Yamamoto Flashcards
Aim
To learn more about chimpanzees’ helping behaviour.
1. whether they can understand the needs of conspecifics.
2. whether they respond to those needs with targeted helping.
Research Method, Design
Lab, repeated measures design
Independent variable
the ability of the chimpanzee to give targeted help in 2 situations:
* Can see the tool use task of the recipient chimpanzee.
* Cannot see.
Dependent variable
targeted helping behaviour (stick or straw)
Sample
5 Socially housed chimpanzees at the Primate Research Institute, Kyoto University, opportunity sampling, Ai (mom) with Ayumu (child)
* Pan (mom) with Pal (child)
* Chloe (mom) with Cleo (child)
Procedure
The helper chimpanzee had to offer the recipient chimpanzee the correct tool. 1 task required a stick and the other straw. The recipient chimpanzee obtained a reward: a juice box. There were 7 objects in the helping chimpanzee’s tray: stick, straw, belt, chain, brush, hose, string. First, the chimpanzee did condition 1 (can see). Next, the chimpanzee did condition 2 (cannot see). Then, they repeated condition 1 (can see) to check for order effects. There were 48 trials carried out in each condition. 24-stick use and 24 straw-use trials were randomly ordered. There were 2 – 4 trials per day. A trial starts when the tray was presented to the helper chimpanzee. A trial ends when the recipient succeeded in obtaining the juice box or when 5 minutes had passed without receiving an object.
Data recording
‘Offers’ were counted when chimpanzees held out objects regardless of if whether the recipients took them. Only the first offer was counted. Participant’s behaviours were recorded using 3 cameras.
Behaviours
- Upon request offer: a tool is offered when the recipient requests. A request was when the recipient poked an arm through the hole.
- Voluntary offer: help is actively offered without the recipient’s explicit request.
- No offer: the tools are taken away without an offer.
Object offer meaning
when chimpanzees offer any object which may be right or wrong. ‘Tool’ is the correct object given. ‘Non-tools’ are any other objects given.
Results for Can See condition
- Object offer = 90% of trials. In the familiarisation phase, object offer was 5%. ‘Upon request offer’ accounted for 90% of all offers.
- Except for Pan, sticks and straws were significantly more frequently offered the non-tools (78% - 97.4%). Pan most frequently offered non-tool, brush, which may be due to past experience.
- Chimpanzees demonstrated flexible targeted helping depending on their partner’s tool-use situation.
Results for Cannot See condition
- Object offer = 90% of trials. Upon request offer accounted for 71.7% of all offers.
- Cleo showed a significant increase in offering help in the ‘cannot see condition’ and this may be due to a carryover effect. This increased voluntary offer as the helper learned that they are expected to offer an object to their partner.
- Stick/straw was not offered more than the non-tools. Except Ayumu did as he kept peeking through the hole. This shows that chimpanzees understood their partner’s goals only when they could see.
Results for 2nd Can See condition
3 chimpanzees who had shown a significant decrease in tool selection in the first condition and a non-significant decrease in the cannot see condition were used.
1. Object offer observed for 98% of trials. Upon request offer for 79% of all offers.
2. Significant decrease in the offer of stick/straw depending on the partner’s situation. This confirms that flexible targeted helping with an understanding of the tool need to complete the task was possible when chimpanzees could see the task for themselves.
Conclusion
- Chimpanzees will help conspecifics in most cases, but usually as a response to a direct request rather than voluntarily.
- Chimpanzees rely on visual confirmation of conspecific needs in order to offer targeted helping.
Strengths
- High Reliability
Weaknesses
- Low ecological validity
