Chapter 23: Exercises

TikTok's For You Page: The Most Powerful Recommendation System Ever Built

The following 35 exercises progress from foundational comprehension through advanced synthesis and application.

Comprehension Exercises

1. [Definition] Explain what the "For You Page" (FYP) is and how it differs architecturally from the social-graph-based feeds used by Facebook and Instagram. Why is following optional on TikTok, and what are the consequences of this design choice?

2. [Definition] What is "completion rate" as used in TikTok's recommendation algorithm? Why is it considered TikTok's most distinctive and powerful engagement signal compared to click-through rate?

3. [Definition] Define the terms "lean-back" and "lean-forward" as applied to media consumption. Classify the following experiences along this spectrum and explain your reasoning: (a) reading a newspaper; (b) watching Netflix with autoplay enabled; (c) browsing Twitter/X; (d) scrolling TikTok's FYP.

4. [Definition] What is "algorithmic precarity" as experienced by TikTok creators? How does TikTok's viral distribution model create this condition, and how does it differ from the audience maintenance challenges faced by creators on legacy social platforms?

5. [Chronology] Trace the corporate history of TikTok from ByteDance's founding through the Musical.ly acquisition and TikTok's global launch. Why was the Musical.ly acquisition particularly important for TikTok's Western growth?

6. [Comprehension] Describe TikTok's cold start advantage. What specific design features allow TikTok to personalize the FYP within approximately 10 videos, when competing platforms require much more interaction history to achieve comparable personalization?

7. [Comprehension] Explain the "variable reward schedule" mechanism and why it is central to TikTok's engagement design. How does the uncertainty of what the next video will be contribute to compulsive scrolling?

8. [Comprehension] What are the specific signal categories that TikTok's algorithm uses? List at least four distinct signal categories and describe what information each captures.

9. [Comprehension] What is "Project Texas," and why did TikTok create it? What national security concern was it designed to address, and why do critics argue it is insufficient?

10. [Comprehension] The chapter discusses "algorithmic influence" as a distinct concern from "data collection" in the TikTok national security controversy. Explain the difference between these two concerns. What would constitute evidence that algorithmic influence was occurring?

Analysis Exercises

11. [Analysis] Compare TikTok's completion rate signal to YouTube's watch time metric. Both measure how long users watch. What are the key differences between these metrics, and why does TikTok's approach produce different creator incentives than YouTube's?

12. [Analysis] The FYP is described as a "lean-back" experience. Analyze the psychological consequences of this design. What cognitive processes are engaged differently in lean-back vs. lean-forward consumption? What are the implications for how users process and evaluate the content they consume?

13. [Analysis] TikTok's cold start algorithm deliberately shows new users a diverse sample of content before narrowing to a personalized feed. Analyze the tradeoffs in this approach. What is gained from initial diversity? What are the risks if the algorithm narrows too quickly?

14. [Analysis] The chapter states that TikTok's FYP "inferred a latent preference that Maya herself may not have been fully consciously aware of." Analyze the epistemological and ethical dimensions of this situation. Is there a meaningful distinction between the algorithm discovering a pre-existing preference and the algorithm creating or constructing a preference through repeated exposure?

15. [Analysis] Apply the concept of "preference amplification" (from Chapter 22) to TikTok's FYP. How does the FYP's feedback loop tend to narrow Maya's content environment over time? What specifically about TikTok's design makes this tendency stronger or weaker than on other platforms?

16. [Analysis] ByteDance's A/B testing culture is described as a mechanism that can discover dark patterns without engineers deliberately designing them. Analyze the argument: "The optimization process is undirected on the wellbeing dimension." What does "undirected" mean here, and what would it mean to "direct" the optimization process toward wellbeing?

17. [Analysis] The chapter discusses the "mirror effect" — TikTok's personalization providing adolescent users like Maya a sense of being understood. Analyze this effect from an identity development perspective. How might this algorithmic mirror help or hinder the genuine work of adolescent identity formation?

18. [Analysis] The chapter distinguishes two distinct national security concerns about TikTok: data collection and algorithmic influence. Evaluate the current evidence for each concern. Which seems better supported by available evidence? Which would be more difficult to detect if it were occurring?

19. [Analysis] The "TikTok brain" hypothesis holds that heavy TikTok use reduces attention capacity. Assess the three possible causal mechanisms discussed in the chapter: (a) direct neurological effects; (b) opportunity cost effects (displacing attention-building activities); (c) sleep disruption effects. Which mechanism do you find most plausible based on existing research, and why?

20. [Analysis] TikTok's FYP is described as more effective at generating engagement than competitor platforms. But is higher engagement necessarily an advantage from the user perspective? Construct an argument that lower engagement (less time on platform, less personalization) might better serve some users' interests.

