Four listeners rated their confidence of whether

an occluder had been present or absent in the

path of the sound stimulus that they heard in three

reverberant contexts: under anechoic conditions

(circles), with the addition of reverberation

simulating a large room (squares), and with

reverberation simulating a small room

(diamonds). The figure shows the relative

frequency of response in each of the five

categories, where the "5" response was used to

indicate maximum confidence that the occluder

had been present between microphone and

speaker when the recording was made.