Measuring Real-Time Cognitive Load and Metabolic Strain as a Function of Communication Signal Ambiguity

Abstract

This document presents a turnkey experimental protocol designed to quantify real-time cognitive load, metabolic expenditure, and autonomic strain as a function of communication signal ambiguity. Moving beyond retrospective self-report questionnaires, the protocol operationalizes human communication through an information-theoretic framework. The paradigm evaluates a crossover interaction between autistic adults and neurotypical controls across two tightly matched conditions: deterministic, high-fidelity logical propositions versus lossy, under-constrained natural language containing dropped antecedents, pragmatic elisions, and ambiguous syntax. Stimuli are operationalized across three distinct natural language domains: workplace task coordination, facility operational procedures, and interpersonal communication. The protocol details full hardware specifications and event-locked synchronization (TTL/LSL) across a multimodal physiological recording stack, including task-evoked pupillometry (locus coeruleus activity), prefrontal functional near-infrared spectroscopy (fNIRS hemodynamic expenditure), electrodermal activity (tonic SCL and phasic SCR), and cardiac heart rate variability (parasympathetic vagal tone via RMSSD and high-frequency power). Analytical pipelines are fully specified using linear mixed-effects models (LMM) with crossed random effects, Drift-Diffusion Models (DDM) for latency distributions, and continuous regressions against Camouflaging Autistic Traits Questionnaire (CAT-Q) scores to isolate the metabolic tax of active social compensation. By isolating signal fidelity as an independent variable, this paradigm enables laboratories to directly measure the biological cost of resolving ambiguous input, reframing neurodivergent communication fatigue as an architectural processing trade-off rather than an intrinsic social deficit.