Influence of Stimulus Layout and Social Presence on Deception-Related Eye Movements and Blinks in the Concealed Information Test

This 2026 study by Foucher and Huckauf investigated how stimulus layout and social presence affect eye movements during deception in the Concealed Information Test. Using a card-based paradigm with 87 participants, the researchers found that concealment with multiple visible objects produces more and shorter fixations plus fewer blinks, and these patterns remain stable across different levels of social presence (alone, video observation, real person observation).

Two experiments using paired-card CIT paradigm with 87 participants, eye tracking via Eyelink 1000, testing three deception conditions (reveal, conceal, fake) and three social presence conditions (no observer, video observation, real person observation), analyzed with linear mixed models.

This research addressed contradictory findings about deceptive eye movements in the CIT by systematically examining stimulus layout effects. Using paired-card presentation as a middle ground between sequential and simultaneous displays, the study found that concealment consistently produced more and shorter fixations when multiple objects were visible. The second experiment extended these findings by examining how social presence (no observation, video observation, real person observation) affects deceptive eye movement patterns. Results demonstrated that multiple-object presentation is sufficient to reverse fixation patterns compared to single-stimulus conditions, providing crucial clarity for eye-tracking applications in deception detection.

These findings provide critical guidance for implementing eye-tracking technology in CIT applications by clarifying how stimulus presentation format affects deceptive behaviors. The research also informs the design of more ecologically valid CIT protocols by examining social presence effects relevant to real-world interrogation environments.

Background & Context

Eye tracking has emerged as a promising augmentation to deception detection methodologies, particularly within the Concealed Information Test (CIT) framework. The CIT uses eye movements and blinks as indicators of deception, with recent findings suggesting fixation patterns depend critically on stimulus layout—particularly the distinction between sequential and simultaneous stimulus presentation. This stimulus layout dependency has created confusion in the literature, with contradictory findings about whether deception produces more or fewer fixations.

Previous research found that presenting cards sequentially one at a time produced fewer and longer fixations during concealment, whereas presenting six cards simultaneously yielded more and shorter fixations. This variability has undermined confidence in eye-tracking measures for deception detection and raised fundamental questions about the cognitive mechanisms underlying deceptive eye movements.

Additionally, the impact of social presence on deceptive eye movements—critical for real-world application of the CIT—remained insufficiently examined. This gap is particularly important because laboratory CIT studies typically use isolated testing conditions that poorly reflect interrogation or screening environments where social observation is inherent.

Research Design & Methodology

The study employed two experiments in which participants selected a card and had to reveal, conceal, or fake its value while all possible cards were displayed in pairs. This paired-card presentation represented a middle ground between fully sequential and fully simultaneous displays, allowing the researchers to test whether multiple-object presentation is sufficient to reverse fixation patterns.

Experiment 1 examined whether deceptive intentions could be differentiated using fixations and blinks, and extended previous findings on the effect of stimulus layout. Based on related work, the first dataset contained gaze data from 87 participants who revealed, concealed, or faked the value of a previously selected card, collected with Eyelink 1000 eye tracking equipment.

Experiment 2 assessed the stability of deception-related eye movements and blinks across various levels of social presence: without observation, observed per video, and observed by a real person. Key dependent measures included:

• Fixation count and duration
• Blink count and duration
• Gaze transitions between cards
• Statistical analysis using linear mixed models with Bayes Factors

Fixation and blink counts were normalized by dividing the number of events by the number of cards actually presented for that instruction, yielding mean values per pair of cards comparable across instructions.

Results & Key Findings

Concealment yielded more and shorter fixations, reproducing the pattern reported with six-card simultaneous displays and indicating a clear effect of stimulus layout on deceptive eye movements. This finding resolved a critical question: the mere presence of multiple objects in view is sufficient to reverse fixation patterns compared to single-stimulus presentation.

Target presentations produced more and shorter fixations, fewer blinks, and more gaze transitions between cards in the concealing and faking-target conditions compared to revealing and faking-faked-target conditions. Specific statistical findings from Experiment 1 included:

• Fixation count was significantly higher in concealing than revealing (diff = 0.95, t(87) = 5.26, p < 0.001) and faking-faked-target (diff = 0.78, t(87) = 4.31, p < 0.001) conditions
• Concealment in a multiple-object CIT elicited more and shorter fixations, and fewer blinks
• In Experiment 2, fixation count was higher in concealing than revealing (diff = 0.43, t(87) = 2.34, p = 0.02)

Regarding social presence effects, the levels of social presence realized in this study did not significantly alter these patterns, indicating that deception-related eye movements and blinks in CITs remain stable under passive social presence. This finding has important implications: deception-related eye movements effects are robust to passive social presence (video or real person).

Discussion & Significance

The pattern suggests that simultaneous object presentation elicits qualitatively different deceptive eye movements than sequential presentation, a factor critical for the interpretation of eye movements in CIT paradigms and may contribute to inconsistent findings. This resolution of contradictory literature represents a major advance, providing a coherent framework for understanding when and why eye movements patterns differ.

The study reveals that deceptive eye movements reflect both cognitive load and strategic gaze modulation. When multiple items are visible simultaneously, deceivers appear to adopt a scanning strategy that produces more frequent but shorter fixations—possibly reflecting attempts to appear interested in all items equally while suppressing prolonged attention to personally relevant information. This contrasts with sequential presentation where longer fixations may reflect deeper processing of critical items.

The robustness of eye movement patterns across social presence conditions is particularly significant for applied settings. The finding that passive observation does not fundamentally alter deception-related eye movements suggests these measures could translate from laboratory to field environments. However, the study specifically tested passive social presence; more interactive or confrontational observation might yield different results.

Limitations & Considerations

The study employed a card-selection paradigm with relatively low personal stakes, which differs substantially from real-world deception scenarios involving crimes, security screening, or high-consequence outcomes. The emotional arousal, motivation to deceive, and consequences of detection are all attenuated in this laboratory analog.

The social presence manipulation involved passive observation only—participants were watched but not actively interrogated or engaged. Real-world interrogations involve dynamic interaction, questioning, and psychological pressure that may alter eye movement patterns beyond what was tested here. The error rate in Experiment 2 averaged only 1.4%, with a maximum of 11.1% for one participant, suggesting the task was relatively simple.

The study design using paired-card presentation represents only one point on the continuum between fully sequential and fully simultaneous displays. Additional research mapping the full gradient of stimulus array sizes would provide more comprehensive understanding of layout effects.

Practical Applications

For polygraph examiners and screening professionals, this research provides critical guidance: the format of stimulus presentation fundamentally shapes what eye movement patterns indicate deception. Practitioners using eye-tracking augmented CITs must carefully standardize stimulus layout, as comparing results across different presentation formats is inappropriate. Simultaneous or multi-item displays appear more suitable for detecting the increased fixation count and reduced blink rate associated with concealment.

The stability of eye movement patterns across social presence conditions is encouraging for field application, suggesting that validated patterns from controlled studies should generalize to testing environments where observation occurs. However, the specific patterns documented here—more and shorter fixations plus fewer blinks during concealment with multiple visible objects—should be considered provisional markers requiring validation in higher-stakes contexts before operational deployment.