Paper Number
PO37                         My Program 

Session
Poster Session

Title
Quantifying and predicting human behavior during interactions with viscoelastic materials

Presentation Date and Time
October 22, 2025 (Wednesday) 6:30

Track / Room
Poster Session / Sweeney Ballroom E+F

Authors (Click on name to view author profile)

  1. Martin, Jeffrey D. (Kenvue)
  2. Jogan, Matjaz (University of Pennsylvania, Perelman School of Medicine)
  3. Teh, Seng Koon (Kenvue)
  4. Burgeson, Eric (University of Illinois Urbana-Champaign, Department of Chemical and Biomolecular Engineering)
  5. Rogers, Simon A. (University of Illinois Urbana-Champaign, Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Jeffrey D. Martin1, Matjaz Jogan2, Seng Koon Teh3, Eric Burgeson4 and Simon A. Rogers4
1Kenvue, Skillman, NJ 08558; 2Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104; 3Kenvue, Singapore, Singapore 118222, Singapore; 4Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL 61801

Speaker / Presenter 
Martin, Jeffrey D.

Keywords
experimental methods; theoretical methods; applied rheology; techniques

Text of Abstract

Human/material interactions are ubiquitous in everyday life and materials with which humans interact are often designed with this interaction in mind. Humans perceive feedback during material deformation, e.g., dynamic resistance to force; however, it is unclear how measurable properties map to perceptual judgements and decision-making.

Over 100 subjects completed discrimination tasks where the objective was to determine which of two viscoelastic stimuli (silly putty) were “more firm” by pressing with the index finger. Tasks varied in difficulty from easy (putty vs. rubber ball) to difficult (identical putties) to variable (putties of differing “hardness”) and were performed with a bare finger and with a rigid finger cover to reduce cutaneous feedback.

Pressing behavior varied significantly across subjects. Variations in behavior with trial specifics like task difficulty, stimulus firmness, and lack of cutaneous feedback will be discussed. Subjects were clustered based on their pressing behavior and several behavioral outliers are present throughout all tasks. Subjects clustered into two large groups of roughly equal size regardless of task difficulty when cutaneous feedback is present, while they clustered into one larger, dominant group and a smaller group regardless of task difficulty when cutaneous feedback is not present.

Several features are evaluated by AUROC as potential predictors of subjects’ “more firm” choice. Simple features such as applied cumulative force-time, max force, and force gradient are sufficient predictors of “more firm” choice, but only when judgments are easy. Basic recovery rheology parameters with clear physical meaning are shown to be excellent predictors of “more firm” choice for all viscoelastic stimuli in a maximum difficulty scenario, suggesting that humans can infer these parameters from material feedback and then use them to judge “firmness” of complex, viscoelastic materials irrespective of individual pressing behavior.