It's not about an Oracle. It's that the mentioning of a topic prior to some conclusion generating observation has practically never generated replicable results. Still, these studies make news all the time because they're easy to p-hack into some interesting conclusion.
Reading the study it appears they went to some pains in not revealing their intentions:
> The caregiver and child were seated across from one another at a table. The child completed an unrelated experiment with the researcher, while the caregiver completed the Scarcity or Control manipulation survey on a tablet. When the caregiver had finished, the researcher left the room under the guise of loading a second survey onto the iPad, leaving the caregiver and child alone with a toy the experimenter happened to offer as she left. A video camera and/or tape recorder recorded their interactions.
The conclusion could be that being reminded or queried about hardships has a chilling effect
