Laumer, I.B.*, Massen, J.J.M.*, Boehm, P.M., Boehm, A., Geisler, A. & Auersperg, A.M.I. (2021). Individual Goffin’s cockatoos (Cacatua goffiniana) show flexible targeted helping in a tool transfer task. PLoS One, 16, e0253416. * co-first authors. (pdf)

Horn, L., Zewald, J.S., Bugnyar, T., & Massen, J.J.M. (2021). Carrion crows and azure-winged magpies show no prosocial tendencies when tested in a token exchange paradigm. Animals, 11, 1526. (pdf

Martin, J.S., Koski, S.E., Bugnyar, T., Jaeggie, A.V. & Massen, J.J.M. (2021). Prosociality, social tolerance, and partner choice facilitate mutually beneficial cooperation in common marmosets. Animal Behaviour, 173, 115-136. (pdf


Horn, L., Bugnyar T., Griesser, M., Hengl, M., Izawa, E.I., Oortwijn, T., Rössler, C., Scheer, C., Schiestl, M., Suyama, M., Taylor, A.H., Vanhooland, L.-C., von Bayern, A.M.P., Zürcher, Y. & Massen, J.J.M. (2020). Sex-specific effects of cooperative breeding and colonial nesting on prosociality in corvids. eLife, 9, e58139. (pdf)


Massen, J.J.M.*, Haley, S.M.* & Bugnyar, T. (2020). Azure-winged magpies’ decisions to share food are contingent on the presence or absence of food for the recipient. Scientific Reports, 10, 16147. *co-first authors (pdf)​


Massen, J.J.M., Bauer, L., Spurny, B., Bugnyar, T. & Kret. M. E. (2020). Reply to: “The data do not support the existence of an ‘Old Boy network’ in science. Some critical comments on a study by Massen et al.” Scientific Reports, 10, 13783. (pdf)


Massen, J.J.M. (2020). Editorial: Studying the evolution of cooperation and prosociality in birds. Ethology, 126, 121-124. (pdf


Horn, L., Hungerländer, N.A., Windhager, S., Bugnyar, T. & Massen, J.J.M. (2018). Social status and prenatal testosterone exposure affect 6–9-year-old children’s prosocial choices. Scientific Reports, 8, 9198. (pdf)

Massen, J.J.M., Bauer, L., Spurny, B., Bugnyar, T. & Kret. M. E. (2017). Sharing of science is most likely among male scientists. Scientific Reports, 7, 12927. (pdf)


Lambert, M.L., Massen, J.J.M., Seed, A.M., Bugnyar, T. & Slocombe, K.E. (2017). An ‘unkindness’ of ravens? Measuring prosocial preferences in Corvus corax. Animal Behaviour, 123, 383-393. (pdf)

Horn, L., Scheer, C., Bugnyar, T. & Massen, J.J.M. (2016). Proactive prosociality in a cooperative breeding corvid, the Azure winged magpie (Cyanopica cyanus). Biology Letters, 12, 20160649. doi: 10.1098/rsbl.2016.0649 (pdf)


Massen, J.J.M., Lambert, M., Schiestl, M. & Bugnyar, T. (2015). Ravens can, but mostly don’t help conspecifics to gain access to food when there is nothing to gain for themselves. Frontiers in Comparative Psychology, 6, 885. doi:10.3389/fpsyg.2015.00885 (pdf)

Sterck, E.H.M., Olesen, C.U. & Massen, J.J.M. (2015). No costly pro-sociality among related long-tailed macaques, Macaca fascicularis. Journal of Comparative Psychology, 129, 275-282. doi: 10.1037/a0039180 (pdf)

Massen, J.J.M., Luyten, I.J.A.F., Spruijt, B.M. & Sterck, E.H.M. (2011). Benefiting dominants or maybe friends: Pro-social choices seem to depend on rank position in long-tailed macaques (Macaca fascicularis). Primates, 52: 237-247. doi: 10.1007/s10329-011-0244-8 (pdf)

Massen, J.J.M., van den Berg, L.M., Spruijt, B.M. & Sterck, E.H.M. (2010). Generous leaders and selfish underdogs: Pro-sociality in despotic macaques. PLoS ONE 5(3): e9734. doi: 10.1371/journal.pone.0009734 (pdf)


Sigmundson, R., Stribos, M., Hammer, R., Herzele, J., Pflüger, L.S., & Massen, J.J.M. (2021). Exploring the cognitive capacities of Japanese macaques in a cooperation game. Animals, 11, 1497. (pdf


Martin, J.S., Koski, S.E., Bugnyar, T., Jaeggie, A.V. & Massen, J.J.M. (2021). Prosociality, social tolerance, and partner choice facilitate mutually beneficial cooperation in common marmosets. Animal Behaviour, 173, 115-136. (pdf


Massen, J.J.M., Schaake, W.A.A. & Bugnyar, T. (2020). A comparison of cooperative cognition in corvids, chimpanzees, and other animals. In: (L. Hopper & S. Ross eds.) Chimpanzees in context. Chicago, USA: University of Chicago Press (pp. 368-390).


