Misperception of exocentric directions in auditory space

Abstract

Previous studies have demonstrated large errors (over 30°) in visually perceived exocentric directions (the direction between two objects that are both displaced from the observer's location; e.g., Philbeck et al., in press). Here, we investigated whether a similar pattern occurs in auditory space. Blindfolded participants either attempted to aim a pointer at auditory targets (an exocentric task) or gave a verbal estimate of the egocentric target azimuth. Targets were located at 20° to 160°a zimuth in the right hemispace. For comparison, we also collected pointing and verbal judgments for visual targets. We found that exocentric pointing responses exhibited sizeable undershooting errors, for both auditory and visual targets, that tended to become more strongly negative as azimuth increased (up to −19° for visual targets at 160°). Verbal estimates of the auditory and visual target azimuths, however, showed a dramatically different pattern, with relatively small overestimations of azimuths in the rear hemispace. At least some of the differences between verbal and pointing responses appear to be due to the frames of reference underlying the responses; when participants used the pointer to reproduce the egocentric target azimuth rather than the exocentric target direction relative to the pointer, the pattern of pointing errors more closely resembled that seen in verbal reports. These results show that there are similar distortions in perceiving exocentric directions in visual and auditory space.Keywords manual pointing; auditory space perception; perception / action; perceived direction; spatial cognition In light of the seemingly effortless accuracy with which we are typically able to interact with objects in the world, the fact that there are sizeable misperceptions of spatial relationships, even in the nearby environment, is remarkable (e.g., Doumen, Kappers, & Koenderink, 2005;Philbeck, 2000). A particularly striking example comes from distortions in perceiving exocentric directions-that is, perceiving the direction from one object to another, both of which are displaced from one's current viewing location. One way to study this involves asking observers to aim a pointer mounted just in front of the body at a nearby target (Haber, Haber, Penningroth, Novak, & Radgowski, 1993;Haun, Allen, & Wedell, 2005;Montello, Richardson, Hegarty, & Provenza, 1999). We have demonstrated large errors in this task, even when both the pointer and the target are within arm's reach (Philbeck, Sargent, Arthur & Dopkins, in press). When participants point without vision, mean errors increase with target eccentricity and peak at −32° for targets at 150° azimuth (i.e., the direction in a horizontal plane Corresponding Author: Joeanna C. Arthur, Department of Psychology, George Washington University, 2125 G. Street, NW, Washington, DC 20052, USA, e-mail: jarthur@gwu.edu, voice: 202-994-7008, fax: 202-994-1602. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a serv...

Non-sensory inputs to angular path integration

“…There was a main effect of Rotation Magnitude (F [2, 36] = 19.64; MSE = 1150.06; p < 0.001). Pairwise planned contrasts (alpha = 0.05) showed significant differences between all pairs of rotation magnitudes.…”

“…There were no main effects of Block Order (F [1,18] = 0.72; p = 0.407) or Rotation Magnitude (F [2, 36] = 2.81; p = 0.074). There was a significant Viewing Context × Block Order interaction (F [1,18] = 17.22; MSE = 4471.52; p < 0.001); in general, when participants received the Preview condition first, the mean constant errors for the No-Preview trials were similar to those of the Preview trials (averaging −14.04 and −13.68°, respectively), whereas when participants received the No-Preview block first, the mean constant errors significantly differed in Preview trials than in the No-Preview trials (averaging −20.38 and 4.39, respectively).…”

“…There was a significant Viewing Context × Block Order interaction (F [1,18] = 17.22; MSE = 4471.52; p < 0.001); in general, when participants received the Preview condition first, the mean constant errors for the No-Preview trials were similar to those of the Preview trials (averaging −14.04 and −13.68°, respectively), whereas when participants received the No-Preview block first, the mean constant errors significantly differed in Preview trials than in the No-Preview trials (averaging −20.38 and 4.39, respectively). There was also a Context × Rotation Magnitude × Block Order interaction (F [2,36] = 6.98; MSE = 1429.06; p = 0.003). Although we have no ready explanation for this complex interaction, the relevant means are shown in Table 2.…”

“…An ANOVA showed an effect of Context (F [1, 17] = 7.31; MSE = 3530.81; p = 0.015), with standard deviations being approximately 82% higher in No-Preview than in Imagined Preview conditions (averaging 24.67° and 13.52°, respectively). There was a main effect of Rotation Magnitude (F [2, 34] = 12.34; MSE = 2219.92; p < 0.001), with standard deviations tending to increase with rotation angle. Table 1 gives the mean coefficients of variation.…”

“…There was no main effect of block order (F [1,17] = 0.003; p = 0.956). There were no statistically significant interactions (Context × Block Order: F [1, 17] = 0.001; Rotation Magnitude × Block Order: F [2, 34] = 1.14; Context × Rotation Magnitude: F [2, 34] = 1.90; Context × Rotation Magnitude × Block Order: F [2, 34] = 1.85; all p’s > 0.05).…”