Observer Physiological State as an Uncontrolled Variable in Attention-Modulated Double-Slit Experiments: A Preregistration-Ready Protocol

A contentious experimental literature claims correlations between observer attention and interference pattern characteristics in double-slit optical systems. Independent replication attempts have identified serious methodological concerns, including false-positive rates of 50% in sham conditions and sensitivity to undisclosed analytical choices. This preregistered protocol proposes that observer physiological state—specifically cardiac coherence indexed by heart rate variability (HRV)—represents an uncontrolled variable contributing to inconsistent outcomes across studies. The design is a 2×2 between-subjects factorial crossing coherence level (high vs. low, induced via resonant vs. non-resonant paced breathing) with mental mode (analytical vs. non-analytical attention). All analytic decisions are fully locked prior to data collection: primary spectral method (AR Burg order 16), fringe visibility algorithm (Fourier-based V = 2A₁/A₀), coherence thresholds (CR > 0.70 high, CR < 0.30 low), and statistical model (linear mixed-effects with Bonferroni-corrected α = 0.025). The protocol integrates the Advanced Meta-Experimental Protocol (AMP) with sham blocks evaluated via cumulative z-scores at fixed intervals, pre-registered pass/fail criteria, and explicit decision rules for calibration failures. Physical negative controls (single-slit, beam-blocked configurations) further strengthen artifact detection. This mechanism-agnostic framework explicitly proposes no physical mechanism by which cardiac activity could influence quantum systems. The win-win epistemic structure ensures valuable scientific contribution regardless of outcome: positive results identify a previously unrecognized moderating variable; null results eliminate observer physiological state as a confound and constrain future theorizing. Sample size: N = 320 (80 per cell) plus pilot N = 40 (excluded from confirmatory analysis). Primary hypothesis test: Coherence × Attention interaction (β₄) at α = 0.025.