John Gottman describes the fourth horseman of the marital apocalyse as stonewalling. What he means by stonewalling is shutting down and withdrawal. Usually a person does this when they are becoming emotionally aroused to the point of fearing the loss of control. Temporarily, this shutting down can be a good thing and interestingly is often taught as a technique to maintain control in anger management classes. However, habitual stonewalling becomes a problem because the stonewalling partner essentially shuts the other partner out. Gottman says,
"Often, a stonewaller thinks that he is simply being neutral rather than being disapproving or removed. It is important to realize that withdrawal during an argument is a very powerful act." p. 97
Gottman says about stonewalling in another place,
"But once either spouse develops into a habitual stonewaller, the marriage becomes fragile." P. 95
Reviewing the four horsemen of the marital apocalypse we can see how they describe a pattern which starts with criticism followed by expression of contempt which leads to defensiveness and culminates in stonewalling. This cycle, or pattern, of negativity can occur hundreds of times over the course of many months and/or years. Eventually the couple becomes ennervated and calls the relationship quits.
Spotting these symptoms of relationship dysfunction can stimulate people to attempt different behaviors and the creation of, hopefully, more constructive patterns of interaction.