Yamamoto

Chimpanzee Flexible Targeted Helping (2012)

Social Approach

looks at how behaviors and cognitions are influenced in social situations

pro-social behavior

(psychology)

any behavior with the intention of helping

ex | clean-up song at the end of Barney playing in daycare makes kids clean up

instrumental helping

(psychology)

help and care based on cognitive appreciations of the need or situation of others; have to be altruistic and have to be empathetic

Background

• prior to this study, it was believed that only humans have altruistic behavior because theory of mind is needed

• prior studies have shown that primates have cooperative behaviors

• previous studies have shown why primates help others

• it is unknown how primates know to help each other

• Yamamoto wants to investigate the cognitive abilities of chimpanzees, specifically if they can engage in targeted helping

Aim

to learn more about the helping behaviors of chimpanzees

Sub-Aim #1

does a chimpanzee have the ability and flexibility to understand needs of another chimp?

Sub-Aim #2

can they respond with targeted helping?

Sub-Aim #3

can they help without being asked?

Hypothesis

Chimps can understand the needs of con-specifics and can respond to those needs with targeted helping

Independent Variable

conditions: can see (1st), can see (2nd), cannot see

Dependent Variable

helping behavior

• percentage of trials of what object is offered 1st by helper

• percentage of trials where stick or straw is offered when it was or wasn’t needed

Method

• Controlled laboratory setting

• Repeated measures - every chimpanzees takes part in all three conditions

• Data collected with structured observation using cameras

cameras

(apparatus)

three video cameras recording the behavior

tray

(apparatus)

holds 7 possible tools (straw, stick, chain, rope, hose, brush, belt)

booths

(apparatus)

one is bigger than the other; hole is cut on wall in between for giving and asking for help

Participants

6 mother-and-child chimpanzees opportunity sampled from the Primate Research Institute in Japan, chosen because they’re all experts in two-tool tasks

Control #1

The tools are always in the same locations on the tray at the start of each trial

Control #2

All chimpanzees undergo the same tool familiarization training

Control #3

The “can see” and “cannot see” conditions are randomly allocated

Step 1

(procedure)

One chimp acts as the tool chimp and the other as the juice chimp

Step 2

(procedure)

The task is for the juice chimp to get the positive reinforcement of the juice, which can only be achieved if they are given the stick to pull it closer or the straw to drink it, supplied by the tool chimp. The juice chimp can stick their arm through the hole to ask for help

Step 3

(procedure)

Before each trial, the tool tray will be pushed into the booth and the tool chimp has time to become familiar with it. The 5 minute timer marks the start o the trial

Step 4

(procedure)

In 5% of trials, the tool chimp passed a tool before the timer began

Step 5

(procedure)

In the first “can see” condition, there will be 48 trials - 24 stick, 24 straw, randomly ordered. The juice chimp either needs the stick or straw to access the juice or drink it

Step 6

(procedure)

In the “cannot see” condition, the situation is the same as “can see,” except there is an opaque wall between the booths

Step 7

(procedure)

The second “can see” condition is used to check for the order effect and see if there is an increase in helping behavior. It is the same as the first “can see” condition, except the 48 stick and straw trials are randomized in a different order

Step 8

(procedure)

The chimps will go through about 4 trials a day, and each trial will be video recorded

Step 9

(procedure)

Only the first tool offered is counted in the data, and it is separated into 2 categories. Category 1, upon request, is if the juice chimp stuck their arm through the hole, and Category 2, voluntary, is if the tool was given before request

Data

quantitative - first tool offered, number of requests made, number of voluntary offers, number of theft transfers

(recorded via cameras)

theft transfers

when the tray is close enough to the hole that the juice chimp reaches in and grabs the tool they need

Finding #1

A tool was offered in 91% of the first “can see” trials. In 90% of these trials, the tool was given upon request. Four of the chimps offered the stick or straw first, and Pan offered the brush 80% of the time

Finding #2

A direct request is important for the onset of helping behavior

Finding #3

A tool was offered in 96% of the “cannot see” trials. In 71% of those trials, the tool was given upon request. The four chimps still offered stick or straw, and Pan offered the brush

Finding #4

A tool was offered in 98% of the second “can see” trials. Four chimps offered the stick or straw more frequently, and Pan’s accuracy went up to 100%

Conclusion #1

Primates have advanced cognitive abilities

Conclusion #2

The likelihood of targeted helping significantly increases when the helper can see what the recipient needs

Conclusion #3

Even when they can’t see what’s needed, chimps can still try to provide help

ethics

use of animals - the study was approved by the Animal Care Committee at Kyoto University

numbers

(ethics - use of animals)

only 6 chimps were used, which was the minimum number needed

housing

(ethics - use of animals)

the chimps were housed socially in their normal environment

deprivation and aversive stimuli

(ethics - use of animals)

the task of getting the positive reinforcement was an enriching, interactive activity

Strength #1

The use of repeated measures allows for comparability of each chimp between conditions

Strength #2

The use of randomization in the 24 stick and 24 straw trials prevents the order effect

Strength #3

The use of cameras to record prevents demand characteristics

Strength #4

This study lends support to the Cognitive Approach because it proves theory of mind in chimps and to the Learning Approach because positive reinforcement is used to teach helping behavior

Weakness #1

Chimps can’t be generalized to all humans, only to small children

Weakness #2

The sample of chimps is all female, mother-child pairs that are already experts at two-tool tasks, making it hard to compare to them with other chimps

Application

(issues & debates)

to teaching children about helping behavior and to help without being asked

Individual v. Situational

(issues & debates)

supports situational because all chimps have theory of mind and the only thing different is the situational role of helper or recipient