Lex Fridman Podcast

#483 – Julia Shaw: Criminal Psychology of Murder, Serial Killers, Memory & Sex

October 14, 2025

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  • Evil is best understood as a continuum of dark personality traits (the Dark Tetrad) rather than a binary label, and understanding the psychological and social levers that lead to harmful behavior requires 'evil empathy.' 
  • The commonality of murder fantasies (up to 70% of men) and the low recidivism rate for homicide suggest that most murders result from arguments escalating out of control, contrasting with the media focus on planned serial killings. 
  • Intuitive judgments of trustworthiness and creepiness are often unreliable, and overconfidence in deception detection, particularly among investigators, can lead to significant errors in the justice system. 
  • Bisexual individuals often face societal hypersexualization and misunderstanding, leading some to prefer non-traditional relationship structures as a result of deeply engaging with their sexuality due to external questioning. 
  • The Kinsey Scale and the more complex Klein Sexual Orientation Grid illustrate that human sexuality exists on a continuum, and individuals may struggle with aligning their present identity, behavior, fantasies, and ideal orientation. 
  • Human autobiographical memory is inherently false, being a creative recombination of information optimized for present problem-solving, which makes individuals highly susceptible to suggestion, including the implantation of false memories of committing crimes through suggestive interviewing techniques. 
  • Contemporaneous evidence, recorded as soon as possible outside the brain, yields the highest quality memory, as subsequent recall is subject to editing and distortion from social interaction and time. 
  • Cognitive restructuring, the deliberate modification of memory aspects, is an effective technique for improving one's emotional state and resilience by reframing negative experiences into positive lessons. 
  • Environmental crime, often involving sophisticated corporate fraud and organized networks, is driven by psychological factors like conformity and rationalization, similar to other forms of large-scale wrongdoing. 

