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Inhan Kang

Yonsei University · Psychology

About the Lab

Professor Inhan Kang's research lab specializes in computational psychometrics and cognitive modeling, focusing on the integration of cognitive theories of decision-making with psychometric models to better understand individual differences in response behavior. The lab develops advanced statistical and machine learning models—such as extended diffusion IRT models, mixture models for fast guessing, and joint response-time and response models—to capture complex dependencies in behavioral data. A key focus is on modeling conditional dependencies between response accuracy and response time, as well as linking neural data with cognitive processes through constrained factor analysis and structural brain network priors. The lab also emphasizes model-based cognitive neuroscience, using computational frameworks to interpret high-dimensional neuroimaging data in light of cognitive mechanisms.

computational psychometricsresponse time modelingcognitive modelingbrain-behavior integrationdiffusion models

Research Overview

Papers
19
Total Citations
125
Papers (5y)
13
Primary Field
Psychology

Research Output Trend

Figures are computed from collected data and may differ slightly.

Publications per year (5y)
13total
2022
2023
2024
2025
2026
Citations per year (5y)
67total
20222023202420252026

Selected Papers

15
1
Article|26 citations·2022
Modeling Conditional Dependence of Response Accuracy and Response Time with the Diffusion Item Response Theory Model
Inhan Kang, Paul De Boeck, Roger Ratcliff
SJR Q1PsychometrikaOA

In this paper, we propose a model-based method to study conditional dependence between response accuracy and response time (RT) with the diffusion IRT model (Tuerlinckx and De Boeck in Psychometrika 70(4):629-650, 2005, https://doi.org/10.1007/s11336-000-0810-3 ; van der Maas et al. in Psychol Rev 118(2):339-356, 2011, https://doi.org/10.1080/20445911.2011.454498 ). We extend the earlier diffusion IRT model by introducing variability across persons and items in cognitive capacity (drift rate in

Experimental and Cognitive PsychologyPsychology
2
Article|21 citations·2021
Qualitative speed-accuracy tradeoff effects can be explained by a diffusion/fast-guess mixture model
Roger Ratcliff, Inhan Kang
SJR Q1Scientific ReportsOA

Rafiei and Rahnev (2021) presented an analysis of an experiment in which they manipulated speed-accuracy stress and stimulus contrast in an orientation discrimination task. They argued that the standard diffusion model could not account for the patterns of data their experiment produced. However, their experiment encouraged and produced fast guesses in the higher speed-stress conditions. These fast guesses are responses with chance accuracy and response times (RTs) less than 300 ms. We developed

Cognitive NeuroscienceNeuroscience
3
Article|14 citations·2020
Modeling the interaction of numerosity and perceptual variables with the diffusion model
Inhan Kang, Roger Ratcliff
SJR Q1Cognitive PsychologyOA
Statistics and ProbabilityMathematics
4
Article|12 citations·2021
A regularization method for linking brain and behavior.
Inhan Kang, Woojong Yi, Brandon M. Turner
SJR Q1Psychological MethodsOA

In a world of big data and computational resources, there has been a growing interest in further validating computational models of decision making by subjecting them to more rigorous constraints. One prominent area of study is model-based cognitive neuroscience, where measures of neural activity are explained and interpreted through the lens of a cognitive model. Although some early work has developed the statistical framework for exploiting the covariation between brain and behavior through fa

Cognitive NeuroscienceNeuroscience
5
Article|10 citations·2023
A Latent Space Diffusion Item Response Theory Model to Explore Conditional Dependence between Responses and Response Times
Inhan Kang, Minjeong Jeon, Ivailo Partchev
SJR Q1Psychometrika

Traditional measurement models assume that all item responses correlate with each other only through their underlying latent variables. This conditional independence assumption has been extended in joint models of responses and response times (RTs), implying that an item has the same item characteristics fors all respondents regardless of levels of latent ability/trait and speed. However, previous studies have shown that this assumption is violated in various types of tests and questionnaires an

Experimental and Cognitive PsychologyPsychology
6
Article|10 citations·2022
A randomness perspective on intelligence processes
Inhan Kang, Paul De Boeck, Ivailo Partchev
SJR Q1Intelligence
Atomic and Molecular Physics, and OpticsPhysics and Astronomy
7
Article|8 citations·2022
Constraining functional coactivation with a cluster-based structural connectivity network
Inhan Kang, Matthew Galdo, Brandon M. Turner
SJR Q1Network NeuroscienceOA

In this article, we propose a two-step pipeline to explore task-dependent functional coactivations of brain clusters with constraints from the structural connectivity network. In the first step, the pipeline employs a nonparametric Bayesian clustering method that can estimate the optimal number of clusters, cluster assignments of brain regions of interest (ROIs), and the strength of within- and between-cluster connections without any prior knowledge. In the second step, a factor analysis model i

