What is the effect of merely expecting an interruption on performance? There's a lot of research about how interruptions affect cognitive performance. 


Are there any studies that have looked at the effect of merely expecting to be interrupted (withou being actually interrupted) on performance? 
What does these studies conclude about the effect of merely expecting an interruption on performance?
Fortin and Masse (2000) explored the effect of expecting an interruption on the ability to accurately produce a timing interval (e.g., producing a 2000 millisecond timing interval):

From the abstract:


  The interference from nontemporal processing on concurrent time
  estimation is usually attributed to disruption in timing caused by
  artentional requirements of nontemporal processing. Here, we examined
  interruption in timing without concurrent nontemporal processing.
  Empty breaks of various durations, during time-interval production,
  lengthened produced intervals. Moreover, an effect of break location
  was observed: Intervals lengthened proportionally to prebreak
  duration. When cued and uncued uninterrupted trials were introduced,
  the lengthening was proportional to the duration for which a break was
  expected. It was concluded that attentional time-sharing between time
  estimation and expectation of its interruption contributed to the
  interference effect in time-estimation research, independently of any
  concurrent processing requirements during time estimation.


So, I suppose you could use this as evidence to support the idea that if an individual is anticipating an interruption, this might consume some attentional  resources, especially if he or she is tuned into a signal that might communicate the commencement of the interruption.

References


Fortin, C. and Masse, N. (2000). Expecting a break in time estimation: Attentional time-sharing without concurrent processing. Journal of Experimental Psychology: Human Perception and Performance, 26, 1788. PUBLISHER PAGE