Gloria Mark

Introduction

Gloria Mark is a psychologist and informatics researcher at the University of California, Irvine, and the most frequently cited source for a number that has entered everyday conversation: 47 seconds, the average length of time people spend on any one screen before switching to another. Chancellor's Professor of Informatics in UC Irvine's Donald Bren School of Information and Computer Sciences and a visiting senior researcher at Microsoft Research since 2012, she has spent two decades instrumenting real workplaces and measuring how knowledge workers actually divide their attention. Her 2023 book Attention Span: A Groundbreaking Way to Restore Balance, Happiness and Productivity brought the findings to a general audience and introduced the idea of "kinetic attention" — the argument that rapid attention-switching is not simply failure but a distinct mode of working that needs to be designed for rather than merely deplored.

Early Life and Education

Mark's academic path was unusually wide. She holds a BFA in art, an MS in biostatistics, and a PhD in psychology from Columbia University, where her doctoral work was in group decision making. The statistical training sits behind the methodological character of her later work, which is quantitative and field-based rather than laboratory-bound.

She moved into technology research almost by accident, as she has described it. Her doctoral adviser had spent time at Bell Labs, and after her PhD she was open to a research-lab job. An opportunity arose at a research institute affiliated with the company Electronic Data Systems, which needed a psychologist to study how groups used technology — a good fit for someone trained in group decision making. That job set the direction for the rest of her career: studying people using computers in real environments rather than in the laboratory.

Academic and Professional Career

Before joining UC Irvine, Mark held positions as a visiting research scientist at the Boeing Company, a senior research scientist at the German National Research Center for Information Technology, and a visiting senior researcher at IBM Haifa. At UC Irvine she became a full professor in the Department of Informatics and later Chancellor's Professor.

Her standing in her primary field is substantial: she was inducted into the ACM SIGCHI Academy in 2017 for contributions to human-computer interaction, has received two Google Research Awards and a National Science Foundation CAREER award, and has been a Fulbright scholar. She served as general co-chair of ACM CHI 2017 and as papers chair of ACM CSCW in 2006 and 2012, and sits on the editorial boards of ACM Transactions on Computer-Human Interaction and Human-Computer Interaction. She has published more than two hundred papers in the leading HCI and computer-supported cooperative work venues.

Major Contributions to Psychology

Measuring attention-switching in the wild

Mark's signature method is direct observation and logging of workers at their own desks. Beginning in 2004 with her student Victor Gonzalez, she measured how long people stayed on any single screen before switching. That first study found an average of about two and a half minutes. By the time of later studies the figure had fallen to 47 seconds, and the median over the most recent five years was roughly 40 seconds — meaning half of all observed screen episodes lasted less than 40 seconds.

The cost of interruption

A second line of work measures what interruptions do. Mark and colleagues reported that after an interruption it can take as long as 25 minutes to return attention to the original task, and that people check email roughly 77 times a day. Her CHI 2008 paper "The Cost of Interrupted Work: More Speed and Stress," with Daniela Gudith and Ulrich Klocke, documented a compensatory pattern: interrupted workers sped up to compensate for lost time, but reported higher stress, frustration and time pressure while producing work of no better quality.

Fragmented work and the myth of the single task

A related line of work, reported with Victor Gonzalez and Justin Harris at CHI 2005 under the title "No Task Left Behind?," examined the structure of working time rather than the length of individual episodes. Their observation was that knowledge workers are rarely engaged in one task at a time in any meaningful sense: they maintain a portfolio of partly finished tasks, switch among them for reasons that are often sensible — waiting on a colleague, blocked on a resource — and experience the resulting fragmentation as a working condition rather than an interruption of one. This reframing matters because it distinguishes switching that degrades performance from switching that is simply how coordinated work gets done.

Self-interruption

Perhaps her most consequential finding, because it complicates the usual story, is that people interrupt themselves roughly as often as they are interrupted by others — she puts the self-interruption rate at about half of all switches. Attention fragmentation is therefore not simply something technology does to passive users; it is also something users do, and the design implication differs accordingly.

