On the eve of our national election, we realize that one challenging issue facing the next president is how to address terrorism and the options for counterterrorism. As psychological research has made clear, what he and his administration say about these issues will influence how the public thinks about them—and will affect our national and international policy. [For more on the power of words, see “When Words Decide,” by Barry Schwartz; Scientific American Mind, August/September 2007.]

Since the attacks on the World Trade Center and the Pentagon in 2001, the Bush administration has used a battle metaphor: the “global war on terrorism” and the “war on terror.” Such descriptive terms simplify complex realities, making them more mentally manageable. But they do not adequately represent the complexities of the problem, resulting in selective perception of the facts, and they may reflect the views of only a few key policy makers. Nevertheless, they can guide national decision making. The wars that began in Afghanistan in 2001 and Iraq in 2003 clearly demonstrate that the concept of a war to combat a method of violence used by nonstate agents is more than rhetoric.

Although the war metaphor has some advantages, the next president should consider other terms that lead to thinking that is more nuanced—and ultimately more effective. Viewing counterterrorism through the lens of law enforcement, for example, may yield more tightly focused tactics that are less likely to provoke resentment and backlash and are also less costly than war. Two other metaphors—relating counterterrorism to disease containment or prejudice reduction—home in on many of the deeply rooted psychological underpinnings of terrorism and, in doing so, suggest strategies that may chip away at the motivations of terrorists and thus may be the most successful at squelching the scourge in the long run [see “Inside the Terrorist Mind,” by Annette Schaefer; Scientific American Mind, December 2007/January 2008].

Declaring War
The Bush administration’s framing of terrorism as an act of war is a departure from past administrations’ ways of thinking. Presidents Richard M. Nixon and Ronald Reagan, for example, preferred a disease metaphor. President Bill Clinton’s general themes were the pursuit of justice, law enforcement and international cooperation. Clinton wanted to deny “victory” to terrorists, but he and other previous presidents stopped short of the word “war.”

President George W. Bush adopted the war construct immediately. On the morning of September 12, 2001, after a meeting of the National Security Council, the president told reporters: “The deliberate and deadly attacks which were carried out yesterday against our country were more than acts of terror. They were acts of war.”

The war metaphor helps to define the American perception of the threat of terrorism. If terrorism is war, then the national security, indeed the existence, of each side is threatened. The conflict is zero-sum; the outcome will be victory for one side or the other. Being in a state of war also requires national unity, and dissent is easily interpreted as unpatriotic. The solution has to be military. Thus, the Department of Defense must play a lead role in shaping policy, and the president’s duties as commander in chief must take precedence over his other tasks. An expansion of executive power accompanies the war metaphor: measures that would not be acceptable in peacetime, such as restrictions on civil liberties and brutal interrogation practices, are now considered essential.

But in several ways, the struggle against terrorism differs significantly from conventional war. First, the entity that attacked the U.S. in 2001 was not a state. It was an organization, al Qaeda, with a territorial base within a weak “failed state,” Afghanistan, whose ruling Taliban regime was not internationally recognized. Since 2001 the entity that the U.S. is fighting has become even more amorphous and less like a state. It has progressed from the so-called terrorist organizations to an ideology that aspires to world domination. David Brooks, writing in the New York Times on September 21, 2006 , called it “chaos theory in human form—an ever-shifting array of state and nonstate actors who cooperate, coagulate, divide, feud and feed on one another without end.”

Victory in a war on terrorism is similarly difficult to define. A typical war ends in the capitulation of the enemy, but al Qaeda is unlikely to surrender formally. In 2006 the revised (2002) U.S. National Security Strategy, articulated in a White House “wartime” document, set a goal “to defeat global terrorism.” It will be difficult to tell when this objective, which involves eradicating a method of violence and a way of thinking, has been met. As a result, the war drags on, breeding disappointment with the results and a public outcry to bring the troops home.

The psychological rationale of war is to bring the enemy to its knees and to convince it and its support base that terrorism is counterproductive. And yet experience in Chechnya, Afghanistan, Iraq, Ireland, and the West Bank and Gaza Strip suggests that the use of military force does little to “prove” the inefficacy of terrorism. Military strikes against terrorist targets may temporarily interfere with terrorists’ ability to launch their operations, but they do not generally lessen the motivation to engage in violence—and may even boost it as a result of the enmity that foreign occupation typically engenders and of the injustice and excesses of war.

