Representation of two geometric features of the environment in the domestic chick (<Emphasis Type="Italic">Gallus gallus</Emphasis>)

We report experiments based on a novel test in domestic chicks (Gallus gallus), designed to examine the encoding of two different geometric features of an enclosed environment: relative lengths of the walls and amplitude of the corners. Chicks were trained to search for a food reward located in one corner of a parallelogram-shaped enclosure. Between trials, chicks were passively disoriented and the enclosure was rotated, making reorientation possible only on the basis of the internal spatial structure of the enclosure. In order to reorient, chicks could rely on two sources of information: the relative lengths of the walls of the enclosure (associated to their left-right sense order) and the angles subtended by walls at corners. Chicks learned the task choosing equally often the reinforced corner and its rotational equivalent. Results of tests carried out in novel enclosures, the shapes of which were chosen ad hoc (1) to induce reorientation based only on the ratio of walls lengths plus sense (rectangular enclosure), or (2) to induce reorientation based only on corner angles (rhombus-shaped enclosure), suggested that chicks encoded both features of the environment. In a third test, in which chicks faced a conflict between these geometric features (mirror parallelogram-shaped enclosure), reorientation seemed to depend on the salience of corner angles. These results shed light on the elements of the environmental geometry which control spatial reorientation, and broaden the knowledge on the geometric representation of space in animals.     

Representing others' actions: just like one's own?

Previous research has shown that observing others' actions can affect individual performance of the same actions. In the present study, we developed a new paradigm to investigate whether and how complementary actions at the disposal of another agent are represented and influence one's own actions. A spatial compatibility task was distributed among two people so that each participant took care of one of two responses. The identical task was performed alone and alongside another participant. There was a spatial compatibility effect in the group setting only. It was similar to the effect obtained when one person took care of both responses. This result suggests that one's own actions and others' actions are represented in a functionally equivalent way.     

Familial handedness and spatial ability: a study with Chinese students aged 14-24

This study tested Annett's right-shift theory on spatial ability with two samples from China. The Vandenberg Mental Rotation Test (MRT), Edinburgh Handedness Inventory, and Family Handedness Questionnaire were administered to 266 high school students and 297 undergraduates. We found very few r++ or r-- among Chinese students. Most Chinese are either moderately right-handed or ambidextrous. Consistent with Casey's finding, we found using different methods to classify handedness leads to different conclusions. However, we did not find the effect of familial handedness that Casey found. Visual strategy is related to success on the MRT but handedness is not.     

Landmark-based spatial search in honeybees. I.

Honeybees were trained to find sugar water in the middle of an array of two landmarks of different colours. Unrewarded tests compared searching on the training array with searching on rotated arrays. On rotated tests, a system using the angles between landmarks would continue to search in the middle. A system using vectors to individual elements would search at locations outside the rotated array at which the distances and compass directions to a subset of landmarks matched. Results indicated that bees used both elements and interlandmark angles, but they relied most on one favourite landmark element. Results support the template model of landmark use in honeybees, with the minor parametric modification that weights given to different elements may be unequal. Received:6 July 1998 / Accepted after revision:7 December 1998     

Getting the big picture: Development of spatial scaling abilities

Spatial scaling is an integral aspect of many spatial tasks that involve symbol-to-referent correspondences (e.g., map reading, drawing). In this study, we asked 3–6-year-olds and adults to locate objects in a two-dimensional spatial layout using information from a second spatial representation (map). We examined how scaling factor and reference features, such as the shape of the layout or the presence of landmarks, affect performance. Results showed that spatial scaling on this simple task undergoes considerable development, especially between 3 and 5 years of age. Furthermore, the youngest children showed large individual variability and profited from landmark information. Accuracy differed between scaled and un-scaled items, but not between items using different scaling factors (1:2 vs. 1:4), suggesting that participants encoded relative rather than absolute distances.     