Stocker, M, Loretto, M.C., Sterck, E.H.M., Bugnyar, T. & Massen, J.J.M. (2020). Cooperation with closely bonded individuals reduces cortisol levels in long-tailed macaques. Royal Society Open Science, 7, 191056. (pdf​)


Massen, J.J.M. (2020). Editorial: Studying the evolution of cooperation and prosociality in birds. Ethology, 126, 121-124. (pdf


Laumer, I.B*, Massen, J.J.M.*, Lorck-Tympner, M., Wakonig, B., Carminito, C. & Auersperg, A.M.I. (in press). Tentative evidence for inequity aversion to unequal work-effort but not to unequal reward distribution in Goffin’e cockatoos. Ethology * co-first authors. (pdf)


Massen, J.J.M., Behrens, F., Martin, J.S., Stocker, M. & Brosnan, S.F. (2019). A comparative approach to affect and cooperative decision-making. Neuroscience & Biobehavioural Reviews, 107, 370-387. (pdf)

Müller, J.J.A., Massen, J.J.M., Bugnyar, T. & Osvath, M. (2017). Ravens remember the nature of a single reciprocal interaction sequence over 2 days and even after a month. Animal Behaviour, 128, 69-78. (pdf)


Schwing, R., Jocteur, E., Wein, A., Noë, R. & Massen, J.J.M. (2016). Kea cooperate better with sharing affiliates. Animal Cognition, 19, 1093–1102. doi: 10.1007/s10071-016-1017-y (pdf)


Asakawa-Haas, K., Schiestl, M., Bugnyar, T. & Massen, J.J.M. (2016). Partner choice in raven (Corvus corax) cooperation. PLoS ONE, 11, e0156962. doi: 10.1371/journal.pone.0156962 (pdf)

Massen, J.J.M., Ritter, C. & Bugnyar, T. (2015). Tolerance and reward equity predict cooperation in ravens (Corvus corax). Scientific Reports, 5, 15021. doi: 10.1038/srep15021 (pdf)

Massen, J.J.M., van den Berg, L.M., Spruijt, B.M. & Sterck, E.H.M. (2012). Inequity aversion and the effect of relationship quality in long-tailed macaques (Macaca fascicularis). American Journal of Primatology, 74: 145-156. doi: 10.1002/ajp.21014 (pdf)

Animal Social Bonds

Boucherie, P., Gallego-Abenza, M., Massen, J.J.M. & Bugnyar, T. (2022). Dominance in a socially dynamic setting: how do ravens cope with changing group compositions and dependent ranks? Philosophical Transactions of the Royal Society B. 377, 20200446. doi: 10.1098/rstb.2020.0446 (pdf)


Morales Picard, A., Mundry, R., Auersperg, A.M., Boeving, E.R., Boucherie, P.M., Bugnyar, T, Dufour, V., Emery, N.J., Federspiel, I., Gajdon, G., Guéry, J.-P., Hegedič, M., Horn, L., Kavanagh, E., Lambert, M.L., Massen, J.J.M., Rodrigues, M., Schiestl, M., Schwing, R., Szabo, B., Taylor, A.H., van Horik, J.O., von Bayern, A.M.P., Seed, A, & Slocombe, K.E. (2020). Why preen others? Predictors of allopreening in parrots and corvids and comparisons to grooming in great apes. Ethology, 126, 207-228. (pdf)


Bouchery, P., Loretto, M.C., Massen, J.J.M., & Bugnyar, T.,  (2019). What constitutes ‘social complexity’ and ‘social intelligence’ in birds? Lessons from ravens. Behavioral Ecology and Sociobiology, 73, 12. (pdf)


Massen, J.J.M. (2017). Friendship in animals. In: (J. Vonk & T.K. Shackelford eds.) Encyclopedia of Animal Cognition and Behavior. New York, USA: Springer Nature. (pdf)


Bugnyar, T. & Massen, J.J.M. (2017). Avian social relations, social cognition & cooperation. In: Avian Cognition (Healy, S & ten Cate, C.J. eds). Cambridge, UK: Cambridge University Press (pp. 314-336).

