April 2023 Newsletter: Selective Auditory Attention: How Our Brain Keeps Us Focused

Have you ever been so engrossed reading something that you didn’t hear someone talking to you? Or hard at work while listening to music and suddenly realize you weren’t really listening for the last few minutes? Although our ears may hear all of the things going on around us, sometimes our brains tune out distracting or irrelevant sounds to help us focus or keep us from becoming overwhelmed as a result of large quantities of sensory information. This phenomenon is known as selective auditory attention and is a topic that falls within the broader subject of psychoacoustics. Read on to learn more about how humans can tune out the world around them.

The field of psychoacoustics encompasses a variety of topics including frequency response, sound intensity, and sound localization, but today we focus on the brain’s ability to selectively focus on certain sounds while leaving others in the background. Some of our previous newsletters have discussed how our ears work from a mechanical standpoint; in summary, acoustic energy in the air is transduced as mechanical energy by our ears. Through a complex process involving organs and neuron networks, the mechanical energy is converted to electrical signals our brains receive and interpret as sound.

Selective auditory attention sometimes seems as simple as not focusing on irrelevant background noise. For instance, the background sound level inside a house may be elevated by traffic noise from a busy street; however, most of the time, our brains choose to focus not on the traffic noise, but instead on more relevant sounds, such as the voices of people around us. This effect can be so pronounced that we “do not hear” the traffic noise. If the background sound changes in level, frequency, or intensity, the noise may shift back into our perception. For example, a loud truck going down the street may cause your brain to shift attention to the constant traffic noise again for a time.

Selective auditory attention can also help to pick out a specific sound amongst multiple other sounds. Sometimes referred to as the cocktail party effect, this phenomenon refers to our brains’ ability to focus on a single conversation in a noisy room. We are able to separate competing conversations into different streams and then decide which streams are most important. The determination of different streams is completed through complex analysis of a multitude of factors. Sound localization helps us identify different sound sources and their locations, working with frequency and intensity perception to filter and separate sources into categories. All of this happens in a fraction of a second, resulting in the ability to comprehend a single conversation within the interference of multiple distracting sounds.

Most sensory perception and analysis occur automatically without active thought. Selective auditory attention is no different, aiding us even without our realization that it is happening at all. It’s another reminder of just how powerful the human brain and the process of hearing is. So, the next time your significant other is talking to you and you’re not listening, tell them it’s your selective auditory attention!

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