In the 1970s and 1980s, it was commonly assumed that terrorist use of weapons of mass destruction (WMD) would be counterproductive because such an act would be widely condemned. “Terrorists want a lot of people watching, not a lot of people dead,” Brian Jenkins (1975:15) opined. Jenkins’s premise was based on the assumption that terrorist behavior is normative, and that if they exceeded certain constraints and employed WMD they would completely alienate themselves from the public and possibly provoke swift and harsh retaliation. This assumption does seem to apply to certain secular terrorist groups. If a separatist organization such as the Provisional Irish Republic Army (PIRA) or the Basque Fatherland and Liberty (Euzkadi Ta Askatasuna—ETA), for example, were to use WMD, these groups would likely isolate their constituency and undermine sources of funding and political support. When the assumptions about terrorist groups not using WMD were made in the 1970s and 1980s, most of the terrorist groups making headlines were groups with political or nationalist-separatist agenda. Those groups, with some exceptions, such as the Japanese Red Army (JRA—Rengo Sekigun), had reason not to sabotage their ethnic bases of popular support or other domestic or foreign sympathizers of their cause by using WMD.

Trends in terrorism over the past three decades, however, have contradicted the conventional thinking that terrorists are averse to using WMD. It has becomeincreasingly evident that the assumption does not apply to religious terrorist groups or millenarian cults (see Glossary). Indeed, since at least the early 1970s analysts, including (somewhat contradictorily) Jenkins, have predicted that the first groups to employ a weapon of mass destruction would be religious sectswith a millenarian, messianic, or apocalyptic mindset.

There is a large economics literature on individual and economy-wide productivity. There is also a fast-growing one on the measurement of individuals’ mental well-being. Yet economists know little about the interplay between emotions and human productivity. Although people’s happiness and effort decisions seem likely to be deeply intertwined, we lack evidence on whether, and how, they are causally connected.

This paper seeks to make two contributions. First, it attempts to alert economists to a psychology literature in which happiness (or more precisely what psychologists describe as positive affect) has been shown to be associated with higher human performance. Here the work of the psychologist Alice Isen has been particularly important. The second contribution of the paper is to design and perform an empirical inquiry that has not been done in the psychology literature. It addresses a question of particular interest to economists (and perhaps to policy-makers). Does happiness make people more productive in a paid task? We provide evidence in a standardized piece rate setting with otherwise fairly well-understood properties that it does.

In 1969 the brutal murders committed in Southern California by the followers of Charles Manson riveted the attention of the American public. The apparently senseless killings of ten people were explained by the media as the result of the strange hypnotic power exercised by Manson, who had convinced the disciples that he was Christ incarnate. Manson, in response, argued that he was nothing more than a mirror, reflecting society's own dark fantasies.

Nearly ten years later, the residents of Jonestown, a commune isolated in the jungles of Guyana, killed a visiting member of the United States House of Representatives and some of his entourage. Then, at the request of their leader, Jim Jones, nearly all of the hundreds of men, women and children of the Temple drank cyanide-laced kool-aid and died in the greatest mass suicide of modern history. At first it was assumed that the suicides were forced, but evidence indicated instead that these people willingly killed themselves and their children in order to accompany their beloved leader, whom they worshipped as a god on earth.

Wide employment of agents in human–computer interaction (HCI) design has proven to be an effective way to construct robust yet flexible software architecture, in which information communication between the user and the technical system is mediated by many kinds of agents. The new interaction paradigm, evolved from traditional HCI, can be called human–agent interaction (HAI). In HAI, users are provided with a novel social collaborator during their tasks: the software agent (Wooldridge & Jennings, 1995). Obviously, this new interaction element opens a series of design considerations. At its core, HAI invites a more consequent evaluation and application of social psychological concepts to guide the agent’s behaviors during interaction.

Hence, a key question is what we can learn from social interaction research in the human context in order to design user-friendly, adaptive, and effective HAI (e.g., Nass & Moon 2000; Reeves & Nass, 1996). This exploitation of social psychological concepts in interaction design is a logical extension of the user psychological approach to human–technology research (Moran, 1981; Oulasvirta & Saariluoma, 2004)—a paradigm approach that is especially effective in projects where the product or technology is new or where the audience characteristics and habits are not yet well defined (Goschnick & Sterling, 2002; Murray, Schell, & Willis, 1997). Thus, it is ideal for contemporary HAI research pursuing psychologically-based, integral agent architectures (Pasquier, Rahwan, Dignum, & Sonenberg, 2006; Rahwan, 2005). In this vein, it is essential to evaluate core issues such as interpersonal communication, influence, persuasion, and decision making in interaction (e.g., Cialdini, 1984; Eagly & Chaiken, 1984; McGuire, 1969, 1985; Petty & Cacioppo, 1981; Sewell, 1989; Zimbardo & Leippe, 1991).