The inevitable decline of fluid intelligence, rise of crystallized intelligence, and what we should do about it


“Midway upon the journey of our life, I found myself within a forest dark, for the straightforward pathway had been lost” – Dhante Aligheiri


I have been reading books about transitioning to a second act of meaning and impact to learn from others instead of figuring it out myself. One of my coaches recommended From Strength To Strength by Arthur C. Brooks. The essence is that what makes us successful early in life, our fluid intelligence, eventually declines, making us less effective at our careers and skills. However, we gain crystallized intelligence, which is valuable in other ways. Those who recognize this are much more successful at navigating this decline and have more impact later in life. The book presents a practical, spiritual and psychological approach to this transition that was very helpful to me. “Fluid intelligence refers to the ability to reason and think flexibly. Crystallized intelligence refers to the accumulation of knowledge, facts, and skills that are acquired throughout life.” (Ziegler et al., 2012). An example of fluid intelligence is solving puzzles at the age of ten. At ten, you haven’t achieved a lot of facts, skills, and knowledge but you are able to reason and think flexibly and creatively to arrive at a solution. Fluid Intelligence peaks as late as 45 (Hartshone et al., 2015) and Crystallized Intelligence rises as we age, peaking in our 70s (Desjardins et al, 2012). As our first curve starts to decline (Fluid Intelligence), we have a second curve of life which begins (Crystallized Intelligence) which brings different strengths, including wisdom. What we do with this wisdom is what is important. 

Knowing this neurobiological transition is inevitable can enable us to navigate the transition with grace and strength. 

Brooks then shifts to his personal spiritual journey and describes the four stages in life in Hinduism which aligns well to this concept of the first and second curves. Grihastha is the second stage and aligns to the first curve, when fluid intelligence enables one to succeed in their career and goals. Vanaprastha begins the second curve of life when crystallized intelligence comes to the fore and you can use your accumulated knowledge to seek deep wisdom: 

  • Brachmacharya – preparing for success later in life, lay foundations of a spiritual life, and gain education that will pave the way for Grihastha. 
  • Grihastha – “householder” stage – build a career and a family, become an expert in your field, and fulfill your obligations and achievements. 
  • Vanaprastha – “retiring into the forest”, become more devoted to deep wisdom, less devoted to pursuing the material. Begins after fulfilling obligations to their families. 
  • Sannyasa – old age, totally dedicated to enlightenment, realizing you are the infinite truth.

If you aren’t careful, you may struggle during the transition to the second curve (corresponding to Vanaprastha), you may grasp at relevance while declining, holding on to achievement, and limit your positive impact. A potential trap in Grihastha is that you may have fed your life with extrinsic goals – money, status, things you can gain using your fluid intelligence, and this may prevent you from moving gracefully into Vanaprastha, leveraging the strength of your crystallized intelligence to deliver positive impact. You may also experience dukkha, which Buddha describes as the unsatisfactoriness of achievement. Mihaly Csikszentmihalyi describes in “Flow – Living at the Peak of Your Abilities” a generative stage in the 40s and 50s where you can pass on your knowledge (crystallized intelligence) to the next generation, giving you a stake in the future by delivering meaningful impact. Brooks describes a better approach to this transition that embraces vulnerability, human connection, and impermanence to gracefully transition to a new strength.

Let’s talk about vulnerability... I have personally found that it is not your strengths that will connect you, but rather your weaknesses that will enable you to connect deeply to others. For example, you might be a 10x coder or a marketing genius, which will be respected but not sufficient, for connection. I have learned this only later in my career. One of my (many) weaknesses is that I feel imposter syndrome – I didn’t go to the best school, I wasn’t the best student, and I had significant failures in both high school and college, barely making through both. This led me to over-emphasize excellence in my craft to prove my worth. I once held a chip on my shoulder for not getting into MIT, CalTech, or Harvey Mudd, and, honestly, I didn’t do the work and didn’t earn it. However, my strengths of grit and learning things quickly enabled me to achieve a college education. I spent hours in my local public library, for several months, studying Feynman’s lectures on physics to prepare for the Math and Physics Symposium at my local university and earned a full-ride scholarship. In my career, I have jumped from self-taught hacker/coder to engineering leader to product leader to security leader to IT leader, using my strengths of continuous learning and grit to compensate for my academic weakness, becoming competent and expert level through deep study and practice, moving between domains and becoming a generalist business and technology leader. However, my weaknesses are what make me an effective leader. It isn’t excellence in my craft that makes me effective, it is my story and my vulnerability that enables me to connect with individuals and team. The strengths that brought me here are not the same ones needed for the next stage and I can crystallize the accumulated skills, experience, into wisdom that will help others

Human connection – I used to believe I was excellent at being alone, and was wrong. I am happy with solitude but not happy with social isolation. Brooks talks about finding real friends, not deal friends, to help with the transition from the first curve to the second. How many people would you say know you well? List the real friends and list when you last talked to them. Then count the ones that you could call if you were in jail (and don’t count your significant other if you have one). You now know if you need to invest in this area of your life if have no one that will bail you out! I am grateful to have numerous real friends and realize I am not putting the energy in to be with them, know them, and be there for them. Also, I don’t have enough real friends locally, they are mostly are scattered all over the world, and need to invest more locally. My striving and driving has caused me to de-prioritize this essential connectivity that will feed my soul. Cool idea from the book – write down the three things you know your friends need most and help them achieve them.

Reading this book gave me more insight on the path that brought me here and is like a map for the rest of my journey. In adolescence, my sense of self evolved quickly and landed on “hippie/ physics nerd/skater” who hung out with punks in high school, and later, philosophy and theatre majors in college (overly simplified labelling for purpose of story). Throughout, I was seeking the meaning of life, peak experiences, and the grand unified theory of everything. I hopped around, being complacent for some time before challenging myself by quitting my job at thirty and moving to Nepal, once again, seeking peak experiences through yoga, meditation and mountaineering. Then, I began my striver’s journey (Grihastha) by moving to Silicon Valley and diving into the craft of software development, getting married to the love of my life, having a family together, and pushing my career to new levels. When I turned fifty, I started wandering again, looking for meaning. It is almost like I am re-discovering my nineteen-year old self (this time with more crystallized intelligence), using contemplative practices to find meaning again. I began this blog four years ago after deciding to reinvigorate my daily meditation practice, diving into Buddhism, and sharing my journey to remain accountable. In hindsight, this was Vanaprastha. Quite literally, I have been “retiring into the forest” by spending time at our cabin, chopping wood and carrying water to achieve a little more insight, doing long backpacking trips, spending hours in walking meditation, and just sitting in a mountain creek staring at the wind in the leaves

Concluding thought – Don’t chase a bucket list, enjoy the moment and embrace impermanence as the transition occurs. There are whole years during my striving period that I have few memories from. I am pretty sure I helped deliver a bunch of product releases, made some money, and made a dent in the tech industry, but I don’t have vivid and meaningful memories from many of those big achievements. However, I have vivid, joyful, and meaningful memories from small moments – building a kick-ass fort with my son, racing with a friend down Jaipur’s Amber Fort, watching my wife give an amazing speech to her students, and being with my Dad in the last days of his life. If we chase the achievement, we may miss the moment, and, if we neglect impermanence we may grasp at our old self as it flows through your fingers like sand, a victim of the transition instead of the owner.

“Use things, love people, worship the divine.” – Arthur C. Brookes



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