Segments

Dark Tetrad Continuum
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(00:08:16)
  • Key Takeaway: The Dark Tetrad traits (psychopathy, sadism, narcissism, Machiavellianism) exist on a scale, not as a binary classification of monster or non-monster.
  • Summary: Each trait on the Dark Tetrad has a scale where individuals score low or high, classifying them based on likelihood for risky or harmful behaviors. Subclinical levels of these traits are important to understand alongside clinical diagnoses. Scoring high on all four traits correlates with the highest likelihood of harming others.
Nature vs. Nurture of Evil
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(00:10:24)
  • Key Takeaway: Extreme harm is generally not inherent from birth, as evidenced by Hitler’s early life not showcasing the traits he later manifested, suggesting environmental socialization is crucial.
  • Summary: The ‘Baby Hitler’ question addresses whether evil is innate or socialized; the conclusion leans toward environmental shaping over inherent evil. Using the label ’evil’ is problematic because it stops the conversation and creates an artificial differentiation between ‘good’ and ‘bad’ people. Understanding the psychological and social levers that lead to terrible acts is necessary to prevent them.
Dehumanization and Heroic Imagination
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(00:13:02)
  • Key Takeaway: Perpetrating large-scale harm requires dehumanization of the other and deindividuation, where the individual feels swallowed by the group identity.
  • Summary: The bystander effect, exemplified by the Kitty Genovese case, is often driven by reading the room and assuming inaction is correct when a crowd is present. Conversely, the ‘heroic imagination’ involves simulating resistance and intervention to normalize stepping up when witnessing harm.
Psychology of Murder
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(00:43:59)
  • Key Takeaway: Most murders are not premeditated acts by psychopaths but rather impulsive overreactions during fights, often over trivial matters like debt or stolen property.
  • Summary: Society desires extreme reasons for extreme consequences, leading to a focus on serial killers rather than the more common, ‘boring’ impulsive murders. Sanctions in the criminal justice system are often aligned with perceived justice (retribution) rather than crime prevention, as homicide recidivism is very low (1-3%).
Love Scams and Fraud
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(00:51:51)
  • Key Takeaway: Love scams, like the Tinder Swindler case, succeed because fraudsters tailor narratives to exploit what the victim deeply desires to believe, making anyone vulnerable.
  • Summary: Manipulative relationship styles often involve ’love bombing’ and creating an idealized future vision to build rapid emotional investment. Victims of fraud often feel embarrassed afterward, but the failure lies in the manipulation, not the victim’s intelligence or desire to be loved. AI is poised to make this tailored fraud even more effective.
Jealousy and Monogamy Views
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(00:56:37)
  • Key Takeaway: Jealousy in relationships is almost always a red flag indicating insecurity or a desire for control, and it is a known precursor to intimate partner violence.
  • Summary: Research suggests most people are not inherently good at monogamy, leading to cheating, which suggests monogamy is a social construct that may not suit everyone. Open relationships and non-traditional structures should be considered healthy options, and honesty about attraction is crucial, especially early in a relationship.
Navigating Polyamory and Jealousy
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(01:02:30)
  • Key Takeaway: Successful polyamorous relationships depend on entering them from a good place focused on connection, rather than attempting to fix pre-existing personal issues.
  • Summary: Polyamory can be difficult to navigate, similar to any relationship, and attempting to use it to fix personal brokenness leads to hardship. A positive foundation focused on openness and connection yields better outcomes. Bisexual individuals are often drawn to non-traditional relationships partly because they constantly have to justify their sexuality to others.
Bisexuality Terminology and Fluidity
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(01:05:21)
  • Key Takeaway: Researchers often use terms like ‘plurisexual’ or ‘omnisexual’ instead of ‘bisexual’ to avoid confusion with the term’s use in biology or to encompass attraction across all genders.
  • Summary: The term ‘bisexual’ can be confusing in research, leading to the use of plurisexual or omnisexual to denote attraction to all genders. Bisexuality is best understood as the capacity to be attracted to people regardless of gender, not necessarily a fluid state day-to-day. The most common misunderstanding is viewing bisexuality as a transient phase or a stepping stone to being exclusively gay.
Kinsey Scale and Historical Context
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(01:08:02)
  • Key Takeaway: Alfred Kinsey’s post-WWII research established the Kinsey Scale (0-6) demonstrating that most people fall on a continuum between exclusive heterosexuality and homosexuality, challenging the binary view of sexual orientation.
  • Summary: Alfred Kinsey, a biologist studying gall wasps, became a sex research rock star in the 1940s by addressing public curiosity about sexual norms. He found that applying a binary to sexual desire was unhelpful, as most people exhibited tendencies somewhere between exclusively heterosexual (0) and exclusively homosexual (6). The prevalence of identifying as bisexual has shifted over time, being higher among men post-war (due to homo-social environments) and higher among women currently.
Klein Grid and Sexual Identity Mapping
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(01:14:38)
  • Key Takeaway: The Klein Sexual Orientation Grid offers a more detailed framework than the Kinsey Scale by mapping identity across multiple dimensions, including past, present, and ideal states for attraction, behavior, and self-identification.
  • Summary: The Klein Grid helps individuals analyze their sexuality across dimensions like attraction, behavior, and self-identification, considering past, present, and ideal states. Discrepancies between present and ideal states can reveal ’troubled’ aspects of one’s sexuality, which are rooted in societal expectations or personal puzzles, not necessarily dishonesty. Bisexual individuals face higher rates of self-harm and victimization partly due to being less plugged into supportive communities.
Kinks, Fetishes, and Evil Association
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(01:20:22)
  • Key Takeaway: Sexual kinks and fantasies, like BDSM, are far more commonplace than society acknowledges, and associating them with ’evil’ or defective character is harmful, often leading to mental health consequences for those who feel shame.
  • Summary: Kinks are often incorrectly linked to criminal behavior by the public, but research shows many people fantasize about or engage in activities like BDSM consensually. The appeal of certain dynamics, like submission, can stem from the ‘disinhibition hypothesis,’ allowing individuals to let go of daily decision-making pressures. Destigmatizing these desires is crucial because societal villainization of non-normative sexuality or kinks negatively impacts individual mental health.
Visibility and Rights Preservation
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(01:28:18)
  • Key Takeaway: Visibility through coming out and publishing research normalizes marginalized identities, making it harder for society to dehumanize those communities and helping to preserve hard-won rights against potential regression.
  • Summary: The author came out as bisexual in her book Evil to promote visibility, realizing that seeing loved ones within marginalized communities makes dehumanization more difficult. Her book on bisexuality was banned in one country after laws changed, highlighting that acceptance is not linear and rights can be stripped back. Normalizing sexuality issues through visibility is presented as a necessary defense mechanism against future legal or social backlash.
