人體動作的產生與時間與空間有著密切的關係。動作速度與準確度消長的研究在認知心理學與運動行為學領域裡一直都是很熱門的研究議題。一般來說，當平均動作速度增加時，動作結果的空間誤差會隨著增加；但是相反的，動作結果的時間誤差卻是隨著平均動作速度的增加而減少。過去絕大部分這類的研究都專注探討在空間或時間單一維度下的動作準確度。Hancock 與Newell （1985） 提出結合時空 （space-time） 的觀點來了解動作速度與準確度消長的關係，其立意架構植基於動作空間與時間維度間的密切相關：動作時間的測量必須參考空間的標準，測量空間的準度，也須要有時間的參考標準。當空間與時間的動作誤差同時被測量時，兩個維度的動作誤差分布受到動作平均速度影響的趨勢是與諧且密不可分。從應用的角度來看，如欲完整了解動作速度與準確度的關係，必須採取時空架構的論點，從時-空兩維度同時進行觀察與測量。近期研究的結果建議，研究者可以嘗試將時間與空間動作誤差的測量結合成一個時-空變數 （如表現分數、訊息熵），這個時-空變數提供另一個角度來了解與解釋動作速度與準確度的關係。

The speed-accuracy trade-off has been a long standing interest in the field of motor behavior and cognitive psychology. The essence of the speed-accuracy relation is that with an increase in movement speed there is concomitant decrease in movement spatial accuracy. However, human movement always take place in both space and time, it has been shown that increasing movement velocity within the same movement time results in decreasing movement timing error, rather than increasing the error as in a movement spatial accuracy task. Most previous research of the movement speed and accuracy relation considers movement error on only one of these dimensions. Hancock and Newell (1985) proposed a space-time framework of the movement speed-accuracy relation that is based on the space-time principle where the spatial component of movement is always measured with respect to time and the temporal component of movement is always measured with respect to space. Recent research results provided an alternative perspective and a more complete account of the spatial-temporal performance using joint information entropy and performance score to describe and explain the speed and accuracy trade-off phenomenon.