Sources and References

Primary texts

• Zayas, V., Merrill, S. M., & Hazan, C. (2015). Fool around and fall in love: The role of sex in adult romantic attachment formation. In J. A. Simpson & W. S. Rholes (Eds.), Attachment theory and research: New directions and emerging themes (pp. 270–296). Guilford Press.
• Saramago, M. A., & Bauto, D. (2022). Sexual fantasy. In T. K. Shackelford (Ed.), The Cambridge handbook of evolutionary perspectives on sexual psychology. Cambridge University Press.
• Asao, K., Crosby, C. L., & Buss, D. M. (2023). Sexual morality: Multidimensionality and sex differences. Personality and Individual Differences, 204, 112054.
• Cossman, B. (2007). Consensual sex and the practices of citizenship. In Sexual citizens: The legal and cultural regulation of sex and belonging (pp. 105–138). Stanford University Press.
• Moser, C., & Kleinplatz, P. J. (2020). Conceptualization, history, and future of the paraphilias. Annual Review of Clinical Psychology, 16, 379–399.
• Weinberg, T. S. (2023). Research in BDSM: 40 years along. In T. S. Weinberg (Ed.), BDSM and the law (pp. 1–22). Routledge.
• Samenow, C. P. (2010). A biopsychosocial model of hypersexual disorder/sexual addiction. Sexual Addiction & Compulsivity, 17(2), 69–81.
• Lalumiere, M. L., Harris, G. T., Quinsey, V. L., & Rice, M. E. (2005). Rape across cultures and time. In The causes of rape: Understanding individual differences in male propensity for sexual aggression (pp. 11–42). American Psychological Association.
• Carr, A., Duff, H., & Craddock, F. (2020). A systematic review of the outcome of child abuse in long-term care. Trauma, Violence, & Abuse, 21(4), 660–677.
• Chan, H. C. O. (2017). Sexual homicide: A review. In F. Brookman, E. R. Maguire, & M. Maguire (Eds.), The handbook of homicide (pp. 249–268). Wiley.
• Weitzer, R. (2022). Sex work: Types and paradigms. In R. Weitzer (Ed.), Legalizing prostitution: From illicit vice to lawful business (pp. 1–28). New York University Press.
• Salmon, C. (2012). The pop culture of sex: An evolutionary window on the worlds of pornography and romance. Review of General Psychology, 16(2), 152–160.
• Tsapelas, I., Fisher, H. E., & Aron, A. (2010). Infidelity: When, where, why. In W. R. Cupach & B. H. Spitzberg (Eds.), The dark side of close relationships II (pp. 175–196). Routledge.

Supplementary texts

• Baumeister, R. F., & Twenge, J. M. (2002). Cultural suppression of female sexuality. Review of General Psychology, 6(2), 166–203.
• Hazan, C., & Shaver, P. R. (1987). Romantic love conceptualized as an attachment process. Journal of Personality and Social Psychology, 52(3), 511–524.
• Buss, D. M. (2016). The evolution of desire: Strategies of human mating (Rev. ed.). Basic Books.
• Fisher, H. E. (1998). Lust, attraction, and attachment in mammalian reproduction. Human Nature, 9(1), 23–52.
• Laws, D. R., & O’Donohue, W. T. (Eds.). (2008). Sexual deviance: Theory, assessment, and treatment (2nd ed.). Guilford Press.
• Finkelhor, D. (1994). The international epidemiology of child sexual abuse. Child Abuse & Neglect, 18(5), 409–417.
• American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.). American Psychiatric Association.
• Levine, S. B. (2010). What is sexual addiction? Journal of Sex & Marital Therapy, 36(3), 261–275.
• Farley, M. (2004). Bad for the body, bad for the heart: Prostitution harms women even if legalized or decriminalized. Violence Against Women, 10(10), 1087–1125.
• Dines, G. (2010). Pornland: How porn has hijacked our sexuality. Beacon Press.
• Bridges, A. J., Wosnitzer, R., Scharrer, E., Sun, C., & Liberman, R. (2010). Aggression and sexual behavior in best-selling pornography videos. Violence Against Women, 16(10), 1065–1085.

Online resources

• University of Waterloo course materials and lecture content, SRF 205 / PSYCH 363, Fall 2025.
• DSM-5-TR diagnostic criteria via the American Psychiatric Association digital library.
• United Nations Office on Drugs and Crime (UNODC), Global Report on Trafficking in Persons (2022).
• World Health Organization (WHO), ICD-11 classification of paraphilic disorders.

Chapter 1: Introduction and Theoretical Foundations

The Scope of the “Dark Side”

Human sexuality is among the most powerful forces shaping individual experience and social organization. In most academic treatments, sexuality is studied through the lens of health, development, or relationships – emphasizing normative trajectories, healthy functioning, and positive outcomes. This course takes a different approach. By examining the so-called “dark side” of sexuality, we confront phenomena that provoke discomfort, moral debate, and legal regulation: coercive sexual acts, paraphilic interests, commercial sex, addiction, betrayal, and lethal violence intertwined with sexual motivation. The purpose of such inquiry is not to sensationalize but to understand. A rigorous, evidence-based analysis of troubling sexual phenomena is essential for prevention, treatment, clinical practice, policy formation, and – most fundamentally – for protecting vulnerable individuals from harm.

The course is organized around a theoretical model that asks a deceptively simple question: When does sex become dark? The answer requires us to examine the physiological, emotional, cognitive, motivational, and cultural processes that together constitute the full ecology of human sexual experience. When any of these processes is distorted – by coercion, deception, exploitation, obsession, or violence – sexuality shifts from a domain of mutual pleasure and bonding into one of harm and pathology.

A Multi-Process Model of Sexual Darkness

Dr. Rempel’s theoretical framework situates sexual behavior at the intersection of multiple psychological and social processes. Rather than treating “dark” sexuality as a categorical deviation from a “normal” baseline, the model recognizes a continuum. At one end lies consensual, mutually desired sexual activity embedded in relational trust; at the other end lie acts of extreme coercion, exploitation, and violence. Between these poles exists a vast and contested terrain – the domain of fantasy, fetish, moral transgression, power asymmetry, and cultural prohibition.

