Date of Award

Summer 2016

Document Type


Degree Name

Master of Science (MS)



Committee Director

Yusuke Yamani (Director)

Committee Member

Christopher Brill

Committee Member

Philip Langlais


Many professional tasks, including military operations and medical operations, involve a team of operators searching for a target on a common visual display. Previous works on collaborative visual search employed analysis of mean response time (RT) and error rates, which may not offer direct measurement of the capacity of a team nor changes in performance across task time. Workload capacity, indexed by the capacity coefficient, C(t), measures performance efficiency for cognitive systems with multiple and concurrent information-processing channels (Townsend & Nozawa, 1995). The current study applied a workload capacity analysis to quantify performance efficiency of pairs of participants in a difficult visual search task. Sixty-eight participants performed a speeded visual search task both solitarily and in pairs with varying levels of target guidance. Each search display contained a target (O) and non-targets (Cs) where the gaps of either 20% (low target guidance) or 80% (high target guidance) of non-targets predicted the location of the target. Results indicate that solitary participants exhibited significantly faster RT in the high guidance condition than the low guidance condition, whereas paired participants demonstrated no difference in RT across target guidance conditions. Additionally, paired participants exhibited limited capacity in both target guidance conditions, indicating that participants slowed response speeds when working collaboratively compared to solitarily, regardless of levels of target guidance. Providing target guidance information may not prevent operators from slowing individual response speeds in collaborative trials. Present findings have implications for the effectiveness of providing target guidance to speed operator responses in contexts such as, search and rescue, surveillance, and reconnaissance.


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