Here’s a series of experiments that were done to see if multitasking while reading on screen or listening to a lecture impaired comprehension and time.

Pashler, Kang and Renita (2013) looked at 1) the time spent reading and 2) comprehension test scores (these were the dependent variables). The independent variables are 2 different patterns of interruptions: 1) on a predictable/regular pattern after each paragraph, and 2) at a random interval. The control condition was one of no interruptions.

The conditions for each experiment were: Experiment 1) reading an academic passage (like studying a textbook)  Experiment 2) listening to an academic passage which pauses when interrupted (like listening to a recorded lecture) and Experiment 3) listening to an academic passage which can’t be  paused but continues when interrupted (like a class lecture).

The interruptions were messages with opinion questions to answer.

The results are that:
Experiment 1: Reading a 1500 word academic passage on a computer screen
Condition 1:  Reading without interruptions
Condition 2:  Reading with interruptions at paragraph breaks
Condition 3:  Reading with interruptions at random intervals

Findings: a significant effect of study condition: random interruptions increased study time. It didn’t significantly effect comprehension scores, though.

An interesting finding is that participants felt that their comprehension was best in the Read Without Interruption condition and worst in the Random Interruption condition – however, while 89% agreed that messaging or texting while studying affects memory for the material, 89% agreed that they sometimes or often multitasked while studying.

Experiment 2: Listing to an audiotaped lecture of the same type of material as Experiment 1 (The lecture paused when the participants were asked to answer the questions but they had no opportunity to go back and fill in any missed material, unlike Experiment 1).
Condition 1:  Listening  without interruptions
Condition 2:  Listening with interruptions at paragraph breaks
Condition 3:  Listening with interruptions at random intervals

Findings: No significant effect of study condition on comprehension. Again, participants thought that their comprehension was best in the Listen Without Interruption condition and worst in the Random Interruption condition. 87% agreed that messaging or texting while studying affects memory for the material, but 67% agreed that they sometimes or often texted while studying.

Experiment 3: Listing to an audiotaped lecture of the same material as Experiment 1 (This time with no pauses. This would be like listening to a lecture during class.)
Condition 1:  Listening  without interruptions
Condition 2:  Listening with interruptions at random intervals

Findings: Yes, a significant decrease in comprehension scores when randomly interrupted (p <.001, and a Cohen’s d effect size of .57). This mirrors what happens in the classroom – incoming texts are unpredictable, and you can’t put the instructor on pause while you read them. And they do effect your comprehension (Pashler et al., 2013).

These findings suggest that if you can go back and re-read the interrupted passage, or pause while you listen, it might lengthen your time but doesn’t significantly affect your understanding of the material. But texting in class? Yes. It does impair your understanding, and therefore your grades.

Reference

Pashler, H., Kang, S. H. K., & Renita, Y. Ip. (2013). Does multitasking impair studying? Depends on timing. Applied Cognitive Psychology, 27, 593-599. doi: 10.1002/acp.2919