Cognitive NeuroscienceNeuroscience
8
Article|6 citations·2020
A note on decomposition of sources of variability in perceptual decision-making
Inhan Kang, Roger Ratcliff, Chelsea Voskuilen
SJR Q2Journal of Mathematical PsychologyOA
Cognitive NeuroscienceNeuroscience
9
Article|5 citations·2023
A Modeling Framework to Examine Psychological Processes Underlying Ordinal Responses and Response Times of Psychometric Data
Inhan Kang, Dylan Molenaar, Roger Ratcliff
SJR Q1PsychometrikaOA

This article presents a joint modeling framework of ordinal responses and response times (RTs) for the measurement of latent traits. We integrate cognitive theories of decision-making and confidence judgments with psychometric theories to model individual-level measurement processes. The model development starts with the sequential sampling framework which assumes that when an item is presented, a respondent accumulates noisy evidence over time to respond to the item. Several cognitive and psych

General Decision SciencesDecision Sciences
10
Preprint|4 citations·2021
Modeling Conditional Dependence of Response Accuracy and Response Time with the Diffusion Item Response Theory Model
Inhan Kang, Paul De Boeck, Roger Ratcliff
OA

In this paper, we propose a model-based method to study conditional dependence be- tween response accuracy and response time (RT) with the diffusion IRT model. To this end, we extend the previously proposed model by introducing variability across persons and items in cognitive capacity and in the initial bias of the response processes. We show that the extended model can explain the behavioral patterns of conditional dependency found in the previous studies in psychometrics. The first variabilit

Experimental and Cognitive PsychologyPsychology
11
Article|3 citations·2024
A Recent Development of a Network Approach to Assessment Data: Latent Space Item Response Modeling for Intelligence Studies
Inhan Kang, Minjeong Jeon
SJR Q1Journal of IntelligenceOA

This article aims to provide an overview of the potential advantages and utilities of the recently proposed Latent Space Item Response Model (LSIRM) in the context of intelligence studies. The LSIRM integrates the traditional Rasch IRT model for psychometric data with the latent space model for network data. The model has person-wise latent abilities and item difficulty parameters, capturing the main person and item effects, akin to the Rasch model. However, it additionally assumes that persons

Experimental and Cognitive PsychologyPsychology
12
Article|1 citations·2025
Integration of latent space and confirmatory factor analysis to explain unexplained person–item interactions.
Inhan Kang, Minjeong Jeon
SJR Q1Psychological Methods

As with many other latent variable models, the confirmatory factor analysis model is built upon the conditional independence assumption, which states that latent variables and item parameters can fully explain covariations between item responses. However, growing evidence in psychological and educational measurement research challenges this assumption, raising concerns regarding conditional dependence (CD). As the main model parameters correspond to the main person and item effects, CD implies t

Experimental and Cognitive PsychologyPsychology
13
Article|1 citations·2025
A Latent Space Graded Response Model for Likert-Scale Psychological Assessments
Ludovica De Carolis, Inhan Kang, Minjeong Jeon
SJR Q1Multivariate Behavioral Research

In this study, we introduce a novel modeling approach for ordinal response data, extending the one-parameter graded response model. The proposed model incorporates unobserved interactions between respondents and items, represented as distances in a two-dimensional Euclidean space, referred to as an interaction map. This latent space graded response model (LSGRM) addresses potential violations of the conditional independence assumption shared by traditional main-effect-only psychometric models an

Management Science and Operations ResearchDecision Sciences
14
Preprint|1 citations·2021
A Randomness Perspective on Intelligence Processes
Inhan Kang, Paul De Boeck, Ivailo Partchev
OA

We study intelligence processes using a diffusion IRT model with random variability in cognitive model parameters: variability in drift rate (the trend of information accumulation toward a correct or incorrect response) and variability in starting point (from where the information accumulation starts). The random variation concerns randomness across person-item pairs and cannot be accounted for by individual and inter-item differences. Interestingly, the models explain the conditional dependenci

Atomic and Molecular Physics, and OpticsPhysics and Astronomy
15
Article|1 citations·2025
Multidimensional Latent Space Item Response Models: A Note on the Relativity of Conditional Dependence
Inhan Kang, Min-Jeong Jeon
SJR Q1PsychometrikaOA

Abstract Conditional dependence (CD) reflects potential interactions between persons and items in measurement, offering valuable information for deriving personalized diagnoses, evaluations, and feedback. The recent integration of psychometric models with latent space provides an effective way to visualize and quantify person–item interactions unexplained by latent variables and item parameters. In such applications, it is important to recognize the relative nature of CD, as models with differen

Computer Networks and CommunicationsComputer Science

Research Areas

Experimental and Cognitive PsychologyCognitive NeuroscienceStatistics and ProbabilityAtomic and Molecular Physics, and OpticsManagement Science and Operations ResearchGeneral Decision Sciences

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