We tested whether the retinal projection of the nose was used to reduce error in free-scan judgments of straight-ahead. Subjects set a luminous target straight ahead with no restrictions on eye position. On half the trials, the nose was visible; on the other half, it was not. Nose visibility did not reduce absolute error. To check response measure sensitivity, an external reference condition was added. The two nose conditions were run with no external surrogate reference, or with a reference on the nose, 3/8 of the way between the target and the observer, or directly in front of the target, which was 183 cm from the observer. There was no advantage of a reference on the nose as compared to no reference, and nose visibility did not interact with the surrogate reference conditiori. However, the external reference became much more effective in reducing absolute error as it approached the target. We called this the Pinocchio effect. It is consistent with the adjacency principle, but its cause is not certain. Most importantly, the Pinocchio effect showed that the null nose result was not simply a matter of an insensitive response measure.
[1]
Jerome H. Kravitz,et al.
The measurement of the constancy of visual direction and of its adaptation
,
1965
.
[2]
Walter C. Gogel,et al.
The adjacency principle and induced movement
,
1972
.
[3]
L MATIN,et al.
Autokinetic Movement: Selective Manipulation of Directional Components by Image Stabilization
,
1964,
Science.
[4]
L. Matin.
Eye Movements and Perceived Visual Direction
,
1972
.
[5]
Hans Wallach,et al.
Rapid adaptation in the constancy of visual direction with active and passive rotation
,
1965
.
[6]
W. Gogel,et al.
Depth adjacency in simultaneous contrast
,
1969
.
[7]
J. Gibson.
The visual perception of objective motion and subjective movement.
,
1994,
Psychological review.
[8]
W C Gogel.
Depth adjacency and cue effectiveness.
,
1972,
Journal of experimental psychology.