昂貴信號、訊息溝通與軍事投射能力：中國對臺軍事演習案例的比較分析

Abstract

自2022年起，中國多次在美中臺重大事件後對臺發動軍事演習，以表達其反對臺獨，又或者是反對美國容許臺灣倚美謀獨的立場與決心。這些行動雖符合昂貴信號理論，卻也出現理論未涵蓋的現象，例如軍演期間的中國海空軍兵力波及日本，顯示中國有意透過第三國製造「國際沉沒成本」來加強對美國信號的可信度。現有理論文獻著重於雙邊關係與國內成本，無法有效解釋此類透過挑釁第三國來發送信號的行為；同時，當前挑釁理論文獻所指出的邏輯，又與昂貴信號目的是要對手讓步的機制存在矛盾。為補充理論空白，本文提出「加強型昂貴信號」概念，並以11起美中臺重大事件進行檢驗。本研究以訊息溝通狀況與軍事投射能力等2個自變數，並以軍演的4種程度為依變數，來探討加強型昂貴信號機制。研究結果支持本文提出的6項假說，確認信號發送國在訊息溝通狀況不佳時，更傾向發送加強型昂貴信號來確保自身意圖正確地讓信號接受國理解，且具有足夠的軍事投射能力與否確實會影響信號發送國的發送考量。同時，本文亦確認加強型信號符合昂貴信號的核心邏輯，也就是信號是在確實需要時才會被發送，而不單只是在有能力時就會被發送。

Since 2022, China has repeatedly launched military exercises against Taiwan in the aftermath of major U.S.-China-Taiwan events. These operations aim to demonstrate Beijing’s opposition to Taiwanese independence and its resolve against what it sees as Washington’s indulgence of efforts by Taiwan to use the U.S. to seek independence. While these exercises align with the logic of costly signaling, they also exhibit patterns not fully captured by existing theories. For example, during some exercises, Chinese military units and weapons have affected areas of Japan, suggesting that Beijing is deliberately provoking third-party countries to create international audience costs in order to enhance the credibility of its signals to the United States. Existing literature primarily focuses on bilateral relationships and domestic costs, making it ill-equipped to explain signaling behaviors that intentionally provoke third countries. Moreover, the logic underpinning current theories of provocation contradicts the core purpose of costly signaling, which is to induce concessions from the target state. To address this theoretical gap, this article proposes the concept of augmented costly signals and tests it using 11 critical U.S.-China-Taiwan events. The study identifies two independent variables—the state of communication and force projection capabilities—and examines their impact on four levels of military exercise intensity as the dependent variable. The findings support all six of the study’s hypotheses. They confirm that when communication is poor, the signaling state is more likely to send augmented costly signals to ensure its intentions are correctly interpreted by the target state. Additionally, whether the signaling state possesses sufficient force projection capabilities significantly influences its decision to escalate signaling. Finally, the study affirms that augmented costly signals are consistent with the core logic of costly signaling: such signals are employed only when truly necessary, rather than simply when the sender has the capacity to do so.