title: The importance of witnessed agency in chimpanzee social learning of tool use.
abstract: Social learning refers to individuals learning from others, including information gained through indirect social influences, such as the results of others' actions and changes in the physical environment. One method to determine the relative influence of these varieties of information is the 'ghost display', in which no model is involved, but subjects can watch the results that a model would produce. Previous research has shown mixed success by chimpanzees (Pan troglodytes) learning from ghost displays, with some studies suggesting learning only in relatively simple tasks. To explore whether the failure of chimpanzees to learn from a ghost display may be due to neophobia when tested singly or a requirement for more detailed information for complex tasks, we presented ghost displays of a tool-use task to chimpanzees in their home social groups. Previous tests have revealed that chimpanzees are unable to easily solve this tool-use task asocially, or learn from ghost displays when tested singly, but can learn after observing conspecifics in a group setting. In the present study, despite being tested in a group situation, chimpanzees still showed no success in solving the task via trial-and-error learning, in a baseline condition, nor in learning the task from the ghost display. Simply being in the presence of their group mates and being shown the affordances of the task was not sufficient to encourage learning. Following this, in an escalating series of tests, we examined the chimpanzees' ability to learn from a demonstration by models with agency: (1) a human; (2) video footage of a chimpanzee; (3) a live chimpanzee model. In the first two of these 'social' conditions, subjects showed limited success. By the end of the final open diffusion phase, which was run to determine whether this new behavior would be transmitted among the group after seeing a successful chimpanzee use the task, 83% of chimpanzees were now successful. This confirmed a marked overall effect of observing animate conspecific modeling, in contrast to the ghost condition. This article is part of a Special Issue entitled: insert SI title.
authors.affiliation: Lester E. Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, Chicago, IL, USA; Michale E. Keeling Center for Comparative Medicine and Research, UT MD Anderson Cancer Center, Bastrop, TX, USA; School of Psychology and Neuroscience, University of St Andrews, St Andrews, Scotland.
authors.forename: Lydia M
authors.initials: LM
authors.lastname: Hopper
authors.affiliation: Michale E. Keeling Center for Comparative Medicine and Research, UT MD Anderson Cancer Center, Bastrop, TX, USA.
authors.forename: Susan P
authors.initials: SP
authors.lastname: Lambeth
authors.affiliation: Michale E. Keeling Center for Comparative Medicine and Research, UT MD Anderson Cancer Center, Bastrop, TX, USA; Department of Experimental Medicine, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Schapiro
authors.affiliation: School of Psychology and Neuroscience, University of St Andrews, St Andrews, Scotland. Electronic address: aw2@st-andrews.ac.uk.
authors.forename: Andrew
authors.initials: A
authors.lastname: Whiten
mesh_terms: D000818:Animals; D005260:Female; D007100:Imitative Behavior; D007858:Learning; D008297:Male; D002679:Pan troglodytes; D012919:Social Behavior; D012931:Social Environment; D053001:Tool Use Behavior
keywords: Chimpanzee; Ghost display; Social facilitation; Social learning; Tool-use; Video display