The author details her team’s research investigating sex differences in serial murder from an evolutionary perspective. Per Trivers’ (1972) Parental Investment Theory, evolved psychological mechanisms serve sex-specific interests to maximize reproductive fitness (genes represented in subsequent generations). As predicted, men – who produce millions of sperm daily and have an increased sex drive – commit serial murder primarily for sexual reasons. Women, who have limited reproductive opportunities compared to men, have evolved to place great importance on resources. As such, women commit serial murder primarily for monetary gain. Moreover, mirroring ancestral agrarian tendencies, male serial killers (MSKs) are hunters (stalkers) of victims, and female serial killers (FSKs) are gatherers of profit and “gather” victims in their immediate environment, including relatives. The author stresses that an evolutionary perspective (ultimate perspective) does not explain the entirety of serial murder. We must consider converging perspectives, including evolutionary, proximate biological, clinical, traumagenic, cultural, historical, social, and gender-role forces that contribute to the development and growth of the human psyche.

This chapter discusses known motives of female serial killers (FSKs). FSKs’ most common motive for murder was financial gain. An evolutionary psychology model of serial murder is presented. The author discusses how killing children, the antithesis of genesmanship, may be understood from an evolutionary angle. The author reminds the reader that evolved psychology is not an absolute determinant of behavior and that multiple perspectives (e.g., clinical, neural, traumagenic) should be considered to understand a given behavior or mental process. This chapter also presents the outcome (disposition) of serial murder cases in that about 80% were sent to prison, with some receiving the death penalty. This chapter further presents a composite of the “typical” female serial killer (FSK) as described in Harrison et al. (2015) in The Journal of Forensic Psychiatry and Psychology. The author revisits the case of Kristen Gilbert, a FSK whose motives did not neatly fall into a lone typology category. The cases of Judy Buenoano, Rhonda Belle Martin, Lydia Sherman, and Kimberly Clark Saenz illustrate chapter concepts.

This chapter discusses evolutionary theories in psychology (Ekman & Codaro, 2011; Levenson, 2011; Panksepp, 2012; Keltner, Tracy, et al., 2019), also known as motivational theories in philosophy. Building further on the bridging work of McDougall (1908), these theories propose the following causal-mechanistic explanation of emotion. Stimuli activate affect programs (another word for instincts specific to emotions), which in turn give rise to somatic and (subtle and coarse) motor responses and feelings. Some evolutionary theories are hybrids with stimulus evaluation theories in that they postulate that the affect programs is preceded by a stimulus evaluation process. The pure emotions caused by affect programs get mixed with learning and computation, which create flexibility on the input side (by elaborating the number of stimuli that can trigger affect programs) and on the output side (via emotion regulation and planning). Evolutionary theories account for the properties of ontogenetic and phylogenetic continuity, phenomenality, bodily aspect, heat, control precedence, and irrationality, but the non-hybrid version has difficulty accounting for the right kind of (world-directed) Intentionality. Evolutionary theories partition the set of emotions into discrete emotions. Empirical evidence pro and contra the existence of affect programs is discussed.

Not all ontological concerns which surround the concept of (customary) international law (CIL) have disappeared, rather they have shifted. Whereas the existence of a genuine international legal system is taken as a ‘given’, questions still remain about its genesis and the position of CIL within it. Some, for example, still question whether we can truly speak of customary international law, while others recast the concept of CIL through a formalist perspective. Accordingly, formalism, in its moderate form, treats formal sources, documents and/or proclamations as ‘better’ tools for both (a) the preservation of existing rules of CIL and (b) the ‘creation’ of new legal rules. At its more extreme, formalism purports the view that (c) IL (or even CIL) finds its genesis only in formal sources, documents or proclamations. While some formalisation is undeniably helpful and even necessary, we should be more critical of this formalist paradigm. In this way, the chapter seeks to respond to these positions through a revival of the legacy of Sir Henry Maine and the evolutionary conception of law for which he laid out the first foundation. By operationalising this conceptualisation, a new vision spawns for CIL: a vision beyond mere formalism.

Objective: Understand the limitations of certain prescriptive analytical approaches and how to leverage evolutionary searches for acceptable-risk solutions under complex and uncertain conditions.