How robust is public support for unilateral climate policy?

Most governments emphasize the need for reciprocal (“give and take”) international commitments in global climate policy. Nonetheless, existing public opinion polls indicate strong support by individual citizens for unilateral climate policies as well. This raises the question of whether governments could, without risking electoral punishment, afford to pursue more ambitious unilateral climate policies, or whether surveys may have overestimated support for unilateralism due to measurement problems. Based on conjoint and framing experiments embedded in representative surveys in the world's two largest democracies, India and the United States, we engage in a critical re-assessment of earlier survey results. We find robust public support for unilateral climate policy in both countries. Such support declines with increasing costs and increases with growing co-benefits and problem solving effectiveness. We also find, however, that policy conditionality and possible institutional design mechanisms against free-riding by other states (which make the policy “less unilateral” by providing for reciprocation) play no significant role when citizens form their preferences with respect to climate policy. Neither is public support affected by whether policies focus on adaptation (which limits benefits to the investing country) or mitigation (which benefits all countries globally). Overall, these findings suggest that, in view of very slow progress in global climate policy, governments of rich and poor countries could politically afford to push ahead with more ambitious unilateral climate policies.     

Those outsiders: How downstream externalities affect public good provision

Some policy problems pit one group?s interests against another?s. One group may determine provision of a project (such as a dam) that benefits group members but hurts others. We introduce a model of such projects. In-group members may contribute to a common fund that benefits them as a public good. Benefits from the project may vary within the group. Provision has negative downstream externalities: contributions hurt agents outside the in-group (“Outsiders”), rendering them anti-social. Many models of social preferences predict that such externalities should reduce provision, although conditional cooperation or a preference for in-group members may counteract this. We test this model with a lab experiment using Outsiders with whom the in-group members have more and less contact. With homogeneous in-group benefits, the presence of negative downstream externalities reduces contributions by half when they have closer contact with Outsiders but not at all when they have had no contact. We introduce a rotating high-return position that allows subjects to trade favors. In this setting, contributions of non-privileged members diminish slightly when faced with the negative externality given closer contact with Outsiders, and not at all with less contact. Reciprocal giving occurs whether or not Outsiders are present.     

Social relationships among adult female baboons (Papio cynocephalus) II. Variation in the quality and stability of social bonds

A growing body of evidence suggests that social bonds have adaptive value for animals that live in social groups. Although these findings suggest that natural selection may favor the ability to cultivate and sustain social bonds, we know very little about the factors that influence the quality or stability of social bonds. Here, we draw on data derived from a 16-year study of baboons living in seven different social groups in the Amboseli basin of Kenya to evaluate the quality and stability of social bonds among females. Our results extend previous analyses, which demonstrate that females form the strongest bonds with close maternal and paternal kin, age mates (who may be paternal kin), and females who occupy similar ranks but are not maternal relatives. Here we show that the same factors influence the quality and strength of social bonds. Moreover, the results demonstrate that the quality of social bonds directly affects their stability.     

Can time-weighted average concentrations be used to assess the risks of metsulfuron-methyl to Myriophyllum spicatum under different time-variable exposure regimes?

We tested the effects of the herbicide metsulfuron-methyl on growth of the submerged macrophyte Myriophyllum spicatum under laboratory conditions using different exposure scenarios. The exposures of each scenario were comparable in the concentration × time factor, viz., the same 21-d time-weighted average (TWA) concentrations but variable in peak exposure concentrations (ranging from 0.1 to 21 000 ng ai L⁻¹) and exposure periods (1, 3, 7, 14 or 21 d). To study recovery potential of the exposed M. spicatum plants we continued the observation on shoot and root growth for another 21 d in herbicide-free medium so that the total observation period was 42 d. Non-destructive endpoints, length and number of new shoots and roots, were determined weekly from day 14 onwards. Destructive endpoints, dry-weight (DW) of main shoots, new shoots and new roots, were measured at the end of the experiment (t = 42 d).Metsulfuron-methyl exposure in particular inhibited new tissue formation but was not lethal to main shoots. On days 21 and 42 after start exposure, EC₁₀/EC₅₀ values for new tissues expressed in terms of peak concentration (=measured concentration during exposure periods of different length) showed large differences between exposure scenarios in contrast to EC₁₀/EC₅₀ values for days 21 and 42 expressed in terms of 21-d and 42-d TWA concentrations, respectively. At the end of the experiment (day 42), 42-d TWA EC_x values were remarkably similar between exposure scenarios, while a similar trend could already be observed on day 21 for 21-d TWA EC_x values. For the macrophyte M. spicatum and exposure to the herbicide metsulfuron-methyl the TWA approach seems to be appropriate to use in the risk assessment. However, the data from the toxicity experiment suggest that on day 21 also the absolute height of the pulse exposure played a (minor) role in the exposure - response relationships observed.     

