Blending into naturalistic scenes: Cortical regions serving visual search are more strongly activated in congruent contexts

Abstract

Visual attention allows us to navigate complex environments by selecting behaviorally relevant stimuli while suppressing distractors, through a dynamic balance between top-down and bottom-up mechanisms. Extensive attention research has examined the object-context relationship. Some studies have shown that incongruent object-context associations are processed faster, likely due to semantic mismatch-related attentional capture, while others have suggested that schema-driven facilitation may enhance object recognition when the object and context are congruent. Beyond the conflicting findings, translation of this work to real world contexts has been difficult due to the use of non-ecological scenes and stimuli when investigating the object-context congruency relationship. To address this, we employed a goal-directed visual search task and naturalistic indoor scenes during functional MRI (fMRI). Seventy-one healthy adults searched for a target object, either congruent or incongruent within the scene context, following a word cue. We collected accuracy and response time behavioral data, and all fMRI data were processed following standard pipelines, with statistical maps thresholded at p < .05 following multiple comparisons correction. Our results indicated faster response times for incongruent relative to congruent trials, likely reflecting the so-called pop-out effect of schema violations in the incongruent condition. Our neural results indicated that congruent elicited greater activation than incongruent trials in the dorsal frontoparietal attention network and the precuneus, likely reflecting sustained top-down attentional control to locate the targets that blend more seamlessly into the context. These findings highlight the flexible interplay between top-down and bottom-up mechanisms in real-world visual search, emphasizing the dominance of schema-guided top-down processes in congruent contexts and rapid attention capture in incongruent contexts.

Keywords: Context incongruency; Ecological stimuli; Frontoparietal; Visual attention; fMRI.

Fig. 1.. Task Design & Behavioral Results.

(Top panel): Each trial began with a 500 ms cue word indicating the target item, followed by a 1000 ms fixation cross. The target object was then presented within an indoor scene for 4000 ms, during which participants freely searched for the target. Participants responded as to the side of the target object (left or right) using a button pad and responses were recorded during the scene presentation and within 1000 ms after its offset. A variable inter-trial interval of 750 to 1250 ms followed. “Congruent trials” featured objects consistent with the scene, while “incongruent trials” featured objects inconsistent with the scene. (Bottom panel): While the accuracy data did not show any conditional differences, there was a significant reaction time (RT) difference, with participants being slower during congruent compared to incongruent trials. Asterisks indicate significant differences between conditions. *p = .001.

Fig. 2.. Overall task effect.

Three-dimensional rendered projections and cross-sections showing dorsal frontoparietal activations, as well as activations in the bilateral anterior insula, occipital visual cortices, and other regions, elicited by the overall effect of task execution. The task execution contrast averaged activity across conditions (correct trials only). Results are displayed at a cluster-level corrected p-FWE = .05, with a minimum cluster size of 200 used for visualization only.

Fig. 3.. Brain Regions Exhibiting Stronger Activation in the Congruent Condition.

Three-dimensional rendered projections and cross-sections showing dorsal frontoparietal (FEF and IPS bilaterally), precuneus, and visual occipital cortical regions where activation was stronger during congruent compared to incongruent trials. No brain regions exhibited stronger activation during incongruent trials. Results are displayed at a cluster-level corrected p-FWE = .05, with a minimum cluster size of 200 used for visualization only.