Ken Sim
Department of Psychology, Department of Engineering
National University of Singapore
2012/2013 Semester 1
The Effects of Contextual Cues on Visual Categorization
Zi Yang Ang, Yan Ting Chan, Ken Sim, Chaoqian Chen, Yu Chen, Mayank Ashok Jain
Department of Psychology, Department of Engineering
National University of Singapore
2012/2013 Semester 1
Abstract “Do you spot the animal faster than the bird?” Ever since the early studies by Eleanor Roach in the late 70s, much work has been done on categorization. Views on early processing have shifted from “basic level advantage” to “superordinate level advantage”. Recently, Mack and Palmeri claim that superordinate level advantage is only present at short stimulus presentation times. They suggest that at short presentation times, categorization relies more on contextual cues provided by the background, rather than actual object information. We aim to find if the superordinate level advantage at short presentation times can be attributed to contextual cues. We compared human reaction times when categorizing bird pictures as containing either an animal (superordinate level), or bird (basic level) in 3 background types (coherent, incoherent, neutral).
Human subjects require an additional 15ms to categorize a bird as a bird (basic level) than as an animal (superordinate). Human subjects also showed the fastest categorization when objects are in neutral backgrounds, followed by coherent and finally, objects in incoherent backgrounds are slowest at being categorized. There is no significant interaction between categorization level and background types showing that the superordinate level advantage might not be due to contextual cues.
Introduction
The field is split with differing opinions on perceptual categories. In 1976, Rosch and colleagues proposed a basic level advantage – i.e. we access basic level perceptual categories faster
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