Viviana A. Weekes-Shackelford, PhD

Evolutionary Psychologist


The effects of children on parental psychology
Men and women with children from a previous mateship seeking to establish a new mateship are likelyto have been a recurrent social feature of human evolutionary history. Previous research indicates that contextual factors, such as access to personal resources and temporal context of the mateship desired (e.g., marriage or one-night stand), influence preferences for qualities in a potential mate. Because the presence of a child from a previous mateship presents a different set of adaptive problems than those presented when there is no child from a past mateship, we propose that men and women with children, relative to men and women without children, will differ in the importance placed on several mate preferences, and that these shifts in preferences may follow an adaptive logic.

One avenue of research that is currently being explored using the aforementioned rationale is the possibility that mothers may use their daughters to attract mates. Separation and relationship dissolution were likely recurrent features of ancestral human life. Mothers likely retained any children from a dissolved mateship, and, therefore, would have been the sole provider for herself and her children. If men have evolved preferences for cues that highlight women’s current and future reproductive potential, then female psychology may include features designed to exploit these preferences in male psychology. I address the possibility that women may use their reproductive age daughters as “sexual lures,” to acquire a new mate following relationship dissolution. It is hypothesized that women with daughters approaching or at reproductive age will remarry (a) at a higher rate and (b) sooner than will women with sons. Roughly 500 participants with and without children completed either a paper survey or an online survey.

One emphasis of this line of research is on examining how sexual psychology changes after becoming a parent. Past research on this topic has focused on the negative mating consequences (e.g., decreased mate value) for individuals with children compared to individuals without children, a finding to which the researchers in this symposium do not object. A goal of this research program is to provide an empirical enlightenment of some of the sexual psychological intricacies when a child becomes a part in the mating equation.

Filicide (child-killing), filicide-suicide, and parental psychology
My colleague and I (Weekes-Shackelford & Shackelford, 2003) have used archival homicide databases to investigate why parents commit filicide (i.e., kill one or more of their children). Stepparents commit filicide at higher rates than do genetic parents. According to M. Daly and M. I. Wilson (1994), motivational differences generate differences in the methods by which stepparents and genetic parents kill a child. Using Canadian and British national-level databases, Daly and Wilson (1994) found that stepfathers are more likely than genetic fathers to commit filicide by beating and bludgeoning, arguably revealing stepparental feelings of bitterness and resentment not present to the same degree in genetic fathers. Genetic fathers, in contrast, are more likely than stepfathers to commit filicide by shooting or asphyxiation, methods which often produce a relatively quick and painless death. We sought to replicate and extend these findings using a United States national-level database of over 400,000 homicides. The results replicated those of Daly and Wilson (1994) for genetic fathers and stepfathers. In addition, we identified similar differences in the methods by which stepmothers and genetic mothers committed filicide.

Our research on filicide-suicide is an extension of our research on filicide (Shackelford, Weekes-Shackelford, & Beasley, in press; Beasley, Weekes-Shackelford, & Shackelford, 2003). Relative to many other types of homicide, filicide is a rare event. Filicide followed by the offender’s suicide is rarer still. The contexts and circumstances surrounding filicide-suicide may nevertheless provide insight into parental psychology. Some research suggests, for example, that filicidal genetic parents are more likely to commit suicide than are filicidal stepparents. Using a database that includes incident-level information on over 22,000 homicides committed in Chicago during the years 1965-1994, we tested five hypotheses about filicide-suicide. We did not find support for the hypothesis of differential risk of suicide following filicide by genetic parents and stepparents. We did replicate previous work indicating that: (1) filicides that include multiple victims are more likely to end in the offender’s suicide than are filicides that include a single victim, (2) parents are more likely to commit suicide following a filicide of an older child than a filicide of a younger child, (3) older parents, relative to younger parents, are more likely to commit suicide following filicide, and that (4) fathers, relative to mothers, are more likely to commit suicide following filicide.

I am currently analyzing information on all filicides reported in the Broward County Sun-Sentinel for the years 1986 to 1995. A general objective of this work is to secure more detailed information about each filicide than is available in comparable filicide databases. Recent research on homicide-suicide (e.g., Malphurs & Cohen, 2002) and on wife-killing (e.g., Brewer & Paulsen, 1999) has used successfully the newspaper as a source of obtaining information that may not otherwise be available in existing homicide databases. A key goal of this new line of research is to identify with greater precision the predictors of filicide (and filicide-suicide) and thereby provide social workers and others in the helping professions with the tools to reduce the likelihood of these crimes.

