The Neuroendocrinological Architecture of Cognition: A Comprehensive Analysis of Testosterone's Modulatory Effects on Intelligence Quotient (IQ) and Emotional Intelligence (EQ) in Men

The intricate relationship between neuroendocrinology and human cognitive architecture has long been a focal point of behavioral neuroscience, evolutionary biology, and clinical psychology. Among the diverse array of hormonal agents that regulate human behavior, testosterone—a primary androgenic steroid hormone—exerts profound organizational effects during fetal development and potent, dynamic activational effects throughout the entire human lifespan. Historically, the scientific consensus regarding testosterone in men was primarily constrained to its role in reproductive physiology, the development of secondary sexual characteristics, and the facilitation of aggressive, competitive, or dominant social behaviors. However, subsequent decades of advancements in psychometric testing, functional neuroimaging (fMRI), electroencephalography (EEG), and large-scale endocrine profiling have categorically demonstrated that testosterone deeply modulates higher-order cognitive functions. Specifically, it influences both the Intelligence Quotient (IQ)—encompassing fluid and crystallized intelligence—and Emotional Intelligence (EQ), including cognitive empathy, emotional regulation, and advanced social cognition.

The prevailing empirical data strictly contraindicate a monolithic, linear, or uniformly "masculinizing" conceptualization of testosterone’s effect on the human brain. Instead, the expansive literature consistently demonstrates highly nuanced, task-specific, biphasic, and non-linear dynamics. The functional cognitive outcomes of testosterone are inextricably linked to the precise cognitive domain being assessed, the neurodevelopmental timing of the androgenic exposure (prenatal organizational programming versus postnatal activational fluctuations), the moderating influence of concurrent neuroendocrine signals (such as the glucocorticoid cortisol), and the specific neural circuitry engaged during targeted cognitive or emotional tasks.

The Taxonomy of Intelligence and the Endocrine System

To accurately assess the modulatory effects of testosterone on intelligence, it is necessary to utilize a rigorous taxonomic definition of the Intelligence Quotient (IQ). According to the psychometrically based theory originally introduced by Raymond Cattell in 1943, general intelligence is not a singular entity but is broadly categorized into two distinct, albeit interacting, domains: fluid intelligence and crystallized intelligence.1

Crystallized intelligence refers to the retrieval, application, and utilization of acquired knowledge, cumulative experience, and learned operational schemas. It involves the ability to deduce secondary relational abstractions by applying previously learned primary relational abstractions, a capacity that typically remains stable or even improves with age.1 Fluid intelligence, conversely, represents the raw, unlearned capacity to process novel information, identify complex patterns, engage in logical extrapolation, and solve problems completely independent of previously acquired knowledge.2 Fluid intelligence is highly correlated with essential cognitive skills such as rapid comprehension, working memory efficiency, and dynamic problem-solving.2 The neuroendocrinological literature indicates that testosterone exerts a selective, highly complex, and temporally dependent influence on these cognitive domains, particularly fluid intelligence.

The Inverted-U and Polynomial Modulations of Fluid Intelligence

Investigations into the correlation between serum total testosterone levels and fluid intelligence—often measured utilizing standardized psychometric instruments such as Cattell’s Culture Fair Intelligence Test or the Intelligence Structure Test 2000 R—reveal that the relationship is neither strictly positive nor negative. Instead, it operates on a highly specific non-linear, curvilinear continuum.3 In populations of young adult men, fluid IQ generally tends to increase commensurately with endogenous testosterone levels up to a certain physiological threshold; however, at excessively high concentrations, this positive correlation rapidly deteriorates.4

Extensive statistical modeling demonstrates that the relationship between endogenous testosterone and fluid intelligence in men is best described by a polynomial regression equation of the third order, rather than a simple linear trajectory.8 These complex models indicate a baseline positive correlation where low circulating testosterone corresponds to low fluid IQ, and moderately high testosterone corresponds to peak fluid IQ. However, men exhibiting exceptionally high or supraphysiological levels of testosterone frequently demonstrate lower fluid intelligence scores, resulting in a complex plateau or an inverse U-shaped functional curve.4

The second-order implications of these findings suggest the existence of a neuroendocrinological "Goldilocks zone." Optimal cognitive functioning, specifically in domains requiring rapid abstraction, mental rotation, and working memory, appears to necessitate a moderate-to-high homeostatic range of testosterone.9 Extreme deviations from this physiological window—either pathologically hypogonadal or exogenously/endogenously hypergonadal states—prove cognitively disadvantageous for fluid reasoning.8

Endocrine Profile (Testosterone Concentration)	Observed Impact on Fluid Intelligence (IQ)	Postulated Neurobiological Mechanism
Hypogonadal (Very Low)	Suboptimal. Associated with reduced visuospatial speed, delayed reaction times, and impaired executive function.	Insufficient androgen receptor activation in the hippocampus and prefrontal cortex; reduced neurotrophic support (NGF).
Moderate to High-Normal	Optimal. Strongly associated with peak performance in novel problem-solving, pattern recognition, and spatial abstraction.	Ideal saturation of neural androgen receptors; optimal cerebrovascular perfusion and cortical neuroplasticity.
Supraphysiological (Very High)	Suboptimal. Associated with declining fluid intelligence, reduced cognitive reflection, and increased heuristic reliance.	Potential androgen receptor downregulation; hyper-excitability of subcortical affective networks superseding prefrontal cortical control.