The model identifies five interacting process domains:

1. Physiological and emotional processes – the neurobiological substrates of arousal, desire, attachment, and bonding, including the role of sex in forming and maintaining romantic attachments.
2. Cognitive processes – sexual fantasies, schemas, scripts, and the mental representations that organize sexual desire and direct behavior.
3. Motivational processes – the goals and drives underlying sexual behavior, including pleasure-seeking, power, dominance, intimacy, reproduction, and self-regulation.
4. Cultural regulation through morality – the moral frameworks societies use to categorize sexual acts as acceptable, deviant, sinful, or criminal.
5. Cultural regulation through symbolic and legal systems – the laws, norms, and institutional practices that govern sexual citizenship and define the boundaries of permissible sexuality.

This multi-process framework provides the scaffolding for the entire course. Each subsequent topic – from paraphilias to pornography, from sexual assault to infidelity – can be analyzed by asking which processes have been disrupted, distorted, or exploited, and what consequences follow for individuals and communities.

Chapter 2: Physiological and Emotional Processes in Sexuality

The Neurobiology of Desire and Arousal

Sexual experience begins in the body. The human sexual response involves a cascade of neurochemical events: dopamine surges in the mesolimbic reward pathway drive desire and approach behavior; norepinephrine heightens arousal and focused attention; serotonin modulates mood and satiation; oxytocin and vasopressin facilitate bonding and attachment. These systems did not evolve in isolation – they are deeply integrated with the brain’s broader reward, stress, and social bonding circuitry.

Helen Fisher’s influential tripartite model distinguishes among lust (driven primarily by androgens and estrogens), attraction (driven by dopamine and norepinephrine), and attachment (driven by oxytocin and vasopressin). Each system can operate independently, which partly explains the complexity and potential conflicts within sexual experience: one can feel lust without attachment, attraction without lust, or deep attachment without passionate desire.

Sex and Attachment Formation

Zayas, Merrill, and Hazan (2015) advance the provocative thesis that sexual activity plays a central causal role in the formation of adult romantic attachment bonds – not merely as a consequence of attachment, but as a mechanism that drives attachment formation. Drawing on Bowlby’s attachment theory and Hazan and Shaver’s extension of that theory to adult romantic relationships, the authors argue that sexual intercourse activates the same neurobiological systems (particularly oxytocin release) that underlie infant-caregiver bonding.

The Attachment System in Adulthood

Attachment theory, originally developed by John Bowlby to explain infant-caregiver bonds, was extended to adult romantic relationships by Hazan and Shaver (1987). In the adult context, the romantic partner serves as the primary attachment figure – a source of proximity, safe haven, and secure base. Zayas et al. argue that sexual behavior is the primary behavioral mechanism through which adults form these attachment bonds. The physical intimacy of sexual contact triggers neurochemical cascades – particularly oxytocin release during orgasm – that promote feelings of closeness, trust, and emotional security.

“Fooling Around” as a Bonding Mechanism

The phrase “fool around and fall in love” captures the authors’ central claim: casual sexual encounters, even those undertaken without romantic intent, can inadvertently trigger attachment processes. This has significant implications for understanding the “dark side” of sexuality. If sexual activity inherently promotes bonding, then contexts involving deception (e.g., one partner feigning romantic interest to obtain sex), coercion, or power asymmetry become particularly harmful because they exploit a fundamental biological vulnerability. The person who “falls in love” through sexual contact may find themselves emotionally bonded to a partner who does not reciprocate, creating conditions for exploitation, manipulation, and psychological harm.

Implications for Dark Sexuality

The attachment perspective illuminates several dark-side phenomena:

• Sexual coercion and assault: Victims may experience confusing attachment responses to perpetrators, complicating recovery.
• Sex addiction: Compulsive sexual behavior may represent a disordered attachment strategy – repeatedly seeking the neurochemical rewards of bonding without achieving stable attachment.
• Infidelity: Extra-pair sexual contact may trigger unintended attachment bonds that destabilize primary relationships.
• Prostitution and sex work: The repeated activation of attachment circuitry in commercial contexts may have psychological consequences for both workers and clients.

Chapter 3: Cognitive and Motivational Processes

Sexual Fantasy

Saramago and Bauto (2022) examine sexual fantasy from an evolutionary psychological perspective, treating fantasy not as pathology but as a universal cognitive phenomenon that serves adaptive functions. Sexual fantasies are mental representations of desired sexual scenarios. They range from the mundane to the elaborate, from the conventional to the transgressive, and they are experienced by the vast majority of adults across cultures.

Prevalence and Content

Research consistently finds that sexual fantasies are nearly universal. Studies suggest that over 95% of adults report having sexual fantasies, with men reporting somewhat higher frequency than women. The content of fantasies shows both commonalities and sex differences. Men’s fantasies tend to emphasize visual imagery, novelty, multiple partners, and physical attributes; women’s fantasies more often include relational context, emotional connection, and narrative complexity – though there is substantial overlap.

Evolutionary Functions of Fantasy

From an evolutionary perspective, sexual fantasy may serve several functions:

• Mate assessment: Fantasies allow individuals to mentally “try out” potential mates, evaluating their desirability and compatibility without the costs and risks of actual sexual encounters.
• Sexual rehearsal: Fantasies may prepare individuals for sexual encounters, reducing anxiety and increasing competence.
• Arousal enhancement: Fantasy during sexual activity can increase arousal and satisfaction.
• Desire regulation: Fantasy may help maintain sexual interest within long-term relationships by providing novelty and variety in the mental domain.

