Silverfish do more damage to players on easy difficulty than on normal difficulty

When the difficulty is set to easy, players attacked by mobs will take 50% the normal damage, plus 1 damage (half a heart). Since silverfish only do 1 damage, this means their attack gets cut to 0.5 damage, then the extra 1 damage is added and they end up doing 1.5 damage (three quarters of a heart).