This book constitutes the refereed proceedings of the 12th International Conference on Engineering Psychology and Cognitive Ergonomics, EPCE 2015, held as part of the 17th International Conference on Human-Computer Interaction, HCII 2015, held in Los Angeles, CA, USA, in August 2015. The total of 1462 papers and 246 poster papers presented at the HCII 2015 conferences was carefully reviewed and selected from 4843 submissions. These papers address the latest research and development efforts and highlight the human aspects of design and use of computing systems. The papers accepted for presentation thoroughly cover the entire field of human-computer interaction, addressing major advances in knowledge and effective use of computers in a variety of application areas. The 49 contributions included in the EPCE proceedings were organized in the following topical sections: cognitive aspects of display and information design; applied cognitive psychology; safety, risk and human reliability; and aviation and space safety.