In the past, researchers focused on the effects of temperature and chemical composition, but the variable of pressure was ignored, mainly because past laboratory techniques could not create a high-pressure environment. Even if high pressures could have been attained, it would have been impossible to observe and verify what changes were occurring in the materials.
過去的研究著重在溫度變化與化學成分對物質的影響，唯獨「壓力」這個變項一直以來都被忽視，原因是過去的實驗技術創造不出高壓環境，也無法觀察、確定物質在高壓下會發生什麼變化。