The primary goal of the empirical research outlined in this thesis was to examine a number of the factors contributing to the design of more ergonomic multisensory warning signals, that is, signals that elicit efficient and effective responses from interface operators under demanding conditions. To achieve this goal, a series of experiments was conducted in order to examine the nature and consequences of the crossmodal links inherent in spatial attention between various different sensory modalities, such as audition, vision, and touch, in an applied setting. In particular, a laboratory-based simulated driving task was used to investigate the effectiveness of various different auditory and vibrotactile cues in orienting a driver's attention to potential emergency driving events seen through the front windscreen or rearview mirror. The results of the first set of auditory spatial cuing experiments highlighted a significant performance advantage when the target driving events occurred in the cued, rather than the uncued, direction, with the biggest benefits being seen following spatially-predictive auditory or verbal cues. The second set of vibrotactile spatial cuing experiments demonstrated the potential utility of vibrotactile warning signals for presenting spatial information to car drivers, and the results were successfully replicated in a study using a high-fidelity driving simulator. The third set of experiments, incorporating an orthogonal task design, were conducted in order to examine the mechanisms responsible for the advantageous spatial cuing effects reported in the earlier experiments. Taken together, the results demonstrated that while directional congruency between a warning signal and target driving event may be sufficient to facilitate performance due to the priming of the appropriate response, attentional facilitation (i.e., perceptual enhancement) typically requires the co-location of the cue and target within the same functional region of space. In sum, this thesis demonstrates the potential value of approaching the design of effective multisensory warning signals for human operators by studying the information processing mechanisms in the human brain. The findings outlined here add to the literature concerning the brain's differential representation of stimuli presented in peripersonal as opposed to extrapersonal space. Further experimental chapters detail experiments that examined verbal directional cuing, olfactory cuing, and crossmodal interactions in virtual haptic environments.