A long-term, stable romantic relationship with a committed, caring partner has many psychological benefits, which we know from the oodles of psychological research published about them. So it’s a good thing to try and protect one’s relationship from external influences. One of the most difficult to recover from and damaging influences is cheating.

If cheating will harm a relationship (and cheating appears to be one of the primary reasons cited in many, if not most, relationship breakups), what can be done to minimize it?

After all, isn’t it human nature — and the nature of temptation — to constantly look for desirable alternatives?

One of the ways people look to protect their long-term relationship is to simply remain inattentive to those alternatives. Research has demonstrated that being inattentive to attractive members of the opposite sex generally promotes relationship success.

But new research (DeWall et al., 2011) suggests it’s not so simple. If the circumstances or situation implicitly limit a person’s attention to an attractive alternative, that alternative suddenly becomes “forbidden fruit.”

And all that more attractive.

The researchers call this the “forbidden fruit hypothesis,” based upon previous research that has demonstrated that people find things more desirable when they off-limits or forbidden. There’s something in human nature that wants what it can’t have. (Or perhaps we can have it, but with serious consequences.)

This hypothesis is consistent with another psychological theory called the “ironic process model.” This model suggests that suppressing thoughts about something will lead that thing to become even more salient. The more we try and not to think about something, the more we think about it.

To test their forbidden fruit hypothesis, the researchers conducted a series of three experiments involving undergraduate students.

In the first experiment, 42 students who were in a committed relationship that was at least a month old performed a visual discrimination task where their attention was subtly manipulated by the researchers in one group, and not manipulated in a control group. The task was simple — press the letter E or F on the keyboard when they appeared on the screen, replacing one of the two photographs shown on the screen. One photograph was of an attractive person, the other of an average-looking person.

The researchers manipulated the task by showing the letter that needed to be pressed 80 percent of the time in the place of the average-looking person. Therefore, in order to complete the task as efficiently as possible, subjects needed to force themselves to look away from the attractive-looking person.

The researchers at the end of the task then administered an infidelity cheating scale that measured attitudes about cheating, and a relationship satisfaction survey. They then compared the two groups to see if a significant difference emerged.

The results of this first experiment supported the researchers’ hypothesis. Participants whose attention to attractive alternatives was implicitly limited reported less satisfaction and commitment to their current relationship partner, compared with those in the control group. The limited group also had more positive attitudes toward relationship infidelity.

The second experiment was carried out in a similar manner with another set of 36 undergraduate students, with an additional component — memory. Would subjects whose attention was manipulated (unbeknownst to them) remember the faces of the attractive people more?

We have a better memory for attractive alternatives we’re not allowed to have.

The researchers again found that the answer was yes — participants whose attention was directed away from attractive alternatives showed better memory for those attractive alternatives. This is a counter-intuitive finding — we better remember attractive people’s faces when our attention is actually limited.

The third experiment is too complicated to explain here in this short space, but involved what psychologists call a “visual cuing task” (for those interested, they used a version of the visual dot-probe procedure). The result of this experiment of 158 students again confirmed that when they implicitly limited attention to attractive relationship alternatives, participants subsequently displayed heightened attention to attractive opposite-sex stimuli.

Limiting participants’ attention basically enhanced their subsequent scanning and monitoring of their environment for attractive relationship alternatives.

There are three primary limitations with the research described here that the researchers note. One, the experiments were all conducted on relatively younger undergraduate students who were in shorter long-term relationships than most married couples, so it’s not clear whether these findings would generalize to longer-term married couples. Two, the studies were all laboratory experiments involving artificial stimuli — photographs of attractive and ordinary looking people, conducted on a computer. Third, the researchers did not directly measure the effects on long-term psychology or behavioral relationship outcomes.

However, notwithstanding these limitations, the upshot of the researchers’ findings is that the advice, “Just don’t look” isn’t really going to be all that helpful in a relationship. Situations that limit a person’s attention to attractive alternatives — even when that limit is unconscious — lead those alternatives to taken on a desirable “forbidden fruit” quality.

Put with the existing research literature on this subject, the researchers suggest that when inattention to attractive alternatives is internally motivated, it leads to positive relationship processes. We have to consciously limit — and want to limit — our looking for attractive alternatives outside of our relationship.

If, however, that limit is externally motivated — such as by simply the presence of one’s partner or the situation itself — then it could add to undermining relationship success and promote infidelity.

The researchers conclude, “Probably the most effective solution involves working on enhancing relationship processes that naturally lead to decreased attention [to attractive alternatives], such as focusing on positive aspects of one’s partner.”

Good advice for all of us in long-term relationships. And perhaps a way to help avoid future infidelity.


DeWall, CN, Maner, JK, Deckman, T, & Rouby, DA. (2011). Forbidden fruit: Inattention to attractive alternatives provokes implicit relationship reactance. Journal of Personality and Social Psychology, 100(4), 621-629.