Singles are just as happy as those in relationships - if it means they can avoid turmoil and strife, new research from the University of Auckland shows.

At a time when the number of single people is on the rise due to higher rates of divorce and marrying later in life, singles with a strong desire to avoid conflict achieve similar levels of happiness and wellbeing as their coupled-up counterparts, the study found.

The research results challenge previous research which has consistently shown being hitched leads to a happier and healthier life.

School of Psychology doctoral candidate Yuthika Girme, who led the study involving more than 4,000 New Zealanders, says it is one of the largest of its kind, and the largest ever undertaken on being single in New Zealand.

"This is actually the first evidence that being single doesn’t necessarily undermine life satisfaction or wellbeing and in fact may offer benefits including protection against being hurt or rejected by relationship partners," Ms Girme says.

Using a nationally-representative sample of 4,024 participants drawn from the database of the New Zealand Attitudes and Values Study run by University of Auckland Associate Professor Chris Sibley, the latest research examined how individual differences in behaviours impact on relationship status and happiness. Previous studies have been limited to demographic factors such as age.

The research was in two parts, with Study 1 surveying 187 University of Auckland under-graduate students - both single and in relationships and ranging in age from 19 to 54 years - on their life satisfaction and wellbeing. Average relationship length in Study 1 was 2.48 years.

The second part of the study, Study 2, was longitudinal, tracking 2,461 women and 1,563 men aged 18 to 94 years over a full year to measure life satisfaction and wellbeing. Across the year, 21.5% of participants were single and 78.5% in a relationship with the same partner. Average relationship length in Study 2 was 21.88 years.

Life satisfaction was then mapped against a scale measuring what psychology researchers call "avoidance" and "approach" behaviours. People high on the avoidance scale try to avoid conflict, while those high on the approach scale are more likely to want to enhance growth and closeness in their relationships.

The study found that people who chose to avoid conflict - high on the avoidance scale - were just as happy being single as their coupled-up counterparts while those higher on the approach scale were happiest when involved in a romantic relationship.

"This study found that people who want to avoid conflict may feel relieved when they don’t have to manage the inevitable ups-and-downs of being in a relationship," Ms Girme says.

"Being single has traditionally been associated with poorer life satisfaction but this research shows that is not the case for people who try to sustain close relationships by avoiding turmoil or conflict."

Happiness for people who scored higher on the avoidance scale could be found in a relationship - but that might depend on how well conflict and problems were managed.

People with the highest scores on the "approach" scale - wanting to enhance growth and intimacy in relationships - were happiest when in a relationship. But they were not unhappy when single, substituting closeness with family and friends for romantic ties.

The research is published today by the Society for Personality and Social Psychology in the journal Social Psychological and Personality Science.