Sex Characteristics of Systolic Blood Pressure Behavior

William Moulton Marston's 1923 paper in the Journal of Experimental Psychology investigates whether biological sex moderates systolic blood pressure responses to deception, arguing that female participants display more pronounced and diagnostically distinct blood pressure elevations when lying compared to male participants. The study represents one of the earliest empirical explorations of individual-difference variables in psychophysiological deception detection, building directly on Marston's foundational work developing the systolic blood pressure test from 1915 onward.

Using a discontinuous systolic blood pressure measurement technique — a standard blood pressure cuff and sphygmomanometer with manual readings at set intervals — Marston compared physiological responses to structured deceptive and truthful questioning across male and female participant groups in a controlled laboratory paradigm.

Published in the same year as the landmark Frye v. United States ruling that excluded polygraph evidence, this study represented Marston's effort to broaden the empirical base of his systolic blood pressure deception test. The research systematically compared cardiovascular responses between male and female participants during controlled deceptive and truthful questioning using his discontinuous blood pressure measurement technique. This work built upon earlier observations by Elizabeth Holloway Marston about emotion-driven blood pressure changes and aimed to determine whether deception-linked physiological responses were uniform across sexes. The study contributed to the theoretical foundation of deception detection by profiling baseline blood pressure patterns for each sex and tracking deception-related elevations.

This early investigation of individual differences in physiological deception responses laid groundwork for understanding how demographic factors might influence polygraph accuracy and interpretation in both research and applied settings.

Background & Context

By the early 1920s, the question of whether physiological signals could reliably expose deception was no longer purely theoretical — it had become an urgent scientific and legal problem. The idea of using psychophysiological recordings — in particular, systolic blood pressure — to measure deception in laboratory and legal settings can be traced primarily to William Moulton Marston, largely developed while he was a graduate student at Harvard University from 1915 to 1921. His 1923 paper, "Sex Characteristics of Systolic Blood Pressure Behavior," published in the Journal of Experimental Psychology (Vol. 6, pp. 387–419), pushed that inquiry into entirely new terrain: the question of whether biological sex moderated blood pressure responses to deception.

This was a significant expansion of Marston's earlier deception work. Marston was the creator of the systolic blood pressure test, which became one component of the modern polygraph. His wife, Elizabeth Holloway Marston, had suggested the connection between emotion and blood pressure, observing that "when she got mad or excited, her blood pressure seemed to climb." The 1923 paper can be understood as a systematic attempt to investigate whether that emotionally-driven cardiovascular response was uniform across sexes — or whether women and men produced characteristically different blood pressure signatures when deceiving.

The publication appeared in the same year as the landmark Frye v. United States ruling, which excluded Marston's polygraph testimony from a murder trial on the grounds that the systolic blood pressure test had not yet gained sufficient scientific acceptance. Ultimately, Frye v. United States (1923) was a huge setback for the lie detector's scientific legitimacy — a problem that would continue to plague the polygraph nearly a century later. In this turbulent context, Marston's sex-characteristics study represented both a broadening of the empirical base and an effort to deepen the theoretical grounding of deception detection.

Research Design & Methodology

Marston's investigative method for this study was grounded in the same core instrument he had refined since 1915: the discontinuous systolic blood pressure measurement technique. This technique used a standard blood pressure cuff and a stethoscope to take intermittent readings of the systolic blood pressure of a subject during an examination in order to detect deception. Rather than recording physiological signals continuously — as Larson's later polygraph would do — Marston manually plotted blood pressure readings at discrete intervals during structured questioning.

The 1923 paper extended this paradigm by systematically comparing responses across male and female participants under controlled deceptive and truthful conditions. Participants were subjected to standardized questioning protocols designed to elicit both truthful responses and deliberate deception. Marston's approach allowed him to profile baseline blood pressure patterns for each sex and then track deception-linked elevations relative to those baselines. Key design elements included:

• Discontinuous sphygmomanometric measurement — manual blood pressure readings at set intervals during questioning
• Comparative sex-group analysis — male and female participants tested under matched conditions
• Controlled deception paradigm — participants instructed to lie about specific stimuli or events
• Laboratory and applied settings — Marston drew on experience from both Harvard laboratory experiments and real criminal case testing
• Baseline and reactive measurement — resting systolic pressure compared to pressure during deceptive responses

Marston had begun working on his blood pressure approach to deception in 1915 as a graduate student under the direction of Hugo Münsterberg in the Harvard Psychological Laboratory. By 1923, this represented nearly a decade of methodological refinement, giving the study considerably more procedural maturity than his earliest publications.

Results & Key Findings

The central finding of the 1923 paper was that female participants displayed more pronounced and reliable systolic blood pressure elevations during deception than their male counterparts — a result that Marston interpreted as evidence of sex-based differences in the psychophysiological signature of lying. This claim was sensational by the standards of the era and was widely discussed in popular culture as well as scientific circles.

