"Designed to soothe and calm, the specially-designed blue LED lights have been suspended above the platforms of dozens of Tokyo railway stations in order to stem the nation's spiralling suicide rate."
It is a sort of a societal placebo. Or maybe the subconscious message is "someone cared to put these here for me to prevent me from killing myself, someone cares at least, maybe today is not the day".
In other words I wonder if the color of lights would have been violet or yellow but some "research" had been disseminated that yellow lights are calming and prevent suicide, that combined with the action of someone to install them, then I suspect yellow lights would have worked just as well.
While light has proven an effective treatment for Seasonal Affective Disorder (SAD), an optimal wavelength combination has not been determined. Short wavelength light (blue) has demonstrated potency as a stimulus for acute melatonin suppression and circadian phase shifting.
CONCLUSIONS:
Narrow bandwidth blue light at 607 microW/cm2 outperforms dimmer red light in reversing symptoms of major depression with a seasonal pattern.
There must have been some hypothesis or they wouldn't have studied the result. Probably got lost in translation.
EDIT: When an english speaking reporter can't figure something out in a foreign country they often say "nobody knows ..." but really they mean "I couldn't find a source to tell me ..."
EDIT 2: I'm sorry, I didn't realize this was discussed in the movie. I just got to that part. Clearly the author of the film knows plenty of Japanese people and knows this subject well. At the same time there was still a scientific reason for installing them: other posters are pointing out that there have been studies measuring blue light showing it is a "stimulus for acute melatonin suppression" . Interesting!
> When an english speaking reporter can't figure something out in a foreign country they often say "nobody knows ..." but really they mean "I couldn't find a source to tell me ...
Same is true in English-speaking countries with English-speaking reporters :)
>• Blue lights installed at train stations have reduced suicide by 80 percent at those stations. How or why this works, nobody knows.
I can't stop thinking about this. I've tried to puzzle out some type of reason, but I'm just not getting anything.