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Bhattacharjee, D., Waasdorp, S., Middelburg, E., Sterck, E.H.M., & Massen, J.J.M. (2024). Personality heterophily and friendship as drivers for successful cooperation. Proceedings of the Royal Society B., 291, 20232730. doi: 10.1098/rspb.2023.2730 (pdf)


Bhattacharjee, D., Guðjónsdóttir, A.R., Escriche Chova, P., Middelburg, E., Jäckels, J., de Groot, N., Wallner, B., Massen, J.J.M.‡, & Pflüger, L.S.‡ (2024). Behavioural, physiological and genetic drivers of coping. ‡ Shared senior authors. iScience, 27(2), 108890. doi: 10.1016/j.isci.2024.108890 (pdf)

Horn, L., Bugnyar, T, & Massen, J.J.M. (2023). Testing the effects of kinship, reciprocity, and dominance on prosocial food provisioning in azure-winged magpies (Cyanopica cyana), carrion crows (Corvus corone), and common ravens (C. corax). Ethology, 00, 1-14. doi: 10.1111/eth.13420 (pdf)


Van Dijk, E. S. J.*, Bhattacharjee, D.*, Belli, E. & Massen, J.J.M. (2023). Hand preference predicts behavioural responses to threats in Barbary macaques. * co-first authors. American Journal of Primatology, 85, e23499. doi: 10.1002/ajp.23499 (pdf)


Bhattacharjee, D., Cousin, E., Pflüger, L.S. & Massen, J.J.M. (2023). Prosociality in a despotic society. iScience, 26, 106587. doi: 10.1016/j.isci. 2023.106587 (pdf)


Hammer, R., Stribos, M., Böhm, P.M., Pink, K.E., Wallner, B., Huffmann, M., Massen, J.J.M., & Pflüger, L.S. (2023). A novel methodological framework for group classification during group fission: a case of a semi-free ranging group of Japanese macaques (Macaca fuscata). American Journal of Primatology, 85, e23463. doi: 10.1002/ajp.23463 (pdf) 


Vanhooland, L-C., Szabo, A., Bugnyar, T. & Massen, J.J.M. (2022). A comparative approach of mirror self-recogntion in three corvid species. Animal Cognition. doi: 10.1007/s10071-022-01696-4 (pdf)


Kluiver, C.E., de Jong, J.A., Massen, J.J.M., & Bhattacharjee, D., (2022). Personality as a predictor of time-activity budget in lion-tailed macaques (Macaca silenus). Animals, 12, 1495. doi: 10.3390/ani12121495 (pdf)


Gallup, A.C., Schild, A.B., Ühlein, M.A. Bugnyar, T. & Massen, J.J.M. (2022). No evidence for contagious yawning in ravens (Corvus corax): an observational study. Animals, 12, 1357. doi: 10.3390/ani12111357 (pdf)

Šlipogor, V., Graf, C., Massen, J.J.M., & Bugnyar, T. (2022). Personality and social environment predict cognitive performance in common marmosets (Callithrix jacchus). Scientific Reports, 12, 6702. doi: 10.1038/s41598-022-10296-8 (pdf)

Massen, J.J.M., & Gallup, A.C. (2022). The evidence does not support long-term oxygenation as a functional explanation for the evolution of yawning. Sleep and Breathing. doi: 10.1007/s11325-022-02627-w (pdf)

Kret, M.E., Massen, J.J.M. & de Waal, F.B.M. (2022). My fear is not, and never will be, your fear: On emotions and feelings in animals. Affective science, 3, 182–189. doi: 10.1007/s42761-021-00099-x (pdf)


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)


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)


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

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)


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)


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)


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


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

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)


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., 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


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)


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)


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)


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)

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


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


Laumer, I.B*, Massen, J.J.M.*, Lorck-Tympner, M., Wakonig, B., Carminito, C. & Auersperg, A.M.I. (2020). Tentative evidence for inequity aversion to unequal work-effort but not to unequal reward distribution in Goffin’s cockatoos. Ethology, 126, 185-194. * co-first authors. (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)



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)

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)


Martin, J.S., Massen, J.J.M., Šlipogor, V., Bugnyar, T., Jaeggie, A.V. & Koski, S.E. (2019). The EGA+GNM Framework: An Integrative Approach to Modeling Behavioral Syndromes. Methods in Ecology and Evolution. (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)


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

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)

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)


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)


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)


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)


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)


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


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)


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., 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., 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., 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)


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)


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., 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)



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)


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., 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)


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)



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)


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)


Book chapters

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).


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).



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


Journal Publications


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