The Decision Process in Change Detection
Date Issued
2009
Date
2009
Author(s)
Yang, Cheng-Ta
Abstract
People often fail to detect a large change in the visual environment. This phenomenon, change blindness, has attracted researchers’ interests. The decision failure has been proposed as one of the causes of change blindness. Yet, the processes that underlie the decision mechanism are still unclear. As similarity between the pre- and post-change stimuli can influence the decision, I tested how similarity between faces (Chapter 2), objects (Chapter 3), and Gabor patches (Chapter 4) influences the decision. Previous results have shown that similarity costs detection performance (similarity cost), and the results from Experiments 1 - 3 showed that the similarity cost can override the face-detection advantage. Experiments 4 - 6 tested how different levels of similarity (visual and conceptual similarity) influences the information accumulation process when the exposure duration was 2,000, 1,000, or 180 ms. Ratcliff’s diffusion model was used to analyze the information accumulation process. Results showed that both visual and conceptual similarity decreased the rate of information accumulation. The rate of information accumulation also decreased as a function of the exposure duration, suggesting that participants spend more time on accumulating evidence for a decision when the memory strength of the pre-change objects is weak. In Experiments 7 - 9, I used the systematic factorial technology to investigate the processing of each feature underlying change detection. Results showed that participants used different decision strategies when the detection threshold of each type of change was unequal (Experiment 7). When the detection threshold is controlled, participants conducted a parallel process with a self-terminating rule in detecting changes (Experiment 8). They used a serial processing with a self-terminating rule to detect changes when two objects were presented (Experiment 9). Results suggested that participants are able to change the decision strategy depending on the context. Results from this thesis furthers the understanding of the different aspects of the decision mechanism, including the decision difficulty, the rate of information accumulation, the response criterion, the process architecture, the stopping rule and the process capacity, in the context of change detection. Results may shed light on the comparison and decision processes involved in change detection.
Subjects
change detection
decision
diffusion model.
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