Can auditory objects be subitized?

In vision, humans have the ability to mentally "tag" approximately 4 objects, allowing us to monitor, attend, and interact with them. As a consequence, we can rapidly and accurately enumerate up to 4 objects-a process known as subitizing. Here, we investigate whether a similar ability exists for tagging auditory stimuli and find that only 2 or 3 auditory stimuli can be enumerated with high accuracy. We assess whether this high accuracy indicates the existence of an auditory subitizing mechanism, and if it is influenced by factors known to influence visual subitizing. On the basis of accuracy, Experiments 1 and 2 reveal a potential auditory subitizing mechanism only when stimuli are spatially separated, as is the case for visual subitizing. Experiment 3 failed to show any evidence of auditory subitizing when objects were separated in time, rather than space. All three experiments provide only limited evidence for an age-related decline in auditory enumeration of small numbers of objects. This suggests that poor auditory tagging does not contribute significantly to older adults' difficulties in multitalker conversations. We hypothesize that although auditory subitizing might occur, it is restricted to approximately 2 spatially separated objects due to the difficulty of parsing the auditory scene into its constituent parts. (PsycINFO Database Record (c) 2018 APA, all rights reserved).