Several different psychological and psycho-physiological mechanisms for blushing have been hypothesized by Crozier (2010): "An explanation that emphasizes the blush's visibility proposes that when we feel shame we communicate our emotion to others and in doing so we send an important signal to them. It tells them something about us. It shows that we are ashamed or embarrassed, that we recognise that something is out of place. It shows that we are sorry about this. It shows that we want to put things right. To blush at innuendo is to show awareness of its implications and to display modesty that conveys that you are not brazen or shameless. The blush makes a particularly effective signal because it is involuntary and uncontrollable. Of course, a blush can be unwanted the costs to the blusher on specific occasions are outweighed by the long-term benefits of being seen as adhering to the group and by the general advantages the blush provides: indeed the costs may enhance the signal's perceived value." A number of techniques may be used to help prevent or reduce blushing.