Facial Morphology and Intelligence Stereotypes

The biological embedding of testosterone not only influences cognitive output but also shapes the morphological characteristics that society uses to unconsciously estimate intelligence. Research integrating psychometric testing with geometric morphometrics has explored the relationship between measured intelligence, perceived intelligence, and facial architecture. In studies utilizing thin-plate spline extrapolation on cohorts of biology students tested with the Intelligence Structure Test 2000 R, researchers mapped the facial traits responsible for the attribution of intelligence.3 Because testosterone heavily dictates craniofacial development during puberty (e.g., jaw width, brow ridge prominence), these geometric analyses reveal how subtle androgenic markers influence whether an individual is stereotypically perceived as possessing high fluid or crystallized intelligence, despite the actual cognitive test scores demonstrating the aforementioned non-linear, task-specific realities.3

Task-Specific Paradoxes: Spatial Ability and Intellectual Giftedness

A persistent and fascinating paradox in the study of male cognition revolves around visuospatial and mathematical abilities—domains in which males typically exhibit a statistical advantage at the population level. Despite visuospatial ability being highly sexually dimorphic and generally favoring males, high-resolution within-sex variations demonstrate an inverse relationship. Men with lower endogenous salivary testosterone concentrations routinely perform significantly better on complex spatial and mathematical measures than men with higher circulating testosterone.14 Conversely, women with higher endogenous testosterone tend to score higher on these exact same male-typical measures compared to women with lower testosterone.14 Furthermore, testosterone concentrations do not relate significantly to scores on psychometric tests that usually favor women (such as verbal fluency) or that do not typically show a sex difference, demonstrating distinct task specificity.14

This dynamic is further illuminated when examining intellectually gifted cohorts (individuals possessing an IQ of 130 or higher). Prepubescent and adolescent boys identified as academically gifted exhibit significantly lower salivary testosterone concentrations compared to their non-gifted, neurotypical peers.15 To reconcile the phenomenon where lower postnatal testosterone correlates with higher specific cognitive phenotypes, neurobiologists frequently refer to the "Geschwind-Behan-Galaburda" (GBG) hypothesis.

The GBG model posits that high prenatal testosterone exposure fundamentally alters the developmental trajectory of the fetal brain. Specifically, it is hypothesized to inhibit the growth and arborization of the left cerebral hemisphere while simultaneously inducing compensatory hyper-development in the right hemisphere.15 This prewired cerebral organization—driven entirely by fetal androgens—fosters exceptional spatial, mathematical, and visualization skills.15 However, this early, intense androgenic hyper-exposure may subsequently suppress the postnatal development of the hypothalamo-pituitary-gonadal (HPG) axis, resulting in the lower circulating salivary testosterone levels observed in gifted boys and adult men who excel at these tasks.15 Consequently, a prewired cerebral architecture is an essential prerequisite for determining how activational (adult) testosterone will ultimately affect cognitive abilities.8

Prenatal Androgen Exposure: The 2D:4D Digit Ratio and Neurodevelopment

The crucial distinction between organizational (prenatal) and activational (postnatal/adult) testosterone is fundamental to understanding male cognitive and emotional architecture. Because obtaining direct measurements of amniotic testosterone is ethically and practically challenging, researchers frequently rely on a validated proxy biomarker: the 2D:4D digit ratio. This morphological trait represents the ratio of the length of the index finger (2D) to the ring finger (4D), typically measured from the mid-point of the bottom crease to the tip.16

The 2D:4D ratio is established in utero and remains morphologically constant since birth across a variety of species, from humans and mice to zebra finches.16 It is a highly sexually dimorphic trait; on average, males possess a lower (more masculine) 2D:4D ratio than females, indicating higher prenatal testosterone exposure relative to prenatal estrogen exposure.16 Analysis of amniocentesis samples confirms that the digit ratio is negatively correlated to prenatal testosterone but positively correlated to estrogen exposure.16 Individuals with clinical conditions such as Congenital Adrenal Hyperplasia (CAH), which exposes the female fetus to high androgen loads, present with lower, masculinized digit ratios.16 Conversely, males with Klinefelter's syndrome possess higher, feminized ratios.16

Cognitive and Behavioral Correlates of Prenatal Priming

Analyses utilizing the 2D:4D ratio yield highly complex insights into cognitive outcomes. For instance, a lower (masculinized) digit ratio in men correlates negatively with mental rotation and spatial task scores, implying that higher prenatal testosterone facilitates the structural brain development necessary for male-favouring spatial tasks in adulthood.17 This supports the premise that prenatal testosterone organizes the neural hardware required for visual-spatial memory and arithmetic processing.17 Interestingly, an imbalanced 2D:4D ratio has also been observed in morphological disorders; for instance, males with sagittal craniosynostosis (suture fusion) exhibit significantly higher 2D:4D ratios compared to male controls, suggesting an imbalance between testosterone and estrogen signaling during cranial development.17

Furthermore, variations in the 2D:4D ratio have been linked to Specific Learning Disorders (SLD). Significantly lower both-hand ratios are observed in SLD patient groups compared to healthy controls, indicating that extreme deviations in prenatal androgen exposure actively regulate brain development in ways that can directly and adversely impact lifelong learning trajectories and general intelligence.18

The 2D:4D ratio also provides a window into the development of dark triad personality traits, specifically psychopathy and callousness. Research demonstrates a fascinating sexual dimorphism in these associations. In women, greater prenatal testosterone (lower 2D:4D) is associated with greater primary psychopathy.19 However, in men, it is actually greater prenatal estrogen (higher 2D:4D) that is associated with greater callousness.19 This indicates that the organizational effects of steroid hormones on empathic and prosocial neurocircuitry operate on entirely different biochemical axes depending on the genetic sex of the fetus.19

Animal Models of Organizational vs. Activational Effects

The complexity of these neurodevelopmental windows is corroborated by murine models. Research examining the effects of excess neonatal testosterone in wild-type mice reveals that high early androgen loads cause male-specific social and fear memory deficits later in life.20 However, administering testosterone slightly later in development (e.g., Postnatal day 18) does not affect social approach behavior or memory in juvenile mice.20 These models confirm that the brain exhibits highly specific, transient critical periods during which testosterone can permanently organize the neural architecture supporting social cognition and emotional intelligence; outside of these windows, the identical hormone yields no structural effect.

