If you think you're generally good at resisting temptation, you're probably wrong, scientists now say.

"People are not good at anticipating the power of their urges, and those who are the most confident about their self-control are the most likely to give into temptation," said Loran Nordgren, senior lecturer of management and organizations at the Kellogg School of Management, Northwestern University, in Illinois.

The result: Many of us unwittingly expose ourselves to tempting chocolate or cigarettes, leading to a greater likelihood of indulging in addictive behaviors.

Nordgren reached the conclusion through a series of small, offbeat experiments done primarily with college students. The results may hold for the broader population, but that has not been studied.

In one experiment, more than twice as many smokers who thought they could resist temptation lit up a cigarette in a no-smoking test as those who realized they didn't have so much control.

Those who puff out their chests in the face of temptation have a deflated view of others. "They also demonize others," Nordgren told LiveScience. "They take a very dim view of other people who act impulsively, because they have this belief that they themselves wouldn't act this way."

The bottom line, Nordgren says: Avoid situations where such weaknesses thrive, and remember you're not that invincible.

Hunger, cigarettes and sleep

The new study, which will be published in an upcoming issue of the journal Psychological Science, builds on past research showing that when not in the "heat of the moment," individuals have a hard time understanding the depths of their cravings.

"If you aren't feeling a cigarette craving or hunger or sexual arousal at this moment, I believe you have a real difficult time appreciating the transformative force of those experiences," Nordgren said.

And most of the time, we aren't gripped by impulse, he added.

To figure out how this so-called cold state (opposite of the "gripped by impulse" state) influences behavior, Nordgren ran experiments on:

Hunger pangs: Seventy-nine university students and employees rated a list of snacks from least to most favorite and then selected one. Participants were told, "You can eat the snack anytime you like. However, if you return the snack to this location in one week, we will give you four Euros (and you will get to keep the snack you chose)."

Questions also measured participants' level of hunger. Satiated participants exposed themselves to more temptation, generally choosing their first or second favorite snack, while the hungry individuals selected their second or third favorite item. Those with full bellies were also less likely to bring back an uneaten snack, Nordgren said.

Cigarette cravings: Fifty-three university students who smoked were placed into a high- or low-control group, in which a bogus test suggested each had either a high or low capacity for impulse control. Then, the participants had to watch a film called "Coffee and Cigarettes" without smoking. Participants chose their level of temptation with corresponding levels of payoff. They could either keep the unlit cigarette in another room (lowest), on their desk, in their hand, or in their mouth (highest).

On average, low-control students chose to watch the film with the cigarette on the table, and those who thought they could easily resist temptation chose to keep the cigarette in their hand. About 33 percent of the high-control students caved and smoked during the film, while just over 11 percent of the low-control participants lit up.

Mental fatigue: An experiment of 74 college students revealed those who were drained mentally reported having less control of mental fatigue than their bright-eyed counterparts. The "sleepy" students also said they intended to leave about 53 percent of their studying to the last minute, compared with about 60 percent for the non-fatigued group.

The thinking is that the alert students couldn't appreciate the enormous drawbacks of having a drained brain and so chose to leave more studying to the last minute.

Wider implications

The study has implications for all corners of our personal lives, Nordgren figures. For instance, can a recovering alcoholic attend booze-saturated parties and stay sober? Can a dieter frequent his favorite dessert buffets and refrain from binging? Can a committed husband have drinks with a past fling without fear of infidelity?

"The answer is probably 'no,'" Nordgren said. "People have less self-restraint than they think, a false belief that often leads people to expose themselves to more temptation than they can handle."

In addition, he added, the study results suggest people often can’t predict how they will react in a given situation.

"It's not just about eating and addiction, but the 'cold self' has a really hard time understanding what you're capable of in a moment of despair, in a moment of rage," Nordgren said.