Abstract
This paper examines how cognitive and environmental factors influence the formation of dyadic ties. We use agent models instantiated in ACT-R that interact in a social simulation, to illustrate the effect of memory constraints on networks. We also show that environmental factors are important including population size, running time, and map configuration. To examine these relationships, we ran simulations of networks using a factorial design. Our analyses suggest three interesting conclusions: first, the tie formation of these networks approximates a logistic growth model; second, that agent memory quality (i.e., perfect or human-like) strongly alters the network’s density and structure; third, that the three environmental factors all influence both network density and some aspects of network structure. These findings suggest that meaningful variance of social network analysis measures occur in a narrow band of memory strength (the cognitive band); the threshold for defining tie criteria is important; and future simulations examining generative social networks should control and carefully report these environmental and cognitive factors.











Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Notes
When using the original variables for population and run time, we find the same directionality, no change in the standard errors or significance, and no effect on the other variables or the explained variance. The transformed scale does increase the magnitude of the observed effects.
We include both measures because they are not equivalent. We did find instances where our categorical variable (Room Map) was significant when Grid Ratio by itself was not and vice versa.
In our analyses, we ran Cooks D and DFFITS tests. We tested our model on the entire data and subsections of the data. The models effects were stable and we saw no evidence of problems associated with emergence.
In ORA, the treatment of isolated nodes for path-based measures is customizable. We use a simple default where nodes report a ‘0’ to nodes they cannot reach.
In ORA, the treatment of isolated nodes for path-based measures is customizable. We use a simple default where nodes report a ‘0’ to nodes they cannot reach.
References
Allen TJ (1984) Managing the flow of technology: technology transfer and the dissemination of technological information within the R&D organization. MIT Press, Cambridge, MA
Anderson JR (2002) Spanning seven orders of magnitude: a challenge for cognitive modeling. Cogn Sci 26(1):85–112
Anderson JR, Schooler LJ (1991) Reflections of the environment in memory. Psychol Sci 2(6):396–408
Anderson JR, Bothell D, Byrne MD, Douglass S, Lebiere C, Qin Y (2004) An intergrated theory of the mind. Psychol Rev 111(4):1036–1060
Arcangeli A, Eidus I, Wright C (2009) Increasing memory density by using KSM. In: Proceedings of the Linux Symposium. Montreal, pp 19–28
Axelrod R, Hamilton WD (1981) The evolution of cooperation. Science 211(4489):1390–1396
Barrett C, Eubank S, Marathe M (2006) Modeling and simulation of large biological, information and socio-technical systems: an interaction based approach. In: Goldin D, Smoka SA, Wegner P (eds) Interactive computation: the new paradigm. Springer, Berlin Heidelberg, pp 353–394
Bonacich P (1972) Factoring and weighting approaches to status scores and clique identification. J Math Sociol 2(1):113–120
Brantingham PL, Brantingham PJ (1993) Nodes, paths and edges: considerations on the complexity of crime and the physical environment. J Environ Psychol 13(1):3–18
Carley KM (1991) A theory of group stability. Am Sociol Rev 56:331–354
Carley KM (1992) Organizational learning and personnel turnover. Organ Sci 3(1):20–46
Carley KM, Kjaer-Hansen J, Prietula M, Newell A (1990) Plural-Soar: a prolegomenon to artificial agents and organizational behavior. In: Masuch M, Warglien M (eds) Artificial intelligence in organization and management theory. Elsevier, Amsterdam, pp 87–118
Carley KM, Pfeffer J, Reminga J, Storrick J, Columbus D (2012) ORA User’s Guide 2012
Conte R, Andrighetto G, Campennì M (eds) (2014) Minding norms: mechanisms and dynamics of social order in agent societies. Oxford University Press, New York
Cranshaw J, Schwartz R, Hong JI, Sadeh N (2012) The Livehoods Project: Utilizing social media to understand the dynamics of a city. Paper presented at the 6th international AAAI conference on Weblogs and Social Media. Retrieved 10/24/2013
DiFonzo N (2008) The watercooler effect: a psychologist explores the extraordinary power of rumors. Avery, New York