Cognitive Decline, Aging, and Neuroprotection

While prenatal testosterone permanently organizes the neural hardware, the continuous, homeostatic presence of endogenous testosterone is actively required to maintain functional integrity, particularly as men age. The gradual, age-related decline of testosterone in aging men—often termed late-onset hypogonadism or "andropause"—frequently and intimately coincides with observable, progressive declines in cognitive function and fluid intelligence.10

The Critical Role of Bioavailable Testosterone

Population-based clinical studies consistently demonstrate that low levels of endogenous testosterone in healthy older men strongly correlate with poor performance on standardized cognitive batteries, including the Mini-Mental State Examination (MMSE), working memory tasks, and complex visuospatial assessments.10 Crucially, the literature distinguishes between total serum testosterone and bioavailable testosterone. Bioavailable testosterone (testosterone that is free or loosely bound to albumin, excluding the fraction tightly bound to sex hormone-binding globulin) serves as a substantially stronger correlate for cognitive preservation than total serum testosterone.10 Bioavailable testosterone readily and efficiently crosses the blood-brain barrier, allowing it to exert direct neurotrophic and neuroprotective effects on the central nervous system.12

In older men, the relationship between testosterone and spatial/learning abilities often appears highly linear, completely distinct from the biphasic, curvilinear dynamic observed in young adults.12 Higher concentrations of both total and free testosterone in aging males are inversely associated with cognitive decline, effectively preserving processing speed, delayed recall, and verbal memory.12

Exogenous Deprivation and Substitution

The absolute cognitive necessity of testosterone is starkly illustrated in men undergoing androgen deprivation therapy (chemical or surgical castration) for the management of prostate cancer. These patients frequently exhibit rapid, clinically significant visuomotor slowing, impaired spatial rotation, deteriorated working memory, and severe attentional deficits following the abrupt suppression of circulating androgens.12

Conversely, the results of randomized, placebo-controlled trials investigating exogenous testosterone substitution therapy in older men—including those diagnosed with Mild Cognitive Impairment (MCI) or early-stage Alzheimer's Disease (AD)—have yielded moderate but highly selective positive cognitive effects.9 Short-term substitution protocols (e.g., 6 weeks of targeted therapy) have successfully and measurably improved spatial memory and constructional abilities, while longer-term therapies (one year or more) have actively mitigated declines in visuospatial scores.12

The neurobiological mechanisms underpinning these cognitive benefits are multi-faceted. Testosterone acts as a profound neuroprotective agent by upregulating the production of Nerve Growth Factor (NGF) in the hippocampus, protecting neural networks against oxidative stress and apoptosis, and enhancing cerebral glucose metabolism.12 Furthermore, advanced imaging techniques (PET, SPECT, and fMRI) demonstrate that testosterone substitution actively increases cerebral perfusion in regions critical for executive function, such as the midbrain and the superior frontal gyrus.12 In the context of Alzheimer's pathology, testosterone has been observed to inhibit the hallmark biological markers of the disease, including the secretion of -amyloid plaques and the hyperphosphorylation of tau proteins.12

However, testosterone supplementation is not a panacea, and researchers caution that cognitive improvements vary heavily based on the specific cognitive domain assessed.9 Furthermore, confounding variables such as baseline vascular risk factors deeply influence the efficacy of the treatment, reinforcing the concept that an "optimal range" of testosterone is required to realize these cognitive benefits without triggering adverse cardiovascular events.10

Cognitive Reflection, Metacognition, and Impulsivity: System 1 vs. System 2 Processing

Beyond baseline fluid and crystallized intelligence, testosterone significantly dictates how cognitive resources are deployed—specifically, the delicate balance between intuitive, heuristic processing and slow, deliberate analytical reasoning. This cognitive dichotomy is robustly evaluated using the Cognitive Reflection Test (CRT). The CRT relies on "trap" questions intricately designed to elicit a rapid, intuitive, yet mathematically incorrect response (often termed System 1 thinking). To arrive at the correct answer, the subject must actively override their initial cognitive impulse and engage in deliberate, cognitively taxing mathematical calculation (System 2 thinking).25

The classic exemplar of this testing paradigm is the "bat and ball problem": A bat and a ball cost $1.10 in total. The bat costs$1.00 more than the ball. How much does the ball cost? For the vast majority of individuals, the first intuitive answer that comes to mind is that the ball costs 10 cents. However, this is mathematically incorrect, as the bat would then cost $1.10, bringing the total to$1.20. The correct answer requires pausing to calculate that the ball costs 5 cents, and the bat costs $1.05.25

In one of the largest behavioral neuroendocrinology studies of its kind, conducted by researchers at Caltech and the Wharton School, 243 healthy men were randomly administered a dose of exogenous testosterone gel or a placebo prior to taking the CRT.25 The empirical results were profoundly significant: testosterone administration substantially reduced CRT scores.27 Men in the testosterone group were quicker to make snap judgments, submitting the intuitive, incorrect answers at a significantly higher rate than the placebo group.25

Crucially, this cognitive impairment was not due to a lack of mathematical ability. The researchers utilized a separate math task to control for basic arithmetic skills, participant engagement, and motivation levels.25 The effect of testosterone remained statistically robust even after controlling for age, mood, treatment expectancy (whether participants believed they received the hormone), and the concurrent levels of 14 other endogenous hormones.27 Analysis of latency responses (the time spent reasoning before answering) verified the relationship between time spent engaged with the problem and post-decision confidence.26 The data indicated an interaction where participants who received testosterone gave correct answers more slowly than those who received the placebo, demonstrating a significant drag on cognitive reflection.28

