Predictive processes of object-scene integration support attentional and memory mechanisms in healthy and pathological cognitive ageing

The consistency between the semantics of an object and its embedding scene (e.g., a torch vs. toothpaste in a bathroom) modulates its attentional prioritization (e.g., foveal vs. extrafoveal effects) and memory processes associated with it (e.g., the strength of encoding). Yet, little is known about the influence of healthy and pathological cognitive ageing on these mechanisms. In two independent eye-tracking studies: (a) younger (N = 26) and healthy older participants (N = 24), and (b) people with MCI (N = 30) and healthy age-matched controls (N = 32) were asked to detect whether an object, either consistent or inconsistent with the scene context, changed on its identity (became another object), location (moved to another position) or concurrently both these features. During successful recognitions, only younger participants displayed a significantly higher probability of fixating as first targets on inconsistent objects compared to consistent ones. When the object remained in the same spatial location (i.e., identity change) all groups displayed a shorter latency of first fixation for objects encoded as inconsistent. Moreover, in general, gaze duration was higher for inconsistent compared to consistent objects, again independent of age or pathology. Finally, changes happening on inconsistent objects were detected better across all groups but only when they moved location, which is the only condition where the object maintains the same consistency between encoding and recognition. Overall, our results extend our understanding of object-scene integration mechanisms, a timely topic in vision science, by revealing that object semantics guides early overt attention and influences short-term memory processes independently of healthy, and even pathological, cognitive ageing. The only subtle age-related difference we observed was possibly a decline in the useful field of view, which has reduced the accessibility of object semantics in extrafoveal vision.