<p>Friendship may not be unique to humans as chimpanzees also bond with each other based on trust, a new study suggests.<br /><br />The findings suggest that friendship based on trust has evolved much earlier than previously thought. Researchers observed the interactions of fifteen chimpanzees over a five-month period. Based on friendly interactions among chimp pairs, including grooming and eating together, the researchers identified each chimpanzee's closest 'friend' and a 'non-friend.'<br /><br />The researchers from Max Planck Institute for Evolutionary Anthropology in Germany (MPG) then made the chimps to play a modified version of what is known as the human trust game, both with their friend and with their non-friend.<br /><br />In the game, chimps had a choice between pulling a 'no-trust rope' and a 'trust rope.'<br />When the no-trust rope was pulled, the first chimp got immediate access to a food it did not like especially well.<br /><br />When the trust rope was pulled instead, the other chimp got immediate access to a much more tempting food item and the option to send a treat back to the first chimp (or not).<br />The trust rope offered the potential for a win-win, but only if the first chimp trusted the other enough to send something back.<br /><br />Each chimp played the game twelve times with its friend and another twelve times with its non-friend.</p>.<p>The results of those experimental interactions between the chimps showed much greater trust between friends than non-friends.<br /><br />"Chimpanzees were significantly more likely to voluntarily place resources at the disposal of a partner, and thus to choose a risky but potentially high-payoff option, when they interacted with a friend as compared to a non-friend," said researchers.<br /><br />The findings suggest that human friendship is not so unique, researchers said.<br />"Other animals, such as chimpanzees, form close and long-term emotional bonds with select individuals," said Jan Engelmann from MPG.<br /><br />"These animal friendships show important parallels with close relationships in humans. One shared characteristic is the tendency to selectively trust friends in costly situations," he said.<br /><br />The findings were published in the journal Current Biology. </p>
<p>Friendship may not be unique to humans as chimpanzees also bond with each other based on trust, a new study suggests.<br /><br />The findings suggest that friendship based on trust has evolved much earlier than previously thought. Researchers observed the interactions of fifteen chimpanzees over a five-month period. Based on friendly interactions among chimp pairs, including grooming and eating together, the researchers identified each chimpanzee's closest 'friend' and a 'non-friend.'<br /><br />The researchers from Max Planck Institute for Evolutionary Anthropology in Germany (MPG) then made the chimps to play a modified version of what is known as the human trust game, both with their friend and with their non-friend.<br /><br />In the game, chimps had a choice between pulling a 'no-trust rope' and a 'trust rope.'<br />When the no-trust rope was pulled, the first chimp got immediate access to a food it did not like especially well.<br /><br />When the trust rope was pulled instead, the other chimp got immediate access to a much more tempting food item and the option to send a treat back to the first chimp (or not).<br />The trust rope offered the potential for a win-win, but only if the first chimp trusted the other enough to send something back.<br /><br />Each chimp played the game twelve times with its friend and another twelve times with its non-friend.</p>.<p>The results of those experimental interactions between the chimps showed much greater trust between friends than non-friends.<br /><br />"Chimpanzees were significantly more likely to voluntarily place resources at the disposal of a partner, and thus to choose a risky but potentially high-payoff option, when they interacted with a friend as compared to a non-friend," said researchers.<br /><br />The findings suggest that human friendship is not so unique, researchers said.<br />"Other animals, such as chimpanzees, form close and long-term emotional bonds with select individuals," said Jan Engelmann from MPG.<br /><br />"These animal friendships show important parallels with close relationships in humans. One shared characteristic is the tendency to selectively trust friends in costly situations," he said.<br /><br />The findings were published in the journal Current Biology. </p>