Work without email

Mark spent six years looking for an organisation willing to let her restrict employees' email access so that the effects could be measured. The resulting study, published at CHI 2012, found clear benefits from batching or removing email: lower stress, less attention-switching, and an unexpected social gain, as colleagues resorted to face-to-face conversation.

Kinetic attention

In later work she and collaborators added physiological measurement to the logging, using wearable sensors over extended periods to track stress, mood and focus at work rather than relying on participants' reports of their own distraction — a methodological move intended to escape the self-report bias that affects most research on digital behaviour.

In Attention Span, Mark proposes that the ideal of sustained, unbroken "flow" — championed by many popular writers — is the wrong target for most digital work. She argues instead for recognising several distinct modes of attention that vary across the day with mood, task and context, and for scheduling demanding and creative work to coincide with personal peaks rather than attempting uniform focus.

Major Publications

Mark, G., Gonzalez, V. M., & Harris, J. (2005). No task left behind? Examining the nature of fragmented work. Proceedings of ACM CHI 2005.
Mark, G., Gudith, D., & Klocke, U. (2008). The cost of interrupted work: More speed and stress. Proceedings of ACM CHI 2008.
Mark, G., Voida, S., & Cardello, A. V. (2012). "A pace not dictated by electrons": An empirical study of work without email. Proceedings of ACM CHI 2012.
Mark, G., Czerwinski, M., Iqbal, S. T., & Johns, P. (2016). Email duration, batching and self-interruption: Patterns of email use on productivity and stress. Proceedings of ACM CHI 2016.
Mark, G. (2023). Attention Span: A Groundbreaking Way to Restore Balance, Happiness and Productivity. Hanover Square Press. (UK edition: Attention Span: Finding Focus for a Fulfilling Life, William Collins.)

Impact and Legacy

Mark's numbers have become the standard evidence base for public discussion of digital distraction. The 47-second figure appears in journalism, corporate training, education policy and self-help, and her framework has shifted practical advice away from "digital detox" toward scheduling and environment design. Her work also supplies a rare empirical anchor in a debate that otherwise runs on anecdote — a point reviewers of her book made explicitly, noting that the discussion of attention and technology had lacked evidence before she supplied it.

The criticisms are mostly about how her findings get used, and partly about the findings themselves. The 47-second number is not a declining attention span. What Mark measures is the interval between switches of screen content — an operational definition of switching behaviour, not a measure of sustained-attention capacity. Popular usage routinely converts it into the claim that human attention has physiologically shrunk, a claim her data does not support.

It is not a longitudinal study. As the New Scientist review of her book observed, there are no long-term studies tracking attention spans over time, so there is no way to establish that technology caused them to deteriorate. Mark's own comparison is between a 2004 sample and later samples drawn from different organisations with different workers and somewhat different instrumentation. The trend is plausible and she reports that independent studies have found similar values, but it is not a controlled time series.

Small samples, self-selected sites. Mark estimates that her studies cover roughly 1,500 people in total across more than fifteen years, because the method is so labour-intensive. The organisations involved are ones willing to be instrumented — a self-selected group. The email-restriction study took six years to find a single participating employer, which itself indicates how unusual such sites are. Generalisation beyond knowledge workers in willing organisations is therefore uncertain.

Her own data cuts against the alarmist reading. The finding that roughly half of all switches are self-initiated sits awkwardly with narratives that place responsibility entirely with notifications and platform design. Mark's book is notably less fatalistic than the coverage it generates, and she has emphasised that exhaustion, not just distraction, may be what drives switching — a reminder that the cause may be workload rather than the device.

Finally, the concept of an "attention span" as a single measurable quantity has a long and contested history in psychology, going back to the information-processing limits studied by George A. Miller and the claim, associated with Herbert Simon, that a wealth of information creates a poverty of attention. Mark's contribution is empirical granularity rather than a new theory of capacity, and the field still lacks an agreed account of what, if anything, is actually declining.

Learn More

George A. Miller — the study of information-processing limits that framed attention research
Herbert Simon — bounded rationality and attention as a scarce resource
Daniel Kahneman — dual-process accounts of attention and effort

References

Mark, G., Gudith, D., & Klocke, U. (2008). The cost of interrupted work: More speed and stress. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (pp. 165-168). ACM.