Via een nieuwe blogpost van Daniel Willingham ontdekte ik dit nieuwe onderzoek dat iets bevestigt waarvoor ik mijn studenten al langer waarschuw: leerlingen onderbreken tijdens het leren kan negatief zijn. Het is al eerder geweten dat onderbroken worden in een taak voor tijdverlies en meer fouten kan zorgen,

Dit nieuwe onderzoek van Altman et al. bekeek specifiek het effect van de lengte van onderbreking. Daarvoor moesten de deelnemers deze opdracht proberen op te lossen waarbij ze zeven verschillende inschattingen moesten maken na elkaar:

Vervolgens werden de deelnemers random onderbroken waarbij ze een code moesten intikken op het scherm. De lengte van de code kon verschillen, waardoor de lengte van de onderbreking bepaald werd:

En wat is nu het effect? Dan legt uit:

Let’s return to the importance of the interruption delay. Suppose you’re executing a multi-step procedure and you’re interrupted. When you return to your main task any problems you have might be due to memory or attention. If the problem is one of memory (but your attention is fully back on task) we’d expect that you might forget where you are in the sequence, e.g., you were supposed to the “R” task in the UNRAVEL sequence, but you forget and repeat the “N” task. But we wouldn’t expect you’d necessarily make a mistake when answering the “N” task, because attention is fully back on task.

But if the problem is that your distracted, we’d think that both types of problems would be more likely—an interruption would make you lose your place in the sequence (sequence errors) and make you more prone to mistakes in when answering (answer errors).

​The results were quite clear, as shown in the figure

The interruption made subjects forget where they were in the sequence, but it did not seem to affect attention much once they returned to the task, because the interruption didn’t make them more error prone.

​As in other experiments, this one showed that an interruption incurred a cost to response time upon return to the main task. In this experiment, this cost increased with delay, and in light of the error data, we’d interpret this effect as being due to subjects struggling to remember where they were in the sequence.

This memory-based account of the effect of interruptions on sequential tasks is consistent with decades of experimental work showing that the contents of short term memory is compromised by delay.  These results don’t mean attention is not a relevant factor in interruptions, but they do speak to the relative roles of memory and attention in sequenced tasks.

• dat je best er voor zorgt dat je instructie helder is zodat de leerlingen vervolgens in stilte aan de slag kunnen gaan en dat ze je daarna best niet meer onderbreekt,
• dat onderbrekingen in de les door mensen die binnenkomen met een boodschap meer negatieve effecten kunnen hebben dan je denkt,
• idem met boodschappen via bijvoorbeeld PA-systemen.

Abstract van het onderzoek:

We investigated effects of task interruption on procedural performance, focusing on the effect of interruption length on the rates of different categories of error at the point of task resumption. Interruption length affected errors involving loss of place in the procedure (sequence errors) but not errors involving incorrect execution of a correct step (nonsequence errors), implicating memory for past performance, rather than generalized attentional resources, as the disrupted cognitive process. Within the category of sequence errors, interruption length produced a complex pattern of effects, with repetitions of the preinterruption step showing different effects than errors at other offsets from the correct step. A cognitive model we developed previously accounts for the results in terms of decay and rehearsal of memory for past performance and activation spreading through a procedural representation of task knowledge. The model links different types of errors to different cognitive processes, informs potential interventions, and predicts interruption effects for sequential tasks like problem solving and counting.