Dr Sam Roberts

Senior Lecturer

Sam's research is distinctive in combining theories and methods from evolutionary psychology, social psychology and social network analysis to provide important new insights into the dynamics of social relationships.

Sam is Joint Module leader for the Research Dissertation module (PS6001), and teaches across many areas including biological psychology, animal psychology and research methods.


Sam gained a first class degree in Human Sciences at the University of Oxford before going on to complete an MSc in Evolutionary Psychology at the University of Liverpool, for which he was awarded a distinction. He then did a D.Phil. at the University of Sussex, using novel experimental paradigms to investigate social cognition in both wild and captive monkeys and apes.

Following his D.Phil, Sam moved back to the University of Oxford for four years of postdoctoral research, focusing on the structure and dynamics of social networks in humans, before joining the Department in September 2010.


Sam's research explores social relationships and social cognition in human and non-human primates from an evolutionary perspective. He thus has broad interests in social, comparative and evolutionary psychology. He has published his research extensively in leading journals and is part of several large-scale international research collaborations. He has also collaborated with the mobile operator O2/Telefonica to explore the business applications of his research.

Contact Details
Tel: 01244 513091

Email: sam.roberts@chester.ac.uk

Research Gate profile: Sam Roberts

Google Scholar profile: Sam Roberts


Sam is Joint Module Leader for the Research Dissertation (PS6001) module. He also teaches on Core Topics (PS4010),  Animal Psychology (PS6022) and Biological Psychology (PS6034). At Masters level, Sam teaches on Advanced Skills for Research and Practice (PS7303) and Biological Psychology for Conversion (PS7311). Sam supervises research students at both undergradaue and Masters levels.

In recognition of Sam's previous teaching experience, and his commitment to providing an excellent standard of engaging, student-focused teaching, Sam recently become a Fellow of the Higher Education Academy.


Sam's current research combines theories from evolutionary and social psychology with the newly developing methods of social network analysis to provide novel insights into the dynamics of social relationships. He also uses this research approach to investigate how these social relationships may be affected by the use of communication technologies such as Facebook and mobile phones. This approach has led to important new findings including: the patterns of altruism in kin relations and friendships; the time and cognitive constraints on social network size; the relationship between personality and social network size; and how social network sites affect the size and quality of 'offline' social networks. In 2010, Sam was awarded a grant under the EPSRC Knowledge Transfer Scheme (KTS), which enabled a six-month collaboration with the mobile operator O2/Telefonica exploring the business applications of his research findings.

Sam's D.Phil. used several completely novel experimental paradigms to investigate social cognition in primates, including the first experimental investigation into the process of social referencing in free ranging primates. His postdoctoral research focused on the structure and dynamics of social networks in humans. A key aspect of this was to explore how time and/or cognitive constraints limit the number of network members that can be maintained at each level of emotional intensity. The research also focused on how these constraints may be affected by the use of communication technologies such as Facebook and mobile phones.

This postdoctoral research was part of three large scale international research collaborations. The EPSRC/ESRC-funded TESS (Developing Theory for Evolving Socio-cognitive Systems) project and the EU-funded Social Networking for Pervasive Adaptation (SOCIALNETS) project both examine how technology affects social relationships, for better or for worse, and use this knowledge to inform the design of the next generation of communication technology. The Lucy to Language: Archaeology of the Social Brain project is a British Academy funded collaboration which aims to explore what it means to be human, and when and how we, as a species, came to be that way.

Media Coverage

Sam was  interviewed by ABC Radio National in Australia about his research on Facebook. You can hear the interview, and read a transcript, here: ABC Radio National Interview

Sam's recent paper on the persistence of social signatures in human communicaiton, published in the Proceedings of the National Academcy of Sciences, recieved extensive media coverage including in Science, The Times, The Independent, The Economist and the Huffington Post.

Another recent paper published in Nature Communications on the use of intentional gestures in chimpanzees also recieved extensive media coverage, including in the Daily Mail and Science Daily.

Published work

Due to copyright restrictions, for most of the journal articles I am unable to put the PDFs of my publications on this page. If you are unable to access the full text versions of any of the papers through the links below, or would like a copy of the book chapter, please email me and I will be happy to send you the publication.

