Oct 27, 2026 · 55 min
Design portfolios for human behavior, not spreadsheets
Dr. Daniel Crosby on Behaviorally Optimal Portfolios, Risk Composure and the Casino Myth
Investors often undermine their own returns, making psychological sustainability as important as allocation theory.
- 1Behaviorally optimal portfolios prioritize staying invested over maximizing returns on paper.
- 2Risk tolerance, risk capacity, and composure are distinct dimensions that require separate attention.
- 3Speculative apps and constant media exposure can turn investing into a variable-reward behavior loop.
Don't miss
Crosby explains why an unusually exciting investment idea may be a warning sign rather than an opportunity.
The brief
Daniel Crosby argues that portfolio design should work with human psychology rather than demand heroic willpower, distinguishing spreadsheet-optimal from behaviorally optimal investing.
His safety, stability, and success portfolios address different objectives, while separate measures of risk tolerance, capacity, and composure explain why investors react differently.
The conversation contrasts diversified, relatively uncorrelated stability assets with a concentrated, rules-based success portfolio built around value, quality, and momentum.
Prediction markets, sports betting, and stimulating investing apps can turn curiosity into compulsive speculation, especially when unrealistic expectations encourage Hail Mary strategies.
Crosby’s warning is simple: unusual excitement may signal a bad investment idea, while education, rules, humility, and human guidance help preserve discipline.
What was said on this episode
20 statements · 7 positive · 9 negative · 1 mixed · 3 neutral
Understanding behavioral tendencies can turn them into beneficial tools.
“we can understand it and make it work for our own benefit”
Listen at 4:41
Portfolio optimality depends on the investor holding the portfolio.
“whether or not a portfolio is optimal depends on who's holding it”
Listen at 6:11
A portfolio’s effectiveness depends on the investor’s ability to maintain it.
“the portfolio will only be as good or as bad as someone's ability to stick with it”
Listen at 6:21
The average investor in the cited focused equity fund lost money.
“the average investor in that uh in that fund actually lost money”
Listen at 7:07
Investor timing caused losses despite the fund’s strong underlying returns.
“it would run up people would hear about it they'd pile in it would mean revert they second guess it and jump out”
Listen at 7:22
Crosby prioritizes returns adjusted for the anxiety required to achieve them.
“I'm trying to anxiety adjust my returns and get the greatest returns I can for the requisite amount of sleep well at nightness.”
Listen at 8:12
Investment risk has three dimensions that should be measured separately.
“there's actually three different dimensions to risk, and we need to be attending to and measuring them all”
Listen at 14:04
Risk composure measures whether short-term emotions override long-term risk tolerance.
“risk composure is the likelihood that someone's short-term emotional reaction will dislocate their longer-term risk tolerance”
Listen at 15:33
Prediction markets and sports betting have harmed the broader investing community.
“prediction markets and sports betting in particular have done a great disservice to the larger investing community”
Listen at 25:11
Economic and policy conditions have left people feeling financially constrained.
“we're at a place where people feel strapped”
Listen at 25:51
Prudent long-term investing has nothing in common with a five-leg sports parlay.
“prudent, evidence-based, long-term investing and a five-leg parlay on the, you know, MLB playoffs have anything in common just shows how lost we are”
Listen at 27:14
Variable-reward designs make gambling and investing apps highly addictive.
“the variable reward structure of these things is, I mean, every piece of it is maximum addictiveness”
Listen at 34:21
People’s behavior is influenced more by their environment than by intentions or goals.
“people's behavior is has far less to do with their desires their motivations or their goals and it has a great deal more to do with their environment”
Listen at 37:06
Removing gambling apps from phones reduces the likelihood of gambling.
“you would be much less likely to gamble if you don't keep the app on your phone”
Listen at 37:50
Behavior change requires education, supportive environments, and encouragement.
“You've got to educate yourself. You've got to make the environment conducive to the things you want to do and then surround yourself with the right encouragement or support.”
Listen at 38:27
Markets can remain behaviorally irrational for a long period.
“markets can stay behaviorally irrational for a very, very long time”
Listen at 39:52
Crowded market positioning creates investment opportunities.
“opportunities are being created as more and more people crowd into one side of the boat”
Listen at 39:59
Recommendation algorithms amplify users’ existing market biases.
“the algorithm is primed to magnify your biases”
Listen at 41:59
Algorithmic personalization narrows ideas and increases conviction in one-sided market views.
“your world will get smaller, your ideas will get more narrow, and that you will be more convinced of a very lopsided proposition”
Listen at 42:22
Avoiding algorithmically amplified market content is the safest approach.
“abstinence is just about the only form of safety here”
Listen at 42:34
Statements are attributed to the speaker as said on the episode and reflect their view at the time, not PodLume's. They are not advice.
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