Flow, Self-Control and Happiness Revisited: Flow States, the Marshmallow Test, Decision Fatigue and the Hedonic Treadmill

The more famous the study, the more the follow-ups matter

Psychology stories about motivation and happiness are often quoted in self-help content. But many first results were later weakened or reinterpreted by larger studies. This article reads four famous topics side by side with their original and follow-up research.

Flow: when challenge matches skill

In Flow (1990), Csikszentmihalyi called the state of being so absorbed that you lose track of time flow. He studied the daily lives of many people using the experience sampling method, which asks people to record what they are experiencing at random moments during the day.

The conditions that foster flow are fairly clear.

• Balance of challenge and skill: too easy is boring; too hard is anxious.
• Clear goals: you know what to do next.
• Immediate feedback: you can tell right away whether you’re doing well.

Interestingly, during flow there is no room to feel happy. Satisfaction arrives afterwards, when you look back. So flow is closer to using your abilities fully than to “feeling good.” Ways to build a focused environment are covered further in the article on focus, habits and practice.

The marshmallow test: willpower or environment?

Mischel and colleagues (Mischel, Ebbesen & Zeiss, 1972) let children choose between eating one marshmallow now or waiting a little for two. A later follow-up (Shoda, Mischel & Peake, 1990) reported that children who waited longer did better academically in adolescence, and the story that “self-control determines success” spread.

Follow-up research changed the picture.

• Watts, Duncan and Quan (2018) re-examined the question with a larger, more diverse sample. The link between waiting time and later achievement was about half the size of the original, and mostly disappeared once family background and early cognitive ability were taken into account.
• Kidd, Palmeri and Aslin (2013) showed that children who had just seen an adult break a promise waited less. Not waiting may be a rational judgement about whether the environment is reliable, not a lack of self-control.

Decision fatigue and willpower: a well that runs dry?

Baumeister and colleagues (1998) proposed ego depletion: willpower is a resource that gets used up. Decision fatigue — the idea that judgement blurs after a day of decisions — grew from it. A study finding that Israeli parole judges granted parole less often just before meal breaks (Danziger, Levav & Avnaim-Pesso, 2011) is often cited as the classic example.

The evidence has since weakened.

• In a large study where 23 labs ran the same ego-depletion procedure, the effect was close to zero (Hagger et al., 2016).
• For the parole study, critics pointed to case ordering: cases without lawyers may have clustered just before meals (Weinshall-Margel & Shapard, 2011).
• Job, Dweck and Walton (2010) showed that depletion effects were larger in people who believed willpower runs out easily.

Everyone knows that tiredness blurs judgement. But the strong claim that “willpower exists only in a fixed amount” is hard to accept on current evidence.

The hedonic treadmill: does happiness always return to baseline?

Brickman and Campbell (1971) proposed the hedonic treadmill: even after good things happen, we soon get used to them and happiness returns to its usual level. A well-known study found lottery winners were not as much happier as expected (Brickman, Coates & Janoff-Bulman, 1978).

Diener, Lucas and Scollon (2006) reviewed later research and revised the theory.

• Set points differ between people, and most are not neutral but mildly happy.
• Adaptation to events like unemployment or disability is incomplete, so happiness can stay lower for a long time (Lucas, 2007).
• Happiness is therefore not fixed; it can change. Effects tend to last longer from things that stay fresh, like relationships and experiences, than from possessions we quickly get used to.

Summary at a glance

Topic	The first story	After follow-up research
Flow	Flow makes you happy	The conditions are clear; satisfaction comes afterwards
Marshmallow	Children who wait succeed	The link is small; environment matters a lot
Decision fatigue	Willpower runs out	Near-zero effect in large replications
Hedonic treadmill	Happiness returns to baseline	Set points vary and can change

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References

• Csikszentmihalyi, M. (1990). Flow: The Psychology of Optimal Experience. Harper & Row.
• Mischel, W., Ebbesen, E. B., & Zeiss, A. R. (1972). Cognitive and attentional mechanisms in delay of gratification. Journal of Personality and Social Psychology, 21(2), 204–218.
• Shoda, Y., Mischel, W., & Peake, P. K. (1990). Predicting adolescent cognitive and self-regulatory competencies from preschool delay of gratification. Developmental Psychology, 26(6), 978–986.
• Watts, T. W., Duncan, G. J., & Quan, H. (2018). Revisiting the marshmallow test: A conceptual replication. Psychological Science, 29(7), 1159–1177.
• Kidd, C., Palmeri, H., & Aslin, R. N. (2013). Rational snacking: Young children’s decision-making on the marshmallow task is moderated by beliefs about environmental reliability. Cognition, 126(1), 109–114.
• Baumeister, R. F., Bratslavsky, E., Muraven, M., & Tice, D. M. (1998). Ego depletion: Is the active self a limited resource? Journal of Personality and Social Psychology, 74(5), 1252–1265.
• Danziger, S., Levav, J., & Avnaim-Pesso, L. (2011). Extraneous factors in judicial decisions. PNAS, 108(17), 6889–6892.
• Weinshall-Margel, K., & Shapard, J. (2011). Overlooked factors in the analysis of parole decisions. PNAS, 108(42), E833.
• Hagger, M. S., et al. (2016). A multilab preregistered replication of the ego-depletion effect. Perspectives on Psychological Science, 11(4), 546–573.
• Job, V., Dweck, C. S., & Walton, G. M. (2010). Ego depletion—Is it all in your head? Psychological Science, 21(11), 1686–1693.
• Brickman, P., & Campbell, D. T. (1971). Hedonic relativism and planning the good society. In M. H. Appley (Ed.), Adaptation-Level Theory (pp. 287–302). Academic Press.
• Brickman, P., Coates, D., & Janoff-Bulman, R. (1978). Lottery winners and accident victims: Is happiness relative? Journal of Personality and Social Psychology, 36(8), 917–927.
• Diener, E., Lucas, R. E., & Scollon, C. N. (2006). Beyond the hedonic treadmill: Revising the adaptation theory of well-being. American Psychologist, 61(4), 305–314.
• Lucas, R. E. (2007). Adaptation and the set-point model of subjective well-being. Current Directions in Psychological Science, 16(2), 75–79.