My personal subjective experience is also that I find very bright artificial light after dark improves my mood, alertness and cognitive ability.
However, the personal subjective experience isn’t universal: many people I’ve shared home or work spaces with have complained when I’ve installed bright lighting. They’ve found it too bright, or too clinical, or too much glare, or gives them a headache or eyestrain. I have several co-workers who routinely turn off office lights (which I’d prefer to be even brighter) and replace them with dim uplighters.
Also, I’m not at all sure that my personal subjective experience is a robust effect.
The effect of lighting on human productivity is the canonical example of a difficult-to-study phenomenon. The Hawthorne Effect—where research shows an effect of an intervention because some research is being done—is legendarily named after some studies in to the effect on factory productivity of lighting. The story goes that increasing lighting increased productivity—and then changing it back to what it was before also increased productivity. The truth is a little more complicated than that—the Wikipedia article on the Hawthorne Effect touches on some of the issues—but it remains an elusive phenomenon. Also, pretty much all the ‘research’ I can easily put my hand on is obvious puff pieces by lighting companies, or companies showing off how much they have improved things by changing lighting.
Any self-test is hard to blind; as others have noted, a change in lighting is likely to be particularly hard to blind even if you have a separate experimenter. However, perception of brightness is to some degree relative (we judge how bright it is at least partly by comparison to how bright it was where we’ve just been), so with a bit of careful design it could be made less obtrusive—e.g. switching identical-looking bulbs while the subject is out of the room, and have the subject come in through an anteroom that has very low lighting so the experimental room will always seem bright, even if it’s normal level.
I like the experimental ideas. With large enough n, one could have completely separate groups such that they aren’t even aware that light is the experimental variable. But I don’t run a psych department.
My personal subjective experience is also that I find very bright artificial light after dark improves my mood, alertness and cognitive ability.
However, the personal subjective experience isn’t universal: many people I’ve shared home or work spaces with have complained when I’ve installed bright lighting. They’ve found it too bright, or too clinical, or too much glare, or gives them a headache or eyestrain. I have several co-workers who routinely turn off office lights (which I’d prefer to be even brighter) and replace them with dim uplighters.
Also, I’m not at all sure that my personal subjective experience is a robust effect.
The effect of lighting on human productivity is the canonical example of a difficult-to-study phenomenon. The Hawthorne Effect—where research shows an effect of an intervention because some research is being done—is legendarily named after some studies in to the effect on factory productivity of lighting. The story goes that increasing lighting increased productivity—and then changing it back to what it was before also increased productivity. The truth is a little more complicated than that—the Wikipedia article on the Hawthorne Effect touches on some of the issues—but it remains an elusive phenomenon. Also, pretty much all the ‘research’ I can easily put my hand on is obvious puff pieces by lighting companies, or companies showing off how much they have improved things by changing lighting.
Any self-test is hard to blind; as others have noted, a change in lighting is likely to be particularly hard to blind even if you have a separate experimenter. However, perception of brightness is to some degree relative (we judge how bright it is at least partly by comparison to how bright it was where we’ve just been), so with a bit of careful design it could be made less obtrusive—e.g. switching identical-looking bulbs while the subject is out of the room, and have the subject come in through an anteroom that has very low lighting so the experimental room will always seem bright, even if it’s normal level.
I like the experimental ideas. With large enough n, one could have completely separate groups such that they aren’t even aware that light is the experimental variable. But I don’t run a psych department.