Abstract
This experiment explores aspects of attention and visual search using a motion paradigm. The classic visual search paradigm has been used to develop a popular theory of attention (Treisman & Gelade, 1980). This study measures the ability to search for and discriminate moving stimuli as similarity of stimuli varies by average shared shapes between target and distractors (Sun & Shevell, 2009). The aim of this study was to see how reaction times for visual conjunctive search were affected by the role of object shapes. The stimulus was a random dot kinematogram consisting of a central region and four flanking peripheral regions. The distractor regions consisted of a central region and three out of the four peripheral regions, in these distractor regions red shapes move upward and green shapes move downward. The target region consisted of one of the four peripheral regions, in the target region the red shapes move downward and the green shapes move upward. The speed of motion was 14.1°/sec. The observer's 4 AFC task was to judge which one of the four peripheral regions was the target. The results from five observers showed that as average shared shape percentage of target and distractor areas increases, the observer's reaction times increases. The mean reaction times for average shared shapes of 0%, 25%, 50% and 100% were 1.74 sec (SEM = 0.10), 2.46 sec (SEM = 0.11), 3.91 sec (SEM = 0.19) and 4.32 sec (SEM = 0.33) respectively. A one-way ANOVA with repeated measures showed that this difference in reaction time was significant, F(3, 12) = 16.703, p < .001. Future research will examine how performance on visual search for motion is affected by other variables including color, object size and object density.