Flashlights are (often) counter productive

September 2017 ยท 3 minute read

I would have liked to source some scientific material for this, but it is not worth the effort as a simple Google search did not turn up desirable information. The concepts I will briefly discuss, despite being somewhat counter-intuitive, are quite intuitive to grasp once unpacked and will allow you to act all smart whenever (or if ever) this topic arises in your life.

We all know that we need light to see, and that if there is more light, we see better. As such, it is not difficult to jump the conclusion that projecting some light will make you see better in the dark in all cases. It is somewhat more nuanced than that however: if you are searching for something you lost in an unlit closet, more power to you; outside, at night, it is a different story.

Imagine a closet with a broken light. Why on earth would you want to dig there? Perhaps you are looking for something? Seems reasonable, let’s go with that. Another thing that seems reasonable is to grab a flashlight to be able to actually discern what you are looking for because it is indeed reasonable - your light beam will be for one, sufficient to illuminate the entiere place and two, will allow you to see smaller items that you would simply not see otherwise. All is sound in this situation. The flip side is that it is one of the only appropriate situations for a flashlight in your daily life.

Now lets imagine you are walking outside in a dark, dark forest. You are afraid of the dark and do not see as much as you would like to. As such, you take out a flashlight and shine it in front of you. Reasonable? Nope.

Your beam of light just made your situation worse in exactly the two ways cases you wanted to mitigate.

1) You now see less than before.

While it is true that within the narrow projected circle you can discern more objects with greater detail, everything else gone. Assuming that you are a normal person, you will shine the light to where you are looking/walking towards which would be your primary area of focus. This triggers your eyes to adapt to the light, and since your eyes adapt to light globally (peripheral vision is not seperate from your central vision, despite being marginally better in the dark), everything outside of that radius is now a blind spot. Compare that to being able to see everything around you to a good enough degree.

2) You see more than there is

Another unpleasant fact brought upon you by your flashlight are the shadows. Since you are presumably walking and not pretending to be a tree, the shadows generated by your portable light source move around while creating a stark, dark contrast which can be perceived as dangerous elements. Your brain will now be scaring you until you get home with the dark movements that you yourself create.

Bonus: You now attracted a boat-load of bugs and mosquitos

This requires no explanation.


I hope that I have dissuaded you from using flashlights in the future, though it in reality, I do not care.

Extra reading

Why does a light object appear lighter in your peripheral vision when it’s dark? (StackExchange)

Peripheral Vision (Wikipedia)

The eye’s adaption to light and darkness (Wikipedia)

Phones are hard to use. Accidental photo, looks decent anyways.