Why does vantage point affect boundary extension?

Setting the scene for boundary extension: Methods, findings, connections, and theories

A previously viewed scene is often remembered as containing a larger extent of the background than was actually present, and information that was likely present just outside the boundaries of that view is often incorporated into the representation of that scene. This has been referred to as boundary extension. Methodologies used in studies on boundary extension (terminology, stimulus presentation, response measures) are described. Empirical findings regarding effects of characteristics of the stimulus (whether the stimulus depicts a scene, semantics of the scene, view angle, object size, object cropping, object orientation, object color, number of objects, depth of field, object distance, viewpoint production, scene orientation, motion, faces, emotions, modality, whether the scene is multimodal), characteristics of the display (aperture shape, aperture size, target duration, retention interval), and characteristics of the observer (allocation of attention, imagination, age, expectations and strategies, eye fixation, eye movements, monocular or binocular view, vantage point, confinement, prior exposure, expertise, arousal, pathology) on boundary extension are reviewed. Connections of boundary extension to other cognitive phenomena and processes (evolutionary adaptation, Gestalt principles, illusions, psychophysics, invariant physical principles, aesthetics, temporal boundary extension, normalization) are noted, and theories and theoretical considerations regarding boundary extension (multisource model, boundary transformation, mental imagery, 4E cognition, cognitive modularity, neurological mechanisms of scene representation) are discussed.

Does Boundary Extension Need Attention?

When we look at a picture, we tend to remember it by enriching the constructed mental representation with elements not present but probable outside the current view. The tendency to remember the perceived view with a broader scope is known as boundary extension (BE). Does BE benefit from paying reduced attention to the picture? While attention plays a central role in memory, only a few studies to date have investigated this question in the field of BE. In this research, participants completed a BE task in single- and dual-task conditions. The results indicate that BE is eliminated when the attention is divided on the onset of scene construction. We therefore discuss the role of attention in BE.

Predictive Processing of Scene Layout Depends on Naturalistic Depth of Field

Boundary extension is a classic memory illusion in which observers remember more of a scene than was presented. According to predictive-processing accounts, boundary extension reflects the integration of visual input and expectations of what is beyond a scene's boundaries. According to normalization accounts, boundary extension rather reflects one end of a normalization process toward a scene's typically experienced viewing distance, such that close-up views give boundary extension but distant views give boundary contraction. Here, across four experiments (N = 125 adults), we found that boundary extension strongly depends on depth of field, as determined by the aperture settings on a camera. Photographs with naturalistic depth of field led to larger boundary extension than photographs with unnaturalistic depth of field, even when distant views were shown. We propose that boundary extension reflects a predictive mechanism with adaptive value that is strongest for naturalistic views of scenes. The current findings indicate that depth of field is an important variable to consider in the study of scene perception and memory.

Objects influence the shape of remembered views: examining global and local aspects of boundary extension

Boundary extension is a constructive memory error for views of scenes in which viewx tendto be remembered as more spatially expansive than they appeared. In seven experiments xwe examinedwhether local differences in boundary extension within views might exist by presenting par ticipants ith overhead views of single, elongated objects or object pairs on textured ground surfaces i:n whichobjects were oriented either vertically or horizontally. Memory for views' spatial expanse xwas testedwith either a view-recognition test or a border-adjustment test in which participants could ad just thespatial expanse of a test view using the computer's mouse. The border-adjustment test was uused tossess local boundary extension (primarily); the view-recognition test was used to assess paparticipants'emories for the overall spatial expanse of views (ie global boundary extension). Across exexperiments,n the border-adjustment tests specifically, participants showed more spatial expanse along the obobject'songer axis, in some cases restricting the view along the object's shorter axis. In addition, the rerecognition-t data revealed greater boundary extension for views with vertically oriented objects than for x.iviewsth horizontally oriented objects. Taken together, the results suggest that objects in scene x iviews canfect both local and global aspects of memory for spatial expanse of scene views.

Fixating picture boundaries does not eliminate boundary extension: implications for scene representation

Observers frequently remember seeing more of a scene than was shown (boundary extension). Does this reflect a lack of eye fixations to the boundary region? Single-object photographs were presented for 14-15 s each. Main objects were either whole or slightly cropped by one boundary, creating a salient marker of boundary placement. All participants expected a memory test, but only half were informed that boundary memory would be tested. Participants in both conditions made multiple fixations to the boundary region and the cropped region during study. Demonstrating the importance of these regions, test-informed participants fixated them sooner, longer, and more frequently. Boundary ratings (Experiment 1) and border adjustment tasks (Experiments 2-4) revealed boundary extension in both conditions. The error was reduced, but not eliminated, in the test-informed condition. Surprisingly, test knowledge and multiple fixations to the salient cropped region, during study and at test, were insufficient to overcome boundary extension on the cropped side. Results are discussed within a traditional visual-centric framework versus a multisource model of scene perception.

When less is more: Line-drawings lead to greater boundary extension than color photographs

Is boundary extension (false memory beyond the edges of the view; Intraub & Richardson, 1989) determined solely by the schematic structure of the view or does the quality of the pictorial information impact this error? To examine this color photograph or line-drawing versions of 12 multi-object scenes (Experiment 1: N=64) and 16 single-object scenes (Experiment 2: N=64) were presented for 14-s each. At test, the same pictures were each rated as being the "same", "closer-up" or "farther away" (5-pt scale). Although the layout, the scope of the view, the distance of the main objects to the edges, the background space and the gist of the scenes were held constant, line-drawings yielded greater boundary extension than did their photographic counterparts for multi-object (Experiment 1) and single-object (Experiment 2) scenes. Results are discussed in the context of the multisource model and its implications for the study of scene perception and memory.