16. A computer-implemented method, comprising: displaying, on a device interface, a set of candidate objects for object recognition and an image having a missing object, the set of candidate images including the missing object and a first candidate object, wherein the first candidate object does not correspond to the image; detecting a selection of a candidate object from the set of candidate objects; and determining whether the selection was made by a human based on whether the candidate object corresponds to the missing object.
16. A computer-implemented method, comprising: displaying, on a device interface, a set of candidate objects for object recognition and an image having a missing object, the set of candidate images including the missing object and a first candidate object, wherein the first candidate object does not correspond to the image; detecting a selection of a candidate object from the set of candidate objects; and determining whether the selection was made by a human based on whether the candidate object corresponds to the missing object. 17. The computer-implemented method of claim 16 , wherein the determining includes: determining that the selection of the candidate object is made by a bot in response to identifying the candidate object as different from the missing object; or determining that the selection of the candidate object is made by a human in response to identifying the candidate object as the missing object.