Fascinated by the theory that women are the more honest sex, Marston and his wife Elizabeth conducted a series of experiments that indicated men were less reliable subjects in certain respects. Within the framework of the 1923 paper, this translated into an argument that women's blood pressure responses were both larger in magnitude and more diagnostically distinct — meaning that the gap between truthful and deceptive blood pressure readings was cleaner and more interpretable in female subjects.

Key outcomes from the paper included:

• Greater deception-linked BP elevation in women — female participants showed stronger systolic pressure increases when lying compared to male participants
• Higher diagnostic clarity in female responses — the truthful/deceptive contrast in systolic pressure was reported as more consistent among women
• Male responses as more variable — men's blood pressure patterns during deception showed greater individual variability, complicating detection
• Broader emotional reactivity in women — Marston linked his findings to a general theory of female emotional expressivity via autonomic pathways
• Confirmation of systolic BP as deception indicator — across both sexes, significant blood pressure changes accompanied deliberate lying relative to truthful answers

The paper also reported on Marston's broader accuracy data accumulated across criminal case testing. According to Marston, he and his colleagues tested a total of 100 criminal cases in Boston criminal court, and his systolic blood pressure test led to correct determinations in 97 of them. While this 97% accuracy claim was associated with his broader body of work rather than exclusively with the sex-characteristics study, it formed the evidentiary backdrop against which the 1923 paper's sex-differentiated findings were presented.

Discussion & Significance

The significance of this paper operates on multiple levels. Most immediately, it was among the first empirical attempts to treat biological sex as a moderating variable in psychophysiological deception detection — a conceptual step that anticipated modern discussions of individual differences in polygraph validity. Today, researchers continue to debate whether demographic and physiological variables influence detection accuracy, making Marston's framing of the question genuinely prescient even if his methods were primitive.

The paper also sits at a pivotal historical moment. William Marston's work on how deception affects systolic blood pressure formed the foundations for John A. Larson's research and prototyping of his lie detector device in the early 1920s. Larson re-engineered Marston's ideas, creating a device nicknamed the "Sphyggy" by the media, and incorporated Marston's work on systolic blood pressure monitoring with pulse and respiration rates in his device. The 1923 paper appeared simultaneously with Larson's own contribution to the same issue of the Journal of Experimental Psychology, creating a remarkable moment of parallel scientific publication in early polygraph history.

Marston's claim that women were more psychophysiologically detectable liars was widely cited in popular discourse throughout the 1920s and 1930s. Marston was the first to attempt to have instrumental deception test results entered into evidence in court, which resulted in the Frye decision of 1923. His publicity-conscious approach to science — including popular magazine appearances and commercial endorsements — meant that the sex-characteristics findings permeated American public culture far beyond the readership of the Journal of Experimental Psychology.

Limitations & Considerations

By modern standards, the 1923 study carries substantial methodological limitations that substantially constrain the generalizability of its conclusions. The most critical include:

• Absence of blinded evaluation — Marston both administered the test and interpreted the results, creating significant experimenter bias risk
• Discontinuous measurement method — manual, intermittent blood pressure readings are far less sensitive and reliable than the continuous tracings enabled by later instruments
• No standardized questioning protocol published — the absence of a fully documented, reproducible questioning procedure makes replication impossible
• Sex as a binary construct — the study treated male and female as exhaustive, unambiguous categories, ignoring hormonal, social, and individual variability within each group
• Contemporary scientific skepticism — even at the time of publication, critics noted that blood pressure elevations could reflect emotional arousal, cognitive load, or social anxiety rather than deception per se

Larson maintained a skeptical view regarding the polygraph's effectiveness in accurately diagnosing deception. His concerns stemmed from the variability in interpreting physiological data and the psychological pressures surrounding the testing process. These same concerns applied directly to Marston's technique, and they remain relevant to any interpretation of the 1923 findings.

Practical Applications

While the specific sex-differentiated conclusions of the 1923 paper have not been validated by modern controlled research and should not be applied directly to contemporary polygraph practice, the study's broader contribution is substantial. It established the intellectual precedent for investigating individual and demographic differences in physiological deception indicators — a line of inquiry that informs ongoing research into examiner calibration, baseline setting, and subgroup validity in modern polygraph administration.

Marston's test entailed the use of a conventional blood pressure cuff and sphygmomanometer with which he manually plotted the examinee's blood pressure during questioning at several points during the interview. His work represented some of the early approaches to lie detection, though it could not be considered polygraphy as it is now understood. For contemporary practitioners, the study is best understood as a foundational historical artifact — one that documents both the ambitions and the limitations of the field's earliest scientific era, and that reminds examiners why the standardization, instrumentation, and blinded scoring systems of modern polygraph methodology exist.