@article{SchneebergerRoederTaborsky2020,
  author    = {Schneeberger, Karin and R{\"o}der, Gregory and Taborsky, Michael},
  title     = {The smell of hunger},
  series = {PLoS biology},
  volume    = {18},
  journal   = {PLoS biology},
  number    = {3},
  publisher = {PLoS},
  address   = {San Fransisco},
  issn      = {1544-9173},
  doi       = {10.1371/journal.pbio.3000628},
  pages     = {13},
  year      = {2020},
  abstract  = {When individuals exchange helpful acts reciprocally, increasing the benefit of the receiver can enhance its propensity to return a favour, as pay-offs are typically correlated in iterated interactions. Therefore, reciprocally cooperating animals should consider the relative benefit for the receiver when deciding to help a conspecific. Norway rats (Rattus norvegicus) exchange food reciprocally and thereby take into account both the cost of helping and the potential benefit to the receiver. By using a variant of the sequential iterated prisoner's dilemma paradigm, we show that rats may determine the need of another individual by olfactory cues alone. In an experimental food-exchange task, test subjects were provided with odour cues from hungry or satiated conspecifics located in a different room. Our results show that wild-type Norway rats provide help to a stooge quicker when they receive odour cues from a hungry rather than from a satiated conspecific. Using chemical analysis by gas chromatography-mass spectrometry (GC-MS), we identify seven volatile organic compounds that differ in their abundance between hungry and satiated rats. Combined, this "smell of hunger" can apparently serve as a reliable cue of need in reciprocal cooperation, which supports the hypothesis of honest signalling.},
  language  = {en}
}