title: Exploration and exploitation of Victorian science in Darwin's reading notebooks.
abstract: Search in an environment with an uncertain distribution of resources involves a trade-off between exploitation of past discoveries and further exploration. This extends to information foraging, where a knowledge-seeker shifts between reading in depth and studying new domains. To study this decision-making process, we examine the reading choices made by one of the most celebrated scientists of the modern era: Charles Darwin. From the full-text of books listed in his chronologically-organized reading journals, we generate topic models to quantify his local (text-to-text) and global (text-to-past) reading decisions using Kullback-Liebler Divergence, a cognitively-validated, information-theoretic measure of relative surprise. Rather than a pattern of surprise-minimization, corresponding to a pure exploitation strategy, Darwin's behavior shifts from early exploitation to later exploration, seeking unusually high levels of cognitive surprise relative to previous eras. These shifts, detected by an unsupervised Bayesian model, correlate with major intellectual epochs of his career as identified both by qualitative scholarship and Darwin's own self-commentary. Our methods allow us to compare his consumption of texts with their publication order. We find Darwin's consumption more exploratory than the culture's production, suggesting that underneath gradual societal changes are the explorations of individual synthesis and discovery. Our quantitative methods advance the study of cognitive search through a framework for testing interactions between individual and collective behavior and between short- and long-term consumption choices. This novel application of topic modeling to characterize individual reading complements widespread studies of collective scientific behavior.
authors.affiliation: Program in Cognitive Science, Indiana University, Bloomington, IN 47405, USA; School of Informatics and Computing, Indiana University, 919 E. 10th Street, Bloomington, IN 47408, USA. Electronic address: jammurdo@indiana.edu.
authors.forename: Jaimie
authors.initials: J
authors.lastname: Murdock
authors.affiliation: Program in Cognitive Science, Indiana University, Bloomington, IN 47405, USA; Department of History and Philosophy of Science and Medicine, Indiana University, Bloomington, IN 47405, USA; School of Humanities and Social Sciences, Xi'an Jiaotong University, Xi'an, China. Electronic address: colallen@indiana.edu.
authors.forename: Colin
authors.initials: C
authors.lastname: Allen
authors.affiliation: Program in Cognitive Science, Indiana University, Bloomington, IN 47405, USA; School of Informatics and Computing, Indiana University, 919 E. 10th Street, Bloomington, IN 47408, USA; Department of Social and Decision Sciences, Carnegie Mellon University, 5000 Forbes Avenue, BP 208, Pittsburgh, PA 15213, USA; Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA. Electronic address: simon@santafe.edu.
authors.forename: Simon
authors.initials: S
authors.lastname: DeDeo
mesh_terms: D001499:Bayes Theorem; D003657:Decision Making; D005106:Exploratory Behavior; D049672:History, 19th Century; D006801:Humans; D011932:Reading
keywords: Cognitive search; Exploration-exploitation; History of science; Information foraging; Scientific discovery; Topic modeling