Spatial imagery of novel places based on visual scene transformation

The hippocampus is known to maintain memories of object-place associations that can produce a scene expectation at a novel viewpoint. To implement such capabilities, the memorized distances and directions of an object from the viewer at a fixed location should be integrated with the imaginary displacement to the new viewpoint. However, neural dynamics of such scene expectation at the novel viewpoint have not been discussed. In this study, we propose a method of coding novel places based on visual scene transformation as a component of the object-place memory in the hippocampus. In this coding, a novel place is represented by a transformed version of a viewer’s scene with imaginary displacement. When the places of individual objects are stored with the coding in the hippocampus, the object’s displacement at the imaginary viewpoint can be evaluated through the comparison of a transformed viewer’s scene with the stored scene. Results of computer experiments demonstrated that the coding successfully produced scene expectation of a three object arrangement at a novel viewpoint. Such the scene expectation was retained even without similarities between the imaginary scene and the real scene at the location, where the imaginary scenes only functioned as indices to denote the topographical relationship between object locations. The results suggest that the hippocampus uses the place coding based on scene transformation and implements the spatial imagery of object-place associations from the novel viewpoint.     

Brain activation during spatial updating and attentive tracking of moving targets

Keeping aware of the locations of objects while one is moving requires the updating of spatial representations. As long as the objects are visible, attentional tracking is sufficient, but knowing where objects out of view went in relation to one's own body involves an updating of spatial working memory. Here, multiple object tracking was employed to study spatial updating and its neural correlates. In a dynamic 3D-scene, targets moved among visually indistinguishable distractors. The targets and distractors either stayed visible during continuous viewpoint changes or they turned invisible. The parametric variation of tracking load revealed load-dependent activations of the intraparietal sulcus, the superior parietal lobule, and the lateral occipital cortex in response to the attentive tracking task. Viewpoint changes with invisible objects that demanded retention and updating produced load-dependent activation only in the precuneus in line with its presumed involvement in updating spatial working memory.     

Representing Spatial Structure Through Maps and Language: Lord of the Rings Encodes the Spatial Structure of Middle Earth

Spatial mental representations can be derived from linguistic and non‐linguistic sources of information. This study tested whether these representations could be formed from statistical linguistic frequencies of city names, and to what extent participants differed in their performance when they estimated spatial locations from language or maps. In a computational linguistic study, we demonstrated that co‐occurrences of cities in Tolkien’s Lord of the Rings trilogy and The Hobbit predicted the authentic longitude and latitude of those cities in Middle Earth. In a human study, we showed that human spatial estimates of the location of cities were very similar regardless of whether participants read Tolkien’s texts or memorized a map of Middle Earth. However, text‐based location estimates obtained from statistical linguistic frequencies better predicted the human text‐based estimates than the human map‐based estimates. These findings suggest that language encodes spatial structure of cities, and that human cognitive map representations can come from implicit statistical linguistic patterns, from explicit non‐linguistic perceptual information, or from both.     

Potentiation and overshadowing of shape by wall color in a kite-shaped maze using rats in a foraging task

The interaction between redundant geometric and featural cues in open field search tasks has been examined widely with results that are not always consistent. Cheng (1986) found evidence that when searching for food in rectangular environments, rats used the geometrical characteristics of the environment rather than local featural cues, suggesting that geometry had overshadowed featural cues. More recently, Graham et al. (2006) and Pearce et al. (2006) found that wall color facilitated (potentiated) learning about the shape of the environment by rats in a kite-shaped water maze. The first experiment in the present research replicated the paradigm used by Graham et al. and Pearce et al. using rats in a foraging situation, but with conditions similar, and found the same results, potentiation of shape by color. Experiments 2 and 3 revealed overshadowing instead of potentiation of shape by wall color under the same conditions except that the wall colors of the test environment were not the same as those used during training. The results are consistent with an analysis of the role of associations formed between wall color and geometry in such situations (Rhodes et al., 2009) and extend our understanding of how featural and spatial cues interact.