Attentional load affects multisensory integration, but not spatial processing

Can we accurately process what happens in the space around us, even when our mind is overloaded? In a recent study carried out by Maria Silvia Saccani and collaborators, more than 180 participants took part in two online experiments to address this question. Since potential asymmetries in spatial processing may go unnoticed under normal conditions, the researchers introduced a state of perceptual uncertainty: a particularly ambiguous context ideal for revealing subtle differences between stimuli presented on the right or left side of space, and for gaining insight into how our cognitive system functions under complex conditions. Specifically, participants performed an audiovisual integration task in which stimuli capable of inducing the sound-induced flash illusion (i.e., visual stimuli paired with an incongruent number of sounds) were presented either on the right or left side of space. This setup allowed for the study of audiovisual integration while also offering an indirect way to examine spatial processing in a complex context.
The results showed that the illusion became more pronounced as attentional load increased, suggesting that even seemingly automatic processes like multisensory integration are influenced by the availability of attentional resources. However, contrary to what is observed in individuals with brain damage, no differences emerged between left- and right-sided stimuli: in healthy cognitive systems, attention appears to remain spatially balanced, even under cognitive stress. Since both experiments produced similar outcomes, it seems that the amount of attentional engagement, rather than the type of attentional resources involved, played a critical role.

Articolo: Saccani, M. S., Contemori, G., Del Popolo Cristaldi, F., & Bonato, M. (2025). Attentional load impacts multisensory integration, without leading to spatial processing asymmetries. Scientific Reports, 15(1), 1-19.
https://doi.org/10.1038/s41598-025-95717-0