A comparison of visual and auditory representational momentum in spatial tasks

Abstract

Similarities have been observed in the localization of the final position of moving visual and moving auditory stimuli: Perceived endpoints that are judged to be farther in the direction of motion in both modalities likely reflect extrapolation of the trajectory, mediated by predictive mechanisms at higher cognitive levels. However, actual comparisons of the magnitudes of displacement between visual tasks and auditory tasks using the same experimental setup are rare. As such, the purpose of the present free-field study was to investigate the influences of the spatial location of motion offset, stimulus velocity, and motion direction on the localization of the final positions of moving auditory stimuli (Experiment 1 and 2) and moving visual stimuli (Experiment 3). To assess whether auditory performance is affected by dynamically changing binaural cues that are used for the localization of moving auditory stimuli (interaural time differences for low-frequency sounds and interaural intensity differences for high-frequency sounds), two distinct noise bands were employed in Experiments 1 and 2. In all three experiments, less precise encoding of spatial coordinates in paralateral space resulted in larger forward displacements, but this effect was drowned out by the underestimation of target eccentricity in the extreme periphery. Furthermore, our results revealed clear differences between visual and auditory tasks. Displacements in the visual task were dependent on velocity and the spatial location of the final position, but an additional influence of motion direction was observed in the auditory tasks. Together, these findings indicate that the modalityspecific processing of motion parameters affects the extrapolation of the trajectory.

The effect of velocity on auditory representational momentum

“…The lower range of RM size in our study is in line with the finding that action paradigms result in larger visual RM size than perceptual paradigms. 1 Results from stimuli moving toward the midline in the study by Schmiedchen et al 9 confirm the effect of target velocity found in this study. However, our results do not support the finding that stimuli moving toward the periphery resulted in an opposite effect of target velocity on RM size.…”

“…Also, the current study is the first to provide the full range of localization cues by using broadband noise stimuli. Besides the differences in response measurement paradigm described above, these factors influencing spatial information may be underlying the difference in findings compared to the studies by Getzmann et al 6 and Schmiedchen et al 9 The similarities between RM in the present study and visual RM suggests that our stimuli were adequate in engaging the RM mechanism at all velocities examined. Future studies are needed to clarify the effect of spatial information on auditory RM.…”

“…However, spatial information may play a role in the mechanism underlying RM, which is limited for example by the spatial acuity of the auditory system in the region of target endpoints, or by the target spectrum. Compared to the study by Schmiedchen et al, 9 localization acuity was higher in regions where targets moving toward the periphery ended. Also, the current study is the first to provide the full range of localization cues by using broadband noise stimuli.…”

“…Getzmann et al found a smaller RM for the faster target velocity with continuous targets. In Schmiedchen et al, 9 RM increased with target velocity for targets moving toward the midline, while targets moving toward the periphery resulted in the opposite effect. Such divergent results make it difficult to describe a model underlying auditory RM.…”

Age-related changes in sound localisation ability

“…This is mostly achieved by using a pointing task, where participants are instructed to indicate the perceived position of a sound source (Shankweiler 1961;Seeber et al 2010;Kerber and Seeber 2012;Kühnle et al 2012;Schmiedchen et al 2012Schmiedchen et al , 2013Freigang et al 2014a) or by alignment of the participant's head and gaze to the direction of the sound source (Lewald et al 2000). Another paradigm used to measure the localisation accuracy is the absolute identification task (Abel et al 2000), where participants have to indicate the sound direction by choosing one of several indicated sound source positions in an nalternative forced-choice task.…”