User Psychology Playbook for Product Managers – A Commentary

Psychology is a subject that fascinates me. Having a good model of how people's minds work not only helps when we deal with others. It also helps us understand our own behaviours and idiosyncrasies. Product Faculty has published User Psychology Playbook for Product Managers which piqued my interest.

To me, the most interesting material challenges your model of the world. If you agree with everything that a book says, have you truly learned anything? I will not be reviewing the entire playbook in detail but instead pick out a few parts that created a moment of dissonance or insight. For transparency, I recently completed the Advanced Product Management course from Product Faculty. I paid for it with my own money and I am a happy customer.

As far as the old brain’s concerned, it’s looking out for number one; it's all about you. Your old brain will ignore any messages that it sees as irrelevant.
-from User Psychology Playbook for Product Managers

In the age of social media and self-PR, it seems clear that people are only looking out for themselves. However, in our evolution-driven brain, the ego is certainly a priority but only insofar as making sure you survive long enough to pass on your DNA. In The Selfish Gene¹, Richard Dawkins lays out the science behind why parents will jump into burning buildings to save their children. Humans and our genetic cousins such as chimpanzees (99% shared DNA) and bananas (~50%) are vessels for our genes to continue replicating. Not only that, studies suggest that there are at least as many bacteria in the human body as there are cells of their host². Now, who is really in charge?

Another interesting aspect of our brain is our capacity for altruism. Jumping into the fire to save your child might make sense to ensure the survival of your DNA but what about the starving child across the globe? The Selfish Gene argues that this wiring evolved from tribal times where any person you meet was likely to share your genes and reciprocate acts of generosity. Altruism, in essence, is a by-product of our evolutionary origins.

That being said, Dawkins notes that understanding how the human brain is wired does not make acts of selfless bravery any less admirable or beautiful. The watchmaker who understands every component that goes into a watch can still marvel at their creation. In this case, our brains misfire in a way that is beneficial to humanity as a whole. In not so good cases, humans have been imbued with a capacity to rise above our genetic wirings but we often succumb to their whims.

When given a long list of items to remember, people are more likely to remember the first item (the primacy effect) and the last item (the recency effect).

Primacy and recency effects have been well established in recall of lists. However, I would argue that one's opinion of a product is not a test of recalling a list of features but your experience of using these features. Garbinsky (2014)⁵ found that in a hedonic situation involving gluttony (chips - my worst enemy, only rivalled by ice cream), people tended to remember the end better than the first due to an effect called memory interference. For example, multilingual people experience situations where you cannot recall a word that you know in another language. This effect also occurs in short-term memory. For this reason, recency effect has a stronger impact than primacy effect.

In 1993, Kahneman et al.³ found that test subjects preferred to submerge their hand in 14 °C water for 60 seconds with the temperature gradually raised to 15 °C compared to 30 seconds at 14 °C water. Clearly, the cumulative discomfort experienced over 60 seconds is greater than 30 seconds but duration does not seem to be a big factor compared to how the experience ended. The preference for ending at 15 °C over 14 °C is the recency effect in the quote above. I once self-administered the cold pressor test (a fancy name for dunking one’s hand in ice water) with water temperature at 4 °C and held for the maximum of 4 minutes as per MacLachlan et al. 2016⁴. I suspect my unusually fond recollection of that event is partially attributable to the fact that the water temperature rose by roughly 1 °C over the duration of the test.

Finally, Varey & Kahneman (1992)⁶ experimentally demonstrated retrospective evaluations of films being well-predicted by a weighted average of the peak and final evaluations. This effect has been confirmed by another study (Redelmier & Kahneman, 1996)⁷ involving colonoscopy patients. More recently, a study (Do, et al., 2008)⁸ applied this theory to the evaluation of material goods and found similar results. For a product to be remembered positively, focus on the peak and final experiences. That being said, for itemized segments within the product like SKU recommendations, the primacy effect can come into play.

