Letter and Podcast Sources
LETTER and PoDCAST BY GINA SOLEIL, FOUNDER OF THE ENERGY CEO™
How We Use Research
Standard across all Energy CEO publications
When we reference a study, statistic, or specific research finding, we share the source below so you can read it for yourself. We don’t cite every widely accepted idea. That would make things more academic than useful. And when the research is still developing, mixed, or uncertain, we’ll tell you that clearly. Our goal is simple: use research honestly, make it understandable, and be clear about what we know, what we don’t, and what’s still being studied.
INFORMED BY
№06 | October 14, 2026
The happiness curve has a missing question
On the midlife low in well-being across 145 countries
Blanchflower, D.G. (2021). Is happiness U-shaped everywhere? Age and subjective well-being in 145 countries. Journal of Population Economics, 34(2), 575–624.
On why the happiness curve remains scientifically debated
Galambos, N.L., Krahn, H.J., Johnson, M.D., & Lachman, M.E. (2020). The U shape of happiness across the life course: Expanding the discussion. Perspectives on Psychological Science, 15(4), 898–912.
On the response defending the happiness curve
Blanchflower, D.G., & Graham, C.L. (2021). The U shape of happiness: A response. Perspectives on Psychological Science, 16(6), 1435–1446.
On emotional stability and mixed feelings as people age
Carstensen, L.L., Turan, B., Scheibe, S., Ram, N., Ersner-Hershfield, H., Samanez-Larkin, G.R., Brooks, K.P., & Nesselroade, J.R. (2011). Emotional experience improves with age: Evidence based on over 10 years of experience sampling. Psychology and Aging, 26(1), 21–33.
On how perceived time shapes priorities and relationships
Carstensen, L.L. (2021). Socioemotional selectivity theory: The role of perceived endings in human motivation. The Gerontologist, 61(8), 1188–1196.
On wealth, emotional well-being, and survival in later life
Steptoe, A., & Zaninotto, P. (2020). Lower socioeconomic status and the acceleration of aging: An outcome-wide analysis. Proceedings of the National Academy of Sciences, 117(26), 14911–14917.
On improving daily life by changing both a person’s support and their home
Szanton, S.L., Xue, Q.-L., Leff, B., et al. (2019). Effect of a biobehavioral environmental approach on disability among low-income older adults: A randomized clinical trial. JAMA Internal Medicine, 179(2), 204–211.
On improvements in depressive symptoms among CAPABLE participants
Szanton, S.L., Leff, B., Wolff, J.L., Roberts, L., & Gitlin, L.N. (2016). Home-based care program reduces disability and promotes aging in place. Health Affairs, 35(9), 1558–1563.
What We Didn’t Claim
The happiness curve describes population patterns, not individual destinies. Forty-seven is not a universal turning point, and comparisons between age groups do not prove that aging causes happiness. Findings on emotional development reflect averages, while the theory that our sense of time shapes our priorities is not a proven explanation for the curve.
In the British aging study, mortality figures came from the original 8,402 participants, while emotional findings came from the 5,018 who survived and remained. The associations do not establish that wealth alone caused the differences.
CAPABLE improved daily functioning at five months, but not every outcome. Findings on depressive symptoms came from a separate 281-person evaluation without a comparison group.
The hope in this letter is a possibility, not a guarantee.
№05 | October 7, 2026
We give dissatisfaction too much credit
On what happens when life satisfaction exceeds what we expected
Bertoni, M., & Corazzini, L. (2018). Asymmetric affective forecasting errors and their correlation with subjective well-being. PLOS ONE, 13(3), e0192941.
On satisfaction with progress and what follows it
Szumowska, E., Jasko, K., Dukała, K., & Górska, P. (2025). Goal cycle: Motivational and emotional antecedents and consequences of goal progress. Motivation and Emotion, 49(4), 384–405.
What We Didn't Claim
This letter and podcast do not claim that dissatisfaction is bad, that it never motivates, or that satisfaction will make you more productive or successful. The German study measured how satisfied people expected to be with their lives, not career or financial goals, and it shows a pattern, not proof of cause and effect. People in that study who fell short of their expectations also lowered them, so expectations do not only move upward. The goal-progress finding comes from 390 university students followed over one semester, and it is an association. No study has tested what happens to a person's drive when dissatisfaction is removed. And a lasting sense of emptiness or low mood is different from the everyday restlessness described here and may deserve professional attention.
№04 | September 30, 2026
Joy is not a reward for finishing
On the guilt that can come with leisure
Koo, H.J., Piff, P.K., Götz, F.M., Stieger, S., & Shariff, A.F. (2026). Leisure guilt. Personality and Social Psychology Bulletin. Advance online publication.
On how believing leisure is wasteful changes how much we enjoy it
Tonietto, G.N., Malkoc, S.A., Reczek, R.W., & Norton, M.I. (2021). Viewing leisure as wasteful undermines enjoyment. Journal of Experimental Social Psychology, 97, 104198.
On why unfinished work follows us home
Wendsche, J., Weigelt, O., & Syrek, C.J. (2026). Unfinished work tasks and work-related thoughts during off-job time: Meta-analysis of the Zeigarnik effect in a work-recovery context. Anxiety, Stress, & Coping, 39(4), 385–407.
On what positive emotion does to attention
Fredrickson, B.L., & Branigan, C. (2005). Positive emotions broaden the scope of attention and thought-action repertoires. Cognition & Emotion, 19(3), 313–332.
On savoring positive experiences
Bryant, F.B. (2021). Current progress and future directions for theory and research on savoring. Frontiers in Psychology, 12, 771698.