When Fantasy Becomes “Dark”

The critical question for this course is: when does sexual fantasy cross into the domain of darkness? Several thresholds can be identified:

• Content involving non-consent: Fantasies about coerced or forced sexual encounters are surprisingly common – particularly among women, where “ravishment” fantasies have been documented in multiple studies. However, researchers emphasize that fantasy is not equivalent to desire: a fantasy of being ravished does not indicate a desire to be assaulted. Fantasy provides a safe cognitive space in which taboo scenarios can be explored without real-world consequences.
• Content involving minors: Fantasies involving children represent a clear clinical and legal concern, as they may be associated with pedophilic disorder and elevated risk of offending.
• Obsessive or intrusive quality: When fantasies become compulsive, intrusive, or the sole source of arousal, they may indicate a paraphilic disorder or obsessive-compulsive spectrum condition.
• Behavioral enactment without consent: The translation of fantasy into behavior becomes “dark” when it involves non-consenting partners or violates legal and ethical boundaries.

Motivational Processes

Sexual behavior is driven by a complex interplay of motivations that extend far beyond reproduction. Understanding these motivations is essential for analyzing dark sexuality, because the same act can have very different moral and psychological significance depending on the underlying motive.

Taxonomy of Sexual Motivations

Research identifies numerous motivations for sexual activity, including:

• Pleasure and physical gratification – the most commonly reported motivation across genders.
• Intimacy and emotional closeness – using sex to express love, deepen connection, or maintain relational bonds.
• Self-affirmation and esteem – seeking sexual validation to bolster self-worth.
• Power and dominance – using sex to assert control, demonstrate superiority, or humiliate.
• Stress relief and coping – turning to sex as a regulatory strategy for negative emotions.
• Reproduction – the desire for offspring.
• Curiosity and experimentation – exploring novel experiences or testing personal boundaries.
• Conformity and social pressure – engaging in sex to meet perceived social expectations or partner demands.

Motivation and Darkness

When motivations shift from mutual pleasure and intimacy toward power, control, or self-medication, the risk of harmful outcomes increases dramatically. Sexual assault is fundamentally an act of power and domination, not of uncontrolled desire. Compulsive sexual behavior often involves using sex as a maladaptive coping mechanism. Exploitation in commercial sex frequently involves power asymmetries rooted in economic desperation, trafficking, or coercion. A motivational analysis thus provides a critical lens for distinguishing consensual sexual variation from genuinely harmful conduct.

Chapter 4: Cultural Regulation of Sexuality

Sex and Morality

The Multidimensionality of Sexual Morality

Asao, Crosby, and Buss (2023) present a rigorous empirical analysis of sexual morality, arguing that it is not a unitary construct but a multidimensional one. Drawing on evolutionary psychology, they propose that moral judgments about sexuality reflect evolved psychological mechanisms designed to navigate the adaptive challenges of mating, pair-bonding, and parental investment.

Their research identifies several distinct dimensions of sexual morality:

• Fidelity norms – moral rules governing sexual exclusivity within committed relationships.
• Consent norms – moral principles requiring mutual agreement for sexual activity.
• Decency norms – standards of modesty, propriety, and sexual restraint in public contexts.
• Purity norms – moral frameworks treating certain sexual acts as inherently contaminating or defiling.
• Exploitation norms – moral prohibitions against using power, deception, or coercion to obtain sex.

Sex Differences in Sexual Morality

Asao et al. document consistent sex differences in moral judgments about sexuality. Women tend to hold stricter moral attitudes toward casual sex, promiscuity, and sexual infidelity than men. These differences are interpreted through the lens of parental investment theory: because women bear higher minimum obligatory costs of reproduction (gestation, lactation), they have evolved greater selectivity in mate choice and stronger moral disapproval of behaviors that threaten paternal investment or relationship stability.

Men, conversely, show stronger moral disapproval of sexual behaviors that threaten paternity certainty – particularly female infidelity – while expressing relatively more tolerance for male promiscuity. These asymmetries in moral judgment have profound implications for how societies construct sexual norms, punish sexual transgressions, and distribute sexual blame.

Cultural Variation and Universality

While evolutionary psychology emphasizes universal tendencies, the authors acknowledge substantial cross-cultural variation in sexual morality. Some societies are sexually permissive; others are highly restrictive. Religious traditions, economic systems, and political structures all shape the specific moral codes that regulate sexuality in a given community. However, certain moral concerns – particularly around consent, exploitation, and fidelity – appear to have cross-cultural resonance, suggesting a common evolutionary foundation.

Consensual Sex and Citizenship

Legal Regulation of Sexual Life

Brenda Cossman (2007) shifts the analysis from evolutionary psychology to legal and political theory, examining how modern liberal democracies regulate consensual sexual behavior through the concept of sexual citizenship. Cossman argues that citizenship is not merely a matter of political rights and obligations but extends to the regulation of intimate life. The state defines which forms of consensual sexual expression are granted legal protection and social recognition, and which are marginalized, criminalized, or rendered invisible.

The Boundaries of Acceptable Sexuality

Cossman’s analysis reveals that even in ostensibly liberal societies, significant boundaries constrain sexual citizenship:

• Marriage and monogamy remain the privileged framework for sexual expression in most legal systems.
• LGBTQ+ rights, while expanding, continue to face legal and cultural resistance in many jurisdictions.
• Sex work occupies an ambiguous legal position – often tolerated in practice but criminalized in law.
• Non-normative sexual practices (e.g., BDSM, polyamory, public sexuality) exist in a legal grey zone where consent alone does not guarantee legal protection.

Practices of Citizenship

Cossman introduces the concept of “practices of citizenship” to describe how individuals negotiate the boundaries of sexual regulation in their daily lives. Sexual citizens are not merely passive subjects of legal rules; they actively construct their sexual identities, communities, and practices in relation to – and sometimes in defiance of – legal and moral norms. This framework is particularly useful for understanding how marginalized sexual communities (e.g., BDSM practitioners, sex workers, polyamorous individuals) develop their own norms of consent, safety, and ethics that may diverge from mainstream legal standards.

