"When she says 'It's getting late,' he may hear 'So let's skip the preliminaries,'" Motley says. "The problem is that he is interpreting what she said by trying to imagine what he would mean -- and the only reason he can imagine saying 'It's getting late' while making out is to mean 'Let's speed things up.'"

Motley calls it the "introspection" explanation: "Males' inferred meanings for women's indirect sexual resistance messages are more similar to the meanings males would have intended by those same messages than to the meanings women intend."

The research appears in "Studies in Applied Interpersonal Communication" (Sage Publications, 2008), a new book edited by Motley. The book is due on academic bookshelves soon.

Previous research has found that up to 85 percent of college women have had at least one experience in which a man attempts to escalate physical intimacy beyond the point that she has said "stop," experiences they usually regard as unpleasant.

Motley's research during the past decade suggests miscommunication is a significant reason for the problem in many cases. (The research does not address rape or other situations in which a man indeed understands "no" but ignores it.)

In one study, Motley gave 30 female and 60 male UC Davis undergraduates a multiple-choice questionnaire that asked about 16 common "female resistance messages." The messages ranged from very direct -- "Let's stop this" -- to very indirect -- "I'm seeing someone else." Four potential interpretations were listed for each message; only one was "stop."

For "I'm seeing someone else," for example, the following four interpretations were listed:

a) You want to go further but you want him to know that it doesn't mean that you're committed to him;

b) You want to go further but you want him to be discreet, so that the other guy doesn't find out;

c) You want to go further but you want him to realize, in case you end up "going together," that you may do this with someone else while you're seeing him;

d) You don't want to go further.

The women in the study were asked to recall a time when they used one of the messages, and to choose the answer that best matched what they meant when they said it. Half of the men were asked to recall a time when they were with a woman who communicated each message, and to choose the interpretation that best matched what they thought the woman meant when she said it. The other 30 men were instructed to choose the interpretation that best matched what they would mean if they were to communicate the messages.

The questionnaire study showed that men were accurate at interpreting direct resistance messages like "Let's stop this." But they were as apt to interpret "Let's be friends" to mean "keep going" as to mean "stop." And few of them would mean "stop" if they were to deliver any of the indirect messages themselves.

In related studies, Motley has also shown that most women use indirect messages out of concern that men will be offended or angered by direct messages -- but that most men actually accept direct resistance messages easily and without negative reactions.

"Studies in Applied Interpersonal Communication" also reports Motley's research into the behaviors and conditions that determine the fate of platonic friendships when one party develops unrequited romantic feelings for the other. Chapters by other researchers explore such topics as interpersonal guilt, how to give advice so people will listen to it, and what constitutes effective emotional support.

While intended as an academic text, the book contains practical conclusions and recommendations. For example, Motley's chapters lay out these lessons from his research into unwanted escalation of sexual intimacy:

-- Men need to be aware of the many ways that women may say "stop" without using the word "stop."
-- When a man asks himself during intimacy, "Why did she say that?" he should not try to answer the question by imagining what he would mean if he said the same thing.
-- When in doubt, ask. "So it's getting late; does that mean we should stop?"
-- Women should use direct messages.
-- A woman who cannot be direct should at least work a direct message into the indirect one: "It's getting late, so I'd like to stop."

Source: UC Davis