study summary / 016

Do office plants improve thinking—or only stress?

Four randomized VR experiments found physiological benefits from greenery, but no measurable cognitive improvement.

We put plants into offices hoping people will think better. But do plants actually improve attention and cognition, or do they mainly change how our bodies respond to stress? A 2026 study tested those outcomes separately.

Four controlled experiments

Zhang and Du conducted four randomized experiments in virtual open-plan offices, with 132, 126, 134 and 96 participants respectively (488 participations across experiments). They varied the amount of indoor plants and access to nature or urban window views after a mentally demanding task. Researchers measured heart-rate variability (HRV), electrodermal activity (EDA), mood, attention and cognitive performance.

What the researchers found

All tested quantities of indoor plants were associated with improved HRV and reduced EDA after the task. Medium and high access to natural window views also reduced EDA. But plants did not significantly improve mood or cognitive test performance. Only a high quantity of plants improved reported affective qualities of the space. Window views sometimes improved mood and the perceived quality of the office.

What this means for architecture

A green office should not automatically be marketed as a productivity machine. The more defensible design argument is that greenery can influence short-term physiological recovery and how occupants experience a room. Plant quantity and window access are distinct design decisions, not interchangeable guarantees.

Limits and conclusion

These were short-term experiments in virtual offices, not long-term studies of actual workplaces. HRV and EDA are indirect indicators of autonomic activity, not proof of better health or new neural connections. The reported cognitive benefits were not significant. The study supports cautious design hypotheses, not universal prescriptions.