[Monk 08] IDRG [10.19.10]

Monk, C. A., J. G. Trafton, and D. A. Boehm-Davis. “The effect of interruption duration and demand on resuming suspended goals..� Journal of experimental psychology. Applied 14, no. 4 (December 2008): 299-313. http://www.ncbi.nlm.nih.gov/pubmed/19102614.

• abstract: duration and demand of interruptions / importance of goal rehearsal in mitigating delay

• [Altmann 02] - memory for goals model for studying interruptions - activation decay, longer task resumption times
  • interrupting task: mood checklist over a ToL main task
• [Hodgetts 06b] support for duration effect
• [Gillie 89] no support for duration effect; similar w/ [McDaniel/Einstein] - DV: performance on ProM task - digit monitoring interruption task
• global measures in interruption studies insensitive to goal resumption and resumption time; interruption durations in past experiments may have been reasonable in terms of face validity but may have masked duration effects (39s > 2.75min vs 3 > 18s)
• interruption demand also a factor / inhibiting goal maintenance > longer resumption times
• [Zijlstra 99] - document editing main task w/ menial interruptions (i.e. phone # lookup)
• [Cades 07] n-back better than shadowing for inhibiting goal maintenance;
• [Hodgetts 06b] addition (simple vs complex) interrupting tasks
• "complexity" overloaded term, replace w/ demand, processing demands on working memory that prevent or allow rehearsal of suspended task goals

• experiments: does memory for goals decay? with interleaved interruptions? requires a primary task w/ many subgoals to be performed linearly (i.e. VCR programming task)

• Exp 1: pursuit-tracking interruption task in split screen; 3 interruption durations
• errors: deviations from optimal path, potential for speed/accuracy tradeoff - no sig. difs
• both tasks equally important
• resumption lag compared against IAI - interaction intervals in uninterrupted condition - viewed as appropriate comparison
• main effect of interruption duration found - rationale: sensitive DVs and manipulation of duration
• performance on interruption task worse in short-duration interruption

• Exp 2: fitting resumption lags to log function of memory for goals model
• explains absence of duration effect in [Gillie 89]
• is 13s > 23s p[oint of asymptote?
• no effect of duration of tracking task performance
• implication: interleave tasks - strive to shift attention at least every 15s for optimal resumption times

• Exp. 3: 3 duration x 3 demand mixed design w/ interruption demand as BS factor;
• conditions: no interrupting task, tracking task, verbal n-back test
• sig. main effect of demand b/w n-back condition and others
• sig. main effect of duration in no-task and n-back conditions (not in tracking task - approaching sig.)
• linear contrasts sig. b/q n-back and no task
• decay will happen however we can mitigate its effect to some extent - steeper lags in longer, high demand conditions

• discussion: reminders for primary task state interleaved with interruptions
• shallow vs. deep goal rehearsal
• decay vs. interference models?
• more frequent interruptions > shorter resumption times?
• practical implications: flying, driving, ERs, IM, loss of productivity
• conclusion: mitigating decay processes by rehearsing goals during interruptions

• discussion points:

• in HCI research/applied scenarios- how long are typical interruptions? what other interactions are possible - similarity, social obligations, modality, interference
• face/ecological validity of past interruption studies and their tasks used
• my research: considering similarity as in [Gillie 89], modality as in [Storch 92]
• IAI vs ToT. what DVs are most ecologically valid and account for Zeigarnik effect? reflects long-term effects on productivity?
• how do we measure complexity in HCI research? can it always be empirically measured or do we pilot until several levels of complexity are determined?
• main tasks: nonlinear main tasks? programming and visuospatial tasks? puzzles?
• does log function of decay hold for older adults?
• non-computerised interruptions? effect of modality - interaction with age (cohort effect)
• how to include reminders of main task / ensure deep rehearsal in UI design? which environmental cues to use? recency, frequency
• social obligations of interruptions