Software coders hate in-person interruptions, but physiological stress measures tell a different story

It’s an intimidating prospect to interrupt a software engineer who has achieved a flow state—someone who is completely focused and absorbed in the task at hand. Like anyone, it takes time for coders to reengage in their work, meaning interruptions from bosses, coworkers, and email and messaging notifications can lead to a loss of focus, decreased productivity, increased stress, and a longer time to complete tasks.

But according to a new award-winning study by researchers in Vanderbilt’s Institute for Software Integrated Systems (ISIS), not all interruptions are created equal.

Kevin Leach and Yu Huang, assistant professors of Computer Science, and Yimeng Ma, a senior majoring in Computer Science, conducted a controlled cohort study in which participants completed code writing, code comprehension, and code review tasks while experiencing six different types of in-person and on-screen interruptions. This approach approximates real-life real-world interruptions that engineers face during their workday, the authors said.

The researchers used wristband sensors to collect physiological data, along with self-reported stress ratings. Several of the findings aligned with the researchers’ expectations, Ma said. But one in particular didn’t.

“It’s not surprising that performance worsens when you’re interrupted,” said Leach. “But what we found interesting was that in-person interruptions had a significant impact on physiological measures—specifically, reduction in heart rate variability—suggesting they were physically exhibiting less stress.”

Although the physiological data showed that physiological stress measures were lower with in-person interruptions, participants self-reported in-person interruptions as substantially more stressful than on-screen interruptions, such as pop-ups. “Meaning perception and physiological data don’t always align,” Huang said.

The researchers were diligent in the design of the study. “There’s a big investment up front in study protocol using human subjects. It’s not so easy,” Huang said. “You need to very carefully collect data so we are confident in the later analyses.” The study involved 20 Vanderbilt Computer Science students, each of whom was individually measured during software tasks in two-hour blocks.

Their findings shed light on the nuanced impact of interruptions on developers and underscored the importance of considering objective physiological data and self-perceived stress measures when evaluating developers’ satisfaction and productivity.

Understanding these complexities can inform how software companies and managers can help their developers maintain productivity, like strategies to manage interruptions, assign tasks, and reduce stress in software development settings, they said.

The study was presented at the 2024 International Conference on Software Engineering (ICSE 2024), held in Lisbon, where it won an ACM SIGSOFT Distinguished Paper Award among 143 presented papers.