pulse-flag

pulse-flag is a variable defined in `pulse.el'.
Its value is

nil

Documentation:
Whether to use pulsing for momentary highlighting.
Pulsing involves a bright highlight that slowly shifts to the
background color.

If the value is nil, highlight with an unchanging color until a
key is pressed.
If the value is `never', do no coloring at all.
Any other value means to do the default pulsing behavior.

If `pulse-flag' is non-nil, but `pulse-available-p' is nil, then
this flag is ignored.

You can customize this variable.