Psychological targeting as an effective approach to mass persuasion—the adaptation of persuasive appeals to the psychological characteristics of large groups of individuals with the goal of influencing their behavior

Psychological targeting as an effective approach to digital mass persuasion. S. C. Matz,  View ORCID ProfileM. Kosinski, G. Nave, and D. J. Stillwell. Proceedings of the National Academy of Sciences, November 28, 2017 114 (48) 12714-12719. https://doi.org/10.1073/pnas.1710966114

Significance: Building on recent advancements in the assessment of psychological traits from digital footprints, this paper demonstrates the effectiveness of psychological mass persuasion—that is, the adaptation of persuasive appeals to the psychological characteristics of large groups of individuals with the goal of influencing their behavior. On the one hand, this form of psychological mass persuasion could be used to help people make better decisions and lead healthier and happier lives. On the other hand, it could be used to covertly exploit weaknesses in their character and persuade them to take action against their own best interest, highlighting the potential need for policy interventions.

Abstract: People are exposed to persuasive communication across many different contexts: Governments, companies, and political parties use persuasive appeals to encourage people to eat healthier, purchase a particular product, or vote for a specific candidate. Laboratory studies show that such persuasive appeals are more effective in influencing behavior when they are tailored to individuals’ unique psychological characteristics. However, the investigation of large-scale psychological persuasion in the real world has been hindered by the questionnaire-based nature of psychological assessment. Recent research, however, shows that people’s psychological characteristics can be accurately predicted from their digital footprints, such as their Facebook Likes or Tweets. Capitalizing on this form of psychological assessment from digital footprints, we test the effects of psychological persuasion on people’s actual behavior in an ecologically valid setting. In three field experiments that reached over 3.5 million individuals with psychologically tailored advertising, we find that matching the content of persuasive appeals to individuals’ psychological characteristics significantly altered their behavior as measured by clicks and purchases. Persuasive appeals that were matched to people’s extraversion or openness-to-experience level resulted in up to 40% more clicks and up to 50% more purchases than their mismatching or unpersonalized counterparts. Our findings suggest that the application of psychological targeting makes it possible to influence the behavior of large groups of people by tailoring persuasive appeals to the psychological needs of the target audiences. We discuss both the potential benefits of this method for helping individuals make better decisions and the potential pitfalls related to manipulation and privacy.

Keywords: persuasiondigital mass communicationpsychological targetingpersonalitytargeted marketing

Discussion

The results of the three studies provide converging evidence for the effectiveness of psychological targeting in the context of real-life digital mass persuasion; tailoring persuasive appeals to the psychological profiles of large groups of people allowed us to influence their actual behaviors and choices. Given that we approximated people’s psychological profiles using a single Like per person—instead of predicting individual profiles using people’s full history of digital footprints (e.g., refs. 10 and 14)—our findings represent a conservative estimate of the potential effectiveness of psychological mass persuasion in the field.

The effectiveness of large-scale psychological persuasion in the digital environment heavily depends on the accuracy of predicting psychological profiles from people’s digital footprints (whether in the form of machine learning predictions from a user’s behavioral history or single target Likes), and therefore, this approach is not without limitations. First, the psychological meaning of certain digital footprints might change over time, making it necessary to continuously calibrate and update the algorithm to sustain high accuracy. For example, liking the fantasy TV show “Game of Thrones” might have been highly predictive of introversion when the series was first launched in 2011, but its growing popularity might have made it less predictive over time as its audience became more mainstream. As a rule of thumb, one can say that the higher the face validity of the relationships between individual digital footprints and specific psychological traits, the less likely it is that they will change (e.g., it is unlikely that “socializing” will become any less predictive of extraversion over time). Second, while the psychological assessment from digital footprints makes it possible to profile large groups of people without requiring them to complete a questionnaire, most algorithms are developed with questionnaires as the gold standard and therefore retain some of the problems associated with self-report measures (e.g., social desirability bias; ref. 22).

Additionally, our study has limitations that provide promising avenues for future research. First, we focused on the two personality traits of extraversion and openness-to-experience. Building on existing laboratory studies, future research should empirically investigate whether and in which contexts other psychological traits might prove to be more effective [e.g., need for cognition (2) or regulatory focus (23)]. Second, we conducted extreme group comparisons where we targeted people scoring high or low on a given personality trait using a relatively narrow and extreme set of Likes. While the additional analyses reported in SI Appendix suggest that less extreme Likes still enable accurate personality targeting, future research should establish whether matching effects are linear throughout the scale and, if not, where the boundaries of effective targeting lie.

The capacity to implement psychological mass persuasion in the real world carries both opportunities and ethical challenges. On the one hand, psychological persuasion could be used to help individuals make better decisions and alleviate many of today’s societal ills. For example, psychologically tailored health communication is effective in changing behaviors among patients and groups that are at risk (24, 25). Hence, targeting highly neurotic individuals who display early signs of depression with materials that offer them professional advice or guide them to self-help literature might have a positive preventive impact on the well-being of vulnerable members of society. On the other hand, psychological persuasion might be used to exploit “weaknesses” in a person’s character. It could, for instance, be applied to target online casino advertisements at individuals who have psychological traits associated with pathological gambling (26). In fact, recent media reports suggest that one of the 2016 US presidential campaigns used psychological profiles of millions of US citizens to suppress their votes and keep them away from the ballots on election day (27). The veracity of this news story is uncertain (28). However, it illustrates clearly how psychological mass persuasion could be abused to manipulate people to behave in ways that are neither in their best interest nor in the best interest of society.

Similarly, the psychological targeting procedure described in this manuscript challenges the extent to which existing and proposed legislation can protect individual privacy in the digital age. While previous research shows that having direct access to an individual’s digital footprint makes it possible to accurately predict intimate traits (10), the current study demonstrates that such inferences can be made even without having direct access to individuals’ data. Although we used indirect group-level targeting in a way that was anonymous at the individual level and thus preserved—rather than invaded—participants’ privacy, the same approach could also be used to reveal individuals’ intimate traits without their awareness. For example, a company could advertise a link to a product or a questionnaire on Facebook, targeting people who follow a Facebook Like that is highly predictive of introversion. Simply following such a link reveals the trait to the advertiser, without the individuals being aware that they have exposed this information. To date, legislative approaches in the US and Europe have focused on increasing the transparency of how information is gathered and ensuring that consumers have a mechanism to “opt out” of tracking (29). Crucially, none of the measures currently in place or in discussion address the techniques described in this paper: Our empirical experiments were performed without collecting any individual-level information whatsoever on our subjects yet revealed personal information that many would consider deeply private. Consequently, current approaches are ill equipped to address the potential abuse of online information in the context of psychological targeting.

As more behavioral data are collected in real time, it will become possible to put people’s stable psychological traits in a situational context. For example, people’s mood and emotions have been successfully assessed from spoken and written language (30), video (31), or wearable devices and smartphone sensor data (32). Given that people who are in a positive mood use more heuristic—rather than systematic—information processing and report more positive evaluations of people and products (33), mood could indicate a critical time period for psychological persuasion. Hence, extrapolating from what one does to who one is is likely just the first step in a continuous development of psychological mass persuasion.