Testing, validating and applying a general process model (GSDT) of visual search.

• Applicant: Professor Dr. Wolfgang Schwarz
• Subject Area: General, Cognitive and Mathematical Psychology
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 401109510

Schwarz and Miller (2016) presented a comprehensive quantitative process model, called GSDT, to account for all speed- and accuracy-related aspects characterizing performance in the standard paradigm of visual search. GSDT coherently incorporates and integrates four distinct partial processing mechanisms suggested by previous research within a single unified conceptual frame: visual guidance (G), serial (S) object inspection, diffusion (D) modeling of individual object inspections, and a strategic search termination (T) rule. The aim of the proposed project is to explore the validity and wider applicability of GSDT as well as its limits and boundary conditions in four separate Subprojects: (I.) using eye movement data from multiple fixation search to evaluate GSDT's assumptions about seriality and strategic search termination (eye movements are also recorded and analyzed in all Experiments of Subprojects II and III), (II.) using GSDT to coherently account for semantic, categorical, and typicality effects on all aspects of visual search, (III.) using a new, original visual search paradigm to test central GSDT assumptions about visual guidance and target-distractor discriminability, and finally (IV.) applying GSDT to identify exactly which processing mechanisms contribute and combine to the age-related performance decline in visual search. Beyond these novel aspects we will also extend the limited and inconclusive extant evidence regarding the adequacy and validity of GSDT by using, in all four Subprojects, realistic targets and distractors (high-resolution images of real objects). We will also develop and provide (Python-based) software allowing researchers to apply and fit GSDT in a routine manner to single-observer data obtained with the standard search paradigm. Finally, we will quantitatively and systematically compare GSDT to related comprehensive models of visual search such as GS, CGS, parallel diffusion-based models, or TVA.

• DFG Programme: Research Grants