Restricted vs. Unrestricted Sociosexuality: What Does It Mean?

October 23, 2012

“This restricted/unrestricted business confuses the hell out of me…

Am I right in thinking that it’s more of a measure of attitudes and beliefs instead of actions and results?

Just my opinion, but to me attitudes and beliefs don’t count for much when a person’s actions contradict them.”

Reader Jimmy Hendricks

 One of the most important tasks in selecting a romantic or life partner is assessing the individual’s likelihood of remaining sexually and emotionally faithful over time. Infidelity causes great and often irreversible damage to relationships and families. We can reliably predict someone’s likelihood of engaging in future promiscuous behavior by assessing their sociosexual orientation.

What is sociosexual orientation?

Sociosexuality is a personality trait. The construct of sociosexuality or sociosexual orientation captures individual differences in the tendency to have casual, uncommitted sexual relationships. The term was introduced by Alfred Kinsey, who used it to describe the individual differences in sexual permissiveness and promiscuity that he found in his groundbreaking survey studies on sexual behavior. 

Evolutionary personality psychologists classify men and women on sociosexual orientation between the extremes of unrestricted and restricted. 

Key Features of Sociosexual Orientation

1. Relative to sociosexually restricted individuals, sociosexually unrestricted individuals are more likely to: 

  • Engage in sex at an earlier point in their relationships.
  • Engage in sex with more than one partner at a time.
  • Be involved in sexual relationships characterized by less investment, commitment, love, and dependency. 

2. Sociosexual orientation (just like all other personality traits) is half heritable, half environmental.

A study of a large sample of Australian twins conducted by the great behavior geneticist J. Michael Bailey and colleagues shows that sociosexual orientation is another personality trait that roughly follows the 50-0-50 rule.  Their behavior genetic analysis shows that 49% of sociosexual orientation is heritable (determined by genes), 2% is attributable to shared environment, and 47% to unshared environment.  

3. Half of the men and women in the top (withinsex) 20% of sociosexuality had been sexually unfaithful to a steady partner. This is roughly double the average rate of infidelity in the population.

4. Women in the top female quintile of sociosexuality were nearly as elevated in their relevant sexual experiences as men in the top male quintile, even though the 80th female percentile was equivalent to only the 39th male percentile. This provides further support for the idea, considered elsewhere, that female sexuality constrains male sexuality. That is, given a woman and a man with similar inclinations to casual sex, the woman will realize her ambitions more readily than will the man.

Table 1. Comparison of Top  Quintiles on Self-Reported Behavioral Correlates of the Sociosexuality Scale Scores in Percentages (2000)*

Had sex with someone the same day
you met
Got pregnant, or got someone
pregnant, before marriage
Had sex after having a lot to drink7788
Was unfaithful to a steady partner4863
Had sex with two people in a 24 hour
Ever had a sexually transmitted disease1924

*This is not the SOI, for which no scoring information is available, but a sociosexuality scale conceived by the study’s authors.

5.  While men in general are more unrestricted in sociosexual orientation than women, the variance within each sex is much greater than variance between the sexes.

Table 2. Comparison of Top  and Bottom Quintiles on Self-Reported Behavioral Correlates of the Sociosexuality Scale Scores in Percentages (2000)*

 Women Bottom Women Top Men Bottom Men Top 
Had sex with someone the same day
you met
Got pregnant, or got someone
pregnant, before marriage
Had sex after having a lot to drink25773488
Was unfaithful to a steady partner348563
Had sex with two people in a 24 hour
Ever had a sexually transmitted disease419424

How is sociosexuality measured in the population?

The revised Sociosexuality Orientation Inventory (SOI) is a 9-item questionnaire designed to measure sociosexual orientation on a spectrum from restricted to unrestricted. 

Detailed analyses revealed a highly distinctive pattern of relationships for the three SOI-R facets, supporting their discriminant validity.