Chapter 5: Paraphilias and BDSM

Conceptualizing Paraphilia

Definition and Diagnostic Criteria

A paraphilia is defined as an intense and persistent sexual interest in atypical objects, situations, fantasies, behaviors, or individuals. The DSM-5-TR distinguishes between paraphilias (atypical sexual interests that are not inherently disordered) and paraphilic disorders (paraphilias that cause distress, impairment, or involve harm to others). This distinction is crucial: having an unusual sexual interest is not, in itself, a mental disorder. It becomes a disorder only when it causes clinically significant distress to the individual, impairs functioning, or involves non-consenting persons.

Historical Evolution

Moser and Kleinplatz (2020) trace the historical evolution of the paraphilia concept from its origins in 19th-century sexology through its current formulation in the DSM-5-TR. Early sexologists such as Krafft-Ebing catalogued an extensive taxonomy of “perversions,” treating any deviation from reproductive heterosexual intercourse as pathological. Over the 20th century, the conceptual boundaries of paraphilia gradually narrowed as homosexuality was depathologized (removed from the DSM in 1973), as feminist critiques challenged the equation of female sexuality with passivity, and as the distinction between distress and deviance gained clinical acceptance.

Specific Paraphilias

The DSM-5-TR identifies the following specific paraphilic disorders:

Critiques and Controversies

Moser and Kleinplatz raise several critical objections to the current diagnostic framework:

• Normative bias: The concept of “atypical” sexual interest presupposes a statistical and moral norm that may reflect cultural prejudices rather than objective clinical thresholds.
• Diagnostic reliability: Inter-rater reliability for paraphilic disorder diagnoses is often poor, particularly for disorders that hinge on subjective assessments of “distress” or “impairment.”
• Forensic misuse: Paraphilia diagnoses have been used in sexually violent predator (SVP) civil commitment proceedings, raising concerns about the instrumentalization of psychiatric categories for punitive purposes.
• The consent criterion: The authors argue that the central ethical and clinical issue is not the atypicality of a sexual interest but whether it involves non-consenting persons. A consent-based framework would radically simplify the diagnostic landscape and align clinical practice with contemporary ethical principles.

BDSM: Bondage, Discipline, Dominance, Submission, Sadism, and Masochism

Defining BDSM

BDSM is an umbrella term encompassing a range of consensual sexual practices that involve power exchange, restraint, sensation play, and role-playing. BDSM is distinguished from sexual sadism disorder and sexual masochism disorder by the presence of informed, enthusiastic, and ongoing consent between all participants.

Research Over Four Decades

Weinberg (2023) provides a comprehensive review of 40 years of BDSM research, documenting a dramatic shift in academic and clinical attitudes. In the 1980s, BDSM was widely treated as pathological – a manifestation of childhood trauma, personality disorder, or internalized aggression. By the 2020s, a robust body of empirical evidence has established that:

• BDSM practitioners are psychologically healthy. Large-scale studies consistently find no elevated rates of psychopathology, personality disorder, or childhood abuse among BDSM practitioners compared to the general population. Some studies find that practitioners score higher on measures of psychological well-being, relationship satisfaction, and sexual satisfaction.
• BDSM is practiced by a substantial minority. Survey data suggest that 5–25% of the general population has engaged in BDSM-related activities, depending on how broadly the term is defined.
• BDSM communities have developed sophisticated consent norms. Principles such as “Safe, Sane, and Consensual” (SSC) and “Risk-Aware Consensual Kink” (RACK) provide ethical frameworks for navigating activities that involve physical risk and power asymmetry.

BDSM and the Law

Despite growing acceptance, BDSM remains legally ambiguous in many jurisdictions. In some legal systems, consent is not a valid defense against assault charges arising from BDSM activities, particularly when those activities produce visible injuries. This creates a paradoxical situation in which fully consensual activities between adults may be subject to criminal prosecution. Cossman’s framework of sexual citizenship is directly relevant here: BDSM practitioners occupy a contested position at the boundary of legal and social recognition.

Chapter 6: Sex Addiction and Hypersexual Disorder

The Concept of Sexual Addiction

The idea that sexual behavior can become addictive – compulsive, uncontrollable, and destructive despite negative consequences – has generated intense debate in both clinical and academic circles. The term “sex addiction” is widely used in popular culture and in clinical self-help contexts, but it has not been adopted as a formal diagnostic category in the DSM-5-TR. The World Health Organization’s ICD-11, however, includes Compulsive Sexual Behaviour Disorder (CSBD) as an impulse control disorder.

The Biopsychosocial Model

Samenow (2010) proposes a biopsychosocial model of hypersexual disorder that integrates biological, psychological, and social factors:

Biological Factors

• Neurochemical dysregulation: Abnormalities in dopamine, serotonin, and norepinephrine systems may predispose individuals to compulsive reward-seeking behavior, including compulsive sexual behavior.
• Comorbidity: Hypersexual behavior frequently co-occurs with mood disorders, anxiety disorders, ADHD, and substance use disorders, suggesting shared neurobiological vulnerabilities.
• Neurological factors: Some cases of hypersexual behavior have been associated with frontal lobe lesions, dementia, or medication side effects (e.g., dopamine agonists used in Parkinson’s disease).

Psychological Factors

• Attachment insecurity: Individuals with insecure attachment styles (anxious or avoidant) may use sexual behavior as a regulatory strategy for managing attachment-related distress.
• Trauma history: Childhood sexual abuse, neglect, or other adverse experiences are disproportionately represented in clinical samples of individuals with hypersexual behavior.
• Cognitive distortions: Distorted beliefs about sex, entitlement, or self-worth may maintain compulsive sexual behavior patterns.

Social Factors

• Cultural availability: The proliferation of internet pornography, dating apps, and commercial sexual services has dramatically increased the accessibility of sexual stimulation and partners.
• Social isolation: Loneliness and lack of meaningful social connections may drive individuals toward compulsive sexual behavior as a substitute for genuine intimacy.
• Subcultural reinforcement: In some contexts, high-frequency sexual behavior is normalized or rewarded, reducing motivation for change.

