The text covers a wide range of topics: dopamine, discipline, Reward sensitive, cognitive capacity, etc.

From the text, it is shown that introversion and extroversion varies differently in all these aspects, e.g. introverts being less reward-sensitive while extroverts vice versa.

The claim is then thought to be: Introverts stay mindful and careful dealing with situations, while extroverts largely respond to their impulse.

Chapter 7 of Susan Cain's "Quiet" illustrates how extroversion and introversion manifest in different behavioral patterns, particularly regarding risk, reward sensitivity, and decision-making.

Reward Sensitivity: Extroverts are generally more reward-sensitive, driven by the pursuit of immediate gratification and external validation. This tendency can lead them to take higher risks, often ignoring warning signals. Introverts, on the other hand, are more cautious, focusing on potential downsides and regulating their excitement, which helps them avoid problems.

Discipline and Delayed Gratification: Introverts typically excel in discipline and the ability to delay gratification, contributing to long-term success. In contrast, extroverts may prioritize short-term rewards, which can hinder sustained achievements.

Attention and Focus: Extroverts are often attuned to their external environment. They thrive in social situations and multitasking. Introverts tend to direct their attention inward, reflecting deeply and considering various perspectives, which can lead to more thorough analysis but that may slow their decision-making.

Problem-Solving Approaches: Extroverts may favor speed over accuracy in problem solving, leading to hasty decisions. Introverts are more patient, allowing them to work through challenges effectively.

Flow Experiences: Introverts often find flow in solitary, engaging in activities for their intrinsic value rather than external rewards. This contrasts with extroverts, who might seek flow through social interactions, immediate rewards, people’s validation and judgements.

These traits related to extroversion and introversion influenced individuals respond to challenges and success.

Cain first quoted Einstein, ‘“It’s not that I’m so smart,” said Einstein, who was a consummate introvert. “It’s that I stay with problems longer.”’ (169 Cain). Cain elaborates and extend the idea of staying with problems longer, explaining: allowing oneself to pay effort on the “truly meaningful” activities will benefit oneself more than a quick gold rush.

Advices were to calm oneself down when important decisions has to be made- the rush of dopamine is present when excitement is present, this makes people act more “rashly”, so it is essential to calm down, leading to more insightful decisions made. As Cain talks more about reward sensitivity as well as threat sensitivity among introverted and extroverted people, an important idea is shown: FLOW.

Flow is defined by Cain as “an optimal state in which you feel totally engaged in an activity” (172 Cain). People should focus on the sake of the activity itself instead of the result or the reward that comes along: activities such as “reading, tending and orchard, solo ocean cruising”, quoted Mihaly Csikszentmihalyi, a famous psychology—which makes sense, these activities are highlighted by their significance in terms of its process.

Flow is when people become isolated from the social environment, and no longer seek rewards, or threats. As people feel and experiment with the idea of flow, it can be expanded into their lives—practice every daily task with the aim of focusing on the process.

Cain elaborates, relates the idea of “flow” into guiding likely introverted readers, the audience, to find their flow through their gift as an introvert, the “power of persistence, the tenacity to solve complex problem and the clear-sightedness to avoid pitfalls that trip others up”. The development from an idea to breaking though the paper and addresses the reader significantly allows Cain to elaborate from this idea of flow and advices: stay true to oneself, to one’s nature and instincts while being mindful and aware of the situation; stay unmoved by rewards, make evaluations; no rush, keep one’s own pace and rhythm.

Advices like this relates to the idea of flow, and after this follows up examples of successful introverted people, such as Buffet, Klarman, etc, back to the claim, supporting the power of Introverted people and their insightful mindset.

Cain begins with a story of Alan, who’s an extrovert, lost $700000 when he invest because he’s impulsive, he takes outsized risks and ignore warning signals. This supports her claim that extroverts are often more hotheaded and impulsive when making decisions.

Cain also uses biological a psychological knowledge and concepts to support her claim. She first mention brain structure and limbic system, also how “old brain” , which is reward seeking and pleasure-loving, and “new brain(neocortex)”, which is responsible for thinking, planning, language and decision making influence people’s minds and decision-making. The old and new brain sometimes are in conflict. Cain states that some scientist explore the idea that reward-sensitivity is found in every extrovert, it’s their common trait, explaining why extroverts are often impulsive.

In addition to that, Cain refers to an emotional state called “buzz”, which is a rush of energized and enthusiastic feelings.

She writes that extroverts have a higher degree and frequency of “buzz” than introverts, and they are likely to get extra “buzz” from pursuit and attainment of their goals. Introverts don’t “buzz” easily. “Dopamine” serves as another example, it’s a chemical that carries information between brain cells. Cain says that extrovert’s dopamine appear to be more active than those of introverts, and extroverts have a stronger response in their dopamine system. All of these backs why extroverts often get overexcited, take outsized risks, ignore warnings and introverts are often calm.

Cain highlights the extroverted nature of the finance industry, where boldness, risk-taking, and networking are highly valued. This environment often favors those who are outgoing and assertive, as they are more likely to take risks and make quick decisions in high-pressure situations. However, Cain argues that this emphasis on extroverted traits can also lead to reckless behavior, as seen in the financial crisis of 2008 when Wall Street's aggressive risk-taking resulted in a devastating crash.

Lots of examples were used by Cain. Curry’s example further backs the claim that extroverts are more communicative and calculative. Vincent Kaminski’s example states that aggressive and impetuous people are often more shortsighted, they consider what’s happening now instead of reflecting the past and planning for the future. Psychologists John Brebner and Chris Cooper says extroverts “think less”, “act fast”, and introverts “geared to inspect” while extroverts “geared to respond”.

Cain supports her claim of reward sensitivity by describing its common name:"Deal Fever", and "The Winner's Curse" and also gives an example about AOL-Time Warner merger who wiped out 200 billion dollars of shareholder value.

Buffett avoids conformity and does not follow the crows, he believes that instinct is what makes people unique and special. When people prioritize fitting in, they limit their ability to contribute original ideas and insights. This makes diverse viewpoints undervalued, resulting in poor decision-making. Moreover, conformity hinders personal growth.

By following the herd, individuals may ignore their passions and “gifts”, missing out on their true potential. This example of Buffett encourages readers to trust their judgment and ignore other’s evaluation(in certain situation).