How Cambridge Analytica, which was hired by the Trump and Brexit “Leave” campaigns, builds psychological profiles of Facebook users with personality quizzes
McKenzie Funk / New York Times :
Context & Ripple Effects
Cambridge Analytica's political work first surfaced when Ted Cruz's campaign hired the UK firm in December 2015, and by this piece it was serving both the Trump campaign and Brexit's Leave side. The New York Times details the mechanism behind those contracts: personality quizzes and consumer data assembled into psychological profiles of Facebook users.
What read in 2016 as clever targeting became a reckoning two years later, when sources and documents showed the firm had drawn on harvested personal information from 50M Facebook profiles, and whistleblower Christopher Wylie described machine-learning models producing 253 predictions per profiled record. This article is the early documentation of the method before the scale became public.
First-order effects
- The Trump and Brexit Leave campaigns gain the ability to serve voters ads matched to personality traits inferred from quiz responses and consumer data, rather than demographics alone.
- Facebook users who took personality quizzes had their data and their friends' network data feed these profiles without a clear understanding of the downstream political use.
Second-order effects
- Other campaigns follow the Cruz precedent, making behavioral-targeting vendors a standard line item in political consulting and shifting spend from broadcast to platform microtargeting.
- Facebook's app-platform data policies come under pressure, since the profiling technique depends on third-party apps harvesting not just the taker's data but their friends'.
Third-order effects
- If the pattern holds, election data practices move from trade secret to regulatory subject — the eventual exposure of the 50M-profile harvest shows where the arc leads, toward investigation of how social platforms' data ecosystems are exploited for voter persuasion.
- Political persuasion restructures around psychological segmentation as an industry, with firms competing on the number of predictive attributes they can attach to each voter record.
The trend: Campaigning is shifting from demographic ad buying to personality-based microtargeting built on social-platform data, with the harvesting methods eventually forcing a public and regulatory accounting.