The underlying neurocognitive mechanism suggests two distinct pathways. First, acute elevations in testosterone may actively inhibit the error-checking mechanisms of the prefrontal cortex, a phenomenon described as challenging the "unconscious substitution hypothesis".26 Even when interference questions were included, incorrect reasoners largely had accurate recall of the problem's error-inducing semantic content (the "more than" phrase), indicating that the failure was not in reading comprehension but in cognitive override.26 Second, testosterone may artificially inflate the participant's intra-individual post-decision confidence, generating a powerful somatic feeling that their immediate intuitive gut reaction is definitively correct, thereby prematurely terminating the search for alternative solutions.25

From an evolutionary neuroscience perspective, this dynamic is highly logical. In high-stakes, competitive, or dangerous environments—where acute, endogenous spikes in testosterone naturally occur—rapid, decisive action is often prioritized over prolonged analytical hesitation. While this biological mechanism promotes assertiveness and physical dominance, it inadvertently creates a cognitive vulnerability in modern, abstract analytical tasks requiring epistemic rationality. Hence, a high-testosterone state creates a functional trade-off: it optimizes the brain for immediate, confident action at the direct expense of deep, reflective cognitive monitoring.

Emotional Intelligence (EQ) and Cognitive Empathy

Emotional Intelligence (EQ), conceptually defined as the ability to monitor, regulate, and utilize one's own emotions, as well as the capacity to accurately infer the emotional states and complex intentions of others (empathy), is heavily mediated by the endocrine system. The scientific inquiry into how testosterone influences EQ in men has undergone massive paradigm shifts, characterized by replication crises and the overturning of foundational theories, particularly regarding cognitive empathy.

The "Reading the Mind in the Eyes" Test (RMET)

Cognitive empathy—the intellectual capacity to understand another's mental state—is predominantly quantified using the "Reading the Mind in the Eyes" Test (RMET). The RMET is a 36-item advanced assessment of the "theory of mind" that requires participants to look at cropped photographs of the human eye region and identify the complex emotional state or intention of the subject from four multiple-choice words.30 At the population level, females statistically outperform males on the RMET, driving the initial hypothesis that testosterone biologically suppresses empathic capacity.30

Early, highly influential psychoneuroendocrinology studies strongly supported this suppressive hypothesis. Initial placebo-controlled, within-subject experiments—often utilizing extremely small sample sizes, such as 16 women or 30 men—reported that a single administration of exogenous testosterone severely impaired RMET performance, effectively "blinding" individuals to subtle emotional cues.32 These early studies suggested that the detrimental effect of testosterone on empathy was governed by structural changes in functional brain connectivity. Using fMRI, researchers posited that testosterone administration significantly altered connectivity within the left inferior frontal gyrus (IFG), the anterior cingulate cortex (ACC), and the supplementary motor area (SMA).33 This IFG-ACC-SMA network is critical for the integration of sensory information and action preparation during cognitive empathic behavior; thus, its disruption by testosterone was theorized to be the neurological mechanism impairing emotion recognition.33

Furthermore, it was deeply hypothesized that the severity of this cognitive impairment was directly moderated by the participant's prenatal testosterone exposure, as indexed by the 2D:4D digit ratio. Some initial subsample analyses claimed that testosterone administration only reduced cognitive empathy in participants with relatively low (more masculine) left-hand 2D:4D ratios, cementing the theory that prenatal priming dictates adult endocrine responsiveness.32

The Replication Crisis and the Nave et al. (2019) Consensus

Despite the profound theoretical impact of the initial RMET studies—which heavily influenced public perception of testosterone as an "anti-empathy" hormone—the premise that testosterone directly impairs cognitive empathy in neurotypical men was ultimately destabilized by superior statistical methodologies. In 2019, a massive, double-blind, placebo-controlled replication study conducted by Nave et al. fundamentally rewrote the academic consensus.

This landmark investigation involved 643 healthy men across two independent randomized experiments—representing a sample size roughly 15 to 25 times larger than the original, highly publicized studies.32 The empirical results were unequivocal: testosterone administration yielded no causal impairment on cognitive empathy.32 Furthermore, the study found absolutely no evidence that RMET scores were associated with or moderated by 2D:4D digit ratios, definitively severing the hypothesized link between prenatal androgen priming and adult empathic responsiveness to exogenous testosterone.32

The Nave et al. study demonstrated that previous investigations of this topic were statistically underpowered, often operating with a statistical power of less than 0.3.32 Because the RMET and the 2D:4D ratio are inherently noisy psychometric measures, small sample sizes routinely generated inconsistent or false-positive results that failed to replicate in robust trials.36

Subsequent neuroimaging and neuroendocrine replications have corroborated this behavioral shift. Research from 2022 demonstrated that relative to placebo administration, testosterone administration does not alter the canonical functional brain activity supporting cognitive or affective empathy in men.37 Furthermore, large-scale studies utilizing the Toronto Structured Interview for Alexithymia and the Bermond–Vorst Alexithymia Questionnaire failed to find the previously claimed testosterone-induced dysregulations in the inferior frontal and temporal gyri during RMET execution.38 The modern consensus recognizes that testosterone does not biologically erode a man's capacity to read the mental states of others.32

Empirical Parameter	Early Research Paradigm (Pre-2019)	Modern Consensus Paradigm (Post-2019)
Experimental Sample Sizes	Extremely small and statistically underpowered (e.g., N=16 to N=30).32	Exceptionally large, highly powered RCTs (e.g., N=643).32
Effect on Cognitive Empathy	Strong causal impairment of RMET scores.32	No causal effect; true empathic decoding ability remains intact.32
Role of 2D:4D Ratio	Hypothesized to heavily moderate the severity of adult testosterone impairment.33	No moderation; prenatal priming hypothesis regarding adult empathy is unsubstantiated.32
Neural Substrates (fMRI)	Diminishes functional connectivity in empathy networks (IFG-ACC-SMA).33	Canonical affective and cognitive empathy networks remain functionally unaltered.37

The Amygdala, Prefrontal Cortex, and Emotional Regulation

While exogenous testosterone may not degrade baseline cognitive empathy, endogenous testosterone plays a highly sophisticated, localized role in the real-time regulation of socio-emotional behavior. EQ is not solely about recognizing emotions in others; it fundamentally requires the executive cognitive control to modulate one's own affective reactions to intense social stimuli.

