The key to knowing which ones can actually be released is a concept called cognitive complexity.
知道哪些动物可以被释放到野外的关键是一个叫做认知复杂性的概念。
英语百科
Cognitive complexity
Cognitive complexity describes cognition along a simplicity-complexity axis. It is the subject of academic study in fields including personal construct psychology, organisational theory and human–computer interaction.