3. THE EXPERIMENTAL ANALYSIS OF VISUAL BEHAVIOR
71
Fig. 5. Illustration of left-right mode of interocular transfer obtained with mirror
image arrowhead discrimination. Fish trained to avoid forward-pointing stimulus on
right (but not backward arrowhead) will avoid backward stimulus but not forward
version, when tested via left eye. If these equivalent stimuli were moved into the
frontal binocular field, they would come into register.
mirror image discriminations of objects seen in Fig. 6 can show two
separate modes of interocular transfer. Subjects discriminating either ( a )
the 135" vs. 45" oblique lines or ( b ) the mirror image arrowheads showed
a left-right mode of directional equivalence in that stimuli projecting in
the same direction on the frontal plane are taken as equivalent during
interocular transfer tests. For discriminations ( c ) and ( d ) , a front-back
equivalence is obtained: Similar stimuli project in the same direction on
the lateral plane that parallels the sagittal plane of the body. The two
pairs of stimuli classified by the left-right mode subtended 8"-1O0 of
visual angle, while pairs ( c ) and ( d ) were 15" and 22" in size. Possibly
the stimuli of larger size are more easily broken down into two partsthe front and back units-so that the brain can describe the stimulus in
71
Fig. 5. Illustration of left-right mode of interocular transfer obtained with mirror
image arrowhead discrimination. Fish trained to avoid forward-pointing stimulus on
right (but not backward arrowhead) will avoid backward stimulus but not forward
version, when tested via left eye. If these equivalent stimuli were moved into the
frontal binocular field, they would come into register.
mirror image discriminations of objects seen in Fig. 6 can show two
separate modes of interocular transfer. Subjects discriminating either ( a )
the 135" vs. 45" oblique lines or ( b ) the mirror image arrowheads showed
a left-right mode of directional equivalence in that stimuli projecting in
the same direction on the frontal plane are taken as equivalent during
interocular transfer tests. For discriminations ( c ) and ( d ) , a front-back
equivalence is obtained: Similar stimuli project in the same direction on
the lateral plane that parallels the sagittal plane of the body. The two
pairs of stimuli classified by the left-right mode subtended 8"-1O0 of
visual angle, while pairs ( c ) and ( d ) were 15" and 22" in size. Possibly
the stimuli of larger size are more easily broken down into two partsthe front and back units-so that the brain can describe the stimulus in