Modeling a role of field of view in the extraction of geometric cues during reorientation

Recently, Sturz et al. (2013) provided evidence for a role of field of view (FOV, i.e., amount of the environment visible from a single vantage point) in the reorientation process. Specifically, they found that constraining FOV (i.e., FOV of 50° compared to FOV of 100°) appeared to prevent the extraction of geometric cues. Given this evidence, I attempted to model a role of FOV in the extraction of geometric cues during reorientation. The development of such a model appeared ideal for at least two reasons. First, global geometric cues (e.g., the principal axis of space) must be, by definition, extracted from the entire environment (i.e., 100% of the environment). As a result, I assumed that 100% of the environment was the threshold for extracting global geometric cues. It follows that an inability to have available (either via current view or in memory) the entire environment would necessarily prohibit extraction of global geometric cues. However, I explicitly acknowledge that an empirical threshold for the extraction of global geometric cues is unknown. Second, recent theoretical and empirical efforts have urged for the consideration of the participant\u27s perspective during reorientation—that is, what information is available to the perceiver (e.g., Sturz and Bodily, 2011; Wystrach and Graham, 2012). Should a model be capable of demonstrating that differences in FOV produce differences in the total amount of the environment available, it would provide additional theoretical support for a role of the participant\u27s perspective during reorientation while also providing additional support for a role of FOV in the reorientation process. In other words, it would provide a theoretical demonstration that differences in the amount of the environment available from a single vantage point are able to produce difference in the total amount of the environment that is available to the perceiver, and by extension, delineate FOVs that would not only allow but also prohibit the extraction of global geometric cues during reorientation ..

On Discriminating between Geometric Strategies of Surface-Based Orientation

Recently, a debate has manifested in the spatial learning literature regarding the shape parameters by which mobile organisms orient with respect to the environment. On one hand are principal-axis-based strategies which suggest that organisms extract the major and minor principal axes of space which pass through the centroid and approximate length and width of the entire space, respectively. On the other hand are medial-axis-based strategies which suggest that organisms extract a trunk-and-branch system similar to the skeleton of a shape. With competing explanations comes the necessity to devise experiments capable of producing divergent predictions. Here, we suggest that a recent experiment (i.e., Sturz and Bodily, 2011a) may be able to shed empirical light on this debate. Specifically, we suggest that a reevaluation of the design reveals that the enclosures used for training and testing appear to produce divergent predictions between these strategies. We suggest that the obtained data appear inconsistent with a medial-axis-based strategy and that the study may provide an example of the types of designs capable of discriminating between these geometric strategies of surface-based orientation. Such an approach appears critical to fundamental issues regarding the nature of space and spatial perception

Evidence Consistent With the Multiple-Bearings Hypothesis From Human Virtual Landmark-Based Navigation

One approach to explaining the conditions under which additional landmarks will be learned or ignored relates to the nature of the information provided by the landmarks (i.e., distance versus bearings). In the current experiment, we tested the ability of such an approach to explain the search behavior of human participants in a virtual landmark-based navigation task by manipulating whether landmarks provided stable distance, stable direction, or both stable distance and stable direction information. First, we incrementally shaped human participants’ search behavior in the presence of two ambiguous landmarks. Next, participants experienced one additional landmark that disambiguated the location of the goal. Finally, we presented three additional landmarks. In a control condition, the additional landmarks maintained stable distances and bearings to the goal across trials. In a stable bearings condition, the additional landmarks varied in their distances but maintained fixed bearings to the goal across trials. In a stable distance condition, the additional landmarks varied in their bearings but maintained fixed distances to the goal across trials. Landmark stability, in particular, the stability of landmark-to-goal bearings, affected learning of the added landmarks. We interpret the results in the context of the theories of spatial learning that incorporate the nature of the information provided by landmarks

Asymmetrical Interference Effects Between Two-Dimensional Geometric Shapes and Their Corresponding Shape Words

Nativists have postulated fundamental geometric knowledge that predates linguistic and symbolic thought. Central to these claims is the proposal for an isolated cognitive system dedicated to processing geometric information. Testing such hypotheses presents challenges due to difficulties in eliminating the combination of geometric and non-geometric information through language. We present evidence using a modified matching interference paradigm that an incongruent shape word interferes with identifying a two-dimensional geometric shape, but an incongruent two-dimensional geometric shape does not interfere with identifying a shape word. This asymmetry in interference effects between two-dimensional geometric shapes and their corresponding shape words suggests that shape words activate spatial representations of shapes but shapes do not activate linguistic representations of shape words. These results appear consistent with hypotheses concerning a cognitive system dedicated to processing geometric information isolated from linguistic processing and provide evidence consistent with hypotheses concerning knowledge of geometric properties of space that predates linguistic and symbolic thought