Dunbar RIM (1998) Grooming, gossip, and the evolution of language. Harvard University Press, Cambridge
Epstein JM (2006) Generative social science: studies in agent-based computational modeling. Princeton University Press, Princeton
Epstein JM, Axtell RL (1996) Growing artificial societies: social science from the bottom up. The MIT Press, Cambridge
Everett M, Borgatti SP (2005) Ego network betweenness. Soc Netw 27(1):31–38
Freeman LC (1978–1979) Centrality in social networks conceptual clarification. Soc Netw 1(3):215–239
Georgeon O, Marshall J (2013) Demonstrating sensemaking emergence in artificial agents: a method and an example. Int J Mach Conscious 5(02):131–144
Georgeon O, Morgan JH, Ritter FE (2010) An algorithm for self-motivated hierarchical sequence learning. In: International Conference on Cognitive Modeling, Philadelphia, pp 73–78
Gonzales C, Lebiere C (2005) Instance-based cognitive models of decision making. In: Zizzo D, Courakis A (eds) Transfer of knowledge in economic decision-making. Palgrave Macmillan, New York, pp 148–165
Holland JH (1992) Complex adaptive systems. Daedalus 121(1):17–30
Juvina I, Lebiere C, Martin JM, Gonzalez C (2011) Intergroup prisoner’s dilemma with intragroup power dynamics. Games Econ Behav 2(1):21–51
Kephart WM (1950) A quantitative analysis of intragroup relationships. Am J Sociol 55(6):544–549
Kraut R, Kiesler S, Boneva B, Cummings J, Helgeson V, Crawford A (2002) Internet paradox revisited. J Soc Issues 58:49–74
Kuehl RO (2000) Design of experiments: statistical principles of research design and analysis. Duxbury/Thomson Learning, Belmont
Lebiere C, Gonzalez C, Dutt V, Warwick W (2009) Predicting cognitive performance in open-ended dynamic tasks: a modeling comparison challenge. In: the 9th international conference on cognitive modeling, Manchester
McCarty C, Killworth PD, Bernard HR, Johnsen EC, Shelley GA (2001) Comparing two methods for estimating network size. Hum Organ 60(1):28–39
Milgram S (1967) The small world problem. Psychol Today 1(1):61–67
Miller JH, Page SE (2007) Complex adaptive systems: an introduction to computational models of social life. Princeton University Press, Princeton
Moreno JL, Jennings HH (1938) Statistics of social configurations. Sociometry 1(3/4):342–374
Morgan GP, Carley KM (2011) Exploring the impact of a stochastic hiring function in dynamic organizations. Paper presented at the BRIMS, Retrieved
Morgan JH, Morgan GP, Ritter FE (2010) A preliminary model of participation for small groups. Comput Math Organ Theory 16(3):246–270
Newell A (1990) Unified theories of cognition. Harvard University Press, Cambridge
Newell A, Rosenbloom P, Laird J (1989) Symbolic architectures for cognition. In: Posner M (ed) Foundations of cognitive science. MIT Press, Cambridge
Pavlik PI Jr, Anderson JR (2005) Practice and forgetting effects on vocabulary memory: an activation-based model of the spacing effect. Cogn Sci 29:559–586
Pearl R, Reed LJ (1920) On the rate of growth of the population of the United States since 1790 and its mathematical representation. Proc Natl Acad Sci 6:275–288
Reitter D, Lebiere C (2010) A cognitive model of spatial path planning. Comput Math Organ Theory 16(3):220–245
Reitter D, Lebiere C (2011) Towards cognitive models of communication and group intelligence. In: Proceedings of the 33rd annual meeting of the cognitive science society, Boston, pp 734–739
Ritter FE, Haynes SR, Cohen MA, Howes A, John B, Best B (2006) High-level behavior representation languages revisited. In: Proceedings of the 7th international conference on cognitive modeling, Trieste, pp 404–407
Schelling TC (1971) Dynamic models of segregation. J Math Sociol 1(2):143–184
Silverman BG (2004) Human performance simulation. In: Ness JW, Ritzer DR, Tepe V (eds) The science and simulation of human performance. Elsevier, Amsterdam, pp 469–498
Simon HA (1991) Bounded rationality and organizational learning. Organ Sci 2(1):125–134
Verhulst P-F (1845) Mathematical researches into the law of population growth. Nouveaux Mémoires de l’Académie Royale des Sciences et Belles-Lettres de Bruxelles 18:1–42
Wasserman S, Faust K (1994) Social network analysis: methods and applications, vol 8. Cambridge University Press, New York
Yen J, Yin J, Ioerger TR, Miller MS, Xu D, Volz RA (2001) CAST: collaborative agents for simulating teamwork. In: Proceedings of the 17th international joint conference on artificial intelligence (IJCAI-01), Los Altos, pp 1135–1142
Acknowledgments
This work was supported by a grant from DTRA (HDTRA1-09-1-0054). We thank Jaeyhon Paik for help on the agent design and Jeremy Lothian for assistance with VIPER.
