What were the real origins of the Schachter–Singer two-factor theory?

A historiographical debate — about the history of the idea, not (directly) about emotion itself — raised by Dror (2017). It matters for the wiki because the standard genealogy shapes how the two-factor theory is taught and how its relationship to James–Lange and to autonomic-specificity is understood.

The standard narrative

Schachter & Singer themselves installed it in their 1962 opening: a continuous line from James–Lange through Cannon’s critiques and the adrenalin-injection experiments, culminating in cognitive-arousal theory. Textbooks reproduce it.

Dror’s revision (archival evidence)

• The cognitive view of emotion entered via Festinger’s social-comparison theory: to extend “drive for self-evaluation” from opinions/abilities to emotions, Schachter needed emotions to be partly cognitively determined. The sources were Ruckmick (1936) and Young (1943), not James–Lange.
• The euphoria condition was pure social influence (a euphoric stooge), structurally identical to the affiliation studies.
• James–Lange framing and the Cantril & Hunt / Landis & Hunt citations were added at reviewer (Solomon) request; the original manuscript cited only Marañón (1924). Wheeler: “I don’t think that the James–Lange controversy was important to us.”
• The pure cognitive-arousal theory (any cognition, not social contagion) was first truly enacted in the follow-up Schachter–Wheeler (1962) movie experiment.
• The theory’s real historical significance: universalizing sympathetic arousal as constitutive of every emotion — the culmination of an early-20th-century “adrenalizing” of the emotions (against Cannon’s strong/soft, sympathetic/parasympathetic distinctions and 1940s parasympathetic findings).

Why it stays open

Dror’s is an interpretive reconstruction leaning partly on decades-later recollections; it has not been comprehensively rebutted, but as revisionist history it invites counter-reading. It does not dispute the theory’s content, only its provenance — but that provenance bears on the autonomic-specificity-of-emotion debate, since the “undifferentiated arousal” premise turns out to be a social-psychological import rather than a physiological result.