Based on his research, Gottman (1994: 28) concludes that a 'lasting marriage results from a couple's ability to resolve the conflicts that are inevitable in any relationship'. The key lies in the balance between positive and negative behaviours. Couples whose positive interactions outnumber their negative interactions are known as 'regulated': marital stability is stronger when the ratio of positive to negative behaviours is at least 5:1. Those marriages where negativity prevails are labelled 'non-regulated' and are more likely than regulated ones to be unhappy marriages in which separation and/or divorce are or have been considered (Gottman 1993; Lindahl, Malik and Bradbury 1997).
Not all negative behaviours lead directly to marital distress and dissolution, but four behaviours in particular, known as the 'Four Horsemen of the Apocalypse', have been identified as critical in the process by which a marriage can move towards dissatisfaction and dissolution. Criticism tends to lead to contempt, which in turn leads to defensiveness and finally stonewalling (withdrawal).