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The debate over spanking goes back many years, but the essential question often evades discussion: does spanking actually work? In the short term, yes. You can correct immediate misbehavior with a slap or two on the rear-end or hand. But what about the long-term impact? Can spanking lead to permanent, hidden scars on children years later?

On Friday, a sociologist from the University of New Hampshire, Murray Straus, presented a paper at the International Conference on Violence, Abuse and Trauma, in San Diego, suggesting that corporal punishment does leave a long-lasting mark — in the form of lower IQ. Straus, who is 83 and has been studying corporal punishment since 1969, found that kids who were physically punished had up to a five-point lower IQ score than kids who weren't — the more children were spanked, the lower their IQ — and that the effect could be seen not only in individual children, but across entire nations. Among 32 countries Straus studied, in those where spanking was accepted, the average IQ of the survey population was lower than in nations where spanking was rare, the researcher says.

In the U.S., Straus and his colleague Mallie Paschall of the Pacific Institute for Research and Evaluation, looked at 1,510 children — 806 kids ages 2 to 4, and 704 ages 5 to 9 — and found that roughly three-quarters had endured some kind of corporal punishment in the previous two weeks, according to interviews with the mothers. Researchers measured the children's IQ initially, then again four years later. Those kids who hadn't been spanked in the initial survey period scored significantly better on intelligence and achievement tests than those who had been hit. Among the 2-to-4-year-olds, the difference in IQ was five points; among the older kids, there was a 2.8-point gap. That association held after taking into account parental education, income and other environmental factors, says Straus.

So how might getting spanked on the butt actually affect the workings of the brain? Straus notes that being spanked or hit is associated with fright and stress; kids who experience that kind of trauma have a harder time focusing and learning. In another recent paper that he coauthored with Paschall, Straus writes that previous research has found that even after you control for parental education and occupation, children of parents who use corporal punishment are less likely than other kids to graduate from college.

Still, it's not clear if spanking causes lower cognitive ability or if lower cognitive ability might somehow lead to more spanking. It's quite possible that kids with poor reasoning skills misbehave more often and therefore elicit harsher punishment. "It could be that lower IQ causes parents to get exasperated and hit more," Straus says, although he notes that a recent Duke University study of low-income families found that toddlers' low mental ability did not predict an increase in spanking. (The study did find, however, that kids who were spanked at age 1 displayed more aggressive behavior by age 2, and scored lower on cognitive development tests by age 3.) "I believe the relationship [between corporal punishment and IQ] is probably bidirectional," says Straus. "There has to be something the kid is doing that's wrong that leads to corporal punishment. The problem is, when the parent does that, it seems to have counterproductive results to cognitive ability in the long term."

One problem with Straus' data is that some of the parents who tended to spank may also have been engaging in actual physical abuse of their children. Researchers define corporal punishment as physical force intended to cause pain — but not injury — for the purpose of correcting a child's behavior, not simply hurting him. Studies have shown that very few parents who use corporal punishment also beat their kids, but Straus can't rule out the possibility that his data is confounded by the presence of child abuse, which past research has shown to affect victims' development.

The preponderance of evidence points away from corporal punishment, which the European Union and the United Nations have recommended against, but the data suggest that most parents, especially those in the U.S., still spank their kids. Based on his international data, collected by surveying more than 17,000 college students in various countries, Straus found that countries with higher GDP tended to be those where corporal punishment was used less often. In the U.S., the tendency to hit also varies with income, along with geography and culture; it's most common among African-American families, Southern families, parents who were spanked as children themselves and those who identify themselves as conservative Christians.

But overall the percentage of parents who spank has been steadily declining. Straus says that in 1968, 94% of Americans told surveyors they agreed with spanking. By 2005, the proportion who said it is "sometimes O.K. to spank a child" had fallen to 72%, although most researchers believe the actual incidence of corporal punishment is higher.

The practice has its defenders, and Straus himself admits, with chagrin in his voice, that he spanked his own son. In the 1990s, the American Academy of Pediatrics underwent a bitter fight before finally declaring in 1998 that "corporal punishment is of limited effectiveness and has potentially deleterious side effects."

