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Prior work on perceptual effectiveness has decomposed visualizations into smaller common units (e.g., channels such as angle, position, and length) to establish rankings. While useful, these decompositions lack the computational structure to predict performance for new visualization × task combinations, requiring new experiments for each. We propose an alternative unit of analysis: operationalizing quantitative visualization interpretation as sequences of composable visual decoding operators. Using probability density function (PDF) and cumulative distribution function (CDF) charts, we examine how four chart-specific tasks can be decomposed into five reusable, chart-agnostic perceptual operations and characterize their error profiles through hierarchical Bayesian modeling. We then test generalizability by composing one kind of learned operators to predict performance on a structurally different task: Moritz et al.’s [37] scatterplot mean-estimation experiment, where the chart type, chart dimensions, and analytic goal all differ from the learning conditions. With a pre-registered analysis plan, we compose operators under six candidate strategies and evaluate each against empirical data with no parameters fit to the response data. One strategy captures both bias and variance of observed responses; five alternatives fail in distinguishable ways. We argue that this decoding-operator-oriented approach to empirical visualization research demonstrates the feasibility of a different way of doing empirical visualization research, one where findings compose, and predictions extend beyond the conditions in which they were measured. Free copy of this paper and supplemental materials: https://osf.io/prtfq.

Established channel effectiveness rankings primarily assess magnitude estimation accuracy in complete chart contexts, often neglecting other perceptual tasks such as discriminability, separability, and pop-out. To address this gap, we conducted crowdsourced experiments on seven core visual channels (position, length, tilt, area, curvature, luminance, and saturation) using primitive visual stimuli, a set of visual marks without chart-specific scaffolding to isolate channel-level variation. We evaluated these channels across four perceptual tasks (accuracy, discriminability, separability, and pop-out) and found that channel effectiveness is fundamentally multi-dimensional, with rankings shifting substantially across tasks. For instance, while spatial channels maintain an overall advantage, accuracy depends strongly on whether a fixed spatial anchor is available. Discriminability varies dramatically across channels and value ranges, a pattern we formalized with a novel Anchored Harmonic Weber model. Pairwise channel interactions are often strongly asymmetric. Finally, we identify a dissociation between estimation accuracy and preattentive detection: length shows only moderate detection effectiveness despite top-tier accuracy, while area achieves the highest detection rates despite poor quantitative accuracy, though the latter advantage may partly reflect stimulus-level cues. We synthesize these findings into a scenario-driven perspective for context-sensitive channel selection.

Understanding visual attention is key to designing efficient human-computer interaction, especially for virtual reality (VR) and augmented reality (AR) applications. However, the relationship between 3D spatial attributes of visual stimuli and visual attention is still underexplored. Thus, we design an experiment to collect a gaze dataset in VR, and use it to quantitatively model the probability of first attention between two stimuli. First, we construct the dataset by presenting subjects with a synthetic VR scene containing varying spatial configurations of two spheres. Second, we formulate their selective attention based on a probability model that takes as input two view-specific stimuli attributes: their eccentricities in the field of view and their sizes as visual angles. Third, we train two models using our gaze dataset to predict the probability distribution of a user's preferences of visual stimuli within the scene. We evaluate our method by comparing model performance across two challenging synthetic scenes in VR. Our application case study demonstrates that VR designers can utilize our models for attention prediction in two-foreground-object scenarios, which are common when designing 3D content for storytelling or scene guidance. We make the dataset and the source code to visualize it available alongside this work.

Studies have shown that visualization design affects interpretability when visualization interpretation is the user’s sole task. However, in real-world settings, users often engage with visualizations while performing concurrent tasks, such as when users simultaneously monitor alerts or respond to messages. Such divided attention may alter how users interpret visualizations, potentially increasing the importance of designs that align with viewer expectations. We investigated this possibility through two experiments comparing visualization interpretation under single-task and dual-task conditions. Specifically, we examined how well-established inferred mappings between color, spatial position, and semantic concepts affect interpretation when users perform a concurrent task, both with unlimited viewing time (Exp. 1) and under limited viewing time (Exp. 2). Our results show that divided attention amplifies the performance gap between expectation-aligned and expectation-violating designs, affecting response time, interpretation accuracy, and the ability to produce a judgment under time constraints. To explain these results, we model the user’s decision-making process using a Linear Ballistic Accumulator (LBA) framework. Our findings highlight the increased importance of aligning visualization designs with viewer expectations under divided attention and introduce a process-oriented modeling approach to understanding how expectation and multitasking shape visualization interpretation.

Understanding how individuals interpret charts is a crucial concern for visual data communication. This imperative has motivated a number of studies, including past work demonstrating that causal priors–a priori belief about causal relationships between concepts–can have significant influences on the perceived strength of variable relationships inferred from visualizations. This paper builds on these previous results, demonstrating that causal priors can also influence the types of patterns that people perceive as the most salient within ambiguous scatterplots that have roughly equal evidence for trend and cluster patterns. Using a mixed-design approach that combines a largescale online experiment for breadth of findings with an in-person think-aloud study for analytical depth, we investigated how users' interpretations are influenced by the interplay between causal priors and the visualized data patterns. Our analysis suggests two archetypal reasoning behaviors through which people often make their observations: contextualization, in which users accept a visual pattern that aligns with causal priors and use their existing knowledge to enrich interpretation, and rationalization, in which users encounter a pattern that conflicts with causal priors and attempt to explain away the discrepancy by invoking external factors, such as positing confounding variables or data selection bias. These findings provide initial evidence highlighting the critical role of causal priors in shaping high-level visualization comprehension, and introduce a vocabulary for describing how users reason about data that either confirms or challenges prior beliefs of causality.

Exploratory data visualization tools often prioritize efficiency over reflective thinking, leaving users vulnerable to cognitive biases and superficial analyses. This capacity for reflective thinking, specifically, the ability to monitor one’s own analytical process, is known as metacognitive awareness, yet it remains largely unsupported in visualization design. In this paper, we investigate two potential interventions for improving metacognitive awareness: Socratic prompting, which triggers reflection through contextual questioning, and visualizing interaction traces, which surface behavioral patterns to support self-monitoring. We conducted a between-subjects study (N=36) comparing contextual Socratic prompts delivered via Wizard-of-Oz and a bias-aware visualization interface that surfaces interaction traces against a control condition. We measured metacognitive awareness before and after completing a visualization exploration task using an adapted Metacognitive Awareness Inventory (MAI). Contrary to our expectations, we observed a significant decrease in MAI scores for participants in the interaction trace group, while the Socratic group and control group showed no significant decline. Our findings reveal how certain design features intended to support awareness may instead lead to cognitive overload, distraction, or superficial engagement, ultimately diminishing it. This work contributes empirical support for the growing body of work on promoting reflection with visualizations, highlighting the importance of evaluating interventions not only for their intended effects but also for their unintended consequences. All Supplemental Materials are available at https://osf.io/bnamf.