One of the most famous experiments in psychology is Schachter and Singer’s experiment that was used to support the two-factor theory of emotions: emotions is sympathetic arousal plus cognition about the cause of the arousal (see Dror, 2017, Reisenzein, 2017, for historic reviews).

The classic article “Cognitive, social, and physiological determinants of emotional state” has been cited 2,799 times in WebofScience, and is a textbook classic.

Schachter and Wheeler (1962) summarize the “take-home message” of Schachter and Singer (1962).

In their study of cognitive and physiological determinants of emotional states, Schachter and Singer (1962) have demonstrated that cognitive processes play a major role in the development of emotional states” (p. 121).

The “demonstration” was an experiment in which participants were injected with epinephrine to create a state of arousal or a placebo. This manipulation was crossed with a confederate who either displayed euphoric or angry behavior.

Schachter and Wheeler summarize the key findings.

In experimental situations designed to make subjects euphoric, those subjects who received injections of epinephrine were, on a variety of indices, somewhat more euphoric than subjects who received a placebo injection.

Similarly, in situations designed to make subjects angry and irritated, those who received epinephrine were somewhat angrier than subjects who received placebo.

[Note the discrepancy between the claim “play a major role” and “somewhat more”]

The proceed to make clear that this pattern, although expected, could also have been produced by chance alone.

In both sets of conditions, however, these differences between epinephrine and placebo subjects were significant, at best, at borderline levels of statistical significance.

[Not the discrepancy between “demonstrated” and “borderline significance”]

Schachter and Wheeler conducted another test of the two-factor theory. The study was essentially a conceptual replication and an extension of Schachter and Singer. The replication part of the study was that participants were again injected with a placebo or epinephrine. It is a conceptual replication because the target emotion was amusement, rather than anger or euphoria. Finally, the extension was a third condition in which participants were injected with Chlorpromazine; a sedative. This should suppress activation of sympathetic arousal and dampen amusement.

One dependent variable were observer ratings of amusement. As shown in Table 3, the means were in the predicted direction, but the difference between placebo and epinephrine conditions was not significant.

Ratings of the film were additional dependent variables. Means are again in the same direction, but p-values are not reported and the text mentions that some differences were significant only at borderline levels. The pattern makes clear that this would be the case for the contrasts of the Chlorpromazine condition with the other conditions, but not for the epinephrine – placebo contrast.

Based on these underwhelming and non-significant results, the authors concluded

The overall pattern of experimental results of this study and the Schachter and Singer (1962) experiment gives consistent support to a general formulation of emotion as a function of a state of physiological arousal and of an appropriate cognition (p. 127). 

This claim is false. The replication study actually confirmed that an epinephrine injection seems to have no statistically reliable influence on the intensity of emotions.

Dorr (2017) made an interesting historical observation that Schachter was angry (presumably, without injection of epinephrine) that editors added non-significant to some of the results in the Schachter and Singer (1962) article.

“Since the paper has appeared students have tittered at me, my colleagues look down at their plates.” The most serious issue, among several, was that Tables 6–9 were totally misleading. The “notation ‘ns’ in the p column,” as Schachter explained, “is meaningless. Nothing was tested” (Schachter, S.,
1962, Schachter to R. Solomon, May 3, 1962).”  (Dorr, 2017)

Nothing was tested and nothing was proven, but a theory was born and it lives on in the imagination of hundreds of contemporary psychologists. The failure to provide evidence for it in Schachter and Wheeler was largely ignored. The article has been cited only 145 times compared to 2,799 for Schachter and Singer.

One reason for the impact of Schachter and Singer is that it was published in Psychological Review, while Schachter and Wheeler was published in Journal ol Abnormal and Social Psychology, which later became the Journal of Personality and Social Psychology.

Psychological Review is the journal where a select few psychologists can make sweeping claims with very little evidence, in the hope that other researchers will provide evidence for it. Given that psychology only publishes confirmatory evidence, every Psychological Review is a self-fulfilling prophecy, and every proposed theory will receive empirical support (even if only with marginal significance), and will live forever.

So, what are the take-home messages from this blog post.

1. The two-factor theory of emotions was never empirically supported.
2. Just because it was published in Psych Review, doesn’t mean it is true.
3. Psychology is not an evidence-based science, until it stops worshiping historically important articles as evidence for some eternal truth.
4. It is not bullying if the target of scientific criticism is deceased.

References

Dror, O. E. (2017). Deconstructing the “Two Factors”: The Historical Origins of the Schachter–Singer Theory of Emotions. Emotion Review, 9(1), 7–16. https://doi.org/10.1177/1754073916639663Copy to Clipboard

Reisenzein, R. (2017). Varieties of Cognition-Arousal Theory. Emotion Review, 9(1), 17–26. https://doi.org/10.1177/1754073916639665