The war concept also deafens ears to the underlying troubles of the terrorists—the frustrations and grievances that may have fostered terrorism, as well as the belief systems that lent it ideological sustenance. Meanwhile the metaphor encourages stereotyping and discrimination against members of the broad social categories to which terrorists may belong, such as Muslims, Saudi Arabians or Middle Easterners.

Finally, framing counterterrorism as war has considerable costs. It threatens to corrupt society’s values, disrupt its orderly functioning and reshuffle its priorities. War calls for the disproportionate investment of a nation’s resources, with correspondingly less left for other concerns, including the economy, health care and education. “Collateral damage,” ethnic profiling, harsh interrogation tactics and unlimited internment of suspects may all be condoned in the name of security and excused by the uniqueness of circumstances the war concept implies. These costs are especially steep in a war that has no definite end.

Fighting Crime
Whereas war is a reaction to a massive confrontation, law enforcement generally follows more restricted challenges—akin in many ways to those typically presented by terrorism. For instance, extensive police work, a trial and convictions followed the 1993 truck bombing in the World Trade Center parking garage that resulted in six deaths, hundreds of injuries and property damage just under half a billion dollars. In contrast, war was the response to the 3,000 deaths and tens of billions of dollars in damage from the 9/11 attacks.

In support of the law-enforcement approach, Senator John Kerry of Massachusetts stated in a presidential candidates’ debate in South Carolina in 2004 that although counterterrorism will be “occasionally military,” it should be “primarily an intelligence and law-enforcement operation that requires cooperation around the world.” The United Nations has never been able to agree on a definition of terrorism but has developed articles prohibiting acts such as airline hijacking and violence against diplomatic persons, consistent with a law-enforcement metaphor. After all, terrorists often engage in crime as conventionally defined, and suspected terrorists in the U.S. are typically prosecuted for criminal offenses rather than terrorism—commonly racketeering, possession of firearms and conspiracy.

One advantage of the law-enforcement metaphor over the war concept is its focus on the particular perpetrators in violation of the legal code rather than on an actor vaguely defined as the “enemy.” Such an emphasis is less likely to incite discrimination against entire groups of people. And as an ongoing concern, law enforcement does not suggest the need for an overwhelming financial commitment but rather must compete for resources with education, jobs, housing and welfare.

The law-enforcement idea also limits the costs of mistakes. Civilian casualties, nearly unavoidable in bombing raids of terrorist targets under the war metaphor, are unlikely with law-enforcement policies, which are thus less apt to fuel anger toward the West and thereby boost support for terrorist organizations. What is more, the experience of the Israelis and the British suggests that successful counterterrorism often resembles painstaking police work more than it does war. That is, effective police work requires understanding a local culture and geography, developing local relationships and cultivating local sources of information—efforts for which an army is ill prepared.

International cooperation in counterterrorism is also more possible under the law-enforcement approach. Whereas the international community is basically in favor of law and order, the war metaphor is often too demanding for many states to embrace. For example, although France strongly opposed the Iraq War, American and French law enforcement have cooperated very effectively since 9/11.

And yet terrorism, unlike most crimes, is ideologically inspired. In contrast to typical criminals, who tend to have selfish, personal motivations, terrorists are often trying to change the world and frequently believe they are serving a cause that will achieve a greater good. Because of such grand ideas, terrorists often inspire admiration and respect in their communities. During much of the second Intifada, which began in September 2000 and ended this past June, public opinion polls conducted among Palestinians revealed that about 80 percent supported suicide attacks against Israelis. In such situations, law-enforcement officials may have difficulty convincing the public to help them fight crimes related to terrorism.

Finally, because law-enforcement tactics do not generally dampen the motivation to engage in terrorism, their success in thwarting attacks is often short-lived. Terrorists are a determined and inventive bunch, and sooner or later they are likely to find other means of carrying out their plans, for instance, resorting to suicide missions if necessary.

Containing an Epidemic
The social epidemic metaphor for counterterrorism likens the spread of terrorist ideas to the transmission of infectious disease: an external agent such as a pathogen or violent way of thinking infects a susceptible host—a nonimmune or psychologically vulnerable population—in an environment that brings them together. In that environment a vector—such as the malaria-carrying Anopheles mosquito or the Internet—facilitates the transmission of a pathogen or ideas.

