Who Multi-Tasks and Why? Multi-Tasking Ability, Perceived Multi-Tasking Ability, Impulsivity, and Sensation Seeking

If multi-tasking is a skill, then the people who do it the most should be best at it. Practice makes perfect — that's the logic. If you're constantly juggling your phone, a podcast, and three browser tabs, you've put in the repetitions. That reasoning feels airtight. It's also exactly backwards. David Sanbonmatsu, David Strayer, Nathan Medeiros-Ward, and Jason Watson ran a study at the University of Utah that produced one of the clearest counterintuitive findings in cognitive psychology: the people who multi-task the most are the least capable of doing it well, and they're the last ones to know it. To measure actual multi-tasking ability, the team used the Operation Span task, or OSPAN for short. It's a dual task: participants verify arithmetic problems while simultaneously holding sequences of letters in memory, then recall those letters in order when prompted. It sounds simple, but it taxes precisely the cognitive machinery you need when managing competing demands — working memory and executive control, the brain's ability to keep a goal active while blocking out interference. Participants scored an average of 44 out of a possible maximum, with a standard deviation of 16. Math accuracy was tracked throughout; the thirty-two participants who failed to verify at least 80 percent of the problems were excluded, leaving 277 in the final analysis. Multi-tasking behavior was measured separately, using the Media Multitasking Inventory, or MMI. This index captures how often people use one medium while simultaneously consuming another: television while texting, music while browsing, that kind of thing. The MMI isn't just a count of activities; it weighs concurrent use by how frequently it happens across twelve primary media, producing a single number that rises as simultaneous media use increases. The sample average was about four on that index. And threaded through the whole study was a real-world test case with genuine stakes: self-reported cell phone use while driving. Participants estimated they were on the phone during about thirteen percent of their driving time. Here's where it gets uncomfortable. When Sanbonmatsu and colleagues correlated OSPAN scores with MMI scores, the relationship was negative — r equals negative 0.19, statistically significant. People who scored higher on the objective measure of multi-tasking ability reported doing less of it. Cell phone use while driving showed the same pattern: higher OSPAN, less phone use behind the wheel, r equals negative 0.15. Splitting the sample by quartile makes it concrete: participants in the top quarter of media multi-tasking scored an average OSPAN of 40.3, while those in the bottom quarter averaged 48.7. That's a Cohen's d of 0.52 — a medium-sized effect. For cell phone use while driving, the high-use group averaged an OSPAN of 38.8 versus 45.4 for low users. So who does multi-task the most? The personality data paint a recognizable portrait. High multi-taskers scored higher on impulsivity and sensation seeking — specifically the disinhibition and thrill-seeking subscales of the sensation-seeking measure. Sanbonmatsu and colleagues frame this through an approach-avoidance lens: multiple simultaneous tasks offer stimulation and potential reward, and people with a strong approach orientation — drawn toward gain and less deterred by cost — find that appealing. In the regression predicting media multi-tasking activity, attentional impulsivity was a significant positive predictor, with a standardized beta of 0.22, while the disinhibition facet of sensation seeking also contributed, with a beta of 0.17. For cell phone use while driving specifically, disinhibition was the personality variable that mattered most, with a beta of 0.21. The finding about attentional impulsivity is worth sitting with. Attentional impulsiveness isn't just acting without thinking — it's specifically the difficulty of keeping your attention fixed on one thing. Sanbonmatsu and colleagues note that multi-tasking was most strongly associated with this particular facet of impulsivity. And when you pair that with the negative OSPAN finding, a different story starts to emerge: some people aren't choosing to multi-task so much as they're unable to sustain single-task focus. The distractions win. Switching feels less like a strategy and more like the path of least resistance for an attentional system that struggles to hold a single channel. The authors describe two accounts that both appear to be operating. The motivated account suggests people multi-task because they seek stimulation, overestimate their ability, and underweight the risks. The deficit account argues that people multi-task because they can't block out distractions long enough to stay on one task. In the regression predicting media multi-tasking, OSPAN was a significant negative predictor — a beta of negative 0.25 — while attentional impulsivity was a significant positive predictor. Both are in the model simultaneously, and both hold. These probably overlap in the population; the person who struggles to focus is also likely the person who interprets that struggle as evidence they work better with multiple inputs. Which brings us to the self-perception data, and this is the part that closes the loop in an unsettling way. Participants rated their own multi-tasking ability on a percentage scale, where fifty means exactly average. The mean self-rating was sixty-three. That's significantly above average — a p-value below 0.01 — and one hundred ninety-three of the 277 participants rated themselves above average. Only fifty-four rated themselves below. The correlation between perceived ability and actual OSPAN performance? Essentially zero: r equals 0.08, not significant. People have no reliable insight into how well they actually perform. And the overconfidence wasn't randomly distributed. Heavy multi-taskers averaged a perceived ability rating of sixty-nine point one, versus fifty-nine point two for light multi-taskers — a gap of nearly ten percentage points, with a Cohen's d of 0.55. So the people who objectively score lowest on the OSPAN believe most strongly that they're skilled. Perceived ability also positively predicted both media multi-tasking and cell phone use while driving in the regressions — betas of 0.33 and 0.21 respectively — making it the single strongest predictor of behavior in the model. Put it all together and you get a picture where skill and habit are moving in exactly opposite directions. The people best equipped to manage competing tasks are the ones quietly getting on with a single task. The people most likely to be on their phone while driving are the ones with lower executive control, higher sensation seeking, and the firmest conviction that they can handle it. The paper notes that research suggests more than ten percent of drivers may be on the phone at any given daylight hour, and the National Safety Council estimates distracted driving may contribute to at least twenty-four percent of highway accidents and fatalities in the United States. The psychological profile identified by Sanbonmatsu and colleagues is not the exception — it's structurally common. What this study can't tell us is causal direction. Does multi-tasking erode executive control over time, or do people with lower executive control simply end up multi-tasking more? The correlational design leaves that open. The sample — undergraduates at a single university — also limits how far you can generalize the numbers, even if the directional pattern seems robust. Those are fair caveats. But the core finding doesn't depend on resolving them. The mismatch between perceived and actual ability is real and large. The negative relationship between objective multi-tasking skill and multi-tasking behavior is real. And the person least likely to update their self-assessment in light of that finding is, almost by definition, the person this study is describing — someone whose approach orientation is strong, whose attentional control is limited, and who has interpreted a lifetime of distraction-driven task-switching as evidence of unusual competence. The illusion is self-sealing. That's what makes it worth understanding. This lecture was created by ennepō. Go to https://ennepo.ai to Discover, Create and Follow the latest research in your field. Read when you can. Listen when you want to.