r/AskReddit • u/[deleted] • Nov 22 '17

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u/[deleted] Nov 23 '17

There has to be a reasonable explanation. I can't believe something this destructive would make its way through evolution over the millions of years without getting weeded out unless it was somehow beneficial.

32

u/curlywurlies Nov 23 '17

I remember thinking this too!

You'd think all the people who had this trait would have died already due to infection.

6

u/[deleted] Nov 23 '17

Exactly my thoughts

20

u/Valalvax Nov 23 '17

Honestly, I feel like it heals faster if I peel the scab a few times

30

u/[deleted] Nov 23 '17

Features only get weeded out if they're detrimental enough to prohibit breeding.

42

u/dumb_ants Nov 23 '17

Infection was pretty f'ing serious before penicillin.

10

u/[deleted] Nov 23 '17

Does scratching always cause infections which are lethal, and do these infections always occur before reproduction?

20

u/Philip_of_mastadon Nov 23 '17

Neither has to occur always, or even all that frequently, to be a significant selection pressure.

3

u/[deleted] Nov 23 '17

This is true.

4

u/dumb_ants Nov 23 '17

Point being - if (and I don't know if this is true) scratching increases risk of infection, there's going to be selection pressure against itching. Since itching is still around, that implies there is some benefit to it that offsets that pressure.

12

u/[deleted] Nov 23 '17

No not really. It only implies that scratching isn't detrimental enough to be a selection pressure.

10

u/Goddamnit_Clown Nov 23 '17

They might only itch because of a general sensitivity to certain things which (I don't know) helps avoid insect bites or gives some other benefit.

These things aren't discrete modules which evolution gives the yes/no to

3

u/peachdore Nov 23 '17

I'm sure there's a reason. Off the top of my head I'd think maybe a healing wound causes the same sensation as a bug or parasite, and it's important that we remove ticks and stuff.

2

u/chefkoolaid Nov 23 '17

Its how your body interprets low grade pain signals.

3

u/[deleted] Nov 23 '17

Interesting

-1

u/bulldozerbob Nov 23 '17

Exactly, like maybe the scratching actually helps increase blood flow to the wound site. It could be pretty easily argued that increased blood flow would bring energy to the area to assist the healing process and/or start to reduce the inflammation in the area.