What We Didn't Claim
This letter and podcast do not claim that leisure guilt makes rest less restorative, that unfinished work causes rumination, or that joy will make you more productive or successful. The 14 percent figure comes from roughly 300 U.S. adults sampled over one week, and the relationship between leisure guilt and reduced benefits from leisure is an association, not proof of cause and effect. The positive-emotion experiments captured brief emotional states in a laboratory, not what joy does across an entire working life. Finishing things and working hard are not the problem. And a persistent inability to experience pleasure is different from the everyday pattern described here and may deserve professional attention.
№03 | September 23, 2026
Being liked is not the same as being known
On how we read a room and adjust ourselves to it
Snyder, M. (1974). Self-monitoring of expressive behavior. Journal of Personality and Social Psychology, 30(4), 526–537.
On what happens in the body when we hide what we're feeling
Gross, J.J., & Levenson, R.W. (1993). Emotional suppression: Physiology, self-report, and expressive behavior. Journal of Personality and Social Psychology, 64(6), 970–986.
On the physical cost of holding an expression in check
Roberts, N.A., Levenson, R.W., & Gross, J.J. (2008). Cardiovascular costs of emotion suppression cross ethnic lines. International Journal of Psychophysiology, 70(1), 82–87.
On the difference between privacy and concealment
Larson, D.G., & Chastain, R.L. (1990). Self-concealment: Conceptualization, measurement, and health implications. Journal of Social and Clinical Psychology, 9(4), 439–455.
On what tends to accompany a habit of concealing
Larson, D.G., et al. (2015). Self-concealment: Integrative review and working model. Journal of Social and Clinical Psychology, 34(8), 705–729.
On fatigue and the effort of managing how we're seen
Ai, W., et al. (2025). Intentional use and self-efficacy as distinct facets of impression management and their relationships with socio-motivational, cognitive, and mental health factors. Scientific Reports, 15, 41050.
On why we want to be recognized, not only admired
Swann, W.B., Jr., & Buhrmester, M.D. (2012). Self-verification: The search for coherence. In M.R. Leary & J.P. Tangney (Eds.), Handbook of Self and Identity (2nd ed., pp. 405–424). Guilford Press.
What We Didn't Claim
This letter and podcast do not claim that maintaining a familiar version of yourself burns a measurable amount of energy, that concealment causes depression or anxiety, or that adapting to different people is dishonest. Adjusting how we show up across relationships is ordinary social skill, and often it is care. The 1993 study captures what the body does during a few minutes of suppression, not what years of composure cost. The 2025 study shows what tends to appear together, not what causes what, and it found a different pattern for people who felt capable in social situations. Skill is not the problem.
№02 | September 16, 2026
You may need daylight more than a cup of coffee
On how light supports sleep, wakefulness, and daily rhythm
Brown, T.M., et al. (2022). Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults. PLOS Biology, 20(3), e3001571.
On how natural light helps reset the body clock
Wright, K.P., et al. (2013). Entrainment of the human circadian clock to the natural light-dark cycle. Current Biology, 23(16), 1554–1558.
On caffeine’s benefits for alertness and performance
McLellan, T.M., Caldwell, J.A., & Lieberman, H.R. (2016). A review of caffeine's effects on cognitive, physical and occupational performance. Neuroscience & Biobehavioral Reviews, 71, 294–312.
On how caffeine later in the day can affect sleep
Drake, C., et al. (2013). Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. Journal of Clinical Sleep Medicine, 9(11), 1195–1200.
On how caffeine dose and timing affect sleep
Gardiner, C., et al. (2023). The effect of caffeine on subsequent sleep: a systematic review and meta-analysis. Sleep Medicine Reviews, 69, 101764.
On daytime light, nighttime light, and mental health
Burns, A.C., et al. (2023). Day and night light exposure are associated with psychiatric disorders: an objective light study in more than 85,000 people. Nature Mental Health, 1, 853–862.
What We Didn’t Claim
This letter and podcast do not claim that there's one exact amount of morning light everyone needs, that the 86,000-person study proves light directly causes better mental-health outcomes, or that daylight should be used as a treatment for depression. The research on light is more nuanced than a single number can capture, and when a study shows association rather than cause, we keep the claim within those limits. The camping study followed eight people for one week, which makes it a demonstration of what the body does when the natural signal is restored, not a prescription for anyone in particular.
№01 | September 9, 2026
The life you notice is the life you experience
On how attention filters what reaches awareness
Theeuwes, J. (2025). Attentional capture and control. Annual Review of Psychology, 76, 251–273.
On confirmation bias
Nickerson, R.S. (1998). Confirmation bias: A ubiquitous phenomenon in many guises. Review of General Psychology, 2(2), 175–220.
On negativity bias
Baumeister, R.F., Bratslavsky, E., Finkenauer, C., & Vohs, K.D. (2001). Bad is stronger than good. Review of General Psychology, 5(4), 323–370.
On mind-wandering
Killingsworth, M.A., & Gilbert, D.T. (2010). A wandering mind is an unhappy mind. Science, 330(6006), 932. Sampled 2,250 adults. Mind-wandering occurred in 46.9% of moments.
On mindfulness and rumination
Perestelo-Perez, L., Barraca, J., Peñate, W., Rivero-Santana, A., & Alvarez-Perez, Y. (2017). Mindfulness-based interventions for the treatment of depressive rumination: Systematic review and meta-analysis. International Journal of Clinical and Health Psychology, 17(3), 282–295.
What We Didn’t Claim
This letter and podcast do not claim that mind-wandering causes unhappiness, that positive thinking should replace hard truths, or that clinical mindfulness research applies the same way to everyone in everyday life. When research shows an association rather than cause, or comes from a specific setting or population, we keep the claim within those limits.
Experience life differently.
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