Neuroimaging utilizing resting-state functional connectivity (rsFC) and task-based fMRI highlights the amygdala as a central hub for emotional vigilance. The amygdala is uniquely rich in androgen receptors, making it highly susceptible to testosterone modulation.39 Research measuring long-term Hair Testosterone Concentrations (HTC)—which provide a more stable biomarker than acute salivary or serum levels—reveals that high baseline levels of testosterone in men correspond to an increased salience perception of emotional stimuli.39 When viewing emotionally evocative imagery, individuals with high HTC generate heightened hemodynamic Blood-Oxygen-Level-Dependent (BOLD) responses in the right insula (when processing negative pictures) and the left and right orbitofrontal cortex (OFC) (when processing positive pictures).39 This equates to a state of heightened emotional vigilance.

However, the behavioral manifestation of this vigilance is heavily modulated by the prefrontal cortex (PFC), specifically the dorsolateral prefrontal cortex (DLPFC) and the ventrolateral prefrontal cortex (VLPFC). During affect-incongruent tasks—such as a social approach-avoidance task where a participant must suppress the automatic urge to avoid an angry face and force an "approach" joystick response instead—the brain must actively override automatic emotional reflexes.42 This cognitive override generates intense metabolic activity at the border of the VLPFC and the frontal pole (VLPFC/FP).42

Endogenous testosterone modulates this critical process of emotional regulation via two specific neural pathways:

1. Local Prefrontal Activity: Men with lower endogenous testosterone levels must generate substantially larger VLPFC/FP neurovascular responses to successfully override automatic emotional tendencies. This implies that low testosterone forces the prefrontal cortex to work significantly harder to exert top-down emotional control over the amygdala.42
2. Effective Connectivity: Testosterone directly dictates the dynamic coupling between the prefrontal cortex and the amygdala. Men with high endogenous testosterone demonstrate a positive coupling between the VLPFC/FP and the amygdala during emotional overriding, effectively integrating cognitive control with emotional arousal. Conversely, men with low testosterone exhibit a negative or completely decreased coupling connection during these affect-incongruent conditions.40

Furthermore, EEG studies utilizing incongruent trials of the flanker task (e.g., when the target face is happy) show that testosterone levels are negatively correlated with response accuracy and positively correlated with N2 latency, suggesting that high testosterone can briefly delay the neuro-electrical processing of conflicting emotional information.45 Similarly, in Stroop tasks involving fearful facial expressions, testosterone negatively correlates with the difference in accuracy between congruent and incongruent trials.45

Across the whole sample resting-state functional connectivity (rsFC), higher testosterone is also associated with stronger connectivity between the right amygdala and the right middle occipital gyrus (MOG), predicting specific personality facets.40 These findings illuminate how testosterone functions as a context-dependent bridge between subcortical affect (the amygdala) and cortical rationality (the PFC). Rather than merely dulling EQ, appropriately balanced testosterone optimizes the specific neurocircuitry required to exert deliberate control over emotional reflexes.

The Dual-Hormone Hypothesis: Cortisol as the Endocrine Gatekeeper

A critical methodological failure in early behavioral endocrinology was attempting to analyze the effects of testosterone in an endocrine vacuum. The functional behavioral output of testosterone—particularly regarding EQ, emotional regulation, empathy, and status-seeking behavior—is not determined solely by the androgen itself. Instead, it is fundamentally gated by the concurrent concentration of cortisol, the body's primary glucocorticoid stress hormone. This vital interaction is codified in the Dual-Hormone Hypothesis.46

The dual-hormone hypothesis posits that cortisol acts as an active inhibitor of the androgen receptor system. Therefore, the psychological and behavioral traits traditionally associated with high testosterone—assertiveness, leadership, social dominance, risk-tolerance, high emotional intelligence, and low emotional distress—only reliably manifest when cortisol levels are simultaneously low.46

When cortisol levels are high (indicating acute psychosocial or systemic biological stress), the neural and behavioral pathways of testosterone are biochemically blocked.48 Consequently, a man presenting with high testosterone but concurrently high cortisol will not exhibit dominant, confident, or emotionally intelligent leadership behaviors. Instead, his decision-making profile shifts heavily toward risk aversion, and he may experience paradoxically elevated personal distress during social evaluations.46

This interplay fundamentally dictates complex decision-making paradigms, such as the Iowa Gambling Task (IGT). In male participants, the dual regulation of these hormones navigates decision-making during phases of uncertainty and risk; high cortisol impairs decision-making in uncertainty phases, whereas testosterone benefits risk-phase decisions only when cortisol's inhibitory effect is absent.46 Furthermore, psychosocial stress profoundly modulates how testosterone influences prosocial behavior and empathic stress. In highly stressful situations, elevated cortisol combined with testosterone can alter heart rate variability (HRV) and interact with oxytocin reactivity, meaning that empathic resonance—the ability to physically share another's stress—fluctuates based on the observer's hormonal stress profile rather than their baseline testosterone alone.51

Implications for Collective EQ and Group Leadership

The profound intersection of testosterone, cortisol, and EQ is particularly pronounced when analyzing group dynamics and collective performance. Moving beyond individual profiling, researchers analyze the "collective hormonal profile" of working groups. Groups comprised of individuals possessing a biological profile of high testosterone and low cortisol routinely exhibit the highest levels of performance and optimal profit-maximizing decision-making.50

