Behavioral and emotional consequences of brief delays in human–computer interaction

It was thought that computer-performance-related problems in human–computer interaction (HCI) would become negligible with the constant increase in computing power. However, despite major advances in computer technology, contemporary HCI is still characterized by brief delays in computer responsiveness caused, for example, by background processes or network delays. Research on long system-response times (SRTs) indicates that delays may have negative behavioral and emotional consequences. However, there are fundamental differences between previously researched long SRTs and delays as they occur in contemporary HCI, such as different timings and occurrence probabilities. Therefore the previous research is not necessarily applicable to modern HCIs. We developed a paradigm aimed at mimicking important aspects of contemporary HCI to empirically test the effects of sporadic brief delays with an average duration of 1.6 s. Results showed performance decrements in the response directly following a delay in terms of increased reaction times and error rates. Furthermore, blocks in which delays occurred were less liked than blocks without delays, suggesting that delays may affect the emotional state. The data provide evidence that delays cause a significant deterioration of performance, and indicates that delays in contemporary HCI may negatively affect work productivity, work satisfaction, and health-and-safety. Suggestions for HCI design and the relationship to user interruption are discussed.