What numbers can you use to back up your claims? Amazon [...] know[s] that if we can see lots of other people have enjoyed a product, we'll be more likely to purchase it too.

When making decisions on purchases, humans do not evaluate a product or service holistically but substitute this cognitively intensive task with an easier one. Kahneman discussed this substitution bias in his book Thinking, Fast and Slow⁹. A sports car offers horse power, torque, 50-50 weight distribution, and a quick 0-60 time as substitute questions for the more difficult question of whether or not the car is right for you.

In his book, Kahneman gave an example of a stock trader who purchased Ford stocks because he liked their cars. Unfortunately, how much one likes a car is not the same question as how well-priced the company stock is. For what is often people’s second biggest single-item expense, car purchases tend to be laden with emotion.

Tinder revolutionized online dating by reducing the emotional friction involved. Rather than having to pour their hearts out in a message to a stranger, only to be ignored or rejected, now people just had to swipe right

Tinder took the dating world by storm by reducing the emotional cost of potential rejections to a swipe-and-forget process. The matching process is also random to the user, akin to a slot machine. Minimal emotional cost and randomness of matching led to a $18.6 B market cap of Match Group, the parent company of Tinder and other major dating platforms. Ironically, the long-term and prevalent use of these dating apps can affect the matrimonial zeitgeist for the worse.

1.6 billion swipes a day world-wide turns dating into a numbers game. Pull the slot machine lever enough times, and you are mathematically guaranteed to hit the jackpot. However, there are some downsides to chronic gambling. Reduced emotional cost has the consequence of devaluing individual relationships where people run at the first sight of trouble, on to their next match. Over time, this can lead to a decline in successful long-term relationships.

A danger of building massively successful products is the unknown unknowns. It is unlikely that companies like Facebook or Twitter had foreseen all the ways that their product would be used today. Products that took advantage of the brain’s neural circuitry is changing the circuitry itself. Unfortunately, companies driven by the profit motive are not necessarily looking out for their users' best interests. It is our duty then, as users, to be informed and prioritize our well-being. Products have limitless potential to add value to a person’s life but you should always be its master, not its slave.

¹Dawkins, R. The Selfish Gene. Oxford; New York: Oxford University Press, 1989.
²Sender R, Fuchs S, Milo R. Revised Estimates for the Number of Human and Bacteria Cells in the Body. PLoS Biol. 2016;14(8):e1002533. Published 2016 Aug 19. doi:10.1371/journal.pbio.1002533
³Kahneman, Daniel, et al. “When More Pain Is Preferred to Less: Adding a Better End.” Psychological Science, vol. 4, no. 6, Nov. 1993, pp. 401–405, doi:10.1111/j.1467-9280.1993.tb00589.x.
⁴MacLachlan, Cameron et al. “The Cold Pressor Test as a Predictor of Prolonged Postoperative Pain, a Prospective Cohort Study.” Pain and therapy vol. 5,2 (2016): 203-213. doi:10.1007/s40122-016-0056-z
⁵Garbinsky, Emily N. et al. “Interference of the End.” Psychological Science 25 (2014): 1466 - 1474.
⁶Varey, C., & Kahneman, D. (1992). Experiences extended across time: Evaluation of moments and episodes. Journal of Behavioral Decision Making, 5, 169-186.
⁷Redelmeier, D. A., & Kahneman, D. (1996). Patients' memories of painful medical treatments: Real-time and retrospective evaluations of two minimally invasive procedures. Pain, 66(1), 3–8. https://doi.org/10.1016/0304-3959(96)02994-6
⁸Do, A.M., Rupert, A.V. & Wolford, G. Evaluations of pleasurable experiences: The peak-end rule. Psychonomic Bulletin & Review 15, 96–98 (2008). https://doi.org/10.3758/PBR.15.1.96
⁹Kahneman, D. (2011). Thinking, fast and slow. New York: Farrar, Straus and Giroux.