This specific hormonal configuration facilitates a psychological state of "relaxed dominance." The high testosterone provides the biological drive for social standing, appropriate emotional connectedness, and assertiveness, while the low cortisol ensures a reduction in stress-axis activity, preventing the emotional hijackings and interpersonal friction that destroy group cohesion.48 Interestingly, dynamic tests reveal that if a leader experiences an acute, positive change in testosterone coupled with a negative change (drop) in cortisol, they might experience increased personal distress. However, researchers question whether this distress strictly represents a shortcoming in emotional intelligence or a necessary, adaptive physiological vigilance mechanism during acute leadership transitions.47

Attempting to predict a man’s EQ, resilience, or cognitive control solely by measuring his testosterone is scientifically inadequate. The regulatory power of testosterone is intrinsically reliant on the permissive, low-stress neurochemical environment dictated by the hypothalamic-pituitary-adrenal (HPA) axis. Furthermore, this delicate hormonal balance is highly susceptible to external confounding variables. Substances such as caffeine can have dose-dependent effects on testosterone (with some studies showing increases and others showing negative associations with caffeine metabolites), while viral infections and gut dysbiosis can severely disrupt the endocrine equilibrium, subsequently altering cognitive and emotional baselines.51

Reassessing Autism, Gender Dysphoria, and Neurodevelopmental Theories

The comprehensive reevaluation of testosterone's effect on empathy and cognitive processing has generated intense academic scrutiny and direct ramifications for clinical theories of neurodevelopment. Most notably, the "Extreme Male Brain" (EMB) theory of autism spectrum disorder (ASD) has faced significant methodological challenges in the 2020s.

Championed by researchers such as Simon Baron-Cohen, the EMB theory conceptualizes human cognition along two highly sexually dimorphic axes: "systemizing" (the drive to analyze, explore, and construct rules-based systems, statistically favoring males) and "empathizing" (the drive to identify and appropriately respond to others' mental states, statistically favoring females).31 According to the EMB framework, autism represents a hyper-masculinized cognitive profile characterized by extreme systemizing and severely diminished empathizing. This cognitive phenotype is ostensibly driven by abnormally high fetal testosterone exposure, which organizes the brain into an extreme manifestation of typical male cognition.31 Individuals with ASD routinely exhibit severe deficits on the RMET, displaying what researchers previously termed an "extreme typical male pattern".30

However, as robust, high-powered replication evidence emerges demonstrating that testosterone does not actually impair cognitive empathy in neurotypical men, the foundational premise of the EMB theory has been profoundly destabilized. Modern neurodevelopmental reviews consistently criticize the EMB theory for lacking uniform anatomical evidence linking ASD specifically to extreme male brain development.56 Furthermore, the theory struggles to account for the increasing intersectionality observed in clinical psychiatry, particularly the high co-occurrence of ASD and Gender Dysphoria (GD) in adolescents.57

In clinical settings, it has been noted that the extreme male brain theory appears primarily applicable only to individuals Assigned Female at Birth (AFAB) experiencing GD, and fails to adequately explain the etiology in individuals Assigned Male at Birth (AMAB).57 Consequently, alternative theoretical frameworks are rapidly gaining traction as they provide superior explanatory power for the phenotypic diversity of ASD.

1. The Imprinted Brain Theory: This model stands in direct opposition to the EMB theory, stipulating that autism is the result of exaggerated paternal gene expression and genomic imprinting, rather than exaggerated androgenic virilization.56
2. Sensory Processing Theory: This framework posits that the core deficits of ASD are rooted in the integration of sensory stimuli. For instance, in AMAB individuals with co-occurring ASD and GD, symptoms are frequently associated with unpleasant tactile sensations caused by male body hair, making sensory processing theory more clinically applicable than androgen-based theories.57
3. Obsession and Resistance Theories: Psychological explanations focusing on the nature of clinical obsession and a biological resistance to social norms have proven more robust in accounting for the correlation between ASD and GD across both sexes.57

While prenatal testosterone undeniably shapes general neurodevelopment, reducing complex spectrum conditions like autism to an "overdosed male brain" is now viewed by modern psychiatry as overly reductive. The highest-powered neuroendocrinological data confirms that sex differences in cognition may not be as substantial as required to support the EMB hypothesis, and psychometric tools may be inherently biased toward topics that boys are merely socialized to use.36 Finally, the administration of high-dose testosterone treatments in transgender people has been shown to actively increase serotonin transporter binding, suggesting that exogenous androgens interact with monoamine systems in ways that fundamentally alter mood and social cognition outside the simplistic bounds of the EMB model.24

Conclusion

The intersection of neuroendocrinology and cognitive psychology reveals that testosterone acts as a fundamental architectural architect in utero and a highly complex, context-dependent modulator in adulthood. The relationship between testosterone and the intelligence quotient (IQ) demonstrates that fluid intelligence and spatial abstraction require precise physiological calibration. Moderate levels of testosterone support peak cognitive processing, while both hypogonadal and supraphysiological states actively degrade performance, resulting in an inverted U-shaped dynamic. Moreover, the decline of bioavailable testosterone in aging populations serves as a potent, predictive biomarker for cognitive decline, positioning androgen maintenance and substitution therapy as critical factors in neuroprotection against memory degradation, Alzheimer's pathology, and spatial deterioration.

In the realm of emotional intelligence (EQ) and executive function, the paradigm has shifted dramatically. Exogenous testosterone exerts its influence not by permanently degrading a man's capacity for cognitive empathy—a notion thoroughly debunked by modern, high-powered statistical replications like the Nave et al. mega-trial—but by altering real-time cognitive strategies and emotional latency. Acute elevations in testosterone actively suppress slow, deliberate cognitive reflection in favor of rapid, intuitive heuristic processing, optimizing the brain for decisive action over meticulous analysis. Furthermore, endogenous testosterone dictates the functional connectivity between the prefrontal cortex and the amygdala, governing the neural efficiency with which a man can consciously override powerful affective impulses.

