Not related to frogs, but my rescue bearded dragon "Lucy" as her previous owners called her, let her eat almost all insects because she hadn't transitioned to greens and other plant matter as a juvenile or sub-adult. Needless to say, they never held her either, unless cleaning her tank which by the appearance of it, they didn't do often. When I got her, she was defensive, puffed out her beard, made herself look bigger, stretched out, and for 1-3 weeks I kept holding her to the point of I wasn't going to hurt her. I gave her super-worm salads, and she while I was getting a super-worm in the salad dish, grabbed it out of my hand. I now hand feed her most foods, unless they are crickets (I hate them btw) or a salad. Also, when-ever she sees our shorkies get out of their boxes, she claws at her tank, and follows me around to get out. She has become so tame in that regard, when-ever I try to put her back in the tank, she scrambles up my arm and tries to evade me. I'm pretty sure that has to use some intelligence, and who knows, maybe frogs have the same "Tame" instincts, but their "Wild" instincts take top priority