  The functional object-oriented network (FOON) has been introduced as a
knowledge representation, which takes the form of a graph, for symbolic task
planning. To get a sequential plan for a manipulation task, a robot can obtain
a task tree through a knowledge retrieval process from the FOON. To evaluate
the quality of an acquired task tree, we compare it with a conventional form of
task knowledge, such as recipes or manuals. We first automatically convert task
trees to recipes, and we then compare them with the human-created recipes in
the Recipe1M+ dataset via a survey. Our preliminary study finds no significant
difference between the recipes in Recipe1M+ and the recipes generated from FOON
task trees in terms of correctness, completeness, and clarity.