Roberts, S. G. B., & Roberts, A. I. (2016). Social brain hypothesis: Vocal and gesture networks of wild chimpanzees. Frontiers in Psychology, 7, 1756. doi:10.3389/fpsyg.2016.01756

Roberts, A. I., & Roberts, S. G. B. (2016). Wild chimpanzees modify modality of gestures according to the strength of social bonds and personal network size. Scientific Reports, 6, 33864. doi:10.1038/srep33864

Molho, C., Roberts, S. G. B., de Vries, R. E., & Pollet, T. V. (2016). The six dimensions of personality (HEXACO) and their associations with network layer size and emotional closeness to network members. Personality and Individual Differences, 99, 144-148. doi: http://dx.doi.org/10.1016/j.paid.2016.04.096

Aledavood, T., López, E., Roberts, S. G. B., Reed-Tsochas, F., Moro, E., Dunbar, R. I., & Saramäki, J. (2016). Channel-specific daily patterns in mobile phone communication. In S. Battiston, F. de Pellegrini, G. Caldarellli, & E. Merelli (Eds.), Proceedings of ECCS 2014: European Conference on Complex Systems (pp. 209-218): Springer. doi: 10.1007/978-3-319-29228-1_18

Hooper, J., Sharpe, D., Roberts, S.G.B. (2016). Are men funnier than women, or do we just think they are? Translational Issues in Psychological Science, 2, 54-62. doi: 10.1037/tps0000064

Roberts, A. I., & Roberts, S. G. B. (2015). Gestural communication and mating tactics in wild chimpanzees. PLoS One, 10(11), e0139683. doi:10.1371/journal.pone.0139683 [Open access]

Aledavood, T., López, E., Roberts, S. G. B., Reed-Tsochas, F., Moro, E., Dunbar, R. I. M., & Saramäki, J. (2015). Daily rhythms in mobile telephone communication. PLoS ONE, 10(9), e0138098. doi: 10.1371/journal.pone.0138098 [Open access]

Roberts, S. B. G., & Dunbar, R. I. M. (2015). Managing relationship decay: Network, gender and contextual effects. Human Nature, 26(4), 426-450. doi: 10.1007/s12110-015-9242-7 [Open access]

Roberts, S.G.B., Arrow, A., Gowlett, J.A.J., Lehmann, J. & Dunbar, R.I.M. (2014). Close social relationships: An evolutionary perspective. In: R.I.M. Dunbar, C. Gamble & J.A.J. Gowlett (Eds.), Lucy to Language: The Benchmark papers(pp. 151-180). Oxford, Oxford University Press. http://ukcatalogue.oup.com/product/9780199652594.do

Saramäki, J., Leicht, E. A., Lopez, E., Roberts, S. G. B., Reed-Tsochas, F. & Dunbar, R. I. M. (2014) Persistence of social signatures in human communication. Proceedings of the National Academy of Sciences, 111 , 942-947. doi:10.1073/pnas.1308540110

Roberts, A. I., Vick, S.-J., Roberts, S. G. B.  & Menzel, C. R. (2014). Chimpanzees modify intentional gestures to coordinate a search for hidden food. Nature Communications, 5:3088.  doi: 10.1038/ncomms4088 

Roberts, A. I., Roberts, S. G. B. & Vick, S.-J. (2014). The repertoire and intentionality of gestural communication in wild chimpanzees. Animal Cognition, 17, 317-336. doi: 10.1007/s10071-013-0664-5

Curry, E. O., Roberts, S. G. B. & Dunbar. R. I. M. (2013). Altruism in social networks: Evidence for a "kinship premium". British Journal of Psychology,  104, 283-295. doi: 10.1111/j.2044-8295.2012.02119.x

Miritello, G., Moro, E., Lara, R. Martinez-Lopez, R., Belchamber, J., Roberts, S. G. B. & Dunbar, R. I. M. (2013). Time as a limited resource: Communication strategy in mobile phone networks. Social Networks, 35, 89-95.   doi:10.1016/j.socnet.2013.01.003     This article is openly available on arXiv: arXiv:1301.2464 [physics.soc-ph].