Clinical Implications

The biopsychosocial model has practical implications for treatment. Effective interventions must address all three domains – for example, combining pharmacotherapy (for neurochemical dysregulation) with psychotherapy (for attachment issues and cognitive distortions) and social support (for isolation and subcultural reinforcement). The model also cautions against reductive approaches that attribute compulsive sexual behavior solely to moral failure or willpower deficiency.

Chapter 7: Sexual Violence

Sexual Assault and Rape

Definitions and Prevalence

Sexual assault encompasses any non-consensual sexual contact, from unwanted touching to completed rape. Rape is typically defined as non-consensual penetration achieved through force, threat, or incapacitation. Prevalence estimates vary by methodology and jurisdiction, but large-scale surveys consistently indicate that sexual assault is disturbingly common: approximately 1 in 5 women and 1 in 71 men in North America report experiencing completed or attempted rape in their lifetime.

Rape Across Cultures and Time

Lalumiere, Harris, Quinsey, and Rice (2005) examine the cross-cultural and historical evidence for rape, finding that it appears in virtually every known human society, albeit at vastly different rates. This universality has led some scholars to propose evolutionary explanations, while others emphasize the role of patriarchal social structures and cultural attitudes.

Evolutionary Perspectives

The evolutionary analysis of rape is among the most controversial topics in the social sciences. Two main hypotheses have been proposed:

• The adaptation hypothesis: Proposed most prominently by Thornhill and Palmer, this hypothesis suggests that rape may represent an evolved conditional mating strategy – a “last resort” for males with limited access to consensual mating opportunities. This hypothesis does not claim that rape is morally acceptable or inevitable; it claims only that selection pressures may have shaped psychological mechanisms that, under certain conditions, increase the probability of coercive sexual behavior.
• The by-product hypothesis: This alternative holds that rape is not itself an adaptation but a by-product of other evolved traits – high male sex drive, desire for sexual variety, general aggressiveness, and the capacity for coercion. Under this view, rape emerges from the intersection of these traits with situational facilitators (e.g., opportunity, intoxication, power asymmetry) rather than from a specialized “rape module.”

Both hypotheses are consistent with the epidemiological evidence. Neither implies genetic determinism or excuses perpetrators. The evolutionary framework is analytically useful precisely because it identifies the psychological and situational risk factors that prevention programs must address.

Cross-Cultural Variation

While rape appears universal, its prevalence varies enormously across cultures. Societies with strong patriarchal norms, high gender inequality, tolerance of interpersonal violence, and weak legal sanctions for sexual violence tend to have higher rates of rape. Conversely, societies with greater gender equality, strong legal protections, and cultural norms emphasizing sexual consent tend to have lower rates. This cross-cultural variation underscores that rape is not an inevitable consequence of human biology but is profoundly shaped by social and cultural contexts.

Victim Impact

The consequences of sexual assault are severe and wide-ranging:

• Psychological: PTSD, depression, anxiety, substance abuse, suicidality, and sexual dysfunction.
• Physical: Injury, sexually transmitted infections, unwanted pregnancy.
• Social: Stigmatization, relationship disruption, economic hardship, secondary victimization by legal and institutional systems.
• Long-term: Chronic health problems, impaired trust, and difficulties in subsequent intimate relationships.

Sexual Pressure and Coercion

Not all non-consensual sexual activity involves physical force. Sexual coercion refers to a continuum of tactics used to obtain sexual compliance from an unwilling partner, including:

• Verbal pressure: Persistent requests, emotional manipulation, guilt-tripping.
• Exploitation of authority: Using positional power (e.g., employer-employee, teacher-student) to obtain sexual access.
• Intoxication: Deliberately incapacitating a partner through alcohol or drugs.
• Deception: Misrepresenting intentions, relationship status, or identity to obtain consent.
• Economic coercion: Withholding resources or threatening economic consequences to compel sexual compliance.

Sexual coercion is particularly insidious because it often occurs within established relationships, where the boundaries between persuasion, negotiation, and coercion can be ambiguous. Research indicates that sexual coercion is substantially more common than forcible rape and is experienced by a significant proportion of both women and men, though women are disproportionately affected.

Chapter 8: Child Sexual Abuse

Concepts and Definitions

Child sexual abuse (CSA) is defined as any sexual activity involving a child (typically under 16 or 18, depending on jurisdiction) in which the child cannot give informed consent due to developmental immaturity. CSA encompasses a wide range of behaviors, from non-contact offenses (exhibitionism, exposure to pornography) to contact offenses (fondling, oral sex, penetration).

Prevalence

Meta-analyses of international data suggest that approximately 20% of women and 8% of men have experienced some form of CSA before reaching adulthood. These figures likely underestimate true prevalence due to underreporting, shame, and memory-related factors. CSA occurs across all socioeconomic, ethnic, and cultural groups, though certain risk factors – including family dysfunction, parental substance abuse, social isolation, and prior victimization – increase vulnerability.

Perpetrator Characteristics

The majority of CSA perpetrators are known to the victim – family members, family friends, authority figures, or other trusted adults. Stranger perpetration, while it receives disproportionate media attention, accounts for a minority of cases. Not all perpetrators meet diagnostic criteria for pedophilic disorder; many are opportunistic offenders who exploit access, authority, and the vulnerability of children.

Long-Term Outcomes

Systematic Review Evidence

Carr, Duff, and Craddock (2020) provide a systematic review of outcomes for children who have experienced maltreatment, including sexual abuse, in long-term care settings. Their findings paint a sobering picture:

• Mental health: CSA is associated with elevated lifetime risk of depression, anxiety, PTSD, borderline personality disorder, dissociative disorders, eating disorders, and substance use disorders.
• Interpersonal functioning: Survivors frequently report difficulties with trust, intimacy, and relationship maintenance. Revictimization – experiencing subsequent sexual or physical violence – occurs at elevated rates.
• Sexual functioning: CSA is associated with a range of sexual difficulties, including sexual aversion, compulsive sexual behavior, difficulty with arousal, and confusion about sexual identity.
• Physical health: Long-term physical health consequences include chronic pain, gastrointestinal disorders, obesity, and increased risk of sexually transmitted infections.
• Cognitive and educational outcomes: CSA can impair academic achievement, cognitive development, and occupational functioning.

