Although I know that over time there is both idiom shift and changes in belief about the residence and mechanisms of various human characteristics, I nevertheless find it amusing and interesting that the translators’ notes* for Ps. 8:10 (“…he who probes the mind and conscience is God the righteous.”) and Ps. 16:7 (“I bless the LORD who has guided me; my conscience admonishes me at night.”) indicate that the word for which the English “conscience” has been used would be literally translated as “kidneys.” Also, in Ps. 26:2 (“Probe me, O LORD, and try me, test my heart and mind;”), “heart and mind” is literally “kidneys and heart.”
*for the Jewish Publication Society’s 1985/1999 Tanakh translation as published in The Jewish Study Bible, Oxford University Press, New York, 2004.