Pollet, T. V., Roberts, S. G. B. & Dunbar, R. I. M. (2013). Going that extra mile: Individuals travel further to maintain face-to-face contact with highly related kin than with less related kin. PLOS ONE8(1), e53929. doi:10.1371/journal.pone.0053929  [Open access]

Binder, J., Roberts, S. G. B. & Sutcliffe, A. (2012). Best friends and good friends: Differences between close relationships in the support group and sympathy group. Social Networks, 34, 206-214 doi: 10.1016/j.socnet.2011.12.001

Roberts, A. I., Vick, S.-J., Roberts, S. G. B., Buchanan-Smith, H. M., & Zuberhuler, K. (2012). Structure-based repertoire of manual gestures in wild chimpanzees: Statistical analysis of a graded communication system. Evolution and Human Behavior, 33, 578-589. doi: 10.1016/j.evolhumbehav.2012.05.006

Vlahovic, T. A., Roberts, S. G. B. & Dunbar, R. I. M. (2012). Effects of duration and laughter on subjective happiness within different modes of communication. Journal of Computer-Mediated Communication, 17, 436-450.                           doi: 10.1111/j.1083-6101.2012.01584.x

Roberts, S. G. B. & Dunbar, R. I. M. (2011). Communication in social networks: Effects of kinship, network size and emotional closeness. Personal Relationships, 18, 439-452. doi: 10.1111/j.1475-6811.2010.01310.x

Roberts, S. G. B. & Dunbar, R. I. M. (2011). The costs of family and friends: An 18-month longitudinal study of relationship maintenance and decay. Evolution and Human Behavior, 32, 186-197.                                                               doi: 10.1016/j.evolhumbehav.2010.08.005

Pollet, T. V., Roberts, S. G. B. & Dunbar, R. I. M. (2011) Extraverts have larger social network layers but do not feel emotionally closer to individuals at any layer. Journal of Individual Differences. 32, 161-169.  doi: 10.1027/1614-0001/a000048

Pollet, V., Roberts, S. G. B. & Dunbar, R. I. M. (2011). Use of social network sites and instant messaging does not lead to increased offline social network size, or to emotionally closer relationships with offline network members. Cyberpsychology, Behavior and Social Networks, 14, 253-258. doi: 10.1089/cyber.2010.0161

Roberts, S. G. B. (2010). Constraints on social networks. In: R. Dunbar, C. Gamble & J. Gowlett (Eds.), Social Brain, Distributed Mind (pp. 117-138). Oxford: Oxford University Press/British Academy.

Roberts, S. G. B., Dunbar, R. I. M., Pollet, T. V. & Kuppens, T. (2009). Exploring variation in active network size: Constraints and ego characteristics. Social Networks, 31, 138-146. doi: 10.1016/j.socnet.2008.12.002

Lu, Y-E., Roberts, S. G. B., Dunbar, R. & Lió, P. & Crowcroft, J. (2009). Size matters: Variation in personal network size, personality and effect on information transmission. CSE ’09: International Conference on Computational Science and Engineering 2009, 4, 188-193. doi: 10.1109/CSE.2009.179

Lu, Y-E., Roberts, S. G. B., Cheng, T.M. K., Dunbar, R. I. M. Lió, P. & Crowcroft, J. (2009). On optimising personal network size to manage information flow. CNIKM ’09: Proceedings of the 1st ACM international workshop on complex networks meets information and knowledge management, 19-26. doi: 10.1145/1651274.1651279

Roberts, S. G. B., McComb, K. & Ruffman, T. (2008). An experimental investigation of referential looking in free-ranging Barbary macaques (Macaca sylvanus). Journal of Comparative Psychology, 122, 94-99.                                                     doi: 10.1037/0735-7036.122.1.94

Roberts S. G. B., Wilson, R., Fedurek, P. & Dunbar, R. I. M. (2008). Individual differences and personal social network size and structure. Personality and Individual Differences, 44, 954-964. doi: 10.1016/j.paid.2007.10.033

Oliveira, R. F., Rosenthal, G. G., Schlupp, I., McGregor, P. K., Cuthill, I. C., Endler, J. A.,...Waas, J. R. (2000). Considerations on the use of video playbacks as visual stimuli: The Lisbon Workshop consensus. Acta Ethologica, 3, 61-65. doi: 10.1007/s102110000019