Moderating Factors

Not all survivors experience the same outcomes. Several factors moderate the impact of CSA:

• Severity and duration: More severe, prolonged, and invasive abuse is associated with worse outcomes.
• Relationship to perpetrator: Intra-familial abuse (incest) tends to produce more severe consequences than extra-familial abuse.
• Disclosure and response: Supportive, believing responses to disclosure are protective; disbelief, blame, or institutional cover-up exacerbates harm.
• Therapeutic intervention: Evidence-based treatments, particularly trauma-focused cognitive-behavioral therapy, can significantly improve outcomes.

Contexts and Illustrative Scenarios

CSA occurs in diverse contexts, each presenting distinct dynamics:

• Intra-familial abuse: Often characterized by gradual grooming, secrecy, and the exploitation of trust and dependency. The child’s attachment to the perpetrator creates profound loyalty conflicts.
• Institutional abuse: Occurs in schools, churches, sports organizations, and residential care facilities. Institutional contexts can facilitate abuse through hierarchical authority structures and cultures of secrecy.
• Online exploitation: The digital age has created new vectors for CSA, including online grooming, the production and distribution of child sexual abuse material (CSAM), and sextortion.
• Child marriage and culturally sanctioned practices: In some cultural contexts, sexual contact with children is normalized through early marriage or traditional practices, raising complex questions about cultural relativism and universal human rights.

Chapter 9: Sexual Homicide and Extreme Violence

Sexual Homicide

Definition and Typology

Sexual homicide is defined as a murder in which sexual activity, fantasy, or motivation plays a primary role. Chan (2017) reviews the literature on sexual homicide, noting that it represents a rare but extreme endpoint on the continuum of sexual violence. Sexual homicides account for a small fraction of all homicides (estimates range from 1% to 4% in North America), but they receive disproportionate public attention due to their horrifying nature and the cultural fascination they provoke.

Chan identifies several subtypes of sexual homicide:

• Rape-murder: Homicide committed during or after a sexual assault, often to eliminate the witness or as an expression of rage.
• Sadistic murder: Homicide in which the perpetrator derives sexual gratification from the suffering, torture, or death of the victim. This subtype is most closely associated with sexual sadism disorder.
• Serial sexual murder: Repeated sexual homicides committed by the same perpetrator over time, typically driven by elaborate fantasies and compulsive patterns.

Perpetrator Profiles

Research on sexual murderers identifies several recurring characteristics:

• Developmental adversity: High rates of childhood abuse, neglect, and family dysfunction.
• Fantasy preoccupation: Elaborate, violent sexual fantasies that develop during adolescence and escalate over time.
• Social isolation: Poor social skills, limited intimate relationships, and difficulty forming secure attachments.
• Psychopathy and antisocial traits: Elevated scores on measures of psychopathy, particularly traits related to callousness, lack of empathy, and grandiosity.
• Paraphilic interests: High rates of multiple paraphilias, particularly sexual sadism, exhibitionism, and voyeurism.

Sexual Sadism

Sexual sadism disorder involves recurrent, intense sexual arousal from the physical or psychological suffering of another person, and it is the paraphilia most closely associated with violent offending. Not all sexual sadists commit violent acts – some confine their interests to consensual BDSM contexts – but when sadistic interests combine with psychopathic personality traits, poor impulse control, and opportunity, the risk of severe violence is substantially elevated.

Hybristophilia: Attraction to Killers

A culturally fascinating phenomenon related to sexual homicide is hybristophilia – sexual attraction to individuals who have committed violent crimes. High-profile serial killers have received thousands of letters, marriage proposals, and romantic overtures from admirers. Explanations for this phenomenon include:

• Evolutionary mate preference for dominance and danger: Some theorists suggest that attraction to powerful, dominant males – even violent ones – may reflect an evolved female preference for protective mates, misdirected toward extreme exemplars.
• Celebrity and notoriety: Media attention transforms killers into cultural figures, and parasocial attraction to famous individuals is a well-documented psychological phenomenon.
• Rescue fantasy: Some admirers may believe they can “change” or “save” the offender, reflecting a caregiving motivation.
• Sensation seeking: Attraction to danger and transgression may reflect individual differences in risk tolerance and novelty seeking.

Chapter 10: Commercial Sex

Prostitution and Sex Work

Defining the Terms

The terminology used to describe commercial sex is itself politically charged. The term prostitution emphasizes the transaction and has traditionally carried connotations of deviance and moral condemnation. The term sex work frames commercial sex as a form of labor, emphasizing agency, labor rights, and occupational health. Both terms are used in the literature, and the choice of terminology often signals the author’s theoretical and political orientation.

Types and Paradigms

Weitzer (2022) identifies a spectrum of sex work types, varying in setting, autonomy, income, and risk:

Weitzer identifies two competing paradigms that dominate academic and policy debates:

The Oppression Paradigm

This perspective, associated with radical feminism and abolitionists such as Melissa Farley, holds that prostitution is inherently exploitative and harmful. Key claims include:

• Prostitution is a form of violence against women, regardless of whether it is “chosen.”
• The vast majority of sex workers experience coercion, trafficking, or economic desperation.
• Legalization or decriminalization normalizes exploitation and increases trafficking.
• The only ethical policy response is the abolition of the sex industry, typically through the criminalization of buyers (the “Nordic model”).

The Empowerment Paradigm

This perspective, associated with sex worker rights organizations and some liberal feminist scholars, holds that sex work can be a legitimate occupation when freely chosen. Key claims include:

• Many sex workers exercise genuine agency and prefer sex work to available alternatives.
• Criminalization increases stigma, violence, and health risks for sex workers.
• Decriminalization (as in New Zealand) improves working conditions, access to healthcare, and legal protections.
• The distinction between forced and voluntary sex work must be maintained.