An analysis of reciprocal exchange of helping behavior in the red-cockaded woodpecker (Picoides borealis)

We examine the frequency of reciprocal exchanges of helping behavior in three red-cockaded woodpecker populations to determine if such exchanges might constitute a significant fitness benefit of helping. Specifically, we determine how often helpers, once they become breeders, are assisted by young they previously helped raise. The estimated frequencies of reciprocal exchange of helping based on survival and status transition probabilities are low (2%). Observed frequencies of reciprocity are significantly higher than estimated frequencies in two of the three populations studied, suggesting that male fledglings more often remain on their natal territory as helpers if another helper is already present. High rates of retention of young males as helpers on high-quality territories or preferential helping of kin, as well as preferential helping of former care-givers, might explain this result. When the analysis is restricted to helpers unrelated to the young they help raise, which controls for preferential helping of kin and largely eliminates effects of territory quality, empirical estimates of the frequency of reciprocity do not differ from estimates calculated from population demography. We conclude that young males do not preferentially help former care-givers and that reciprocal exchange of help is not an important factor in the evolution of helping behavior in the red-cockaded woodpecker. In this species, all known benefits of helping behavior are indirect (i.e., derived through kin selection ) rather than direct. We discuss the occurrence of unrelated helpers in this context. Received: 10 August 1999 / Received in revised form: 13 February 2000 / Accepted: 19 February 2000     

Philopatry, male presence and grooming reciprocation among female primates: a comparative perspective

Competition for food and a safe location in a group are considered to be the main determinants of variation in social relationships among female primates. The effect of the presence of males is usually overlooked, however. Here we put forward two hypotheses connecting the (relative) number of males in a group, a statistic measuring the strength of positive relationships among females (the degree of reciprocity of grooming) and female residence. Under the first hypothesis, we assumed that philopatric females suffer especially from competition for males. Because females of these species are restrained to their native group and thus do not move to groups where better conditions (i.e. more males) prevail, a higher socionomic sex ratio would imply reduced competition and this should be reflected in better relationships among females (i.e. in a higher degree of reciprocation). The second hypothesis is based on the contention of Wrangham (1987) that groups with more males are better able to defend large food sources: in these groups female relationships would suffer less from within-group competition for food. We therefore also expected a positive correlation between the absolute number of males and grooming reciprocation. To test the hypotheses, matrices of grooming interactions were collected by going through the primatological literature. For ten female-resident and four female-transfer primate species, the degree of grooming reciprocation was quantified using a specially adapted matrix statistic. The results favoured the first (competition for males) hypothesis. The degree of grooming reciprocation among females was positively correlated with socionomic sex ratio, but neither with group size nor with the absolute number of males. Correlations between the degree of reciprocity and sex ratio were confirmed at three levels: within the same group at different points in time, between groups of the same species, and between species. In addition, the degree of reciprocation increased with sex ratio more strongly in typical single/variable male than in multi-male species. This we interpreted as a direct consequence of the lower social availability of males for females in multi-male groups than single-male groups. In turn, this effect may be due to males competing for females in multi-male groups. Received: 28 May 1997 / Accepted after revision: 9 November 1997