Author information
Authors and Affiliations
Corresponding author
Appendices
Appendix 1: Simulation implementation details
To connect ACT-R to VIPER, we implemented the Telnet Agent Wrapper for ACT-R (TAWA) in Common Lisp. It supports logging in, waiting for synchronization, logging, halting, and writing results to CSV files. It also exports a number of functions that provide ways to examine the environment, speak, listen, move, and otherwise control a virtual body in VIPER.
When an ACT-R model is wrapped by TAWA, executions of model code are delayed until a privileged administrator agent signals for synchronization. Error conditions are also caught by TAWA and standard UNIX error codes are returned instead of dropping into the more standard debugger. For example, a successful run returns 0 to the parent process, while any error (e.g., network errors like the server being unreachable) returns a non-zero value. Returning error codes like this allows automated error checking in large-scale experiments.
Because memory decay and networks are strongly temporal, we paid special attention to time. To synchronize the agents, the administrator agent (which does not take part in the experiment) waits for all of the TAWA wrapped agents to finish loading and logging in. It then signals to TAWA to begin the simulation. Because TAWA delays the evaluation of the model code until synchronization, no agent experiences time before the synchronization signal. Further, all ACT-R models are set to run in real-time and for the same amount of “real-time”, so they all halt after the same perceived period. Thus, the total time experienced is the same for all agents.
Early benchmarks showed that ACT-R processes took up about 80 MB per process. We would only have been able to run about 100 processes on a single 8 GB machine before swapping would occur. To reduce the per-process footprint, a number of optimizations were implemented. Basic space reductions were achieved by using the DECLARE Lisp construct, as well as by pre-compiling the components, removing the debugger, and saving the whole system (sans the ACT-R agent model) as a system image. This reduced our per-process memory footprint somewhat, but they were not the biggest contributions towards memory usage reduction.
In SBCL Lisp 1.0.52, the “–merge-core-pages” flag was recently added. This flag enables Kernel Same Page Merging under recent versions of Linux (Arcangeli et al. 2009). This optimization flags shared areas of memory as being able to be merged unless modified. Because a significant percentage of our agents were replicated, we found that we could reduce the per-process memory footprint as low as 8 MB per process (with one shared copy of the merged pages excepted). Thus, the only activities that increase the size of this footprint are changes within individual agent models. Sharing and merging copies increases the number of agents capable, whether on single processors or HPC. Together, these optimizations permit orders of magnitude more agents to be run in a single experiment than many previous efforts, enabling larger-scale analysis than has been previously done. Such large-scale work is planned for future research.
Appendix 2: Analysis by population
2.1 Symmetric ties
2.1.1 Population: 20 agents
See Table 6.
2.1.2 Population: 40 agents
See Table 7.
2.1.3 Population: 60 agents
See Table 8.
2.2 Directed ties
2.2.1 Population: 20 agents
See Table 9.
2.2.2 Population: 40 agents
See Table 10.
2.2.3 Population: 60 agents
See Table 11.
Rights and permissions
About this article
Cite this article
Zhao, C., Kaulakis, R., Morgan, J.H. et al. Building social networks out of cognitive blocks: factors of interest in agent-based socio-cognitive simulations. Comput Math Organ Theory 21, 115–149 (2015). https://doi.org/10.1007/s10588-014-9179-0
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10588-014-9179-0