The Polymorphous Paradigm

Weitzer himself advocates a third approach – the polymorphous paradigm – which recognizes that the sex industry encompasses enormous diversity. Some sex work is coerced and harmful; other sex work is freely chosen and relatively benign. Effective policy must be nuanced enough to address this diversity, rather than treating all commercial sex as uniformly oppressive or uniformly empowering.

Human Trafficking and Sexual Slavery

Definitions

Human trafficking for the purpose of sexual exploitation involves the recruitment, transportation, transfer, harbouring, or receipt of persons by means of threat, force, coercion, abduction, fraud, deception, or abuse of power for the purpose of sexual exploitation. Sexual slavery refers to conditions in which individuals are held in servitude and compelled to perform sexual acts against their will.

Scale and Demographics

The International Labour Organization estimates that approximately 4.8 million people are trapped in forced sexual exploitation worldwide at any given time. The majority of victims are women and girls, though men and boys are also affected. Trafficking routes span every continent, and both developing and developed nations serve as source, transit, and destination countries.

Risk Factors and Recruitment

Traffickers exploit multiple vulnerabilities:

• Poverty and economic desperation – offering false promises of legitimate employment.
• Migration and displacement – targeting refugees, undocumented migrants, and displaced populations.
• Youth and naivety – grooming and manipulating young people, often through romantic relationships.
• Substance dependence – using addiction as a mechanism of control.
• Prior victimization – targeting individuals with histories of abuse or neglect.

Consequences

Victims of trafficking and sexual slavery experience severe and cumulative harm:

• Complex PTSD, depression, anxiety, and dissociative disorders.
• Physical injuries, sexually transmitted infections, and reproductive health complications.
• Substance abuse, often coerced by traffickers as a means of control.
• Social isolation, loss of identity, and barriers to reintegration.
• Legal vulnerability – in many jurisdictions, trafficking victims are treated as criminals rather than victims.

Policy Responses

International frameworks, particularly the Palermo Protocol (2000), establish standards for the prevention of trafficking, prosecution of traffickers, and protection of victims. However, implementation varies widely, and the effectiveness of current approaches remains contested. The intersection of trafficking with immigration enforcement, sex work policy, and poverty reduction makes this one of the most complex policy challenges in the domain of dark sexuality.

Chapter 11: Pornography

The Pop Culture of Sex

Evolutionary Perspectives on Pornography

Salmon (2012) examines pornography through an evolutionary lens, arguing that the content and consumption patterns of pornography reflect evolved psychological differences between men and women. Men, who have evolved a stronger orientation toward visual sexual stimuli, sexual novelty, and low-investment mating opportunities, consume visual pornography at substantially higher rates than women. Women, who have evolved a stronger orientation toward relational context, emotional connection, and partner quality, are disproportionately represented among consumers of romance fiction – what Salmon calls “female erotica.”

This evolutionary framework does not imply that pornography consumption is morally neutral or biologically determined. Rather, it provides a descriptive account of why pornography takes the forms it does and why consumption patterns differ by sex.

The Landscape of Modern Pornography

The advent of the internet has transformed pornography from a stigmatized, difficult-to-access commodity into a ubiquitous, freely available feature of the digital landscape. Key developments include:

• Accessibility: “Tube sites” provide unlimited, free access to vast libraries of pornographic content.
• Volume: Hundreds of thousands of new pornographic videos are uploaded daily.
• Diversity: The range of available content has expanded dramatically, encompassing every conceivable sexual interest, including many that would have been difficult to find before the internet.
• Interactivity: Webcam platforms, virtual reality, and AI-generated content have created new modes of pornographic experience.
• Youth exposure: The average age of first exposure to internet pornography has declined, with many children encountering explicit content before the age of 12.

Debates Over Harm

The question of whether pornography is harmful remains one of the most contested issues in sexuality research:

Arguments for Harm

• Normalization of aggression: Content analyses, including Bridges et al. (2010), find that a substantial proportion of best-selling pornographic videos contain depictions of physical aggression (spanking, gagging, choking) and verbal aggression (name-calling, insults), overwhelmingly directed at women. Critics argue that exposure to such content normalizes sexual aggression, objectification, and gender inequality.
• Sexual script theory: Repeated exposure to pornographic scripts may shape viewers’ expectations about sex, leading to dissatisfaction with real-world partners, unrealistic body image standards, and pressure to perform acts depicted in pornography.
• Compulsive use: A subset of consumers reports difficulty controlling their pornography use, with associated distress, relationship conflict, and functional impairment.
• Impact on relationships: Some studies find associations between pornography consumption and reduced relationship satisfaction, though the direction of causation is debated.
• Child exploitation: The production of CSAM is an inherently abusive and illegal enterprise, and the internet has facilitated its proliferation.

Arguments Against Harm (or for Benefits)

• Catharsis and substitution: Some researchers argue that pornography provides a safe outlet for sexual fantasies, potentially reducing the incidence of sexual offending. Ecological data showing declines in sexual violence concurrent with increases in pornography availability are cited in support, though the causal interpretation is contested.
• Sexual education: For individuals with limited sexual experience or knowledge, pornography may serve (however imperfectly) as a source of information about sexual practices.
• Sexual minority visibility: Pornography has historically been one of the few spaces in which non-normative sexualities (LGBTQ+ identities, BDSM practices) are represented, providing visibility and community for marginalized groups.
• Methodological limitations: Critics of the “harm” literature note that many studies rely on cross-sectional designs, correlational analyses, and non-representative samples, making causal claims about pornography’s effects difficult to sustain.

Chapter 12: Infidelity and Sexual Betrayal

Defining Infidelity

Infidelity refers to a violation of the explicit or implicit agreement of sexual and/or emotional exclusivity within a committed relationship. The definition of infidelity is itself culturally and relationally variable: what counts as betrayal depends on the norms and expectations established (or assumed) within a particular relationship. In contemporary Western societies, infidelity typically encompasses:

• Sexual infidelity: Engaging in sexual activity with someone other than one’s committed partner.
• Emotional infidelity: Forming a deep emotional or romantic attachment to someone outside the relationship, even in the absence of sexual contact.
• Online infidelity: Engaging in sexual or romantic interactions through digital platforms (sexting, online affairs, pornographic chat).

