Patricia Kanngiesser

Publications of Patricia Kanngiesser

• Grooming network cohesion and the role of individuals in a captive chimpanzee group.

  Authors: Patricia Kanngiesser, Cédric Sueur, Katrin Riedl, Johannes Grossmann, Josep Call

  American journal of primatology. 08/2011; 73(8):758-67.

  Social network analysis offers new tools to study the social structure of primate groups. We used social network analysis to investigate the cohesiveness of a grooming network in a captive chimpanzeeSocial network analysis offers new tools to study the social structure of primate groups. We used social network analysis to investigate the cohesiveness of a grooming network in a captive chimpanzee group (N = 17) and the role that individuals may play in it. Using data from a year-long observation, we constructed an unweighted social network of preferred grooming interactions by retaining only those dyads that groomed above the group mean. This choice of criterion was validated by the finding that the properties of the unweighted network correlated with the properties of a weighted network (i.e. a network representing the frequency of grooming interactions) constructed from the same data. To investigate group cohesion, we tested the resilience of the unweighted grooming network to the removal of central individuals (i.e. individuals with high betweenness centrality). The network fragmented more after the removal of individuals with high betweenness centrality than after the removal of random individuals. Central individuals played a pivotal role in maintaining the network's cohesiveness, and we suggest that this may be a typical property of affiliative networks like grooming networks. We found that the grooming network correlated with kinship and age, and that individuals with higher social status occupied more central positions in the network. Overall, the grooming network showed a heterogeneous structure, yet did not exhibit scale-free properties similar to many other primate networks. We discuss our results in light of recent findings on animal social networks and chimpanzee grooming.

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• The limits of endowment effects in great apes (Pan paniscus, Pan troglodytes, Gorilla gorilla, Pongo pygmaeus).

  Authors: Patricia Kanngiesser, Laurie R Santos, Bruce M Hood, Josep Call

  Journal of comparative psychology (Washington, D.C. : 1983). 07/2011; 125(4):436-45.

  The endowment effect describes the bias that people often value things that they possess more than things they do not possess. Thus, they are often reluctant to trade items in their possession forThe endowment effect describes the bias that people often value things that they possess more than things they do not possess. Thus, they are often reluctant to trade items in their possession for items of equivalent value. Some nonhuman primates appear to share this bias with humans, but it remains an open question whether they show endowment effects to the same extent as humans do. We investigated endowment effects in all four great ape species (Pan paniscus, Pan troglodytes, Gorilla gorilla, Pongo pygmaeus) by varying whether apes were endowed with food items (Experiment 1, N = 22) or tools that were instrumental in retrieving food (Experiment 2, N = 23). We first assessed apes' preferences for items of a pair and their willingness to trade items in their possession. We then endowed apes with one item of a pair and offered them to trade for the other item. Apes showed endowment effects for food, but not for tools. In Experiment 3, we endowed bonobos (N = 4) and orangutans (N = 5) with either one or 12 food items. Endowment effects did not differ between species and were not influenced by the number of endowed food items. Our findings suggest that endowment effects in great apes are restricted to immediate food gratification and remain unaffected by the quantity of food rewards. However, endowment effects do not seem to extend to other, nonconsumable possessions even when they are instrumental in retrieving food. In general, apes do not show endowment effects across a range of different commodities as humans typically do.

• The effect of creative labor on property-ownership transfer by preschool children and adults.

  Authors: Patricia Kanngiesser, Nathalia Gjersoe, Bruce M Hood

  Psychological science. 09/2010; 21(9):1236-41.

  Recognizing property ownership is of critical importance in social interactions, but little is known about how and when this attribute emerges. We investigated whether preschool children and adultsRecognizing property ownership is of critical importance in social interactions, but little is known about how and when this attribute emerges. We investigated whether preschool children and adults believe that ownership of one person's property is transferred to a second person following the second person's investment of creative labor in that property. In our study, an experimenter and a participant borrowed modeling-clay objects from each other to mold into new objects. Participants were more likely to transfer ownership to the second individual after he or she invested creative labor in the object than after any other manipulations (holding the object, making small changes to it). This effect was significantly stronger in preschool children than in adults. Duration of manipulation had no effect on property-ownership transfer. Changes in the object's identity acted only as a secondary cue for children. We conclude that ownership is transferred after an investment of creative labor and that determining property ownership may be an intuitive process that emerges in early childhood.

• Searching in the middle-Capuchins' (Cebus apella) and bonobos' (Pan paniscus) behavior during a spatial search task.

  Authors: Patrizia Potì, Patricia Kanngiesser, Martina Saporiti, Alessandra Amiconi, Bettina Bläsing, Josep Call

  Journal of experimental psychology. Animal behavior processes. 01/2010; 36(1):92-109.

  In this study we show that bonobos and capuchin monkeys can learn to search in the middle of a landmark configuration in a small-scale space. Five bonobos (Pan paniscus) and 2 capuchin monkeys (CebusIn this study we show that bonobos and capuchin monkeys can learn to search in the middle of a landmark configuration in a small-scale space. Five bonobos (Pan paniscus) and 2 capuchin monkeys (Cebus apella) were tested in a series of experiments with the expansion test paradigm. The primates were trained to search in the middle of a 4- or 2-landmark configuration, and were then tested with the same configuration expanded. Neither species searched in the middle of the expanded 4-landmark configuration. When presented with a 2-landmark configuration and a constant or variable inter-landmark training distance, the subjects sometimes searched preferentially in the middle of the expanded configuration. We discuss 2 alternative explanations of the results: extracting a middle rule or averaging between different goal-landmark vectors. In any case, compared to adult humans, primates appear highly constrained in their abilities to search in the middle of a configuration of detached landmarks. We discuss some of the factors that may influence the primates' behavior in this task.

• Bonobos, chimpanzees, gorillas, and orang utans use feature and spatial cues in two spatial memory tasks.

  Authors: Patricia Kanngiesser, Josep Call

  Animal cognition. 11/2009;

  Animals commonly use feature and spatial strategies when remembering places of interest such as food sources or hiding places. We conducted three experiments with great apes to investigate strategyAnimals commonly use feature and spatial strategies when remembering places of interest such as food sources or hiding places. We conducted three experiments with great apes to investigate strategy preferences and factors that may shape them. In the first experiment, we trained 17 apes to remember 12 different food locations on the floor of their sleeping room. The 12 food locations were associated with one feature cue, so that feature and spatial cues were confounded. In a single test session, we brought the cues into conflict and found that apes, irrespective of species, showed a preference for a feature strategy. In the second experiment, we used a similar procedure and trained 25 apes to remember one food location on a platform in front of them. On average, apes preferred to use a feature strategy but some individuals relied on a spatial strategy. In the final experiment, we investigated whether training might influence strategy preferences. We tested 21 apes in the platform set-up and found that apes used both, feature and spatial strategies irrespective of training. We conclude that apes can use feature and spatial strategies to remember the location of hidden food items, but that task demands (e.g. different numbers of search locations) can influence strategy preferences. We found no evidence, however, for the role of training in shaping these preferences.

• Searching in the Middle—Capuchins' (Cebus apella) and Bonobos' (Pan paniscus) Behavior During a Spatial Search Task

  Authors: Patrizia Potì, Patricia Kanngiesser, Martina Saporiti, Alessandra Amiconi, Bettina Bläsing

  Journal of Experimental Psychology: Animal Behavior Processes, v.36, 92-109 (2010).