Dichotic Listening

Overview

Source: Laboratory of Jonathan Flombaum—Johns Hopkins University

It is a well-known fact that the human ability to process incoming stimuli is limited. Nonetheless, the world is complicated, and there are always many things going on at once. Selective attention is the mechanism that allows humans and other animals to control which stimuli get processed and which become ignored. Think of a cocktail party: a person couldn’t possibly attend to all of the conversations taking place at once. However, everyone has the ability to selectively listen to one conversation, leading all the rest to become unattended to and nothing more than background noise. In order to study how people do this, researchers simulate a more controlled cocktail party environment by playing sounds to participants dichotically, i.e., by playing different sounds simultaneously to each ear. This is called a dichotic listening paradigm.

This experiment demonstrates standard procedures for investigating selective auditory attention with a paradigm called dichotic listening.

Procedure

1. Apparatus and stimuli

Use two sets of headphones and two pieces of hardware for playing auditory stimuli. Ultimately, the experiment requires the ability to play two separate auditory signals through separate headphones. This can be done with a sound mixer or with a computer. But it can be done easily and without technical expertise by using two separate pieces of hardware.
Select three different recordings with informational content that can be tested for comprehension. These recordings are the

Results

The graph in Figure 1 shows the percent of questions answered correctly by condition. The red dotted line (at 20%) shows expected guessing performance (chance), given that each question included five choices. The participant was able to answer more questions correctly for the attended compared to the unattended passage, reflecting the ability to attend selectively to a single stimulus when more than one is present. But the participant also answered more questions correctly in the one passage baseline con

Application and Summary

Dichotic listening has been used for many purposes to understand the nature and capacities of selective attention. For example, it has been used with a concurrent visual task to investigate the extent to which visual and auditory attention compete with one another—an important issue for understanding when and how humans are able to multitask.

One of the most influential applications of the paradigm has been in the study of the human brain’s lateralization for processing language. T