Frank J. Sulloway

Political conservatism as motivated social cognition.

Analyzing political conservatism as motivated social cognition integrates theories of personality (authoritarianism, dogmatism-intolerance of ambiguity), epistemic and existential needs (for closure, regulatory focus, terror management), and ideological rationalization (social dominance, system justification). A meta-analysis (88 samples, 12 countries, 22,818 cases) confirms that several psychological variables predict political conservatism: death anxiety (weighted mean r = .50); system instability (.47); dogmatism-intolerance of ambiguity (.34); openness to experience (-.32); uncertainty tolerance (-.27); needs for order, structure, and closure (.26); integrative complexity (-.20); fear of threat and loss (.18); and self-esteem (-.09). The core ideology of conservatism stresses resistance to change and justification of inequality and is motivated by needs that vary situationally and dispositionally to manage uncertainty and threat.

Exceptions That Prove the Rule - Using a Theory of Motivated Social Cognition to Account for Ideological Incongruities and Political Anomalies: Reply to Greenberg and Jonas (2003)

A meta-analysis by J. T. Jost, J. Glaser, A. W. Kruglanski, and F. J. Sulloway (2003) concluded that political conservatism is partially motivated by the management of uncertainty and threat. In this reply to J. Greenberg and E. Jonas (2003), conceptual issues are clarified, numerous political anomalies are explained, and alleged counterexamples are incorporated with a dynamic model that takes into account differences between “young” and “old” movements. Studies directly pitting the rigidity-of-the-right hypothesis against the ideological extremity hypothesis demonstrate strong support for the former. Medium to large effect sizes describe relations between political conservatism and dogmatism and intolerance of ambiguity; lack of openness to experience; uncertainty avoidance; personal needs for order, structure, and closure; fear of death; and system threat.

Parental investment: How an equity motive can produce inequality

The equity heuristic is a decision rule specifying that parents should attempt to subdivide resources more or less equally among their children. This investment rule coincides with the prescription from optimality models in economics and biology in cases in which expected future return for each offspring is equal. In this article, the authors present a counterintuitive implication of the equity heuristic: Whereas an equity motive produces a fair distribution at any given point in time, it yields a cumulative distribution of investments that is unequal. The authors test this analytical observation against evidence reported in studies exploring parental investment and show how the equity heuristic can provide an explanation of why the literature reports a diversity of birth order effects with respect to parental resource allocation.

Birth Order, Sibling Competition, and Human Behavior

Sibling competition is widespread among bird and animal species and sometimes leads to siblicide. By influencing the strategies that siblings employ in their struggles for dominance, birth order affects the outcomes of such contests. In our own species, birth order is a proxy for disparities in age, physical size, and status, all of which contribute to personality. In addition, birth order is related to the roles and niches available to offspring within the family system. On average, firstborns—who tend to act as surrogate parents—are more conscientious than laterborns, whereas laterborns are more agreeable, extraverted, and nonconforming. As strategies for dealing with rivals in a dominance hierarchy, as well as for optimizing parental investment, these sibling differences are consistent with a Darwinian perspective on family life. So are other links between personality and family dynamics, particularly those associated with parental investment and parent-offspring conflict. In adulthood, human behavior continues to reflect these formative influences, although such behavioral dispositions generally need to be catalyzed by appropriate situations in order to be fully expressed.

Philornis downsi parasitism is the primary cause of nestling mortality in the critically endangered Darwin’s medium tree finch (Camarhynchus pauper)

Darwin’s medium tree finch (Camarhynchus pauper) meets the 2009 International Union for Conservation of Nature Red List criteria for a critically endangered species because it has “a very small range on a single island” and is “declining rapidly owing to the effects of the parasite Philornis downsi”, habitat degradation, and introduced predators. The medium tree finch is only found in patches of remnant highland forest on Floreana Island, where it co-exists with breeding populations of small and large tree finches (C. parvulus and C. psittacula). Here, we examine the intensity of P. downsi in nests of small, medium, and large tree finches on Floreana. We expected that parasite intensity would increase with finch body size, and with greater rainfall, and would also correlate with increased nestling mortality. We found a trend in the expected direction for parasite intensity and rainfall. Combined meta-analytically with data from a previous study, the overall trend for the two studies was significant. We also found a significant linear trend in parasite intensity with finch body size. In addition, the medium tree finch exhibited a somewhat higher parasite intensity than would be expected based on body mass alone. Of 63 active medium tree finch nests, 17 nests had nestlings: all of which were infested with P. downsi. Only 25% of medium tree finch nestlings fledged, 28% were depredated, 41% died due to P. downsi parasitism, and 6% died for other reasons.

The Confluence Model: Birth Order as a Within-Family or Between-Family Dynamic?

