Vanderbilt University |
When
we track moving objects there are often distracting objects moving
among our targets. Previous research leaves open the question whether
distractor information is processed during tracking. Although
distractors are irrelevant to the tracking task, processing some
information about them, such as motion, may prevent distractors from
being confused as targets. Our prior research with textured objects
suggests that people use motion information to help them track targets
(St. Clair, Huff, & Seiffert, 2010, JOV). Tracking objects was
worse when the motion of the texture conflicted with the motion of the
objects. If distractor motion is used, tracking should be affected by
the motion of textures on distractors, regardless of the motion of
textures on targets. Observers tracked 3 of 10 textured squares moving
linearly and independently in a textured area. The texture in each
square moved two times the square's speed either forward, in the same
direction as the square, or, backward, in the opposite direction of the
square. Texture direction was assigned to targets and distractors
independently for a total of four conditions: 1) all squares had
forward texture, 2) all squares had backward texture 3) targets had
forward texture and distractors had backward texture, and 4) targets
had backward texture and distractors had forward texture. Tracking
accuracy was higher when targets had forward texture (mean proportion
correct M = .79) than when they had backward texture (M = .61; t(18) =
11.13, p<.01), replicating our previous work showing target motion
is used during tracking. Similarly, tracking accuracy was higher when
distractors had forward texture (M = .72) than when they had backward
texture, (M = .68; t(18) = 3.98, p<.01). This suggests that people
are sensitive to distractor motion during tracking. |