Kalcher-Sommersguter, E., Preuschoft, S., Franz-Schaider, C., Hemelrijk, C.K., Crailsheim, K. & Massen, J.J.M. (2015). Early maternal loss affects social integration of chimpanzees throughout their lifetime. Scientific Reports, 5, 16439. doi: 10.1038/srep16439 (pdf)

Massen, J.J.M. & Koski, S.E. (2014). Chimps of a feather sit together. Chimpanzee friendships are based on homophily in personality. Evolution and Human Behavior, 35: 1-8. doi: 10.1016/j.evolhumbehav.2013.08.008 (pdf)

Massen, J.J.M. & Sterck, E.H.M. (2013). Stability and durability of within- and between-sex social bonds of captive rhesus macaques (Macaca mulatta). International Journal of Primatology, 34: 770-791. doi: 10.1007/s10764-013-9695-7 (pdf)

Massen, J.J.M., Sterck, E.H.M. & de Vos, H. (2010). A review of close social associations in animals and humans: Functions and mechanisms of friendship. Behaviour, 147: 1379-1412. doi: 10.1163/000579510X528224 (pdf)

Massen, J.J.M. (2010). ‘Friendship’ in Macaques. Economics and Emotions. Utrecht University. ISBN: 978-90-393-5325-7. (pdf)

Yawning and other Contagious Behaviors

Gallup, A.C., Kret, M.E., Eldakar, O.T., Folz, J., & Massen, J.J.M. (2021). People that score high on psychopathic traits are less likely to yawn contagiously. Scientific Reports, 11, 23779. doi: 10.1038/s41598-021-03159-1. (pdf


Massen, J.J.M.*, Hartlieb, M.*, Martin, J.S.*, Leitgeb, E.B., Hockl, J., Kocourek, M., Olkowicz, S., Osadnik, C., Verkleij, J.W., Zhang, Y., Bugnyar, T., Němec, P. & Gallup, A.C.  (2021). Brain size and neuron numbers drive differences in yawn duration across mammals and birds. Communications Biology, 4, 503. *co-first authors (pdf)


Van Berlo, E., Díaz-Loyo, A.P., Juárez-Mora, O.E., Kret, M.E. & Massen, J.J.M. (2020). Experimental evidence for contagious yawning in Bornean orangutans (Pongo pygmeus). Scientific Reports, 10, 22251. (pdf)


Gallup, A.G. & Massen, J.J.M. (2020). Intranasal oxytocin, empathy, and contagious yawning in dogs and humans. Applied Animal Behaviour Science, 224, 104971. (pdf)


Gallup, A. C., Moscatello, L. & Massen, J.J.M. (2020). Yawn duration predicts brain weight across domesticated dog breeds. Current Zoology. (pdf)


Massen, J.J.M. & Gallup, A.C. (2017). Why contagious yawning does not (yet) equate to empathy. Neuroscience & Biobehavioral Reviews, 80, 573-585. (pdf)


Gallup, A.C. & Massen, J.J.M.# (2016). There is no difference in contagious yawning between men and women. Royal Society Open Science, 3, 160174. doi: 10.1098/rsos.160174  # both authors contributed equally (pdf)


Massen, J.J.M., Šlipogor, V. & Gallup, A.C. (2016). An investigation of behavioural contagion in common marmosets (Callithrix jacchus): an observational study. Frontiers in Comparative Psychology. 7, 1190. doi: 10.3389/fpsyg.2016.01190 (pdf)


Massen, J.J.M., Church, A. & Gallup, A.C. (2015). The influence of political affiliation and status on auditory contagious yawning in humans. Frontiers in Psychology, 6, 1735. doi: 10.3389/fpsyg.2015.01735 (pdf)

Massen, J.J.M., Dusch, K., Eldakar, O.T. & Gallup, A.C. (2014.) A thermal window for yawning in humans: Yawning as a Brain Cooling Mechanism. Physiology & Behavior, 130: 145-148. doi: 10.1016/j.physbeh.2014.03.032 (pdf)

Massen, J.J.M., Vermunt, D.A. & Sterck, E.H.M. (2012). Male yawning is more contagious than female yawning among chimpanzees (Pan troglodytes). PLoS ONE, 7(7): e40697. doi:10.1371/journal.pone.0040697 (pdf)


Šlipogor, V., Massen, J.J.M., Schiel, N., Souto, A., & Bugnyar, T. (2021). Temporal consistency and ecological validity of personality structure in common marmosets (Callithrix jacchus): a unifying field and laboratory approach. American Journal of Primatology, e23229. (pdf)


Martin, J.S., Massen, J.J.M., Šlipogor, V., Bugnyar, T., Jaeggie, A.V. & Koski, S.E. (2018). The EGA+GNM Framework: An Integrative Approach to Modeling Behavioral Syndromes. Methods in Ecology and Evolution. (pdf)

