In the experiment a two-way factorial design, with the independent variables "distance of the sound source" and "type of texture gradient", was used. Ten subjects had to judge the distance of the sound of a barking dog which was randomly presented at 8 distances (2, 4, 6, 8, 10, 12, 14, and 16 m in front of the observer). The factor "type of texture gradient" was varied in three steps: (a) normally textured room conditions; (b) optically shortened distance by a painted pattern of compressed stripes on the ground; and (c) optically lengthened distance by a painted pattern of stretched stripes. The stripe-pattern consisted of 23 black-and-white compartments ranging from 120 cm to 10 cm. In the "shortening condition", the texture starts with the narrowest stripe in front of the subject; in the "lengthening condition", the texture starts with the widest stripe in front of the subject. The sound was emitted by 8 loudspeakers, which were spatially arranged according to the 8 different distances. The speakers were numbered from 1 to 8, corresponding to their spatial position. After each presentation the subjects had to name the number of the sound-emitting speaker. The whole experimental session consisted of three blocks in which each of the 8 distances were presented 11 times in random order. One block of 88 trials corresponds to one experimental condition, in which a complete within-subjects design resulted.