Sometimes spanking seems like the only way to get through to an unruly toddler. But the price for fixing his poor short-term conduct might be an even more troublesome outcome in the future.

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In his rambling diatribe to the U.N. General Assembly Wednesday, Libyan President Muammar Gaddafi criticized the world body for being unfair to small nations. This comment struck a chord with the Swiss, since Gaddafi has been on a self-proclaimed mission to destroy their little country.

A few weeks ago, Gaddafi submitted a proposal to the U.N. to abolish Switzerland and divide it up along linguistic lines, giving parts of the country to Germany, France and Italy. Although the motion was thrown out because it violates the U.N. Charter stating that no member country can threaten the existence of another, some Swiss leaders are still concerned that Libya could use its year-long presidency of the U.N. General Assembly, which began on Sept. 15, to keep up his vitriolic attacks on their country. (See TIME's Exclusive Interview with Gaddafi on Obama, Israel and Iran)

Gaddafi's animosity toward Switzerland may seem bizarre — or maybe not, given the Libyan leader's all-female bodyguard squad and penchant for pitching Bedouin tents during state visits to other countries. Relations between Libya and Switzerland soured in July 2008 when Gaddafi's son Hannibal and his wife were arrested by police in Geneva for allegedly beating their two servants at a local hotel. Gaddafi was so enraged by his son's two-day detention, he immediately retaliated by shutting down local subsidiaries of Swiss companies Nestlé and ABB in Libya, arresting two Swiss businessmen for supposed visa irregularities, canceling most commercial flights between the two countries and withdrawing about $5 billion from his Swiss bank accounts. (Read: "Libya Flips Over Swiss Detention.")

Then came Gaddafi's suggestion that Switzerland be carved up like a wheel of Swiss cheese. During the G-8 summit in Italy in July, Gaddafi said Switzerland "is a world mafia and not a state," adding that the Italian-speaking part of the country should be returned to Italy, the German-speaking part given to Germany and the French-speaking part ceded to France. In an attempt to defuse the tensions between the countries, as well as to win the release of the two Swiss nationals being held in Libya, Swiss President Hans-Rudolf Merz traveled to Tripoli in August to apologize for Hannibal's arrest. The move was highly criticized in Switzerland, with repeated calls for his resignation. (See pictures of the rise of Gaddafi.)

The reaction among the Swiss public to Gaddafi's idea of splitting up the country has been a mix of outrage and incredulity. "Even though Gaddafi is a leader of a country and the current head of the African Union, he loses credibility when he comes up with outrageous comments like that," says Daniel Warner, a political scientist at the Graduate Institute of International Studies in Geneva. Others see irony in Gaddafi's comments. "It's a paradox that Gaddafi wants to dismantle Switzerland because, as he claims, it is not a homogenous country, while Libya is divided by a desert into two regions that hate each other," says Baptiste Hurni, a Socialist parliamentarian who blogs about Libya. (See the Top 10 U.N. General-Assembly Moments.)

Despite the fact Gaddafi is still holding two Swiss nationals, many Swiss have found much to laugh about in his statements. The newspapers abound with tongue-in-cheek comments from readers not only questioning Gaddafi's sanity but also wondering how Switzerland would be divided up if the Libyan leader's motion were to be taken seriously. "Who is going to get the Matterthorn?" one reader asks in the Lausanne daily Le Matin. "Linguistically it belongs to Germany but geographically it borders Italy." Another reader in Le Matin said he is "scandalized that Austria is not getting its fair share," while a Geneva resident wrote that he doesn't want his region to be annexed to France and asked about the possibility of linking it to French-speaking Quebec instead.

Most everyone agrees on one point: Libya should not be casting stones. "Is the U.N. going to listen to a longstanding democracy or to a longstanding dictatorship?" 19-year-old Eduard Hediger said in a recent Le Matin podcast. If Gaddafi's long-winded speech to the General Assembly is any indication, the U.N. may not have much of a choice in the matter.