Salient object changes influence overt attentional prioritization and object-based targeting in natural scenes.

Nicola C Anderson,Mieke Donk,Leonardo Chelazzi

doi:10.1371/journal.pone.0172132

Abstract

A change to an object in natural scenes attracts attention when it occurs during a fixation. However, when a change occurs during a saccade, and is masked by saccadic suppression, it typically does not capture the gaze in a bottom-up manner. In the present work, we investigated how the type and direction of salient changes to objects affect the prioritization and targeting of objects in natural scenes. We asked observers to look around a scene in preparation for a later memory test. After a period of time, an object in the scene was increased or decreased in salience either during a fixation (with a transient signal) or during a saccade (without transient signal), or it was not changed at all. Changes that were made during a fixation attracted the eyes both when the change involved an increase and a decrease in salience. However, changes that were made during a saccade only captured the eyes when the change was an increase in salience, relative to the baseline no-change condition. These results suggest that the prioritization of object changes can be influenced by the underlying salience of the changed object. In addition, object changes that occurred with a transient signal (which is itself a salient signal) resulted in more central object targeting. Taken together, our results suggest that salient signals in a natural scene are an important component in both object prioritization and targeting in natural scene viewing, insofar as they align with object locations.

Highlights

A key question in research on attention and oculomotor control in natural scene viewing is the extent to which eye movements and attention may be governed by the low-level visual features of the scene or more high-level, cognitive factors
In order to simplify the analysis, the proportion of eye movements that landed on the critical object in the case in which no change occurred was subtracted from the proportion of eye movements that landed on the object in the case in which changes were made during a saccade and during a fixation
A 2 (Trial type) by 4 (Fixation index) by 2 (Direction of change) mixed analysis of variance was conducted on the proportion of first eye movements that landed on the object

Summary

Introduction

A key question in research on attention and oculomotor control in natural scene viewing is the extent to which eye movements and attention may be governed by the low-level visual features of the scene or more high-level, cognitive factors. This has been the focus of much debate; it is becoming increasingly clear that while bottom-up stimulus features play a role in where people look, this is heavily influenced by cognitive factors. Evidence that bottom-up, stimulus features influence oculomotor control stems from early attempts to model visual attention via a ‘salience map’ [1,2]. There is evidence that such models perform fairly well in predicting

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