Here is a case where we need to think critically about expert opinions (according to Juho Ritola’s theory of Reasonable Credulity). Daniel Kahneman makes the following claim in Thinking, Fast and Slow.
People who are cognitively busy are also more likely to make selfish choices, use sexist language, and make superficial judgments in social situations.[1] … Too much concern about how well one is doing in a task sometimes disrupts performance by loading short-term memory with pointless anxious thoughts. The conclusion is straightforward: self-control requires attention and effort. …
A series of surprising experiments by the psychologist Roy Baumeister and his colleagues has shown conclusively that all variants of voluntary effort – cognitive, emotion, or physical – draw at least partly on a shared pool of mental energy [the limited strength model of self-control]. …
Baumeister’s group has repeatedly found that an effort of will or self-control is tiring; if you have had to force yourself to do something, you are less willing or less able to exert self-control when the next challenge comes around. The phenomenon has been named ego depletion. …
The evidence is persuasive: activities that impose high demands on System 2 require self-control, and the exertion of self-control is depleting and unpleasant.[2] (pp.41-42; followed by a description of Baumeister’s hypothesis about the physiological underpinning of ego depletion in terms of glucose depletion, citing the well-known Lemonade Experiment)
But, Baumeister’s theory of Ego Depletion is far from conclusive. Here is a troubled history of this theory.
(1) Baumeister’s theory of Ego Depletion became the widely accepted and extremely influential paradigm for understanding self-control and willpower, with the publication of his groundbreaking paper “Ego Depletion: Is the Active Self a Limited Resource?” in 1998 (cited over 3,000 times by Baumeister’s academic peers since then). Baumeister then co-wrote a pop-science plus self-help book with NYT science writer John Tierney, Willpower: Rediscovering the Greatest Human Strength (2012), talking about the secrets of self-control and how to master it. Its main ideas are simply illustrated in this video:
(2) But the theory has been challenged, to say the least.
- Reproducibility failure: “Publication bias and the limited strength model of self-control: has the evidence for ego depletion been overestimated?” Evan C. Carter & Michael E. McCullough, Frontiers in Psychology, July 2014.
- Possibly mere placebo effect – beliefs about willpower can affect self-control performance: “Beliefs about willpower determine the impact of glucose on self-control,” Veronika Job et al. National Academy of Sciences, August/September, 2013.
- Maybe motivational switches play the key role: “Why self-control seems (but may not be) limited,” Michael Inzlicht et al. Trends in Cognitive Sciences, March 2014.
- A more recent meta-analysis of both sides the debate, showing that the available evidence is inconclusive: “Is Ego Depletion Real? An Analysis of Arguments,” Malte Friese et al., Personality and Social Psychology Review, March 2018.
- Here is a vivid illustration of Inzlicht’s philosophically as well as scientifically interesting alternative theory, according to which self-control is a kind of emotion (a negative feeling):
(3) Here are some helpful reviews and discussions.
- Slate: ego depletion theory may have been debunked. At the end of this post there is a short video debunking myths about male-female brain differences, which also includes a segment suggesting that beliefs can affect performance.
- Harvard Business Review: we may have been wrong for 30 years.
- How to graciously accept that one may have been wrong about self-control all these years. This blogpost is an admirable piece of critical thinking in action, showing how critical-thinking skills can make one’s belief-set more adaptive and responsive to new information (as Ritola points out at the end of his paper).
- What do we do now? – practical implications and new directions, with a few suggestive hacks for achieving the results that we once expected to use the self-control mechanism to achieve.
- Cultivate a sense of intellectual humility, recognizing that even the brightest of all scientists have their cognitive blind spots, that it’s important to ask “Might I be wrong about this theory?” now and then, and that it’s ok to admit “I was wrong.”
(4) Bigger problems
- Reproducibility crisis in psychology, as described here and here.
- Publication biases, esp. that of favoring positive results and withholding negative results. This affects meta-analyses in particular, as they tend to look at published and hence mostly positive studies. (It’s worth adding, though, that the psychology community now tries to mitigate this problem by adopting and enforcing the Registered Reports method — i.e. conducting peer reviews before the results are known.)
- Media attention bias.
- Citation bias.
Here is a helpful and quite succinct video presentation of the trouble with the field of psychology as is reflected in the history of the Ego Depletion theory:
[1] This can be a phenomenon of moral licensing.
[2] This reference to unpleasant feeling is closer to Michael Inzlicht’s theory that self-control is an emotion.