What Is the Delayed Answer Test?
The delayed answer test (DAT) is an experimental methodology used in laboratory research to investigate the timing relationship between stimulus presentation and physiological arousal during deception. The DAT demonstrated a key finding in PDD science: that the physiological responses measured by the polygraph are triggered primarily by the cognitive processing of the stimulus (hearing and comprehending the question) rather than by the motor act of speaking a deceptive answer.
How the DAT Works
In the delayed answer test paradigm, questions are presented to the examinee in the usual manner, but the examinee is instructed to delay their verbal response for a specified period after the question is asked — typically 10 to 30 seconds. This creates a temporal separation between two events: the moment the examinee hears and processes the question, and the moment they actually produce their verbal answer (whether truthful or deceptive).
By analysing the timing of physiological responses relative to both the question presentation and the delayed answer, researchers were able to determine which event triggered the autonomic nervous system activity that polygraph instruments record.
Key Findings
Research using the DAT consistently showed that significant physiological changes — increases in electrodermal activity, changes in respiratory patterns, and cardiovascular shifts — occurred in the seconds immediately following the question presentation, well before the examinee spoke their answer. The act of vocalising the lie produced comparatively little additional physiological response beyond what had already been triggered by the cognitive processing of the question’s meaning.
This finding has several important implications:
- Stimulus-driven responding — Polygraph responses are fundamentally about the examinee’s cognitive and emotional reaction to the question content, not about the physical act of lying
- Support for cognitive theories — The results are consistent with dual process theory and the fear of detection model, which emphasise the psychological processing that occurs when a deceptive examinee confronts a question about the matter they are concealing
- Validation of scoring windows — The finding supports the standard practice of evaluating physiological responses in the window beginning at question onset rather than at the answer, which is how modern numerical scoring systems operate
Relevance to Field Practice
The DAT is not used in operational polygraph examinations — it is strictly a laboratory research tool. However, its findings underpin several practical elements of modern polygraph methodology. The response scoring windows used in validated test data analysis methods are calibrated based on research (including DAT studies) showing that meaningful physiological responses begin within a few seconds of stimulus presentation and peak before or shortly after the verbal answer.
The DAT also provides a scientific basis for understanding why silent answer tests (where the examinee does not answer verbally) can still produce interpretable physiological data: the critical physiological event is the cognitive processing, not the vocalisation.
References
The DAT paradigm is primarily associated with the work of Dawson (1980), whose research on the relationship between response timing and deception contributed to the broader understanding of the psychophysiological mechanisms that underlie polygraph testing.