People attribute more secondary emotions to their ingroup than to outgroups. This effect is interpreted in terms of infrahumanization theory. Familiarity also could explain this differential attribution because secondary emotions are thought to be less visible and intense than primary ones. This alternative explanation to infrahumanization was tested in three studies. In Study 1, participants attributed, in a between-participants design, primary and secondary emotions to themselves, to their ingroup, or to an outgroup. In Study 2, participants answered for themselves and their ingroup or for themselves and an outgroup. In Study 3, participants made attributions to the ingroup or a series of outgroups varying in terms of familiarity. The data do not support an explanation in terms of familiarity. The discussion centers on conditions not conducting to infrahumanization.

According to Leyens et al.'s (2000) theory, intergroup discrimination involves a differential appraisal of the ingroup's and the outgroup's uniquely human characteristics. Four experiments investigated how emotions that are considered uniquely (i.e. secondary emotions) and non uniquely (i.e. primary emotions) human (Demoulin et al., 2001a) are differentially associated with the ingroup and the outgroup. Using the Implicit Association Task (IAT) we found a stronger association of ingroup names with uniquely human emotions and of outgroup names with non uniquely human emotions, than the reverse. Whereas Study 2 used negative emotions, all other experiments used positive emotions. In Study 3, two IAT indices were collected: an emotional index and a standard evaluative one. While the outgroup was constituted by North African names in the first three studies, Study 4 staged French-speaking Belgians (i.e. the ingroup) versus Dutch-speaking Belgians (i.e. the outgroup). The results are discussed within the framework of psychological essentialism, according to which uniquely human characteristics form the essence of the ingroup.

People tend to infra-humanize by attributing more human essence to their in-group than to out-groups. In the present article, we focus on the attribution of primary and secondary emotions to operationalize the human essence. We propose that, in order to infra-humanize, people need to be categorized in meaningful groups. In addition, we argue that what differentiates meaningful from nonmeaningful groups is that the people essentialize, perceiving members of the group as sharing an underlying, common essence. Also, we hypothesize that participants will identify more with their in-group in the case of meaningful groups. Three types of groups were created to manipulate the meaningfulness of the categorization. Participants were either randomly assigned to a group or they chose their group as a function of their preferences for a colour or the type of career they wished to pursue. As expected, infra-humanization occurred only where the categorization's criterion was meaningful. In addition, in-group identification, but not essentialism, mediated the impact of the categorization criteria on the tendency to infra-humanize. Data also showed that infra-humanization is different from classic in-group favouritism. This is because in-group favouritism, but not infra-humanization, was observed in the situation where group membership was based on random assignment. In other words, for infra-humanization to occur mere categorization is not enough; meaningfulness is also needed. For in-group favouritism to arise, the knowledge of being part of a group is a sufficient prerequisite. The discussion focuses on conditions for reducing infra-humanization and on the relationship between in-group favouritism and out-group derogation.

According to Leyens et al.'s (2000) theory, intergroup discrimination involves a differential appraisal of the ingroup's and the outgroup's uniquely human characteristics. Four experiments investigated how emotions that are considered uniquely (i.e. secondary emotions) and non uniquely (i.e. primary emotions) human (Demoulin et al., 2001a) are differentially associated with the ingroup and the outgroup. Using the Implicit Association Task (IAT) we found a stronger association of ingroup names with uniquely human emotions and of outgroup names with non uniquely human emotions, than the reverse. Whereas Study 2 used negative emotions, all other experiments used positive emotions. In Study 3, two IAT indices were collected: an emotional index and a standard evaluative one. While the outgroup was constituted by North African names in the first three studies, Study 4 staged French-speaking Belgians (i.e. the ingroup) versus Dutch-speaking Belgians (i.e. the outgroup). The results are discussed within the framework of psychological essentialism, according to which uniquely human characteristics form the essence of the ingroup.

A total of 519 wild animals belonging to eleven species were collected during a two year study in a cutaneous leishmaniasis endemic area in Venezuela (La Matica, Lara State). The animals were captured in home-made Tomahawk-like traps baited with maize, bananas or other available local fruits, and parasites were isolated from 27 specimens. Two different species were found naturally infected with flagellates, i.e., cotton rats (Sigmodon hispidus) and black rats (Rattus rattus).Characterization of the parasites using PCR, kDNA restriction pattern and hybridization with species-specific probes revealed the presence of Leishmania (L.) mexicana in three of the black rats and Leishmania (V.) braziliensis in two others. The latter species was also identified in the single positive specimen of S. hispidus. The results suggested both species of animals as possible reservoirs of Leishmania sp.