The disease metaphor of terrorism guides intelligible questions as to the origins of an outbreak, its boundaries, social contours and method of transmission, along with who is most at risk of “infection.” It casts terrorism, like disease, as an outgrowth of a complex interaction among people, pathogens and the environment. It thus suggests that rolling back terrorism requires a multipronged effort to tackle each of these elements just as controlling malaria requires preventive methods that target its environmental contributors, such as spraying the ponds in which the mosquitoes breed and supplying people with protective clothing and mosquito nets.

This metaphor offers a lens through which to more closely examine the underlying psychological forces behind terrorism. The agent or pathogen in this case is a terrorism-justifying ideology that includes a collective grievance, such as humiliation of one’s nation or religious group, a culprit or party responsible for the grievance, and a belief that terrorism is a morally justifiable and effective tool for redressing the grievance. A hate-mongering leader typically helps to promote a potent “us versus them” social psychology, setting in motion powerful group dynamics centered on the ideology.

A terrorist philosophy may be propagated by any of several vectors or vehicles, one of the most prominent being the mosque, where young Muslims are inculcated with an unquestioning reverence for Allah. The Middle Eastern prisoners whom a team of psychologists led by one of us (Post) interviewed in 2002 consistently cited the mosque as the place where most members were initially introduced to the Palestinian cause.

The Internet may also facilitate spread of the ideological pathogen. In 2007 Army Brigadier General John Custer, head of intelligence at central command, responsible for Iraq and Afghanistan, stated on CBS News: “Without doubt, the Internet is the single most important venue for the radicalization of Islamic youth.” Experts estimate that 5,000 jihad sites are currently in operation. In one recruitment drive, potential converts are bombarded with religious decrees and anti-American propaganda, provided with manuals on how to be a terrorist and—as they are led through a maze of secret chat rooms—given instructions on how to make the journey to Iraq to fight U.S. and coalition forces there.

The Internet is thus one obvious target for counterterrorism. In the Saudi Al-Sakinah (“Tranquility”) campaign, Muslim legal scholars and propagators of Islam—assisted by psychologists and sociologists—enter extremist Web sites and forums and converse with the participants to bring them to renounce their extremist ideas. The campaign’s organizers believe these efforts have been successful in many cases (although that claim needs to be more rigorously examined).

In addition to these vehicles, the propagation of terrorism requires a receptive population. Such susceptibility can arise from early socialization to a terrorism-justifying ideology and personal circumstances that render the ideology appealing. Inculcation at an early age can build hatred into a child. In one campaign, the Hezbollah Shiite youth movement “Imam al-Mahdi Scouts,” tens of thousands of children aged eight to 16 are indoctrinated with the ideology of radical Iranian Islam, whereas kindergarteners are a target audience for the educational efforts of Hamas.

Personal suffering and frustrations can add to the vulnerability. For people growing up or currently living in repressed or limited socioeconomic conditions, academic or economic achievement may seem remote. Thus, many people seek success instead as fighters for a terrorist cause. Traumatic experiences such as having a relative or friend killed by the enemy may increase the desire to embrace collectivistic causes. Creating alternative paths to success might immunize a susceptible population by enabling bright, educated individuals to thrive within their culture rather than striking out in despair.

Stemming Prejudice
Rather than approaching terrorism as a problem perpetuated by the terrorists alone, as the other three metaphors do, the metaphor of prejudice reduction shifts the focus from a unilateral to a bilateral concern and casts terrorism as one expression of tense and deteriorating intergroup relations. A poignant example of such incendiary associations involves Muslim immigrants in Europe and the ethnically native European populations. Three of the terrorist pilots in the September 11 attacks—Mohamed Atta, Marwan al-Shehhi and Ziad Jarrah—were young Muslims who spent extended periods living in Europe. Since then, a series of attacks, interrupted attacks and plots has been linked to other young Muslims with European background. Most recently, eight Muslim doctors or doctors in training working in British hospitals were arrested in connection with two attempts to explode car bombs in downtown London on June 29, 2007, and an attempt the next day to ram a flaming Jeep into the main entrance of the Glasgow airport.

