Before the Civil War, all third generation New Light Calvinists used the BEST (Biblical Evidence of Salvation Test) method in the the Inquiry Room. Third generation New Light Calvinists examined seekers in the inquiry Room for "disinterested benevolence" as the initial evidence of regeneration.

Joseph Bellamy (1719-1790)

Samuel Hopkins' (1721-1803)

When Samuel Hopkins and Joseph Bellamy changed the initial evidence of regeneration from “religious affections” to “disinterested benevolence”, they gave New Light Calvinism a pseudo-scientific basis for the Inquiry Room. For the first time, seekers in the throws of law works could be intelligently guided from self-centered emotions to disinterested (unselfish) agreement with the decrees of God. In the First Great Awakening, many evangelicals understood the initial evidence of regeneration in terms of mystical affects of the Holy Spirit called “religious affections”. These affections were often accompanied with embarrassing, uncontrolled displays of emotional excitement. Denominational splits were caused in the First Great Awakening when local ministers objected to traveling preachers manipulating sinners and saints in their districts, leading large numbers into superficial, repentance and submissions to God that did not stand the test of time. Religious affections became a liability for New Light Calvinist ministers.

Religious affections were not a problem for Arminian and Old Light Calvinists. The reason was both Arminian and Old Light Calvinists did not have the expectation of immediate regeneration when a person repented and submitted to God. Here are the reasons:
1) Both Arminian and Old Light Calvinist ministers saw common grace, common faith and common repentance as available to sinners at any time. The moment a sinner decides he wants to be saved is not necessarily the time God regenerates.
2) Both Arminian and Old Light Calvinist ministers knew “The heart is deceitful above all things, and desperately wicked: who can know it? I the Lord search the heart, I try the reins, even to give every man according to his ways, and according to the fruit of his doings” (Jer 17:9-10). Fruit produced by a heart over a long period of time is the only reliable evidence of regeneration.
3) Both Arminian and Old Light Calvinist ministers expected seekers to use the means of grace and go through a period of law works before God regenerated. 
“The law was our schoolmaster to bring us unto Christ, that we might be justified by faith” (Gal 3:24).
4) Both Arminian and Old Light Calvinist ministers expected the church to be the place where seekers would confirm their salvation.  “brethren, give diligence to make your calling and election sure: for if ye do these things, ye shall never fall” (2 Peter 1:10).

Religious affections were a problem only for New Light Calvinists, since New Light Calvinists were the only ministers that saw regeneration as a definite requirement of the effective decision for Christ. Since religious affections had traditionally been the evidence of regeneration, they had to change this view.

The emotional camp meetings of the Second Great Awakening reminded everyone of the need for a rational way of dealing with seekers. This was why the Inquiry Room was seen as a necessary tool of third generation New Light Calvinists who called for an immediate decision for Christ.

The third generation New Light Calvinists Inquiry Room was used to give seekers a Biblical Evidence of Salvation Test (BEST). But the abstract nature of disinterested benevolence was tied to rational acceptance of God’s decrees, not emotional experiences of righteousness, peace and joy in the Holy Spirit. The acceptance of God’s decrees in time evolved into mere intellectual assent to scripture, so by the end of the nineteenth century, fifth generation New Light Calvinists used the Inquiry Room to give seekers a Belief In Scripture Test (BIST).