Boundary extension: Findings and theories

Abstract

A view of a scene is often remembered as containing information that might have been present just beyond the actual boundaries of that view, and this is referred to as boundary extension. Characteristics of the view (e.g., scene or nonscene; close-up or wide-angle; whether objects are cropped, static, or in motion, emotionally neutral or emotionally charged), display (e.g., aperture shape and size; target duration; retention interval; whether probes of memory involve magnification/minification or change in physical distance), and observer (e.g., allocation of attention; age; planned fixation, gaze direction, and eye movements; monocular or binocular viewing; prior exposure; neurological correlates) that influence boundary extension are reviewed. Proposed mechanisms of boundary extension (perceptual, memory, or motion schema; extension-normalization; attentional selection; errors in source monitoring) are discussed, and possible relationships of boundary extension to other cognitive processes (e.g., representational momentum; remembered distance and remembered size; amodal completion; transsaccadic memory) are briefly addressed.

Boundary Extension in Face Processing

“…In case of amodal completion, the information about the occluded parts of an object is not supported by sensory modalities. Hubbard et al (2010) proposed that, although object completion is unlikely to be the cause of BE, BE might induce amodal continuation/completion of a cropped object, as in case of a partially occluded object (Hubbard et al, 2010). Gottesman and Intraub (2002) proposed that amodal continuation of surfaces plays fundamental role in scene perception, especially for surfaces truncated by boundaries.…”

“…Although visual imagery and perception showed significant overlap, research highlighted that imagery involves more top-down processing and more prefrontal cortex involvement than perception (Ganis et al, 2004;Mechelli, Price, Friston, & Ishai, 2004). Hubbard et al (2010) showed that early visual processing areas were not involved in BE and proposed that BE is underpinned by high-level processes. These findings highlight the possible role of mental imagery in BE.…”

“…These findings may be explained by the role of BE in facilitation of the subsequent scene recognition . For instance, anticipating a movement may increase BE in the expected direction and may aid spatial integration of the successive views (Hubbard et al, 2010). Similarly, implied motion in frozen-motion pictures and abrupt disappearance of a moving target cause displacement in memory toward the direction of motion (Freyd, 1983;Freyd & Finke, 1984;Futterweit & Beilin, 1994).…”

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

“…Boundary extension is an error in scene representation in which memory overflows the boundaries of a view (Intraub & Richardson, 1989; see Hubbard, Hutchison, & Courtney, 2010; Intraub, 2010; Michod & Intraub, 2009). Why do we remember seeing what we clearly never saw?…”

No imagination effect on boundary extension

“…BE occurs when viewers falsely remember seeing a wider angle of a scene than they had actually studied (e.g., Hubbard, Hutchison, & Courtney, 2010). Source memory is the ability to keep track of where information came from (e.g., Johnson, Hashtroudi, & Lindsay, 1993;Lindsay, 2008).…”