Alas, it's well established that any change in working conditions will improve productivity (temporarily). Turn up the lights -- people work better! Turn down the lights -- people work better! So the control condition should have had a "sham" change, like decorating the space with Lego robots or something.
I was looking at a training video that was filmed in the 80's at the old City Light Building and was amazed at how colorful the offices were: big plants, brightly colored furniture and cube panels, very cheerful.
Today, our offices are beige and gray. Great views, particularly if you are by a window, but the color scheme is a real snore.
I worked with an elderly lady whose name was Fern. She was pleasant good worker, but I wouldn't say either of us was, ooh, shudder, yuck.... productive.
My office plant is named Jennifer Matilda Cockmonster and she is a total drama queen. Near three feet tall from table to top when recently watered; swooning all over the desk after a long weekend. She does not make me more productive but she does make me feel more emotionally stable by comparison.
I think the effect is less likely to be because of plants emitting oxygen and more because the visual presence of the plants is soothing and thus beneficial to morale. Solution:
Run a study with three cohorts. One group with plants, one group with realistic fake plants, one group with no plants. Monitor oxygen levels at several parts of the office.
Today, our offices are beige and gray. Great views, particularly if you are by a window, but the color scheme is a real snore.
Run a study with three cohorts. One group with plants, one group with realistic fake plants, one group with no plants. Monitor oxygen levels at several parts of the office.