The confluence model explains birth-order differences in intellectual performance by quantifying the changing dynamics within the family. Wichman, Rodgers, and MacCallum (2006) claimed that these differences are a between-family phenomenon—and hence are not directly related to birth order itself. The study design and analyses presented by Wichman et al. nevertheless suffer from crucial shortcomings, including their use of unfocused tests, which cause statistically significant trends to be overlooked. In addition, Wichman et al. treated birth-order effects as a linear phenomenon thereby ignoring the confluence models prediction that these two samples may manifest opposing results based on age. This article cites between- and within-family data that demonstrate systematic birth-order effects as predicted by the confluence model. The corpus of evidence invoked here offers strong support for the assumption of the confluence model that birth-order differences in intellectual performance are primarily a within-family phenomenon.

Species collapse via hybridization in Darwin's tree finches.

Species hybridization can lead to fitness costs, species collapse, and novel evolutionary trajectories in changing environments. Hybridization is predicted to be more common when environmental conditions change rapidly. Here, we test patterns of hybridization in three sympatric tree finch species (small tree finch Camarhynchus parvulus, medium tree finch Camarhynchus pauper, and large tree finch: Camarhynchus psittacula) that are currently recognized on Floreana Island, Galápagos Archipelago. Genetic analysis of microsatellite data from contemporary samples showed two genetic populations and one hybrid cluster in both 2005 and 2010; hybrid individuals were derived from genetic population 1 (small morph) and genetic population 2 (large morph). Females of the large and rare species were more likely to pair with males of the small common species. Finch populations differed in morphology in 1852–1906 compared with 2005/2010. An unsupervised clustering method showed (a) support for three morphological clusters in the historical tree finch sample (1852–1906), which is consistent with current species recognition; (b) support for two or three morphological clusters in 2005 with some (19%) hybridization; and (c) support for just two morphological clusters in 2010 with frequent (41%) hybridization. We discuss these findings in relation to species demarcations of Camarhynchus tree finches on Floreana Island.

Birth Order and Risk Taking in Athletics: A Meta-Analysis and Study of Major League Baseball:

According to expectations derived from evolutionary theory, younger siblings are more likely than older siblings to participate in high-risk activities. The authors test this hypothesis by conducting a meta-analysis of 24 previous studies involving birth order and participation in dangerous sports. The odds of laterborns engaging in such activities were 1.48 times greater than for firstborns (N = 8,340). The authors also analyze performance data on 700 brothers who played major league baseball. Consistent with their greater expected propensity for risk taking, younger brothers were 10.6 times more likely to attempt the high-risk activity of base stealing and 3.2 times more likely to steal bases successfully (odds ratios). In addition, younger brothers were significantly superior to older brothers in overall batting success, including two measures associated with risk taking. As expected, significant heterogeneity among various performance measures for major league baseball players indicated that older and younger brothers excelled in different aspects of the game.

Change and constancy in developmental contexts

As the 21st century begins, social forces are creating substantial diversity in developmental settings through the child’s early life course. Aconsiderable proportion of youth will experience disruptions in family structure, fluctuations in levels of economic resources, and residential moves that may involve changes in peer groups and schools. This paper reviews a set of conceptual distinctions that are well suited to the study of the dynamic properties of context. The paper also underscores the importance of integrating the life course with behavioural genetics to determine more accurately the joint contributions of environments like the family and genotypes to development. Because both person and context exhibit change and stability through time, an understanding of these complex interactions will require generative collaborations among developmentalists from diverse disciplinary backgrounds.

Panmixia supports divergence with gene flow in Darwin's small ground finch, Geospiza fuliginosa, on Santa Cruz, Galapagos Islands

The divergence‐with‐gene‐flow model of speciation has a strong theoretical basis with a growing number of plausible examples in nature, but remains hotly debated. Darwin’s finches of the Galápagos Archipelago have played an important role in our understanding of speciation processes. Recent studies suggest that this group may also provide insights into speciation via divergence with gene flow. On the island of Santa Cruz, recent studies found evidence for adaptive divergence in Darwin’s small ground finch, Geospiza fuliginosa, between ecologically contrasting arid and humid zones. Despite the short geographical distance between these zones, strong disruptive selection during low rainfall periods is expected to generate and maintain adaptive divergence. Conversely, during high rainfall periods, when disruptive selection is predicted to be weakened, population divergence in adaptive traits is expected to break down. Because periods of low and high rainfall irregularly alternate, the geographical pattern of adaptive divergence can be assumed to break down and, importantly, regenerate in situ. Here, we use microsatellite allele frequency data to assess the genetic population structure of G. fuliginosa on Santa Cruz. We sample 21 sites and four ecological zones across the island. We reject hypotheses of population substructure linked to ecological and geographical differences among sites in favour of a single panmictic population. Panmixia implies high levels of gene flow within Santa Cruz, which favours selection over genetic drift as a valid process generating phenotypic divergence in G. fuliginosa on Santa Cruz. We discuss how our findings may support classic adaptation, phenotypic plasticity, matching habitat choice or any combination of these three processes.