Non-lethal conflict in parent-child relationships
My colleagues and I are in the process of collecting data on non-lethal conflict between children and their parents. A key objective of this research is to develop a parent-child conflict inventory to better understand conflict in parent-child relationships. Using the act nomination method (Buss & Craik, 1983), participants are asked to list and describe (a) behaviors for which they got in trouble, (b) their parents’ and/or stepparents’ response and (c) current conflict with their parents and/or stepparents. This inventory is tailored to specific time periods during childhood (i.e., childhood and preadolescence). The survey materials have been constructed to elicit responses unique to these time periods. The responses will be organized into an inventory of these behaviors that request participants to indicate whether these behaviors occurred while they were growing up, whether their parents and stepparents used various forms of discipline, and the severity of the discipline. This inventory will be useful as context-specific and relationship- specific assessment of non-lethal conflict between children and parents, with a special focus on clear assessments of the differential quality and frequency of conflict between (a) children and genetic parents, and (b) children and stepparents. Like the research on filicide and filicide-suicide, research on non-lethal parent-child conflict has excellent funding potential. Several federal agencies fund research on parent-child conflict, particularly conflict that includes child abuse and neglect. These agencies include, for example, the National Institute of Child Health and Human Development and the United States Department of Justice. We expect that our research on parent-child conflict will be supported by external funding.

Spousal-killings and spousal psychology
A recent and already productive line of work in which my colleagues and I have been involved is work on lethal conflict between spouses. For example, my colleagues and I (e.g., Shackelford, Buss, & Weekes-Shackelford, 2003; Weekes-Shackelford, Shackelford, & Buss, 2003) recently have explored the contexts in which a woman might be more likely to be killed by her romantic partner. The killing of women by their husbands poses an enigma for social scientists. Why do relationships presumably characterized by love sometimes result in death? A variety of hypotheses have been offered to explain this puzzling pattern. Among the most prominent are (a) sheer proximity and opportunity, (b) epiphenomenal byproducts of a male psychology designed for coercive control of women, and (c) evolved mate-killing mechanisms. One way to test these hypotheses is to examine the contexts in which wife-killings occur. We secured access to a homicide database that included 345 spouse killings perpetrated by husbands in the context of a “lovers triangle,” a context that signifies sexual infidelity. Results indicated that a woman’s age, and hence reproductive status, predicts vulnerability to being killed in the context of a lovers triangle. We are planning several lines of future work in this area, including, for example, examining the specific contexts in which wives kill their husbands.

Female orgasm and sperm competition
Conflict within the family includes conflict between romantic partners about sexual behavior. My colleagues and I recently completed several studies focused on identifying areas of conflict and cooperation between men and women involved in romantic relationships (Shackelford, Weekes-Shackelford, et al., 2000; Shackelford, LeBlanc, Weekes-Shackelford, et al., 2002). In one study, for example, we targeted female sexual behavior. Female coital orgasm may be an adaptation for retaining preferentially the sperm of males with “good genes.” One indicator of good genes may be physical attractiveness. Accordingly, R. Thornhill, S. W. Gangestad, and R. Comer (1995) found that women mated to more attractive men reported an orgasm during a greater proportion of copulations than did women mated to less attractive men. In one study (Shackelford, Weekes-Shackelford, et al., 2000), my colleagues and I replicated this finding, with several design variations. We collected self-report data from 388 women residing in the United States or in Germany. The results supported the hypothesis that women mated to more attractive men are more likely to report an orgasm at the most recent copulation than are women mated to less attractive men, after statistically controlling for several key variables.

In another study, my colleagues and I (Shackelford, Leblanc, Weekes-Shackelford, et al., 2002) focused on male sexual behavior. Specifically, we were interested in how the time a couple spends apart from each other might affect or be associated with changes in his sexual behavior. We used a questionnaire to investigate male sexual behavior for 194 men in committed, sexual relationships in the United States and in Germany. As predicted, a man who spends a greater (relative to a man who spends a lesser) proportion of time apart from his partner since the couple’s last copulation reported (a) that his partner is more attractive, (b) that other men find his partner more attractive, (c) greater interest in copulating with his partner, and (d) that his partner is more sexually interested in him. All effects were independent of total time since the couple’s last copulation and the man’s relationship satisfaction. Research on human sexual behavior has reasonably good funding potential. We will seek external funding to support out continuing work on sexual conflict and cooperation between men and women. We will target agencies such as the National Institutes of Health and the Foundation for the Scientific Study of Sexuality.