Journal Article

The origin of bursts and heavy tails in human dynamics

Barabási, Albert-László

2005

Overview

We are all individuals... but What determines the timing of human actions? A big question, but the science of human dynamics is here to tackle it. And its predictions are of practical value: for example, when ISPs decide what bandwidth an institution needs, they use a model of the likely timing and activity level of the individuals. Current models assume that an individual has a well defined probability of engaging in a specific action at a given moment, but evidence that the timing of human actions does not follow this pattern (of Poisson statistics) is emerging. Instead the delay between two consecutive events is best described by a heavy-tailed (power law) distribution. Albert-László Barabási proposes an explanation for the prevalence of this behaviour. The ‘bursty’ nature of human dynamics, he finds, is a fundamental consequence of decision making. The dynamics of many social, technological and economic phenomena are driven by individual human actions, turning the quantitative understanding of human behaviour into a central question of modern science. Current models of human dynamics, used from risk assessment to communications, assume that human actions are randomly distributed in time and thus well approximated by Poisson processes 1 , 2 , 3 . In contrast, there is increasing evidence that the timing of many human activities, ranging from communication to entertainment and work patterns, follow non-Poisson statistics, characterized by bursts of rapidly occurring events separated by long periods of inactivity 4 , 5 , 6 , 7 , 8 . Here I show that the bursty nature of human behaviour is a consequence of a decision-based queuing process 9 , 10 : when individuals execute tasks based on some perceived priority, the timing of the tasks will be heavy tailed, with most tasks being rapidly executed, whereas a few experience very long waiting times. In contrast, random or priority blind execution is well approximated by uniform inter-event statistics. These finding have important implications, ranging from resource management to service allocation, in both communications and retail.

• Publisher: Nature Publishing Group UK,Nature Publishing,Nature Publishing Group
• Subject: Applications / Behavior / Behavior - physiology / Biology, psychology, social sciences / Commerce / Communication / Decision Making / Exact sciences and technology / Human Activities - psychology / Human Activities - statistics & numerical data / Human Activities - trends / Humanities and Social Sciences / Humans / Internet / letter / Mathematics / Models, Biological / Models, Statistical / multidisciplinary / Poisson Distribution / Probability and statistics / Probability theory and stochastic processes / Random Allocation / Research methodology / Resource Allocation / Resource management / Risk Assessment / Science / Science (multidisciplinary) / Sciences and techniques of general use / Special processes (renewal theory, markov renewal processes, semi-markov processes, statistical mechanics type models, applications) / Statistical analysis / Statistics / Stochastic processes / Task analysis / Time Factors