Application Exercises

21. [Application] Design an experiment to test whether TikTok's FYP constructs user preferences (through repeated exposure shaping what users like) or merely reveals pre-existing preferences (by surfacing content users already would have liked). What variables would you measure? What would constitute evidence for each hypothesis?

22. [Application] You are TikTok's head of product, and you have been asked to redesign the cold start experience to prioritize user wellbeing over rapid engagement. What changes would you make to the first 10-video experience? What specific risks to wellbeing would you try to mitigate?

23. [Application] Using the signal architecture described in Section 23.3, analyze the following scenario: A 14-year-old user who has never used TikTok downloads the app and watches five videos in sequence: (1) a diet tip video, (2) a body transformation video, (3) a calorie counting tutorial, (4) a before/after weight loss video, (5) an eating disorder "recovery" video that they watch 80% of. What would the algorithm infer about this user? What content would it show next? What are the wellbeing implications?

24. [Application] A content creator has gone viral on TikTok once (2 million views on a single video, gaining 100,000 followers) but subsequent videos have averaged 10,000 views. Write an analysis of the algorithmic and psychological factors that create this "post-viral slump." What options does the creator have?

25. [Application] Draft a regulatory proposal for TikTok's recommendation algorithm that addresses at least two of the following concerns: (a) rapid over-personalization, (b) emotional escalation tendencies, (c) adolescent user vulnerability, (d) national security data concerns, (e) creator algorithmic precarity. For each provision you propose, explain what it would require technically, how compliance would be verified, and what tradeoffs it involves.

26. [Application] TikTok gives substantial weight to the "Not Interested" explicit negative feedback signal. Design an expanded negative feedback system that would give users more nuanced control over their FYP without requiring significant additional user effort. What specific feedback options would you add? How would you make them accessible without cluttering the interface?

27. [Application] The chapter describes TikTok's video length expansion from 15 seconds to potentially 30 minutes. Analyze how this evolution changes the completion rate signal as a recommendation metric. What new pathologies does a 10-minute video completion rate create compared to a 30-second video completion rate?

Synthesis Exercises

28. [Synthesis] The FYP's departure from social-graph feeds represents one of the most significant architectural changes in social media history. Synthesize the consequences of this departure across three dimensions: (a) for users (how the experience of social media changes); (b) for creators (how the economics and dynamics of content creation change); (c) for society (how the information environment changes when social graphs no longer mediate content distribution).

29. [Synthesis] The chapter presents TikTok's recommendation system as more powerful than predecessors. But "more powerful" relative to what objective? Synthesize an argument that TikTok's FYP is more powerful at generating engagement but less powerful at achieving several other goals a social media platform might have — fostering genuine social connection, supporting diverse content discovery, protecting adolescent mental health, or promoting civic discourse.

30. [Synthesis] ByteDance's Zhang Yiming has spoken of "algorithmic curation as the most efficient form of content discovery." Evaluate this claim against the specific evidence presented in this chapter and Chapter 22. In what specific ways is algorithmic curation more efficient than alternatives? What does it gain efficiency by sacrificing?

31. [Synthesis] The viral lottery on TikTok creates both opportunity (any creator can reach millions) and precarity (audience maintenance is uncertain and algorithmically dependent). Synthesize an analysis of whether the TikTok creator ecosystem is, in aggregate, better or worse for content creators than legacy social media creator ecosystems. Consider economic factors, psychological factors, creative autonomy factors, and distributional equity factors.

32. [Synthesis] TikTok's national security controversy involves questions that extend beyond TikTok: should countries be able to restrict social media platforms based on ownership by foreign adversaries? Synthesize the competing values at stake — national security, free expression, platform competition, international commerce — and evaluate what principles should guide policy in this area.

Research and Creative Exercises

33. [Research] Research ByteDance's acquisition of Musical.ly in 2017. What was the purchase price? What concerns did U.S. regulators raise about the acquisition at the time? What was the Committee on Foreign Investment in the United States (CFIUS) review process, and what did it conclude? How does the regulatory treatment of this acquisition look in retrospect, given subsequent developments?

34. [Research] Research the empirical literature on social media use and attention spans in adolescents. Find at least three peer-reviewed studies published between 2020 and 2025. For each study: What did it measure? What were its findings? What were its methodological limitations? Based on your review, what is the most defensible current scientific position on TikTok and adolescent attention?

35. [Creative] Write a 600-800 word diary entry from Maya's perspective, covering her first month with TikTok. The entry should show: (a) the initial non-personalized experience; (b) the moment of feeling understood by the algorithm; (c) the gradual narrowing of her FYP; (d) the first time she notices that she has been scrolling for longer than she intended. The entry should be psychologically realistic and should demonstrate understanding of the technical mechanisms driving Maya's experience, without making those mechanisms explicit in Maya's narration.