Relative quantity judgment by Asian elephants (Elephas maximus).

Area of Science:

• Cognitive Ethology
• Animal Behavior
• Comparative Psychology

Background:

• Understanding numerical cognition in non-human animals is crucial for evolutionary insights.
• Relative Quantity Judgment (RQJ) is a fundamental cognitive ability involving the comparison of magnitudes.
• Previous studies have explored RQJ in various species, but findings vary.

Purpose of the Study:

• To investigate if Asian elephants possess the capacity for relative quantity judgment (RQJ).
• To examine how elephants perform RQJ under simultaneous and sequential presentation conditions.
• To compare elephant RQJ mechanisms with those observed in other animal species.

Main Methods:

• Elephants were presented with two baskets containing differing quantities of bait (up to 6 items) simultaneously.
• Elephants were also tested with sequential bait presentations, obscuring total quantities.
• The task required elephants to select the basket with the larger quantity in both experimental designs.

Main Results:

• Elephants consistently chose the larger quantity significantly more often in both experimental setups.
• No evidence of disparity effects (performance decrease with smaller quantity differences) was observed.
• No evidence of magnitude effects (performance decrease with increasing total quantity) was found.

Conclusions:

• Asian elephants exhibit robust relative quantity judgment abilities.
• The absence of disparity and magnitude effects suggests unique quantity processing mechanisms in elephants.
• These findings challenge existing models of numerical cognition in animals and highlight interspecies differences.