International Journal of Industrial Ergonomics 34 (2004) 407–419 Measurement of human trust in a hybrid inspection system based on signal detection theory measures Xiaochun Jiang a, *, Mohammad T. Khasawneh b , Reena Master c , Shannon R. Bowling c , Anand K. Gramopadhye c , Brian J. Melloy c , Larry Grimes d a Department of Industrial and Systems Engineering, North Carolina A&T State University, 1601 E. Market Street, Greensboro, NC 27411, USA b Department of Systems Science and Industrial Engineering, State University of New York at Binghamton, Binghamton, NY 13902, USA c Department of Industrial Engineering, Clemson University, Clemson, SC 29634-0920, USA d Department of Experimental Statistics, Clemson University, Clemson, SC 29634-0920, USA Received 17 June 2003; accepted 7 May 2004 Available online 26 June 2004 Abstract Human trust plays an important role in influencing operator’s strategies toward the use of automated systems. Therefore, a study was conducted to measure the effect of human trust in a hybrid inspection system given different types of errors (i.e., false alarms and misses). The study also looked at which of the four dimensions of trust (competence, predictability, reliability and faith) were the best predictors of overall trust. Results from the study reveal that trust is sensitive to the type of errors made by a system and suggest that subjective ratings of trust and the properties of the system can be used to predict the allocation of functions in hybrid inspection systems. Relevance to industry The study conducted here is applicable to inspection tasks in manufacturing and service industries. The results obtained indicate that subjective ratings of operators’ trust can be used as a basis for predicting and optimizing operator’s allocation behavior and system performance. Furthermore, designers can use these results to help decide which functions to allocate to the human or to the system based on previous experiences and interaction with the system. r 2004 Elsevier B.V. All rights reserved. Keywords: Trust; Function allocation; Hybrid inspection 1. Introduction Customer awareness regarding product quality and increased incidences of product liability litigation has increased the importance of the inspection process in manufacturing industries ARTICLE IN PRESS *Corresponding author. Tel.: +1-336-334-7780; fax: +1- 336-334-7729. E-mail addresses: xjiang@ncat.edu (X. Jiang), agramop@ ces.clemson.edu (A.K. Gramopadhye). 0169-8141/$-see front matter r 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.ergon.2004.05.003