Random walks on semantic networks can resemble optimal foraging.

When people are asked to retrieve members of a category from memory, clusters of semantically related items tend to be retrieved together. A recent article by Hills, Jones, and Todd (2012) argued that this pattern reflects a process similar to optimal strategies for foraging for food in patchy spatial environments, with an individual making a strategic decision to switch away from a cluster of related information as it becomes depleted. We demonstrate that similar behavioral phenomena also emerge from a random walk on a semantic network derived from human word-association data. Random walks provide an alternative account of how people search their memories, postulating an undirected rather than a strategic search process. We show that results resembling optimal foraging are produced by random walks when related items are close together in the semantic network. These findings are reminiscent of arguments from the debate on mental imagery, showing how different processes can produce similar results when operating on different representations.

[1]  H. Eysenck.  PRIMARY MENTAL ABILITIES , 1939 .

[2]  W. A. Bousfield,et al.  An Analysis of Sequences of Restricted Associative Responses , 1944 .

[3]  L. Thurstone.  Primary mental abilities. , 1938, Science.

[4]  C. Adcock,et al.  Primary Mental Abilities. , 1971, The Journal of general psychology.

[5]  John R. Anderson.  Fran: A Simulation Model of Free Recall , 1972 .

[6]  Zenon W. Pylyshyn,et al.  What the Mind’s Eye Tells the Mind’s Brain: A Critique of Mental Imagery , 1973 .

[7]  Allan Collins,et al.  A spreading-activation theory of semantic processing , 1975 .

[8]  E. Charnov.  Optimal foraging, the marginal value theorem. , 1976, Theoretical population biology.

[9]  A. Tversky.  Features of Similarity , 1977 .

[10]  John R. Anderson.  Arguments concerning representations for mental imagery. , 1978 .

[11]  Roger N. Shepard,et al.  Additive clustering: Representation of similarities as combinations of discrete overlapping properties. , 1979 .

[12]  R. Shiffrin,et al.  Search of associative memory. , 1981 .

[13]  J. W. Hutchinson,et al.  Nearest neighbor analysis of psychological spaces. , 1986 .

[14]  D. Salmon,et al.  A comparison of the category fluency deficits associated with Alzheimer's and Huntington's disease , 1989, Brain and Language.

[15]  W. Batchelder,et al.  Predicting Clustering From Semantic Structure , 1993 .

[16]  John R. Anderson,et al.  The Adaptive Character of Thought , 1990 .

[17]  M. Lezak.  Neuropsychological assessment, 3rd ed. , 1995 .

[18]  M. Goodale.  Image and Brain: The Resolution of the Imagery Debate , 1995 .

[19]  G. Winocur,et al.  Clustering and switching as two components of verbal fluency: evidence from younger and older healthy adults. , 1997, Neuropsychology.

[20]  Jeffrey C. Lagarias,et al.  Convergence Properties of the Nelder-Mead Simplex Method in Low Dimensions , 1998, SIAM J. Optim..

[21]  M. Freedman,et al.  Clustering and switching on verbal fluency tests in Alzheimer's and Parkinson's disease , 1998, Journal of the International Neuropsychological Society.

[22]  Thomas A. Schreiber,et al.  The University of South Florida free association, rhyme, and word fragment norms , 2004, Behavior research methods, instruments, & computers : a journal of the Psychonomic Society, Inc.

[23]  Richard M. Shiffrin,et al.  Word Association Spaces for Predicting Semantic Similarity Effects in Episodic Memory. , 2005 .

[24]  Joshua B. Tenenbaum,et al.  The Large-Scale Structure of Semantic Networks: Statistical Analyses and a Model of Semantic Growth , 2001, Cogn. Sci..

[25]  Mark Steyvers,et al.  Topics in semantic representation. , 2007, Psychological review.

[26]  Michael T. Turvey,et al.  Human memory retrieval as Lévy foraging , 2007 .

[27]  T. Griffiths,et al.  Google and the Mind , 2007, Psychological science.

[28]  Michael N Jones,et al.  Representing word meaning and order information in a composite holographic lexicon. , 2007, Psychological review.

[29]  Thomas L. Griffiths,et al.  Latent Features in Similarity Judgments: A Nonparametric Bayesian Approach , 2008, Neural Computation.

[30]  P. Todd,et al.  Patch leaving in humans: can a generalist adapt its rules to dispersal of items across patches? , 2008, Animal Behaviour.

[31]  Peter Pirolli,et al.  Information Foraging , 2009, Encyclopedia of Database Systems.

[32]  Joaquín Goñi,et al.  The semantic organization of the animal category: evidence from semantic verbal fluency and network theory , 2011, Cognitive Processing.

[33]  Thomas T. Hills,et al.  Human foraging behavior : a virtual reality investigation on area restricted search in humans , 2010 .

[34]  Pablo Villoslada,et al.  Switcher-Random-Walks: a Cognitive-Inspired Mechanism for Network Exploration , 2009, Int. J. Bifurc. Chaos.

[35]  J. Borge-Holthoefer,et al.  Modeling Abnormal Priming in Alzheimer's Patients with a Free Association Network , 2011, PloS one.

[36]  Thomas T. Hills,et al.  Dynamic search and working memory in social recall. , 2012, Journal of experimental psychology. Learning, memory, and cognition.

[37]  Thomas L. Griffiths,et al.  Human memory search as a random walk in a semantic network , 2012, NIPS.

[38]  Edward Vul,et al.  A Bayesian Optimal Foraging Model of Human Visual Search , 2012, Psychological science.

[39]  Thomas T. Hills,et al.  Optimal foraging in semantic memory. , 2012, Psychological review.

[40]  Thomas T. Hills,et al.  Mechanisms of age-related decline in memory search across the adult life span. , 2013, Developmental psychology.

[41]  Jeremy M Wolfe,et al.  When is it time to move to the next raspberry bush? Foraging rules in human visual search. , 2013, Journal of vision.

[42]  David B. Pisoni,et al.  Using Cognitive Models to Investigate the Temporal Dynamics of Semantic Memory Impairments in the Development of Alzheimer’s Disease , 2013 .

[43]  Graham Thompson,et al.  Searching Semantic Memory as a Scale-Free Network: Evidence from Category Recall and a Wikipedia Model of Semantics , 2013, CogSci.

[44]  M. Dougherty,et al.  Optional Stopping and the Termination of Memory Retrieval , 2014 .