ESTILO DE CRIANZA PARENTAL PREPONDERANTE Tabla 17 Estilo de crianza parental

Only 10 of the 17 actions elicited in the experimental design also occurred in interactions with conspecifics. Of these 10, only 6 were used as intentional gestures with conspecifics, and only 5 of those could be determined to reliably predict signallers’ observable goals. The gestures that appeared in both experimental and natural

communicative attempts were raspberry face (hit ground/object), and offer. Four of these gestures (shake object, reach, wave, cage bang) were used to initiate affiliation or play in conspecific interactions. The gesture offer seemed to be used with conspecifics to draw another’s attention to an object that the signaller was holding. Raspberry face met the criteria for use as an intentional gesture, but there were not enough examples of it to determine whether it had a particular function. The four “affiliate/play” gestures seen in both contexts were particularly salient examples of the set of gestures associated with the affiliate/play meaning in conspecific interactions. It is possible that these gestures are used when the signaller is particularly excited. This could help to explain their occurrence in both play and food-begging contexts. Lending support to the excitement hypothesis; shake object was observed during display behaviour by both males and females, but it was typically directed towards visitors at the zoos or did not have a clear recipient and so was not included in the study of conspecific gesture. It is also possible that the

artificially-imposed distance between signaller and recipient in the experimental design meant that the signaller required the cooperation of the experimenter to fulfil their goal of retrieving the food, thus causing the signaller to use affiliative signals in her attempt to elicit aid. Though the end result in both the cooperative experimental and food-sharing natural scenarios is the same, the signaller may make a distinction between requesting aid from a keeper and food-sharing from a conspecific and subsequently choose different types of gestures.

The different types of gestures used by the orangutans in experimental and natural settings unfortunately meant that direct comparison of strategy in the two conditions was not possible. The strategies orangutans used when communicating with conspecifics seemed to be aimed at reiterating or emphasising their goals when recipients did not

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respond as desired, and appeared to take into account whether recipients could have seen the past gestures or not. The strategies orangutans used in the experimental setting appear instead to focus attracting the attention of the experimenter (who remained unresponsive for long periods of time) and differed based on how close the experimenter came to fulfilling the signaller’s goal.

5.5 Discussion

The sequences of gestures produced by the same six orangutans under natural circumstances to conspecifics demonstrated both persistence and elaboration (see Chapter 4). However, it was difficult to determine what the specific goal of the signaller was in each situation and whether the recipient’s subsequent actions represented

misunderstanding, refusal, or response to each gesture. The experimental design allowed us to control for both the goal of the signaller and the response of the recipient. In

addition, the periods during which the experimenter was unresponsive elicited extremely long sequences of gestures from the orangutans, which allowed observation and analysis of more complex patterns of gestures. Rather than relying on a single transition from the first to second gesture to gain insight into persistence strategies, the sequences produced by the six experimental subjects often provided 5 or more transitions to analyse. The sequences produced during the three experimental pre-delivery phases and the two post- delivery phases that involved persistence ranged from 1 to 25 gestures long, but on average contained slightly over 6 gestures (mean 6.39 ± 5.01).

The six orangutans tested appeared to have a specific goal in mind, i.e. gaining a desirable food item, which they attempted to achieve indirectly by communicating with the human experimenter. As they did in conspecific interactions (Chapter 3), the

orangutans in the experiment persisted in their communicative attempts when their goal was not met. This effect of persistence was also found in the chimpanzees tested in the Leavens et al. (2005). Orangutans have previously been found to be sensitive to the visual

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attention of an interlocutor in experimental settings (Liebal et al. 2004; Poss et al. 2006), but the orangutans in the current experiment went much further, acting on the apparent understanding of the recipient. The orangutans in the present study appeared to

distinguish between being partially understood (when given part of the desired food) and being completely misunderstood (when given an unwanted food item). Their subsequent communicative attempts reflected this distinction. When confronted with a response that suggested partial understanding of their desire, the orangutans continued to use those signals they had used before the delivery of any food, often giving a signal repeatedly. When they were given the wrong item altogether, they instead chose to use other signals rather than to repeat those used already, and they avoided signal repetition, often

attempting each new behaviour only once. The combined results of the communicative strategies identified in natural and experimental conditions suggest that orangutans are highly sensitive to the behaviour of their intended recipients and alter their

communicative attempts in a manner consistent with an understanding of others as autonomous, intentional beings.

The strategy employed by the orangutans under experimental conditions

resembles that of the parlour game “charades,” in which the player tries to get her team to guess the name of a book or movie by acting it out non-verbally. As the player

gesticulates on stage, her team calls out their guesses as to what is being portrayed. If your team is close to your answer, the best strategy is to repeat and refine the signals that have already partially worked. But if your team completely misunderstands your

gestures, it is better to switch to new signals until they guess something close to your goal. This strategy not only maximizes a player’s efficiency in choosing an effective indicator, but also communicates to the team how close they are to understanding the intended meaning. While the communication sequences of the orangutans here are perhaps not as sophisticated, they nonetheless accomplish the same objectives. By maximizing efficiency at searching for an understood signal and homing in on those that achieve partial success, orangutans are able to overcome misunderstandings. In the absence of a shared lexicon, one way of arriving at a shared meaning is to adopt a

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a signal indicating how well you have been understood. If the recipient can use this information, then the signaller and recipient will be able to arrive at a common

understanding much faster. This strategy offers one possible pathway toward constructing a shared lexicon from learned or ritualized signals. Though there is no evidence that meaningful orangutan gestures are acquired through this process, investigation into the strategies employed in the intentional communication of apes may nevertheless provide insight into the pre-linguistic devices that helped construct the very earliest forms of hominin language.

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