Ultimately, testosterone operates within an interdependent, highly sensitive endocrine network. Its biological capacity to facilitate optimal social cognition, emotional regulation, and effective leadership is inherently gated by cortisol. Recognizing this dual-hormone dynamic, alongside the non-linear dose-response curves of fluid intelligence and the refutation of the Extreme Male Brain theory, marks a definitive departure from archaic, reductive models of testosterone as a simple "masculinizing" or "anti-social" agent. Instead, it must be understood as a highly sophisticated neuromodulator, intricately linking systemic physiological states to the apex functions of human intellect and emotional control.

Works cited

1. Fluid Intelligence Test Scores Across the Schooling: Evidence of Nonlinear Changes in Girls and Boys, accessed April 6, 2026, https://changing-sp.com/ojs/index.php/csp/article/view/345
2. Fluid and crystallized intelligence - Wikipedia, accessed April 6, 2026, https://en.wikipedia.org/wiki/Fluid_and_crystallized_intelligence
3. Perceived Intelligence Is Associated with Measured Intelligence in Men but Not Women | PLOS One, accessed April 6, 2026, https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0081237
4. Curvelinear correlations between total testosterone levels and fluid intelligence in men and women - PubMed, accessed April 6, 2026, https://pubmed.ncbi.nlm.nih.gov/9845018/
5. The curvelinear correlations between the total testosterone levels and fluid intelligence in men and women - PubMed, accessed April 6, 2026, https://pubmed.ncbi.nlm.nih.gov/9622799/
6. Curvelinear Correlations Between Total Testosterone Levels and Fluid Intelligence in Men and Women - ResearchGate, accessed April 6, 2026, https://www.researchgate.net/publication/13661315_Curvelinear_Correlations_Between_Total_Testosterone_Levels_and_Fluid_Intelligence_in_Men_and_Women
7. High Testosterone Is Correlated With Higher Fluid, Verbal, spatial Intelligence and IQ. : r/UnpopularFacts - Reddit, accessed April 6, 2026, https://www.reddit.com/r/UnpopularFacts/comments/x7h0yy/high_testosterone_is_correlated_with_higher_fluid/
8. Testosterone and nonverbal intelligence in right-handed men with successful and unsuccessful educational levels - PubMed, accessed April 6, 2026, https://pubmed.ncbi.nlm.nih.gov/11913330/
9. Effects of Testosterone Therapy on Cognitive Function in Aging: A Systematic Review - PMC, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC5079177/
10. Testosterone and Cognitive Function: Protecting Your Brain After 60 -, accessed April 6, 2026, https://goldmanlaboratories.com/blogs/blog/testosterone-brain-function
11. Testosterone and cognitive function : European Journal of ... - Ovid, accessed April 6, 2026, https://www.ovid.com/00023063-200655060-00001
12. Testosterone and cognitive function: current clinical evidence of a relationship - Millennium Wellness Center, accessed April 6, 2026, https://www.hormonebalance.org/images/documents/Beauchet%2006%20Testosterone%20Cognitive%20Function%20EJE.pdf
13. The Curvelinear Correlations Between the Total Testosterone Levels and Fluid Intelligence in Men and Women - ResearchGate, accessed April 6, 2026, https://www.researchgate.net/publication/13442754_The_Curvelinear_Correlations_Between_the_Total_Testosterone_Levels_and_Fluid_Intelligence_in_Men_and_Women
14. The relationship between testosterone levels and cognitive ability patterns - PubMed, accessed April 6, 2026, https://pubmed.ncbi.nlm.nih.gov/1745699/
15. Testosterone and the Brain: From Cognition to Autism - PMC, accessed April 6, 2026, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8603719/
16. 2D:4D Ratio and its Implications in Medicine - PMC, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC5296424/
17. The ratio of the 2(nd) to 4(th) finger length predicts spatial ability in men but not women, accessed April 6, 2026, https://www.researchgate.net/publication/7418629_The_ratio_of_the_2nd_to_4th_finger_length_predicts_spatial_ability_in_men_but_not_women
18. The relationship between digit ratio (2D:4D) and intelligence levels in specific learning disorders - PubMed, accessed April 6, 2026, https://pubmed.ncbi.nlm.nih.gov/39084185/
19. The association between the 2D:4D ratio and psychopathic characteristics - PMC, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC9792753/
20. Excess Neonatal Testosterone Causes Male-Specific Social and Fear Memory Deficits in Wild-Type Mice | eNeuro, accessed April 6, 2026, https://www.eneuro.org/content/12/8/ENEURO.0020-25.2025
21. Low Serum Testosterone Concentrations Are Associated With Poor Cognitive Performance in Older Men but Not Women - PMC, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC8591394/
22. Low Serum Testosterone Concentrations Are Associated With Poor Cognitive Performance in Older Men but Not Women - Frontiers, accessed April 6, 2026, https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2021.712237/full
23. Associations between Serum Testosterone Fall and Cognitive Function in Prostate Cancer Patients - AACR Journals, accessed April 6, 2026, https://aacrjournals.org/clincancerres/article/10/22/7575/185355/Associations-between-Serum-Testosterone-Fall-and
24. On the effects of testosterone on brain behavioral functions - PMC, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC4330791/
25. Testosterone Makes Men Less Likely to Question Their Impulses - www.caltech.edu, accessed April 6, 2026, https://www.caltech.edu/about/news/testosterone-makes-men-less-likely-question-their-impulses-55864
26. The Bat-and-Ball Problem: Stronger evidence in support of a conscious error process - PMC, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC6800670/
27. Single-Dose Testosterone Administration Impairs Cognitive Reflection in Men - PubMed, accessed April 6, 2026, https://pubmed.ncbi.nlm.nih.gov/28771393/
