Cross-Modal Interactions Differ Across Sounds in the Extreme Periphery

Visual detection can be facilitated or inhibited by the simultaneous presentation of non-visual sensory signals. Adding a sound to a difficult visual detection task in the fovea or parafovea typically results in improved task performance. The effect of multisensory stimulation is less straightforward at the edge of the visual field, also known as the extreme periphery. Past research has indicated that not all auditory signals are integrated equally with visual signals in the extreme periphery. Certain sounds may have an inhibiting effect on the detection of visual targets whilst others can facilitate visual detection. Here we systematically investigate the cueing effect of different sounds on detection of extremely peripheral targets. Angular thresholds for visual detection were mapped with separate staircases for left/right peripheral flashes paired with: 1Khz (HIGH) or 300Hz (LOW) beep, White NOISE burst, or NO sound. Observers (N=8) responded "Left", "Right", or "No Target" for the visual target location. Observers were able to detect and correctly localize visual targets at significantly higher eccentricities with LOW sound pairings (M=96.66 degrees) compared to the other conditions (HIGH, M=93.24 degrees; NOISE, M=92.97 degrees; NO, M=92.93 degrees; Repeated Measures ANOVA p<.001, all post-hoc t-test showed LOW pairings p<.05, all others n.s.). The results may relate to differences in localizability for the sounds and their effects on spatial attention. These findings contribute to the understanding of sensory integration at the edge of vision and support previous indications that not all sounds play the same role in visual detection in the extreme periphery of healthy human vision.