The odd one out – what does your brain pay attention to?
Second-year Psychology students participating in the University Honours College or in the Departmental Excellence Program complete a Research Seminar in which they learn to communicate science to various audiences, including the general public. For one assignment, the students write a popular science paper. This year a selection of these papers is published on Mindwise. Today’s piece is by Pia Kreijkes.
Imagine you are in your local supermarket with the quest to buy some fruit. You are skimming over the display of Granny Smith apples, when your attention is suddenly caught by a single apple. Which one could that be? The odd one out! When you see one green apple after the other and then unexpectedly encounter a red one amongst them, you will probably attend to this apple more than to the others. The processing of novel stimuli, such as an apple that stands out of the crowd, appears to have a priority for the brain (Schonmaker, & Meeter, 2014).
Now picture yourself leaving the store. When you are stepping outside, stop and listen to the sounds that surround you. You may hear a car engine, people laughing, or dogs barking. This auditory composition of the noises of a city, is also called an urban soundscape. It is the hearing environment in which one is immersed at a given moment. As attending to the whole soundscape at once demands too much of your brain’s processing capacities, you usually focus on only some sounds. Which ones could that be? The odd ones out? It may be the screeching of tires indicating the danger of a quickly approaching car, or even the twittering of a bird.
“As attending to the whole soundscape at once demands too much of your brain’s processing capacities, you usually focus on only some sounds.”
Supervised by Dr. Jacob Jolij and Dr. Mijke Hartendorp, a group of Honours students including myself asked ourselves how we could investigate which city sounds are particularly likely to catch a listener`s attention. More specifically, we examined the possibility of identifying to which sounds persons attend at a given moment, based on their brain activity. This would be an advantage over relying on their subjective reports, because people would be less distracted by monitoring what they are currently hearing.
To record the brain activity that is elicited by listening to particular sounds, we used an electroencephalogram (EEG). Our first experiment involved a listening task known as the auditory oddball paradigm, in which a rare target sound (for example, the twittering of a bird) is randomly presented among more frequent distractor sounds (car engines). The listeners counted how many birds they heard, and tried to ignore the cars, while their brain activity was being recorded. This kind of experiment had been conducted before, however, unlike in most previous studies we used naturally recorded sounds rather than simple beeps. This way our results could be generalized to the real world.
In the second experiment we took the first study even a step further: rather than presenting single sounds, we presented a whole urban soundscape. This consisted of an ongoing stream of sounds recorded in the nearby town of Assen. It included cars, motorbikes, voices, and birds, and this represents an actual street ambiance. As before, participants were asked to count all birds while trying to ignore everything else. The added complexity in studying natural stimuli is highly challenging; nevertheless, we hoped that the EEG signals would show to which sounds the listeners attended.
“Much effort is given to improve the auditory soundscapes of today’s cities. These are characterized by the ever-increasing noise pollution that may pose severe health risks for citizens”
Knowing to which sounds people attend in an urban environment may have implications for urban planning. Much effort is given to improve the auditory soundscapes of today’s cities. These are characterized by the ever-increasing noise pollution that may pose severe health risks for citizens. One approach might be to reduce the overall noise level. However, this may not be enough; Dubois and Raimbault (2005) reason that loudness alone is not necessarily disturbing. For instance, subjective evaluations depend on not only the physical properties but also on the nature of the sounds. Whereas one may find loud cars bothersome, loud children might be experienced as less disturbing. What might also matter is whether a person actually attends to a sound or not. If one did not consciously hear it, one would supposedly not find it disturbing.
The question arises whether all people tend to pay attention to the same sounds or not. It could very well be that there are certain sounds that stick out regardless of who is listening to them; these might be attention-grabbing in general. If this line of research proves to be successful, it might be possible to find the odd sounds in our cities’ auditory environments. In other words, we may identify which city sounds stand out against the others, just as a red apple stands out against the green ones. These sounds could then become the target of deliberate interventions that benefit all of us living in noisy cities.
We thank INCAS3, particularly the members of the Cognitive Systems Group, for the inspiration and discussion which led to the idea for this study.
Raimbault, M., & Dubois, D. (2005). Urban soundscapes: Experiences and knowledge. Cities, 22(5), 339–350. doi:10.1016/j.cities.2005.05.003
Schomaker, J. J., & Meeter, M. M. (2014). Novelty detection is enhanced when attention is otherwise engaged: An event-related potential study. Experimental Brain Research, 232(3), 995-1011. doi:10.1007/s00221-013-3811-y
Author: Pia Kreijkes
Bio: In 2013-2014 Pia Kreijkes was a second-year Bachelor student in the English psychology program as well as in the University Honours program. She is spending the Fall of her third year as an exchange student in Montreal, Canada, taking courses at McGill University and completing a research internship at the St. Justine Hospital. Pia’s main interests lie in developmental neuropsychology and educational psychology. In particular, she is interested in the influences of early childhood experiences on brain development and children’s motivation to learn and succeed in school. Besides her studies, she is a student editor for Mindwise and a reviewer for the Groningen student journal Honours Review.