An analysis of 8,522 participants from an online study indicates that the SOIR is appropriate for individuals of any normal-range educational level, including hetero-, bi- and homosexuals, singles and individuals of any relationship/marital status, and at least the age range of 18 to 60 years. However, some facets do not work very well for sexually inexperienced and asexual individuals.

The SOI assesses three facets of sociosexuality:

A. Past Behavior in terms of number casual and changing sex partners

1. With how many different partners have you had sex within the past 12 months?

2. With how many different partners have you had sexual intercourse on one and only one occasion?

3. With how many different partners have you had sexual intercourse without having an interest in a long-term committed relationship with this person?

B. The explicit Attitude towards uncommitted sex

4. Sex without love is OK.

5. I can imagine myself being comfortable and enjoying “casual” sex with different partners.

6. I do not want to have sex with a person until I am sure that we will have a long-term, serious relationship.

C.  Sexual Desire for people with whom no romantic relationship exists.

7. How often do you have fantasies about having sex with someone you are not in a committed romantic relationship with?

8. How often do you experience sexual arousal when you are in contact with someone you are not in a committed romantic relationship with?

9. In everyday life, how often do you have spontaneous fantasies about having sex with someone you have just met?


All nine items are aggregated to form a full scale score that represents the global sociosexual orientation. 

The distinctive pattern of relationships among the three areas include the following:

  • Sex differences were pronounced for Desire, mediocre for Attitude and nonexistent for Behavior.
  • Only Desire made unique contributions to the prediction of past sexual and relationship behaviors, observer-rated attractiveness, self-perceived mate value and female flirting behavior.
  • Attitude appeared responsible for the effects of sociosexuality on mate preferences, assortative mating, and a romantic partner’s flirtatiousness outside the relationship. 
  • Desire had strong independent effects on relationships with sex drive, relationship quality, and male flirting behavior.
  • Behavior and Desire, but not Attitude, predicted the number of sexual partners and changes in romantic relationship status over the next 12 months.

Does Sociosexuality Vary Over Time Depending on Age or Circumstances?

Sociosexual orientation is a personality trait, and is relatively stable over the life course; in other words, people are either sociosexually restricted or unrestricted most of their lives. 

What other personality traits predict unrestricted sociosexuality?

  • Findings indicated that both unrestricted women and men described themselves as attractive and not ethically consistent.
  • Unrestricted women described themselves as not being moralistic and as varying their roles, depending on the situation.
  • Unrestricted men described themselves as irresponsible, unproductive, not warm, not anxious, and assertive.
  • Relationships were demonstrated between unrestricted sociosexuality for men and narcissism and psychopathy.

Is unrestricted sociosexuality the same as a strong desire for sexual variety?

An unrestricted individual is likely to achieve a high score in the Sexual Desire portion of the test, but will also have behaved in accordance with those desires, and exhibit liberal attitudes towards uncommitted sex. The desire for sexual variety is just one aspect of sociosexuality.

Sexual Strategies Theory (SST; Buss & Schmitt, 1993) argues that because women, compared with men, have a greater minimal level of parental investment (Trivers, 1972), they are more sensitive to resource limitations and thus have a greater stake in the success of the relationship with their reproductive partner. It follows that women’s optimal strategy for maximizing reproductive success is to establish and maintain a committed relationship with a single partner who will contribute to their offspring’s viability. For men, however, SST suggests that pursuing a variety of sexual partners may have evolved as an effective strategy for maximizing reproductive success. 

Among college students, Buss and Schmitt found the following difference in the preferred number of sexual partners:

Pedersen replicated the study in 2002, and found the same sex differences when plotting the means for each time period. However, Pedersen et al noticed that the mean values were highly skewed by a small number of individuals at the upper end. Restributing the results by median yielded the following result: 



The debate continues, and it is beyond the capabilities of this blogger to distinguish the scientific merits of each case. At first pass, the data strikes me as compatible in the sense that Sexual Strategies Theory may still apply, though the distribution of individuals would be skewed left.