28. (PDF) Single-Dose Testosterone Administration Impairs Cognitive Reflection in Men, accessed April 6, 2026, https://www.researchgate.net/publication/316001989_Single-Dose_Testosterone_Administration_Impairs_Cognitive_Reflection_in_Men
29. Study Shows Men Make Bad Decisions Because of Testosterone - Inverse, accessed April 6, 2026, https://www.inverse.com/science/30979-study-testosterone-bad-decisions
30. The “Reading the Mind in the Eyes” Test: Complete Absence of Typical Sex Difference in ~400 Men and Women with Autism | PLOS One, accessed April 6, 2026, https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136521
31. Men and women with autism have 'extreme male' scores on the 'Eyes test' of mindreading, accessed April 6, 2026, https://www.cam.ac.uk/research/news/men-and-women-with-autism-have-extreme-male-scores-on-the-eyes-test-of-mindreading
32. Does testosterone impair men's cognitive empathy? Evidence from two large-scale randomized controlled trials | Proceedings B | The Royal Society, accessed April 6, 2026, https://royalsocietypublishing.org/rspb/article/286/1910/20191062/85244/Does-testosterone-impair-men-s-cognitive-empathy
33. Testosterone levels impair emotion-recognition ability during test - Salimetrics, accessed April 6, 2026, https://salimetrics.com/testosterone-levels-impair-emotion-recognition-ability-during-test/
34. Does testosterone impair men's cognitive empathy? Evidence from two large-scale randomized controlled trials - PMC, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC6742992/
35. Testosterone reduces functional connectivity during the 'Reading the ..., accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC6345363/
36. Does testosterone impair men's cognitive empathy? Evidence from ..., accessed April 6, 2026, https://royalsocietypublishing.org/doi/10.1098/rspb.2019.1062
37. Testosterone administration does not alter the brain activity supporting cognitive and affective empathy - ResearchGate, accessed April 6, 2026, https://www.researchgate.net/publication/359689918_Testosterone_administration_does_not_alter_the_brain_activity_supporting_cognitive_and_affective_empathy
38. fMRI study on alexithymia and affective state recognition in the Reading the Mind in the Eyes Test - Oxford Academic, accessed April 6, 2026, https://academic.oup.com/scan/article/19/1/nsae058/7747398
39. Increased neural reactivity to emotional pictures in men with high hair testosterone concentrations - PMC, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC6917022/
40. Testosterone and the Amygdala's Functional Connectivity in Women ..., accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC10607739/
41. (PDF) Testosterone and the Amygdala's Functional Connectivity in Women and Men, accessed April 6, 2026, https://www.researchgate.net/publication/374722131_Testosterone_and_the_Amygdala's_Functional_Connectivity_in_Women_and_Men
42. Endogenous Testosterone Modulates Prefrontal-Amygdala Connectivity during Social Emotional Behavior - Sci-Hub, accessed April 6, 2026, https://sci-hub.box/10.1093/cercor/bhr001
43. Endogenous Testosterone Modulates Prefrontal–Amygdala ..., accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC3169658/
44. Endogenous Testosterone Modulates Prefrontal–Amygdala Connectivity during Social Emotional Behavior | Cerebral Cortex | Oxford Academic, accessed April 6, 2026, https://academic.oup.com/cercor/article-abstract/21/10/2282/327359
45. The Relationships Among Testosterone, Cortisol, and Cognitive ..., accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC6928062/
46. Role of Cortisol and Testosterone in Risky Decision-Making: Deciphering Male Decision-Making in the Iowa Gambling Task - Frontiers, accessed April 6, 2026, https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2021.631195/full
47. Leader emergence and affective empathy: A dynamic test of the dual-hormone hypothesis, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC7773240/
48. Testosterone and Successful Careers: The Surprising Connection - Maximus, accessed April 6, 2026, https://www.maximustribe.com/resources/testosterone-career
49. Testosterone and self-confidence: How hormones influence our social behavior - Adon Health, accessed April 6, 2026, https://adon-health.de/en/blogs/testosteron/testosteron-und-selbstvertrauen-wie-hormone-unser-soziales-verhalten-beeinflussen
50. Collective hormonal profiles predict group performance - PMC, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC5024601/
51. Understanding the Secular Decline in Testosterone: Mechanisms, Consequences, and Clinical Perspectives - PMC, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC12841019/
52. A pilot study: saliva oxytocin and testosterone in empathic stress responding - medRxiv, accessed April 6, 2026, https://www.medrxiv.org/content/10.1101/2025.11.28.25341194v1.full.pdf
53. Fetal testosterone and empathy: evidence from the empathy quotient (EQ) and the "reading the mind in the eyes" test - PubMed, accessed April 6, 2026, https://pubmed.ncbi.nlm.nih.gov/18633782/
54. Autism in the broader context of cognitive sex differences - PNAS, accessed April 6, 2026, https://www.pnas.org/doi/10.1073/pnas.1817772115
55. Professor Simon Baron-Cohen - Cambridge Neuroscience, accessed April 6, 2026, https://neuroscience.cam.ac.uk/member/sb205/
56. Unique models of embodied cognition and eco-social niches proposed to validate hypothesis of social attunement and mis-attunement with a focus on autism - Frontiers, accessed April 6, 2026, https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2025.1562061/full
57. Gender Dysphoria and Related Symptoms in Autism Spectrum Disorder: A Bilingual Review of the Literature - MDPI, accessed April 6, 2026, https://www.mdpi.com/2076-3425/14/12/1202
58. The Long and Winding Road to Understanding Autism - PMC, accessed April 6, 2026, https://pmc.ncbi.nlm.nih.gov/articles/PMC12452603/