When, Where, Why: Patterns and Predictors

Tsapelas, Fisher, and Aron (2010) provide a comprehensive review of the empirical literature on infidelity, examining its prevalence, correlates, and consequences.

Prevalence

Estimates of infidelity prevalence vary widely depending on definitions and methodology. General population surveys suggest that approximately 20–25% of married men and 10–15% of married women in North America report having engaged in extramarital sexual intercourse at least once. Rates are higher when emotional infidelity and broader definitions of betrayal are included.

Predictors of Infidelity

Research has identified numerous individual, relational, and contextual predictors:

• Individual factors: Higher sociosexuality (unrestricted orientation toward casual sex), lower conscientiousness, higher narcissism, insecure attachment style, and a history of prior infidelity.
• Relational factors: Low relationship satisfaction, poor communication, sexual dissatisfaction, perceived inequity, and declining passion.
• Contextual factors: Opportunity (e.g., travel, workplace proximity), alcohol use, social network norms, and cultural permissiveness.

Evolutionary Perspectives

Evolutionary psychology offers complementary explanations for infidelity:

• Male infidelity may be understood in terms of evolved desires for sexual variety and low-cost reproductive opportunities (Trivers’ parental investment theory).
• Female infidelity may reflect mate-switching strategies (seeking a better long-term partner), genetic benefit strategies (seeking “good genes” from extra-pair partners), or resource acquisition strategies (securing material or social benefits from additional partners).

These evolutionary hypotheses are not mutually exclusive with proximate psychological explanations; they operate at different levels of analysis.

Consequences of Infidelity

The discovery of infidelity typically triggers a profound relational crisis:

• Emotional impact: Betrayed partners commonly experience shock, rage, grief, humiliation, anxiety, and depression. The psychological impact of infidelity discovery has been compared to the trauma response.
• Relationship outcomes: Infidelity is one of the leading predictors of relationship dissolution. However, not all relationships end following infidelity; a substantial minority of couples successfully repair their relationships, often through therapeutic intervention.
• Sex differences in response: Consistent with evolutionary predictions, men report greater distress in response to sexual infidelity (which threatens paternity certainty), while women report greater distress in response to emotional infidelity (which threatens resource and commitment diversion). However, these sex differences are moderate and do not apply uniformly across all individuals or cultural contexts.

Infidelity as a “Dark Side” Phenomenon

Infidelity exemplifies the multi-process model introduced at the beginning of this course. It involves physiological processes (sexual desire for novel partners), cognitive processes (fantasy, rationalization, compartmentalization), motivational processes (pleasure-seeking, unmet needs, power), and cultural regulation (moral condemnation, legal consequences in some jurisdictions, social stigma). The interplay of these factors determines whether a specific instance of infidelity represents a minor relational transgression, a devastating betrayal, or a symptom of deeper individual or relational pathology.

Chapter 13: Integration and Ethical Reflection

The Continuum of Sexual Darkness

Across the topics examined in this course, several unifying themes emerge:

Consent as the Central Ethical Criterion

The most consistent thread linking all “dark side” phenomena is the presence or absence of meaningful consent. Consensual BDSM, however extreme, is fundamentally different from sexual assault. Freely chosen sex work, however stigmatized, differs categorically from trafficking and sexual slavery. Sexual fantasy, however transgressive, differs from behavioral enactment involving non-consenting victims. Consent – informed, voluntary, ongoing, and revocable – is the ethical bright line that separates sexual variation from sexual harm.

However, consent is not always a simple binary. Power asymmetries, economic desperation, developmental immaturity, cognitive impairment, and intoxication can all compromise the capacity for genuine consent. A sophisticated ethical framework must attend to these contextual factors rather than relying on a formalistic understanding of consent.

The Role of Power

Power asymmetry is a recurring feature of dark sexuality. Sexual assault, child sexual abuse, trafficking, coercion, and exploitation all involve the exercise of power over vulnerable individuals. Even in contexts that are nominally consensual – such as sex work or age-disparate relationships – power differentials can undermine the quality of consent and create conditions for harm.

Individual Variation and Risk

Not all individuals who harbor dark sexual interests act on them, and not all who encounter risk factors develop pathological patterns. Individual differences in empathy, impulse control, attachment security, moral reasoning, and social support moderate the pathway from atypical desire to harmful action. Understanding these moderating factors is essential for effective prevention and intervention.

Cultural and Historical Context

What counts as “dark” is not static. Homosexuality was once classified as a mental disorder; BDSM was considered prima facie pathological; pornography was nearly universally condemned. As cultural attitudes evolve, so do the boundaries of sexual acceptability. A historically informed perspective reminds us that contemporary moral judgments are neither timeless nor inevitable – though this observation does not imply that all moral judgments are equally valid or that harm is merely a social construction.

Toward Prevention and Healing

The study of dark sexuality is ultimately in the service of reducing harm. Effective strategies require:

• Evidence-based education: Comprehensive sexuality education that addresses consent, communication, healthy relationships, and media literacy.
• Clinical intervention: Trauma-informed treatment for victims and evidence-based risk management for perpetrators.
• Legal reform: Laws that protect victims, hold perpetrators accountable, and avoid criminalizing consensual behavior between adults.
• Cultural change: Challenging norms that normalize sexual coercion, silence victims, and stigmatize help-seeking.
• Research: Continued empirical investigation into the causes, consequences, and prevention of sexual harm, guided by ethical principles and methodological rigor.

The “dark side” of sexuality is not a foreign territory inhabited only by monsters and deviants. It is a dimension of human experience that touches, directly or indirectly, the lives of virtually every person. Understanding it – with compassion, intellectual honesty, and a commitment to evidence – is among the most important tasks the social sciences can undertake.