Šlipogor, V., Gunhold-de Oliveira, T., Tadić, Z., Massen, J.J.M. & Bugnyar, T. (2016). Consistent inter-individual differences in marmosets (Callitrix jachus) in Boldness-Shyness, Stress-Activity and Exploration-Avoidance. American Journal of Primatology. 78, 961–973. doi: 10.1002/ajp.22566 (pdf)

Massen, J.J.M., Antonides, A., Arnold, A. K., Bionda, T. & Koski, S.E. (2013). A behavioral view on chimpanzee personality: exploration tendency, persistence, boldness and tool-orientation measured with group experiments. American Journal of Primatology, 75: 947-958. doi: 10.1002/ajp.22159 (pdf)

Mating Strategies


Sonnweber, R.S., Massen, J.J.M. & Fitch, W.T. (2015). Post-copulatory grooming: a conditional mating strategy? Behavioural Ecology and Sociobiology, 69, 1749–1759. doi: 10.1007/s00265-015-1987-9 (pdf)

Overduin-de Vries, A.M., Massen, J.J.M., Spruijt, B.M. & Sterck, E.H.M. (2012). Sneaky monkeys: an audience effect on rhesus macaque (Macaca mulatta) sexual behaviour. American Journal of Primatology, 74: 217–228. doi: 10.1002/ajp.21988 (pdf)

Massen, J.J.M., Overduin-de Vries, A.M., de Vos-Rouweler, A.J.M., Spruijt, B.M., Doxiadis, G.G.M. & Sterck, E.H.M. (2012). Male mating tactics in captive rhesus macaques, Macaca mulatta: the influence of dominance, markets and relationship quality. International Journal of Primatology, 33: 73-92. doi: 10.1007/s10764-011-9552-5 (pdf)

3rd-party Understanding

Massen, J.J.M. & Mielke, A. (2021). Third-party interactions. In: (J. Vonk & T.K. Shackelford eds.) Encyclopedia of Animal Cognition and Behavior. New York, USA: Springer Nature. (pdf)

Massen, J.J.M., Szipl, G., Spreafico, M. & Bugnyar, T. (2014). Ravens intervene in others’ bonding attempts. Current Biology, 24, 2733-2736. doi:10.1016/j.cub.2014.09.0731(pdf)

Massen, J.J.M., Pašukonis, A., Schmidt, J. & Bugnyar, T. (2014). Ravens notice dominance reversals among conspecifics within and outside their social group. Nature Communications, 5: 3679. doi: 10.1038/ncomms4679 (pdf)



Miller, R., Lambert, M.L., Frohnwieser, A., Brecht, K.F., Bugnyar, T., Crampton, I., Garcia-Pelegrin, E., Gould, K., Greggor, A., Izawa, E.-I., Kelly, D.M., Li, L., Lou, Y., Luong, L., Massen, J.J.M., Neider, A., Reber, S., Schiestl, M., Seguchi, A., Sepehri, P., Stevens, J.R., Taylor, A.H., Wang, L., Wolff, L.M., Zhang, Y., & Clayton, N.S. (2022). Individual consistency, species differences and the influence of socio-ecological factors on neophobia in 10 corvid species. Current Biology, 32, 74-85. doi: 10.1016/j.cub.2021.10.045 (pdf)


Stocker, M, Prösl, J., Vanhooland, L-C., Horn, L., Bugnyar, T., Canoine, V. & Massen, J.J.M. (2021). Measuring salivary mesotocin in birds - Seasonal differences in ravens’ peripheral mesotocin levels. Hormones & Behaviour, 134, 105015. (pdf)


Wijnen, M.N., Massen, J.J.M., & Kret, M.E. (2021). Gender bias in the allocation of student grants. Scientometrics. (pdf

Sierro, J., Loretto, M.C., Szipl, G., Massen, J.J.M. & Bugnyar, T. (2020). Food calling in ravens (Corvus corax) revisited: who is addressed? Ethology, 126, 257-266. (pdf)


Vanhooland, L.-C., Bugnyar, T. & Massen, J.J.M. (2020). Crows (Corvus corone sp.) check the contingency of their behaviour in a mirror, yet fail to pass the Mirror-Mark Test. Journal of Comparative Psychology (pdf)

Munteanu, A.M., Stocker, M., Stöwe, M., Massen, J.J.M. & Bugnyar, T. (2017). Behavioural and hormonal stress responses to social separation in ravens, Corvus corax. Ethology, 123, 123-135. (pdf)

Gunhold, T., Massen, J.J.M., Schiel, N., Souto, A. & Bugnyar, T. (2014). Memory, transmission and persistence of alternative foraging techniques in wild common marmosets. Animal Behaviour, 91: 79-91. doi: 10.1016/j.anbehav.2014.02.023 (pdf)