When placed in front of a mirror, manta rays are more active (e.g. expose their ventral side to the mirror) and present more frequent and repetitive movements (e.g. furling and unfurling their cephalic lobes) relative to being placed in front of a white board. Such behavior has been interpreted as self-awareness by some scientists, and as social behavior (i.e. the manta believes its reflection is a different individual) by others.
What test, if any, could be performed so as to distinguish which of these cases, self-awareness or social interaction, is causing the mantas to behave in such way?