Transsaccadic representation of layout: What is the time course of boundary extension?

Abstract

How rapidly does boundary extension (BE) occur? Across experiments, trials included a 3-scene sequence (325 ms/picture), masked interval, and repetition of one scene. The repetition was the same view or differed (more close-up or more wide-angle). Observers rated the repetition as same, closer, or more wide-angle than the original view on a 5-point scale. Masked intervals were 100, 250, 625, or 1000 ms in Experiment 1, and 42, 100, or 250 ms in Experiments 2 and 3. BE occurred in all cases: identical views were rated as too "close-up", and distractor views elicited the rating asymmetry typical of BE (wider-angle distractors were rated as being more similar to the original than were closer-up distractors). Most important, BE was evident when only a 42-ms mask separated the original and test views. Experiments 1 and 3 included conditions eliciting a gaze shift prior to the rating test; this did not eliminate BE. Results show that BE is available soon enough and is robust enough to play an on-line role in view integration, perhaps supporting incorporation of views within a larger spatial framework.

No imagination effect on boundary extension

“…In the RSVP procedure, participants are asked to remember three or four specific photographs for a much shorter duration of time, which might contribute to this different pattern for CW trials than with the blocked procedure. Dickinson and Intraub (2008) did vary the study time in an RSVP procedure, but with a much smaller range (42-1,000 ms), and found no effect of study time on BE. Regardless of the procedure, BE patterns were observed, and elaboration did not influence the BE ratings.…”

“…There were two versions of each picture: a wide-angle view, as well as a close-up that was either 10 %, 15 %, or 20 % enlarged and then cropped to the same size as the original (720 × 480 pixels). Dickinson and Intraub (2008) had close-up views that were 8 %-21 % enlargements of the wide-angle views. Both the wide-angle and close-up versions were the same size, but more background was visible in the wide-angle versions (see Fig.…”

“…Thus, Experiments 2a and 2b also involved a different method, in which a series of pictures was presented followed by an immediate memory test using one of the pictures, similar to the design of Dickinson and Intraub (2008). The first block presented standard instructions, and a second block presented elaboration instructions to imagine sounds and odors; this within-participants design also increased the range of conditions under which we explored the relationship between imagination and BE.…”

Visual, haptic and bimodal scene perception: Evidence for a unitary representation

“…Yet, even when perception is limited to the visual modality alone participants frequently remember seeing the continuation of the scene just beyond the boundaries of the view, in the absence of any corresponding sensory input ( boundary extension; Intraub & Richardson, 1989). This can occur very rapidly, across intervals as brief as a saccadic eye movement (Dickinson & Intraub, 2008; Intraub and Dickinson, 2008). Boundary extension may be an adaptive error that facilitates integration of successive views of the world (Hubbard, Hutchison, & Courtney, 2010; Intraub, 2010, 2012).…”

“…Intraub and colleagues (Dickinson & Intraub, 2008; Intraub & Dickinson, 2008; Intraub, 2010; Gagnier & Intraub, 2012; Gagnier, Dickinson & Intraub, 2013) suggest that scene representation is fundamentally an act of spatial cognition. In their multisource model they propose that an amodal spatial structure organizes multiple sources of knowledge (bottom-up and top-down) into a coherent scene representation (see Maguire & Mullally, 2013, for a similar view from the perspective of hippocampal function).…”