Changing custom attribute doesn't send signal?

I'm using a custom color attribute on a Humanoid that changes the colors of the custom body parts. I'm testing it on a single body part with this script:

while true do
    script.Parent.Color = script.Parent.Parent:FindFirstChild("Humanoid"):GetAttribute("color")
end

and I changed the custom attribute to a different color in testing, but nothing happens. Any help would be appreciated!