According to a 2006 report by the Pew Global Attitudes Project, 58 to 70 percent of both Muslims and non-Muslims in Great Britain, France and Germany say that intergroup relations are bad. Cultural differences may explain part of the problem. For instance, many non-Muslim Europeans tend to hold that Muslims are fanatical, violent and disrespectful of women, and most are very or somewhat concerned about the rise of Islamic extremism in their country. As a result of such attitudes, Muslims may be discriminated against in housing, employment and services. Muslim and non-Muslim Europeans also tend not to visit the same stores or entertainment and sporting venues, extending the separation of the two cultures to everyday life.

Although such tensions may not constitute sufficient conditions for terrorism, they may instill the readiness to buy into a terrorism-justifying ideology and are potential harbingers of violent intergroup conflict. For example, 24 percent of British Muslims and 35 percent of French Muslims endorse the statement that violence against civilian targets is sometimes or rarely justified in the service of Islam, according to the Pew report.

Multiple initiatives are under way to enhance integration and reduce friction between Muslims and non-Muslims in Europe. Some of them involve efforts to document discriminatory behavior or civil-rights violations; others strive to promote dialogue or involve legislation to punish discriminatory behaviors in employment, housing and banking.

Despite such efforts, social scientists have done little to evaluate what works to enhance social integration and eliminate tensions. And yet prejudice and discrimination have been among the most intensively studied social psychological phenomena. In particular, a wealth of experimental research has shown that creating opportunities for two groups to meet and interact with each other under agreeable circumstances can go a long way toward reducing prejudice. In the so-called contact hypothesis described by Harvard University psychologist Gordon Allport in his 1954 text The Nature of Prejudice, the key is interaction or contact between equal-status members of each group in the pursuit of common goals.

In 2006 psychologists Thomas F. Pettigrew of the University of California, Santa Cruz, and Linda R. Tropp of Boston College reported in a meta-analysis of 515 studies, which included 713 population samples and 1,383 tests, that rates of prejudice fall significantly with contact. Some types of interventions appear to work better than others do: although incidental contact or travel excursions seem to yield little benefit, residential interaction does help; educational and work-based contact is even more valuable, and the best effects were seen in recreational contexts. And, as Allport had argued, when authorities sanction the meetings, that fact predicts success better than any other factor.

Media or community portrayals of aggressive, humili­ating or discriminatory activities perpetrated by one group against the other, however, may undermine contact in isolated settings. Efforts at prejudice reduction should include media campaigns and enforcement of antidiscrimination policies as well as immigration laws, educational programs and foreign policy initiatives designed to augment the good will generated by contact programs. And because prejudice is strongly related to real economic disparities and is augmented by a sense of injustice, psychological efforts may work best if combined with credible policies aimed at the elimination of objective inequalities.

Prejudicial attitudes are by no means the only explanation for aggression that may translate to terrorism. What is more, the contact prescription that accompanies the idea of prejudice reduction emphasizes cooperative secular activities, thereby failing to address the radical religious notions that fuel terrorism. More generally, the concept of prejudice reduction, like the epidemic metaphor, neglects the short-term challenges posed by terrorism, including the need to counter specific terrorist schemes and protect societies from the immediate threats these entail.

Thus, no single metaphor can fully encapsulate counterterrorism. Each beams a searchlight on specific psychological pieces of the puzzle, illuminating some of its aspects while leaving others in darkness. Jointly, however, these four descriptions manage to convey the considerable complexity behind the violent acts that counterterrorism policies are designed to thwart.

To achieve this broader perspective, we recommend a comprehensive approach involving collaboration between military and law-enforcement experts, along with social scientists who can highlight the likely psychological, political or sociological ramifications of various counterterrorism initiatives. Admittedly, setting up such an alliance may not be easy, and long-term considerations may seem at odds with, or tangential to, current security needs.

Nevertheless, academics are finding their way into the relevant security circles. The Homeland Security Act of 2002 established the University Programs initiative, which has led to centers of excellence at U.S. universities that study the social and behavioral (among other) aspects of terrorism. This law has provided a conduit between academic research in the behavioral and social sciences and a government national security agency. In the future, we hope that new cadres of security experts who have been educated in the group and psychological facets of terrorism will lead the U.S. toward more sophisticated and highly effective counterterrorism strategies.

Note: This article was originally printed with the title, "Talking about Terrorism".