Engineering False Memories of Crime
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(01:39:04)
  • Key Takeaway: It is possible to implant complex false memories, including confessions to crimes that never occurred, in a high percentage of participants using suggestive, leading interview techniques combined with rapport-building.
  • Summary: The PhD research involved implanting false memories of committing a crime (like assault with a rock) in participants using suggestive techniques over just three interviews, achieving a 70% conviction rate in the study sample. This process relies on weaving the false narrative with real details (places, people) to make the memory feel autobiographically true. This possibility demonstrates that generative AI, which is structured as a social interaction, can function as an ‘ultimate false memory machine’ capable of mass gaslighting.
Defending Against Memory Distortion
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(02:00:33)
  • Key Takeaway: To protect important memories, especially in high-stakes situations like witnessing a crime, individuals must immediately record the information outside their brain, as memory is inherently unreliable and subject to constant social editing.
  • Summary: The primary defense against memory distortion is recognizing that the brain is incapable of perfectly accurate autobiographical recall and should not be trusted for critical details. Contemporaneous evidence—recording information as close to the event as possible—is vital, overriding the myth that one should wait until sober or calm to recall events. Memory functions like a Wikipedia page, constantly edited by subsequent social interactions and new information, making external documentation essential for preserving an original account.
Memory Quality and Timing
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(02:00:56)
  • Key Takeaway: Memory quality is highest when recorded contemporaneously, immediately after an event, overriding the common myth that one should wait until sober or calm.
  • Summary: The closer an event is recorded to when it happened, the higher the memory quality; waiting to recall memories after being intoxicated or emotional results in lower quality information. Memories function like editable Wikipedia pages, crowdsourced and edited by subsequent experiences and discussions, necessitating an original, external recording first. Collective memory sessions can increase detail recall, but only if individuals have first documented their own original version to prevent weaving a false narrative.
Conflicting Memory Versions
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(02:04:33)
  • Key Takeaway: Conflicting memory versions arise both between different people recalling the same event and within the same person over time, making evidentiary quality low if original accounts are lost.
  • Summary: Witnesses or alleged victims can present categorically different accounts years later, raising questions about whether initial shyness, external pressure, or problematic therapy caused the change. When memory accounts conflict, the only way to determine truth is by accessing the original versions, as later accounts may be influenced by suggestive therapeutic techniques mirroring false memory research. In the absence of original receipts, conflicting testimonies often devolve into a battle of confidence.
Therapy vs. Evidentiary Role
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(02:06:29)
  • Key Takeaway: Therapists prioritize managing current well-being by helping clients manage emotions related to memories, whereas expert witnesses prioritize evidentiary quality and what actually happened.
  • Summary: Certain therapies, particularly those focused on retroactively finding sources of mental illness, risk implanting false memories by uncautiously exploring the past. Therapists aim to help clients feel better now, meaning the truth of a memory is secondary to its emotional impact, contrasting sharply with the courtroom need for factual accuracy. Cognitive restructuring is a valid technique for shifting the emotional content of true experiences to promote resilience and happiness.
Memory State Dependency
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(02:10:05)
  • Key Takeaway: State-dependent memory dictates that current emotional states (like sadness or embarrassment) activate and spread activation to associated memories of the same feeling, influencing retrospective bias.
  • Summary: If a person is sad, their brain is more likely to recall other sad times because the emotional network is already active, a phenomenon also seen with embarrassment. Happier people generally recall more happy memories, often leading to a rosy reminiscence bias where past experiences are interpreted neutrally or positively in hindsight. This reframing, like viewing a difficult childhood experience as a net positive influence, is what good therapy aims to facilitate without overwriting true experiences.
Memory’s Role in Life Experience
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(02:12:23)
  • Key Takeaway: A significant portion of life’s perceived pleasure is derived from remembering past events rather than the direct, in-the-moment experience, as evidenced by people refusing unremembered holidays.
  • Summary: The value placed on experiences is often disproportionate to the time spent living them versus the time spent remembering them over a lifetime. Attention acts as the glue between reality and memory; outsourcing attention to devices like phones to record events can lead to poor memory encoding. Modifying memories through techniques like cognitive restructuring can be done deliberately to foster a happier life narrative.
Aphantasia and Memory Visualization
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(02:22:31)
  • Key Takeaway: Aphantasia, the inability to create mental imagery, means that memory techniques relying on elaborate visualization, like the memory palace, are ineffective for those affected.
  • Summary: Memory champions often rely on creating elaborate mental pictures, but individuals with aphantasia, who see only black when attempting visualization, cannot utilize these methods. People with aphantasia may process memory through concepts rather than visual representations, potentially leading them to care less about visualizing childhood memories. This highlights significant individual differences in how memory networks are structured and accessed.
Psychology of Environmental Crime
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(02:25:33)
  • Key Takeaway: Environmental crimes, such as the Volkswagen Dieselgate emissions fraud, are often perpetrated by intelligent individuals driven by conformity, rationalization, and industry norms rather than simple malice.
  • Summary: Applying criminal psychology to environmental destruction reveals that corporate actors lie about harmful emissions because they see others in the industry doing the same, creating a harmful, cheating norm. The scale of environmental crime involves complex, multi-level organizations, contrasting with typical violent crime narratives focused on individuals. Identifying heroes, such as whistleblowers or undercover investigators, is crucial for stopping these large-scale, systemic offenses.
Hope and Technological Potential
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(02:40:24)
  • Key Takeaway: Hope for the future stems from the study of darkness, the capacity of technology to implement scientific findings, and the dedication of researchers fighting specific crimes like environmental destruction.
  • Summary: The existence of people studying the mechanisms of darkness provides optimism, as does the new capacity provided by technology to implement science-backed findings, such as using AI to administer the cognitive interview. Julia Shaw co-founded Spot, a tool using chatbot technology to administer the cognitive interview for compliance reporting, aiming to preserve contemporaneous evidence outside the brain. The potential exists for technology to help humans overcome memory shortcomings, provided social science insights are integrated into system design.