短語詞組短語stimulus generalization approach 激勵推廣理論stimulus generalization and assimilation 刺激的泛化和同化gradient of stimulus generalization 刺激類化遞變operant stimulus generalization 操作性刺激泛化primary stimulus generalization 初級刺激類化stimulus generalization gradient 刺激類化梯度 返回 stimulus generalization