選擇性模仿是指嬰兒在不同情境中選擇性地模仿他人的行為，為當今發展心理學備受矚目的議題。在Gergely、Bekkering與Király（2002）著名的研究中，當實驗者的雙手自由放在桌上，示範以額頭碰盒子開燈，嬰兒偏好模仿此新奇動作；但當實驗者雙手緊抓毛毯示範相同的動作則未發現嬰兒有顯著的模仿偏好。有些研究者認嬰兒可以透過目的推理理解他人的意圖，並認為模仿是建立在對意圖的解讀之上；相反地，動作－效果整合理論則認為動作本身的執行困難度與動作－效果連結的穩定性才是影響嬰兒選擇性模仿的主因。 為了解決兩者長久以來對於嬰兒模仿的爭議，本研究修訂Gergely等人（2002）的光盒研究派典，將焦點放在過去一直未受到重視的因果效能概念，降低示範動作的因果效能，嬰兒在實驗過程中會發現示範動作不是每次都能成功讓光盒發亮，藉此釐清目的推理論與動作－效果整合理論對嬰兒選擇性模仿的解釋適當性。實驗1的結果重製了Gergely等人（2002）的實驗結果，實驗2A與實驗2B皆發現18個月大的嬰兒在因果效能較低的情境中很少會模仿示範動作，顯示嬰兒的模仿行為較符合動作－效果整合理論的觀點，主要是受到動作執行的困難度與動作－效果聯結的穩定性的影響。 / Selective imitation refers to a phenomenon which infants differentially imitate the demonstrated action in different contexts. Recently, it has also become a popular research topic in developmental psychology. Gergely, Bekkering and Király (2002) uncovered a classic example of selective imitation. They found that infants tend to imitate the action of touching a light box with their forehead when they saw a model perform the action with her hands placed on the table, but not when her hands were restricted by a blanket. Some researchers claim that infants can interpret others’ intention through teleological reasoning, and they consider infants’ imitation is based on decoding of intentionality. Conversely, ideomotor theory argues that imitation depends on difficulty of the action execution and the stability of link between action and its effect. To address the long-standing dispute with infants’ imitation, we revised the paradigm in Gergely et al. (2002) and focused on the concept of causal efficacy which had been long ignored in the past. Infant would find that the demonstrated action, sometimes won’t turn on the light during the experimentation. In experiment 1, we replicated the results obtained in Gergely et al. (2002). Experiment 2A and 2B both found that 18-month-old infants rarely imitated the demonstrated action when the causal efficacy was relatively low. These results are closer to the ideomotor approach viewpoint of imitation, and it reveals that infants’ imitation depends on difficulty of the action execution and the stability of link between action and effect.