While a successful marriage is not an exact science, science (and common sense) suggests thinking and behaving in a positive way toward one's partner is beneficial. However, one psychologist proposes that for some couples, negative thoughts and actions may actually be better in the long run.

For couples who experience frequent, serious problems, such negative behavior as placing blame on one’s spouse, commanding him or her to change, and being less forgiving seem to be the best way to breed a happy marriage.

Such advice seems counterintuitive, but James McNulty, a psychologist at the University of Tennessee, says what works for happy couples may not work for those with more problems.

"Happy couples do behave certain ways and think more positively, but this might not be creating their happiness necessarily, it may just reflect their happiness," McNulty said. "Because when unhappy couples behave and think the same way, over time they actually seem to get worse."

His recent research suggests marital therapies that encourage couples with major issues to be more critical of one another are potentially beneficial.

Great expectations

McNulty's theory is based on four studies conducted over the past decade.

In the first, 82 newlywed couples were asked to report eight times over the course of four years on how satisfied they were with their marriage.

The couples had been asked at the beginning of their marriage whether they expected to grow stronger in their relationship or to experience rough patches along the way.

The results, published in 2004, showed that having positive expectations about the relationship helped only if the couples met these expectations, McNulty said. Couples with more problems did better if they had expected to encounter obstacles.

"I like to think about this finding like I would think about a student," McNulty said. "Some students are capable of getting A's, some students have to settle for B's and C's. If a student just doesn’t have the skills to get A's, they're probably going to be disappointed if they always expect to get A's. And so that student might do better to expect B's and C's."

Attributing blame

McNulty and his colleagues also looked at whether people tended to hold their partners accountable for negative behavior or excused that behavior, attributing it to something outside the partner's control. (For example: If your partner ignored you, was it because of who your partner is, or because of some outside influence, such as an enormous workload?)

Using data from the previous study and from a second study of 169 couples, published in 2008, the researchers found that, among couples with fewer problems, the ones more satisfied with their marriage usually wrote off negative behaviors as something outside their partner's control. Among couples with more problems, the ones with higher marital satisfaction directly blamed the spouse for his or her bad acts.

"If your partner on average is rarely engaging in negative behaviors, if you don't have very many problems, then it’s best to give the partner the benefit of the doubt," McNulty said. "Even if your partner deserves to be held accountable for a specific event, if it doesn’t happen very often, it's better to sort of look the other way, to look at the bright side."

But, he added, “if you have a partner who's constantly getting into trouble, having problems outside the relationship, inside the relationship, if they're big problems, then it's not such a good idea to look the other way."

Problem solving

In another study, McNulty examined how couples' problem-solving behavior related to the quality of their marriage. When discussing a problem, did they blame or reject the partner or command their partner to change, and did that help or harm their marriage?

The study involved 72 newlywed couples reporting on their marital satisfaction eight times over five years, as well as 135 newlyweds who reported marital satisfaction three times in one year.

"The couples that faced severe problems did better to the extent that they were slightly more negative” in their behavior, McNulty said.

But why would such acrimonious exchanges be beneficial?

There's evidence to suggest negative exchanges motivate partners to change and avoid the bad behavior in the future, McNulty said.

"The downside obviously is that it doesn't make couples feel good in the moment to do that," McNulty said. "But it may motivate them to strengthen their relationship over time."

Forgiveness

McNulty also showed in a 2008 study that couples who were extremely likely to forgive each other did well only if their partners did not engage in "bad" behavior, such as bestowing insults, often.

If such negative behavior was common, a tendency to be less forgiving was better for the marriage.

However, McNulty notes he didn't define exactly what it means to be "more likely to forgive" or "less likely to forgive," a limitation that he said needs to be addressed by future research. While he doesn't think the results mean couples should never forgive each other, "maybe it means, don’t forgive so quickly," he said.

Future research should also look into ways for couples to get the benefits of forgiveness (the good feelings that come with it) without the side effects (the partner simply commits the offensive act again).

"I don’t want to walk around feeling a grudge all the time, but I also don't want my partner to continue engaging in these negative behaviors," McNulty said.

Future outlook

These studies suggest researchers and clinicians should not necessarily look to happy couples as models for how to help couples who have more problems. The results may also explain why therapy seems to be the least effective for couples with the most severe problems.

"We need to rethink the role of positivity in relationships," McNulty said. "It's likely to be more nuanced in its benefits — it may benefit only some couples, and further, most importantly, it actually may harm other couples."

Research examining the outcomes of treatments that encourage couples to be more negative to one another will need to be conducted before these ideas can be put into clinical practice, McNulty said.

A review of McNulty's studies was published in the June issue of the journal Current Directions in Psychological Science.