Moral Intuitions and Emotions: Evaluating the Evidence

We have considered Schnall, Haidt, Clore, & Jordan (2008) as evidence for the idea that moral intuitions rely on the Affect Heuristic (as Sinnott-Armstrong et al (2010) propose). Whenever we encounter potential evidence, we should ask two questions of it. First, is it really evidence? Second, is it sufficient to justify us in accepting the claim we take it to be evidence for?

• stream
• youtube
• slides only

Notes

On this course you will be evaluating quite a lot of scientific evidence. As this is not something you are required to be familiar with doing before taking the course, I shall go through the process of evaluation quite slowly for the first time.

Step 0: Never Trust a Philosopher

This includes me, your lecturer. Always evaluate the evidence for yourself.

Step 1: Is It Really Evidence?

When faced with a potential piece of evidence, there are three questions you should always ask:

1. Has the study been replicated?
2. Are there similar studies? If so, are the findings convergent?
3. Has the study featured in a review? If so, does the review broadly support the findings of this study?

In the case of Schnall et al. (2008), I originally suggested (in the recording and the first version of these notes) that we answer as follows:

1. No, afaik this study has not been replicated. (This is fine; the only concern is when a study has been replicated and the replication failed.¹)
2. Yes, there are similar studies (e.g. Eskine, Kacinik, & Prinz, 2011); yes, these findings are convergent with those of Schnall et al. (2008).
3. Yes, the study has featured in at least one review (Chapman & Anderson, 2013, p. 313). Yes, this review does broadly support the findings of Schnall et al. (2008).

However, since recording this section, I learned that Ugazio, Lamm, & Singer (2012, p. Experiment 1a) report a failed partial replication of Schnall et al. (2008) (thank you Ollie!). Since these authors did not distinguish between high and low private body consciousness, the failure does not appear to be informative and does not undermine the main conclusion (whereas a further update, below, does undermine it).

The review mentioned in (3) provides strong support for the broad conclusion:

‘To date, almost all of the studies that have manipulated disgust or cleanliness have reported effects on moral judgment. These findings strengthen the case for a causal relationship between disgust and moral judgment, by showing that experimentally evoked disgust—or cleanliness, its opposite—can influence moral cognition’ (Chapman & Anderson, 2013, p. 313).

At this point, it seems there is little doubt that we are right to take the findings of Schnall, Haidt, et al. (2008) as evidence. This is what I originally concluded, and what I say in the recording (‘overwhelmingly yes’ at 10:42). However, since then I realised that a meta-analysis by Landy & Goodwin (2015) draws the opposite conclusion,² as does a recent study (Jylkkä, Härkönen, & Hyönä, 2021; thank you Julina!). Authoritative commentaries by Giner-Sorolla, Kupfer, & Sabo (2018, pp. 261–2) and Piazza, Landy, Chakroff, Young, & Wasserman (2018) conclude that the available evidence is not strong.³ If I were recording the lecture today, I would not be quite so bold. Overall we appear to have only weak evidence.

But there is a further question we should ask before accepting the Hypothesis about the Affect Heuristic.

Step 2: Is This Evidence Sufficient to Justify Accepting the Affect Heuristic?

Previously (in Moral Intuitions and Emotions: Evidence) we considered supporting the Hypothesis that the Affect Heuristic is true by appeal to evidence for the correctness of one of its predictions. But this way of supporting the hypothesis has two weaknesses:

• it is post-hoc (the evidence for the prediction existed before the prediction was generated); and
• for all we know other predictions of the hypothesis may be falsified.

Neither weakness means that the evidence entirely fails to support the Hypothesis that the Affect Heuristic provides a correct account of moral intuitions. But these weaknesses do indicate that we require more robust support for the Hypothesis.

In searching for more robust support, we should consider the most successful arguments for heuristics (in reasoning generally, not in ethics specifically), and use these arguments as a model for what we would need to establish the Hypothesis about the Affect Heuristic.

Conclusions

Schnall, Haidt, et al. (2008) do provide good evidence.

We have sufficient evidence to conclude that feelings do influence moral intuitions (although this point will get further consideration in PS: Does emotion influence moral judgment or merely motivate morally relevant action?).

But this evidence is not by itself sufficient to justify accepting the hypothesis that the Affect Heuristic provides a correct account of moral intuitions.

Glossary

References