Abstract
Multiple identity tracking – tracking of distinct moving objects - has been studied in the visual modality for 15 years (see Oksama & Hyönä, 2004, 2008, 2016; Horowitz et al., 2007). However, the visual modality is not the only modality to be used for tracking moving object identities in every-day environments. In real-life there are many occasions when we do not see the targets but we can hear them. For instance, in the military context, a dismounted soldier may hear gunshots around him/her without seeing the shooters. It is extremely important for him/her to able to track the whereabouts of the auditory sources. This raises an important question of the efficiency of tracking multiple moving target identities in the auditory modality. Is the tracking capacity for the auditory modality similar to that in the visual modality (estimate is about 2–3, see Horowitz et al., 2007; Oksama & Hyönä, 2008)? Maybe the auditory modality makes multiple identity tracking more difficult? Alternatively, the capacity limitation may be constrained by higher level cognition and would not be affected by modality. To our knowledge, there is no previous research on this matter. To study this question, we conducted an old-school non-computerized auditory tracking experiment in a gym hall. Participants (N=30), seated in the center of the hall, tracked distinct moving auditory target identities. Four assistants moved quasi-randomly around the blindfolded participant and at the same time repeated orally their names. Two, 3 or 4 moving assistants were designated as targets. The results showed that the auditory tracking accuracy decreased sharply as a function of target-set size (2 targets: 86%; 3 targets: 72 %; 4 targets: 57%). The comparison of the present results to visual tracking suggests that the auditory tracking capacity is much smaller than visual capacity, maybe only a bit more than one target.
Acknowledgement: Academy of Finland, grant #273413