation of their initial heading at the beginning of spatial updating to be able to use it. We discuss the cognitive processes of reference frame selection in spatial updating when body-based cues are absent.