YAMAMOTO et al (2012)

AIM:
To learn more about altruistic behavior in chimpanzees:
• To find if chimpanzees can comprehend the needs of their conspecifics – members of their own species
• To find if they can react to these needs with targeted helping

BACKGROUND:
Unlike humans, animals help more often at a direct request of their conspecific and not voluntarily. Target help is based on the understanding of the situation the individual in need is and therefore the helper requires ‘theory of mind’. Some believed that the ‘theory of mind’ and therefore altruistic helping is only attributed to humans, however, studies have found that primates showed altruistic food sharing. One cognitive explanation for social behavior is targeted/instrumental helping – help is provided when the situational needs are perceived by the helper. Chimpanzees have shown to offer targeted help at the direct request but it not known whether they can interpret the need of conspecifics.

RESEARCH METHOD: 
The experiment was a laboratory one since it took place in an artificial environment.

EXPERIMENTAL DESIGN: 
The chimpanzees took part in both conditions of the study and each condition had several trials, therefore, the experiment had repeated measures design.

VARIABLES:
The independent variable was whether the chimpanzees could see the other chimpanzee’s situation or not (if the panel between the adjacent rooms was transparent or not)
The dependent variable was the targeted help offered by the chimpanzees. This was operationalized as a correct tool or not correct non-tool item offered.

SAMPLE:
The participants were recruited from the Primate Research Institute at Kyoto University and consisted of 5 chimpanzees (Ai, Pan, Ayumu, Pal and Cleo) paired in mother and child. The chimpanzees participated beforehand in studies on helping behavior and were acquainted with the tool-use task in this experiment.

PROCEDURE: 
the task consisted of one chimp being in one room with the need for a stick or a straw in order to get a juice drink. The other chimp had to provide the first with the correct tool out of the 7 available from the adjacent room through a hole in the wall.
Prior to the trials, the chimps had a familiarisation phase in which they could investigate and use each tool to learn its purpose and potential application to situations.
The procedure consisted of 3 conditions: first was the ‘can see’ condition – the chimps could see into the adjacent room as the panel between them was transparent, then the ‘cannot see’ condition – the panel was opaque and therefore the situation was not visible through it, and lastly, another ‘can see’ condition to ensure the actions were intentional and not done because of order effects. Each condition had 48 trials, half of which had the correct tool as the stick and the other half the straw; the order was randomized. There were around 2-4 trials conducted per day.
The trials were considered finished when either the receipent obtained an offered tool or after 5 minutes of no tool being offered. An ‘offer’ was operationalized as a chimp holding a tool for the other, even if the other didn’t take it; only first offers were counted.
The procedure was recorded using a video camera, filming chimpanzee’s behavior. From this, quantitative and qualitative data were extracted, in the form of the number of correct offers given and chimpanzee’s gestures/movement respectively.

RESULTS: 
In the first ‘can see’ condition, offers were given in 91% of the trial, however, mostly upon request. This is a significant increase from the familiarisation phase were only 5% of offers were made. Except for one chimp, the tool offers were more frequent than the non-tool ones – chimps are able to asses the difference between tools and non-tools. In most cases, the chimps offered the correct tool – stick or straw, according to the situation  – they were able to offer targeted help by understanding the other chimp’s situation.
In the ‘cannot see’ conditions – tools were offered 96% of the trials but also mainly upon request. Most chimps offered a tool more frequent than a non-tool. The chimp Pan was offering mainly a brush at first, but when this was removed, she made correct offers.
In the ‘can see’ there was a significant difference between the offer of a stick or straw, meanwhile in the ‘cannot see’ condition there wasn’t. The chimp Ayumu offered correct tools more frequently because he was peeking through the hole between the rooms – he observed the situation in order to evaluate the appropriate tool.
In the second ‘can see’ condition offers were made in 98% of the trials with 80% of them being upon request; there was a significant difference between the offers of stick or straw – confirms the need of situation evaluation.

CONCLUSIONS: 
• Chimpanzees are able to understand the needs of conspecifics and help them solve tasks.
• Chimps will offer help in most cases but rather at direct request than spontaneously
• Chimpanzees require a visual confirmation to understand a conspecific’s goal so to offer targeted help