Domain is a Moving Target for Relational Learning

The domain for relational learning was manipulated by varying the training set size for pigeons that had learned the same/different (S/D) concept. Six pigeons that had learned a S/D task with pairs of pictures with a set size of 1,024 picture items had their training set size reduced to 8 items. Training on the reduced 8-item set was followed by transfer testing that was repeated four times. Transfer performance following reduction of the training set to 8 items was less than it had been when the pigeons were trained with the 1,024-item set, but 25.8% above chance. This partial abstract-concept learning remained constant over the four tests with novel stimuli. The results show that a broad domain established by a large expanding training set can once again become restricted by further training with a small training set

Facilitation of Learning Spatial Relations among Goal Locations does not Require Visual Exposure to the Configuration of Goal Locations

Human participants searched in a virtual-environment open-field search task for four hidden goal locations arranged in a diamond configuration located in a 5 x 5 matrix. Participants were randomly assigned to one of three groups: Pattern Only, Landmark + Pattern, or Cues + Pattern. All participants experienced a Training phase followed by a Testing phase. During Training, visual cues were coincident with goal locations for the Cues + Pattern group, and a single visual cue at a non-goal location maintained a consistent spatial relationship with the goal locations for the Landmark + Pattern group. All groups were then tested in the absence of visual cues. Presence of the visual cue(s) during Training facilitated acquisition of the task, but the Landmark + Pattern group and the Cues + Pattern group did not differ when their visual cues were removed during Testing and performed superior to the Pattern Only group. Results suggest learning based upon the spatial relations among locations may not be susceptible to cue-competition effects and facilitation of learning spatial relations by visual cues does not require visual exposure to the configuration of goal locations

Stroop Interference in a Delayed Match-To-Sample Task: Evidence for Semantic Competition

Discussions of the source of the Stroop interference effect continue to pervade the literature. Semantic competition posits that interference results from competing semantic activation of word and color dimensions of the stimulus prior to response selection. Response competition posits that interference results from competing responses for articulating the word dimension vs. the color dimension at the time of response selection. We embedded Stroop stimuli into a delayed match-to-sample (DMTS) task in an attempt to test semantic and response competition accounts of the interference effect. Participants viewed a sample color word in black or colored fonts that were ongruent or incongruent with respect to the color word itself. After a 5 s delay, participants were presented with two targets (i.e., a match and a foil) and were instructed to select the correct match. We probed each dimension independently during target presentations via color targets (i.e., two colors) or word targets (i.e., two words) and manipulated whether the semantic content of the foil was related to the semantic content of the irrelevant sample dimension (e.g., word sample “red” in blue font with the word “red” as the match and the word “blue” as the foil). We provide evidence for Stroop interference such that response times (RTs) increased for incongruent trials even in the presence of a response option with semantic content unrelated to the semantic content of the irrelevant sample dimension. Accuracy also deteriorated during the related foil trials. A follow-up experiment with a 10 s delay between sample and targets replicated the results. Results appear to provide converging evidence for Stroop interference in a DMTS task in a manner that is consistent with an explanation based upon semantic competition and inconsistent with an explanation based upon response competition

Do Eye Movements During Shape Discrimination Reveal an Underlying Geometric Structure?

Using a psychophysical approach coupled with eye-tracking measures, we varied length and width of shape stimuli to determine the objective parameters that corresponded to subjective determination of square/rectangle judgments. Participants viewed a two-dimensional shape stimulus and made a two-alternative forced-choice whether it was a square or rectangle. Participants’ gaze was tracked throughout the task to explore directed visual attention to the vertical and horizontal axes of space. Behavioral results provide threshold values for two-dimensional square/rectangle perception, and eye-tracking data indicated that participants directed attention to the major and minor principal axes. Results are consistent with the use of the major and minor principal axis of space for shape perception and may have theoretical and empirical implications for orientation via geometric cues

Geometric Encoding

Successful movement between locations first requires the determination of a direction of travel, and understanding the process of determining a direction is the central focus of orientation research. As shown in the top panel of Fig. 1, the general approach to understanding orientation involves training disoriented participants to respond to a particular location within a rectangular enclosure (left). Importantly, this location is often uniquely specified by a distinctive feature. Interestingly, tests in the absence of the distinctive features reveal that participants not only respond to the originally trained location but also to its 180° rotationally equivalent location (right). Responses to this 180° rotationally equivalent location are termed a rotational error (for a review, see Cheng et al. 2013)