Some crossmodal effects hold up under load, others do not
The clearest evidence for resistance comes from audiovisual integration of simple stimuli. When researchers varied working memory load, the spatial congruency effect in audiovisual integration stayed consistent across load conditions, which the authors describe as robust and resistant to cognitive load [3]. In other words, at least one basic crossmodal integration task did not lose its effect when the person's working memory was busier.
Resistance is not universal, however. In value-driven crossmodal spatial attention, high-value stimuli are reported to be more resistant to load effects, which implies that lower-value stimuli are not equally resistant [2]. That study also indicates that cognitive load from an auditory task mainly affected the speed of processing rather than the final perceptual integration [2]. So even within one crossmodal paradigm, load can change how quickly something is processed without necessarily changing the end product.
Why the task and the measure matter
A crossmodal effect is not a single thing. It can refer to how two senses are combined into one percept, how attention is drawn to a location, or how quickly a stimulus is processed. The evidence suggests that load resistance depends on which of these is being measured. Spatial congruency in audiovisual integration remained stable under working memory load [3], while in a crossmodal attention task load primarily changed processing speed rather than the ultimate perceptual integration [2]. A result that looks like resistance on one measure could therefore coexist with a load effect on another.
The broader literature frames this as an open question: whether the automaticity and resistance to cognitive load reported for some cross-modal effects are a general property of multisensory processing or are specific to particular effects [1]. The studies that directly manipulated load point toward task-specificity rather than a single general rule [2][3].
What counts as cognitive load changes the answer
The type of load matters too. In the audiovisual integration study, the load was working memory load [3]. In the value-driven attention study, the load came from an auditory task and affected processing speed [2]. These are different kinds of mental burden, so a crossmodal effect that survives one may not survive another. The question of whether resistance is general therefore depends partly on which load is being tested.
Some studies examine cognitive load without testing resistance to it. For example, one study looked at how cognitive load affects perceived distraction from irrelevant speech and its relationship with attentional control, but it did not ask whether a crossmodal effect resisted load [4]. Another assessed cognitive load from EEG and peripheral biosignals for visually impaired mobility aids and mentioned cross-modal relations, but resistance to cognitive load was not its focus [5]. These studies do not settle the general-versus-specific question, but they show that cognitive load is used in many different research contexts.
Sources used in this answer
Multisensory integration: unveiling the complexities of perception
The paper examines whether automaticity and resistance to cognitive load in cross-modal effects are a general property of multisensory processing or specific to particular effects.
Value‐Driven Crossmodal Spatial Attention: The Role of Perceptual Load
In value-driven crossmodal spatial attention, high-value stimuli are more resistant to load effects, and cognitive load from an auditory task primarily impacts processing speed rather than ultimate perceptual integration.
Audiovisual integration of simple stimuli: spatial congruency effects unaffected by working memory load
Audiovisual integration of simple stimuli, specifically spatial congruency effects, remained consistent across working memory load conditions, indicating resistance to cognitive load in that task.
Effects of cognitive load on perceived internal and external distraction and their relationship with attentional control
The study investigated how cognitive load affects perceived distraction from irrelevant speech and its relationship with attentional control, without addressing resistance to cognitive load.
Research Article Cognitive Load Assessment from EEG and Peripheral Biosignals for the Design of Visually Impaired Mobility Aids
The study assessed cognitive load from EEG and peripheral biosignals for visually impaired mobility aids and mentioned cross-modal relations, but did not focus on resistance to cognitive load.