What You Hear Affects What You See
There are a lot of different models of attention, and the differences between them can be complex and subtle. Most of them, however, treat attention as a limited and expendable resource — you can only pay attention to so many things for so long a time. Is attention really in short supply?
Attention is usually not modality specific: For example, if you’re making a lot of effort paying attention to something that you’re seeing, you’re not likely to be able allocate attention to an acoustic cue as well. In short, there isn’t a store of visual attention, a separate store of aural attention, another one for tactile attention, and so on. There’s just one central store of attention.
Recent evidence has also led many researchers believe that rhythms entrain the attentional system so that it increases the amount of attention allocated at certain temporal locations. For example, if you see a blinking light, neural oscillations will synchronize with the rhythm of the blinking, so that you’re paying more attention at the points when the light is likely to be on.
A study published earlier this year used a fascinating methodology to determine whether or not this entrainment is cross-modal. Participants heard a tone played at regular or irregular intervals for a specified amount of time. At the end, a dot would appear in one of the four corners of a screen (the appearance of the dot was either synchronized with the final tone in the series, played earlier than the tone, or played later than the tone) and the participants would look at it. The researchers measured how long it took the participants to fixate on the dot.
Interestingly, participants were significantly faster to fixate on the dot when it was synchronized with the final tone than when it was not, suggesting that the visual attentional system was entrained by the aural tone series. When the experimenters omitted the final tone, the results remained the same, proving that it wasn’t the final tone itself that speeded up fixation, but the rhythm that preceded it.
Another important note is that participants weren’t directed to attend to the auditory tones. In fact, they weren’t told anything about them at all, suggesting that the entrainment of the attentional system is automatic and unconscious.
Although they may seem intuitively obvious, these findings lend additional insight into how attention works, and give major support to the idea that attention is a limited resource that is shared between different perceptual modalities, and provides proof that entrainment developed through one modality is accessed by other modalities.
Research on neural oscillation has been quite fruitful recently, and this is another example of how this is at the core of processes that we take for granted, like rhythmic attentional entrainment and many other temporal processes in the brain. Exactly how this low-level process is integrated into higher-level systems, like time-keeping and attention, is likely to see a lot more research in the near future.
Miller JE, Carlson LA, & McAuley JD (2013). When what you hear influences when you see: listening to an auditory rhythm influences the temporal allocation of visual attention. Psychological science, 24 (1), 11-8 PMID: 23160202