The marketing cliche "Sex sells" has been embraced by advertisers trying to get their products noticed in an increasingly cluttered space. Yet while the use of explicit sexual imagery can grab attention, it does not always create a favourable impression of the brand.

Earlier research has shown that men view such ads far more positively than women. But a new study by Jaideep Sengupta of HKUST and his co-authors Darren W. Dahl and Kathleen D. Vohs showed that this divide could be crossed if sexually explicit advertisements were presented in the context of a relationship.

They framed their investigations around sexual economics theory (SET), which contends that sex can be viewed as a negotiation in which each party - the man and the woman - wants to get something of value. Since men (on average) have been found to possess a stronger sex drive and are more interested in sex for its own sake, this puts women in a stronger negotiating position in these exchanges.

"SET argues that women are in a position to ask for additional resources to make the exchange equitable, which can be either pecuniary or non-material in nature. Relationship commitment may be seen as a valuable resource offered by the man in the context of a sexual exchange," they said.

In advertising terms, a sexually explicit ad that implied some form of commitment being received in return could produce a more positive response from women. The authors' experiments showed this was indeed the case.

In the first experiment, participants were divided into three groups: one saw a sexually explicit ad for a watch, another saw the same ad with a red ribbon and a tagline that it was a gift from a man to a special woman in his life, while two other groups saw a mountain scene with and without the gift condition.

Women rated the sexually explicit ad 4.67 on a 7-point scale when it was positioned as a gift, and only 3.83 when it was not. There was no such difference with the mountain scene (4.90 with the gift context, 4.76 without).

"This experiment showed that women report a spontaneous negative reaction to advertising containing explicit sexual content, which can be mitigated with a positioning tactic consistent with the idea of a relationship commitment," the authors said.

Interestingly, while men viewed the sexually explicit ad favourably, their opinion was lower with the gift condition, 4.18, than without, 5.02.

"The decline in male attitudes in the gift condition, where there is explicit reference to an exchange of resources, may represent a special context that serves to dampen men's enthusiasm for sexual ads," they said.

A second experiment showed women also viewed a sexually explicit ad more favourably when they were primed to think of a relationship context beforehand. Only female participants were involved this time and before viewing the ad, they were asked to proofread a short text about a male-female couple. One group saw a text where the man was committed to the woman, another where he was disloyal, and a third group where there was only a professional relationship between the two.

Women who saw the committed text reported a more positive attitude to the sexually explicit ad, 3.72, than those who saw the disloyal text, 2.44. The control group rated the ad 3.17.

While the results offered further confirmation that an exchange can improve attitudes towards a sexually explicit ad, it was unclear if the direction of that exchange made a difference, so a third experiment was conducted. The set-up was identical, except that the direction of commitment was switched in the priming text, such that the protagonist (whether loyal or disloyal to her partner) was a woman. Reactions of both female and male participants were obtained.

Generally, women's attitudes to the ad did not improve (even in the case where they read about a loyal woman), showing that simply introducing the idea of a relationship was not the factor; rather, the woman in the text had to be receiving commitment from the man, not the other way around.

"The results indicate that simply heightening the accessibility of thoughts regarding relationship commitment, irrespective of the direction of transfer, is insufficient to favourably influence women's attitudes. It seems that for women, direction indeed matters," the authors said.

A final experiment offered further proof that direction matters for women - but not men. The prime was changed so participants descrambled sentences relating to commitment, rather than proofread text. One set of sentences was about general commitment ("they loved each other") but the other focused on men's expressions of commitment to women ("he loved her").

This female focused prime resulted in more positive attitudes among women towards the sexual ad (3.72 against 2.98 for the couple focused prime) and the brand (4.49 against 3.18). But it did not alter men's attitudes (4.27 against 4.77 in terms of ad attitude and 4.49 against 4.18 in terms of brand attitude).

"This experiment provides strong support for a directional-based influence of relationship commitment. Women will view a sexually explicit ad more favourably when thoughts of commitment proffered by men to women are accessible, but not generalised thoughts of relationship commitment," the authors said.

"We repeatedly found that heightening thoughts relating to relationship commitment didn't influence men's already favourable attitudes to a sexually explicit ad, regardless of the directionality of such thoughts. The one notable exception was when the ad strongly reminded them that they may at times devote monetary resources in pursuit of sexual contact."

Overall, the results support the idea of gender differences in response to sexual advertising and suggest ways that advertisers who use sex to sell can overcome these.

"At one level we echo earlier research that explicit depictions of sex can be problematic, especially with regard to women's spontaneous reactions. However, the appropriate use of positioning and relationship context can improve women's attitudes towards the ad and the brand. Although marketers should exercise caution when using sex to promote products if women are part of the target audience, our research provides guidelines to reduce potential downsides," they said.