Binocular fusion enhances the efficiency of spot-the-difference gameplay.

Kavitha Venkataramanan,Shrikant R Bharadwaj,Amithavikram R Hathibelagal,Swanandi Gawde,Guido Maiello

doi:10.1371/journal.pone.0254715

Kavitha Venkataramanan, Shrikant R Bharadwaj + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0254715

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Journal: PloS one	Publication Date: Jul 20, 2021
Citations: 6	License type: CC BY 4.0

Affiliation: L V Prasad Eye Institute

Abstract

Spot-the-difference, the popular childhood game and a prototypical change blindness task, involves identification of differences in local features of two otherwise identical scenes using an eye scanning and matching strategy. Through binocular fusion of the companion scenes, the game becomes a visual search task, wherein players can simply scan the cyclopean percept for local features that may distinctly stand-out due to binocular rivalry/lustre. Here, we had a total of 100 visually normal adult (18-28 years of age) volunteers play this game in the traditional non-fusion mode and after cross-fusion of the companion images using a hand-held mirror stereoscope. The results demonstrate that the fusion mode significantly speeds up gameplay and reduces errors, relative to the non-fusion mode, for a range of target sizes, contrasts, and chromaticity tested (all, p<0.001). Amongst the three types of local feature differences available in these images (polarity difference, presence/absence of a local feature difference and shape difference in a local feature difference), features containing polarity difference was identified as first in ~60-70% of instances in both modes of gameplay (p<0.01), with this proportion being larger in the fusion than in the non-fusion mode. The binocular fusion advantage is lost when the lustre cue is purposefully weakened through alterations in target luminance polarity. The spot-the-difference game may thus be cheated using binocular fusion and the differences readily identified through a vivid experience of binocular rivalry/lustre.

Highlights

IntroductionIn a typical spot-the-difference game (Fig 1), differences in local features of two otherwise identical scenes are detected using an eye scanning (saccadic eye movements) and visual matching strategy
In a typical spot-the-difference game (Fig 1), differences in local features of two otherwise identical scenes are detected using an eye scanning and visual matching strategy
These results suggest that as long as binocular lustre is experienced from the polarity differences in the local features, they will stand-out in the fusion mode of gameplay and become readily amenable for identification, independent of how large the local feature difference is or what the contrast difference is between the local feature pairs

Summary

Introduction

In a typical spot-the-difference game (Fig 1), differences in local features of two otherwise identical scenes are detected using an eye scanning (saccadic eye movements) and visual matching strategy. The differences typically used in such images include a polarity change in the local feature, presence/absence of the local feature and shape difference in the local feature (Fig 1) This game is challenging to play for two reasons. It imposes a significant cognitive load on the player as they have to scan the scene for a given feature and remember it, saccade to the companion scene and re-scan it for a matching feature and identify changes in the scanned feature, amongst all other distractors. This task is akin to the well-established.

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