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Kea show no evidence of inequity aversion

View Article: PubMed Central - PubMed

ABSTRACT

It has been suggested that inequity aversion is a mechanism that evolved in humans to maximize the pay-offs from engaging in cooperative tasks and to foster long-term cooperative relationships between unrelated individuals. In support of this, evidence of inequity aversion in nonhuman animals has typically been found in species that, like humans, live in complex social groups and demonstrate cooperative behaviours. We examined inequity aversion in the kea (Nestor notabilis), which lives in social groups but does not appear to demonstrate wild cooperative behaviours, using a classic token exchange paradigm. We compared the number of successful exchanges and the number of abandoned trials in each condition and found no evidence of an aversion to inequitable outcomes when there was a difference between reward quality or working effort required between actor and partner. We also found no evidence of inequity aversion when the subject received no reward while their partner received a low-value reward.

No MeSH data available.


Related in: MedlinePlus

Experimental set-up and apparatus used. Rewards of each type were placed in white circular trays in the presentation area, with one reward type per tray. The experimenter offered the subject a token under the gap of the apparatus. Subjects were required to take the token and then return it to the experimenter's hand which was outstretched over the empty metal circular dishes next to the kea. The experimenter then placed the token down so that both birds could see it then gave a reward to the exchanging kea (except for trials in which the partner received a reward without having to exchange). Kea only knew which type of reward they were receiving after they had exchanged the token.
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RSOS160461F1: Experimental set-up and apparatus used. Rewards of each type were placed in white circular trays in the presentation area, with one reward type per tray. The experimenter offered the subject a token under the gap of the apparatus. Subjects were required to take the token and then return it to the experimenter's hand which was outstretched over the empty metal circular dishes next to the kea. The experimenter then placed the token down so that both birds could see it then gave a reward to the exchanging kea (except for trials in which the partner received a reward without having to exchange). Kea only knew which type of reward they were receiving after they had exchanged the token.

Mentions: Subjects were trained and tested in a wooden apparatus (150 × 50 × 100 cm ) (figure 1) that allowed them to sit side by side and interact with the experimenter, but not interfere with each other's interactions with the experimenter and kept them relatively isolated from the rest of the group to minimize distractions. The apparatus had a wooden frame covered in chicken wire enabling subjects to see each other but not interfere with their partner's behaviour. The apparatus could be entered at two separate entry points at opposite ends of the apparatus. Once inside, neither kea could gain access to the other kea's side as the apparatus was divided down the middle with a permanent wire partition. The top of the apparatus was not covered so that subjects could exit the apparatus at any point. Pieces of wooden dowel (5 × 1 cm) were used as tokens for subjects to exchange. Tokens were attached to a thin piece of string (40 cm long) which was held by the experimenter. This was to prevent subjects from leaving the apparatus with tokens and dispersing them throughout the aviary at Willowbank. Four circular trays were positioned on the apparatus, one on the far side of each kea, within reaching distance, and two in the centre of presentation area, out of reach of the kea.Figure 1.


Kea show no evidence of inequity aversion
Experimental set-up and apparatus used. Rewards of each type were placed in white circular trays in the presentation area, with one reward type per tray. The experimenter offered the subject a token under the gap of the apparatus. Subjects were required to take the token and then return it to the experimenter's hand which was outstretched over the empty metal circular dishes next to the kea. The experimenter then placed the token down so that both birds could see it then gave a reward to the exchanging kea (except for trials in which the partner received a reward without having to exchange). Kea only knew which type of reward they were receiving after they had exchanged the token.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383808&req=5

RSOS160461F1: Experimental set-up and apparatus used. Rewards of each type were placed in white circular trays in the presentation area, with one reward type per tray. The experimenter offered the subject a token under the gap of the apparatus. Subjects were required to take the token and then return it to the experimenter's hand which was outstretched over the empty metal circular dishes next to the kea. The experimenter then placed the token down so that both birds could see it then gave a reward to the exchanging kea (except for trials in which the partner received a reward without having to exchange). Kea only knew which type of reward they were receiving after they had exchanged the token.
Mentions: Subjects were trained and tested in a wooden apparatus (150 × 50 × 100 cm ) (figure 1) that allowed them to sit side by side and interact with the experimenter, but not interfere with each other's interactions with the experimenter and kept them relatively isolated from the rest of the group to minimize distractions. The apparatus had a wooden frame covered in chicken wire enabling subjects to see each other but not interfere with their partner's behaviour. The apparatus could be entered at two separate entry points at opposite ends of the apparatus. Once inside, neither kea could gain access to the other kea's side as the apparatus was divided down the middle with a permanent wire partition. The top of the apparatus was not covered so that subjects could exit the apparatus at any point. Pieces of wooden dowel (5 × 1 cm) were used as tokens for subjects to exchange. Tokens were attached to a thin piece of string (40 cm long) which was held by the experimenter. This was to prevent subjects from leaving the apparatus with tokens and dispersing them throughout the aviary at Willowbank. Four circular trays were positioned on the apparatus, one on the far side of each kea, within reaching distance, and two in the centre of presentation area, out of reach of the kea.Figure 1.

View Article: PubMed Central - PubMed

ABSTRACT

It has been suggested that inequity aversion is a mechanism that evolved in humans to maximize the pay-offs from engaging in cooperative tasks and to foster long-term cooperative relationships between unrelated individuals. In support of this, evidence of inequity aversion in nonhuman animals has typically been found in species that, like humans, live in complex social groups and demonstrate cooperative behaviours. We examined inequity aversion in the kea (Nestor notabilis), which lives in social groups but does not appear to demonstrate wild cooperative behaviours, using a classic token exchange paradigm. We compared the number of successful exchanges and the number of abandoned trials in each condition and found no evidence of an aversion to inequitable outcomes when there was a difference between reward quality or working effort required between actor and partner. We also found no evidence of inequity aversion when the subject received no reward while their partner received a low-value reward.

No MeSH data available.


Related in: MedlinePlus