Detection of deception as a function of galvanic skin response recording methodology

This 1972 laboratory study by Moroney and Zenhausern compared different galvanic skin response (GSR) recording methodologies to determine their relative effectiveness in deception detection. The research examined whether constant voltage versus constant current recording techniques yielded differential detection accuracy, addressing important methodological questions during a formative period in polygraph psychophysiology.

Experimental laboratory study comparing different exosomatic GSR recording methodologies (constant voltage vs. constant current techniques) in a controlled deception detection paradigm, likely using mock crime or concealed information scenarios with participants of known ground truth status.

Background & Context

In the early 1970s, polygraph research was grappling with fundamental methodological questions about the optimal ways to measure electrodermal activity for deception detection. The Moroney and Zenhausern (1972) study emerged during a pivotal period when researchers were systematically comparing different physiological recording techniques to determine which methods yielded the most reliable and valid indicators of deception.

At this time, more than 1500 articles on electrodermal activity had been published in professional publications by 1972, yet significant technical debates remained unresolved. The galvanic skin response (GSR) had become a cornerstone measure in polygraph testing, but questions persisted about whether different recording methodologies—particularly constant voltage versus constant current techniques—produced equivalent or differential results in deception detection contexts.

The study represented part of a broader research effort, as it was based on Moroney's 1969 doctoral dissertation at St. John's University. This research addressed a critical gap: while laboratory researchers almost universally found GSR to be superior to other physiological measures, field practitioners often reported inconsistent results, raising questions about whether methodological variations in recording techniques might explain these discrepancies.

Research Design & Methodology

The study employed an experimental approach comparing different galvanic skin response recording methodologies in a deception detection paradigm. Based on the technical literature of the period, the research likely compared exosomatic recording methods—those involving application of external current to measure skin conductance or resistance.

The two primary methodologies under investigation were:

• Constant voltage technique: A steady voltage (typically around 0.5 volts) applied between electrodes, with changes in current flow reflecting alterations in skin conductance
• Constant current technique: A steady weak current passed through the skin, with voltage changes measured to assess skin resistance variations
• Standard laboratory deception paradigm, likely involving mock crime or concealed information scenarios typical of early 1970s research
• Comparison of detection accuracy and response characteristics across different recording methods

The experimental design would have followed conventions established by researchers like Lykken, Orne, and others working on deception detection methodology during this era. Participants likely engaged in laboratory tasks where ground truth (guilty vs. innocent) was known to experimenters, allowing for objective assessment of detection accuracy under each recording condition.

Results & Key Findings

While the specific statistical outcomes are not available in accessible sources, the study's findings contributed to the methodological literature on GSR recording techniques in polygraph applications. The research examined whether the choice between constant voltage and constant current recording methods significantly affected deception detection accuracy.

Key areas of investigation likely included:

• Comparative detection accuracy rates between constant voltage and constant current recording methods
• Signal-to-noise ratios and measurement reliability across different recording techniques
• Response amplitude characteristics and their relationship to deceptive vs. truthful responses
• Practical considerations for field application of different recording methodologies

The study's publication in The Journal of Psychology (volume 80, pages 255-261) and its citation in subsequent authoritative reviews—including the 1983 Office of Technology Assessment report on polygraph validity—indicates that the findings were considered methodologically significant. The research contributed to ongoing debates about standardization of polygraph instrumentation and recording protocols.

Discussion & Significance

This research addressed a fundamental question in psychophysiological measurement: do different recording methodologies for the same underlying physiological response yield equivalent information for deception detection? This question had both theoretical and practical implications for the polygraph field, which was seeking greater standardization and scientific rigor in the 1970s.

The study's importance lies in its contribution to measurement standardization. Later research established that exosomatic recording with direct current became the most widely applied methodology, suggesting that empirical studies like Moroney and Zenhausern's helped establish best practices. The findings likely informed decisions about which recording techniques should be adopted as standard practice in both research and field applications.

From a broader psychophysiology perspective, the research contributed to understanding how methodological choices affect measurement validity. This work paralleled contemporaneous research by investigators like Thackray and Orne, who were systematically comparing different physiological measures (GSR, skin potential response, cardiovascular measures) to determine optimal detection indices.

Limitations & Considerations

As a laboratory study from the early 1970s, this research would have faced several inherent limitations common to analog-era psychophysiological research. Laboratory conditions, while allowing for experimental control, may not fully replicate the psychological dynamics of real-world deception scenarios where consequences are genuine and motivation levels differ substantially.

Technical limitations of 1970s instrumentation would have constrained measurement precision compared to modern digital systems. Electrode technology, amplifier characteristics, and recording fidelity were all less sophisticated than contemporary standards, potentially affecting both absolute accuracy rates and the ability to detect subtle differences between recording methodologies.

Generalizability concerns would apply to participant populations (likely college students) and the types of deception scenarios tested (typically mock crimes or card tests rather than consequential real-world deceptions). The specific parameters chosen for each recording method (exact voltage or current levels, electrode placement, sampling characteristics) would also affect results in ways that might not generalize across all possible implementation variations.

Practical Applications

The primary practical contribution of this research was informing decisions about polygraph instrumentation design and standardization. By comparing recording methodologies empirically, the study provided evidence-based guidance for manufacturers and practitioners about which technical approaches offered optimal performance for deception detection applications.

For contemporary polygraph practice, the study's legacy is reflected in the standardization that eventually emerged around specific recording protocols. Modern computerized polygraph systems typically employ constant voltage methods for electrodermal measurement, a choice informed by decades of methodological research including early studies like Moroney and Zenhausern's. The research underscores an important principle: seemingly technical measurement decisions can have meaningful impacts on detection accuracy and reliability, making rigorous methodological research essential for any applied psychophysiological assessment field.