Angle of Camera View Influences Resumption Lag in a Visual-Motor Task

Abstract

Prior research on interruptions examined the effects of different characteristics of the primary and interrupting tasks on performance of the primary task. One measure is the resumption lag– the time between the end of the interrupting task and the next action in the resumed primary task (Altmann & Trafton, 2004). Prior research showed that an increase in the workload of a task results in an increase in resumption lag (Iqbal & Bailey, 2005). A common feature of prior studies of resumption lag is the use of computer-based tasks. However, interruptions occur in other types of tasks, such as laparoscopic surgery in which errors can result in serious consequences for the patient (Gillespie Chaboyer & Fairweather, 2012). Common interruptions during laparoscopic surgery include equipment failures and communication with team members (e.g., Gillespie et al.,2012). In laparoscopic surgery, a small incision is made in the patient, and a laparoscope is placed inside the body cavity. The surgeon typically views the surgical site on a two-dimensional screen rather than in three-dimensions as in open surgery (Chan et al., 1997). The two-dimensional camera image imposes perceptual and cognitive demands on the surgeon, such as impaired depth perception (Chan et al., 1997; DeLucia & Griswold, 2011) and a limited field-of-view of the site (DeLucia & Griswold, 2011). The present study examined whether top-view and side-view camera angles, which putatively impose different cognitive demands (DeLucia & Griswold, 2011), would differentially affect the resumption lag in a visual-motor task. Participants completed a peg transfer task in which they were interrupted with a mental rotation task of different durations and rotation angles. The duration of the mental rotation task was either short (6 s) or long (12 s), representing relatively low and high cognitive demands, respectively. Smaller rotation angles (0, 60, and 300 degrees from vertical) and greater rotation angles (120, 180 and 240 degrees from vertical) presumably imposed smaller and larger cognitive demands, respectively. Resumption lag was measured as the time between the end of the interruption and the first time a peg was touched in the resumed peg transfer task. Participants needed significantly more time to resume the peg transfer task with the side view compared to the top view, and with the longer mental rotation task duration compared to the shorter duration. The main effect of rotation angle was not significant. The side view also resulted in higher ratings of mental demand, effort, and frustration on the Raw Task Load Index (RTLX), the ratings-only portion of the NASA-TLX (Hart, 2006). Thus, a visual-motor task that is higher in cognitive demand can result in more time to resume a primary task following an interruption. Practical implications are that camera viewing angles associated with lower cognitive demands should be preferred in the operating room when feasible, and that interruption durations should be minimized. However, results also indicated that the side view resulted in longer movement times than the top view, even without an interruption, suggesting that factors other than cognitive demands may account for effects of camera angle on resumption lag; this should be examined in future research.