Landmark Stability: Studies Exploring Whether the Perceived Stability of the Environment Influences Spatial Representation

Abstract

To investigate whether spatial learning complies with associative learning theories or with theories of cognitive mapping, rats were trained in three experiments exploring the effect of variations in spatial predictive relationships. In experiment 1, it was found that making one of two landmarks the sole spatial predictor of reward, by varying the spatial relationship between reward and other cues, reduced the control over search exerted by that landmark compared with that observed when the landmark and context cues were both reliable predictors of reward location. This requirement for landmark stability rather than predictive power appears to contradict results obtained in conventional conditioning paradigms. Discrimination learning was unaffected, suggesting a dissociation between discrimination and spatial learning with respect to the influence of geometric stability. Further experiments used arrays of both single and multiple landmarks. Experiment 2 revealed that the stability of a single landmark improved accuracy of search, but also showed that local stability between a pair of landmarks that moved around the arena together was sufficient to support spatial learning. Experiment 3 examined landmark stability using fixed directional cues in the absence of vestibular disorientation. This also revealed a relative advantage of stable landmarks, but animals presented with a landmark that moved from trial to trial did show some evidence of learning. Parametric manipulation of landmark stability offers an intriguing way of influencing the process of spatial representation and thus understanding better the processes through which egocentric representations of perceived space are transformed into allocentric representations of the real world.

Tests for cognitive mapping in Clark's nutcrackers (Nucifraga columbiana).

“…Some nutcrackers may have also used similar cues to locate the goal during the tests in which the apparatus was removed (see the Discussion section, Experiment 5). The finding is consistent with other work with nutcrackers (Gould-Beierle & Kamil, 1996) and rats (e.g., Biegler & Morris, 1996) in implicating the use of distal room cues during search. In Experiment 2, nutcrackers used local cues provided by the apparatus (e.g., the opening) to attempt to locate the goal.…”

Rhesus monkeys use geometric and nongeometric information during a reorientation task.

“…This ingenious disorientation procedure led Margules and Gallistel to the same conclusion drawn by Cheng, namely that rats failed to use the nongeometric information to correctly locate the target. These findings, and similar findings from other investigators (Biegler & Morris, 1993, 1996; Dudchenko, Goodridge, Seiterle, & Taube, 1997), provide further empirical data, showing that rats reoriented in accord with the shape of the environment but seemed to neglect nongeometric properties of the environment.…”

“…A more plausible explanation would be that these angular cues were not considered by the monkeys as stable or nonmovable. According to Biegler and Morris (1993, 1996), the relative stability of landmarks is an important factor in the development of spatial behaviors. It is generally thought that an object must be considered as immovable in order to be used as a landmark in navigation tasks (for an example with young children, see Acredolo, 1990).…”

“…Differences between the experimental environments, between procedures and motivational factors, could account for the discrepancy observed in the data (Hermer, 1997). For example, in studies by Cheng (1986), Hermer and Spelke (1994, 1996), or Biegler and Morris (1993, 1996), subjects were tested in apparatus with an informative shape (such as a rectangle). In contrast, other studies often placed rats in an environment with a minimal distinctive geometry (most often an enclosed cylinder).…”

Testing landmark-specific effects on route navigation in an ecologically valid setting: a simulated driving study

“…This is consistent with past research showing that proximal landmarks support route knowledge (e.g., Hurlebaus et al, 2008 ; Ruddle et al, 2011 ). Proximal landmarks provide local relative positional information (Benhamou & Poucet, 1998 ; Biegler & Morris, 1996 ) which is useful in route-based navigation tasks. Even though the presence of proximal landmarks in the training block significantly improved route learning, the relatively poorer performance of the PD compared to the D group in the transfer block suggested that the mere presence of the distal landmarks is not what facilitated successful route navigation, but rather the lack of proximal landmarks.…”