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Faces Don't Lie: Facial Coding Beats Surveys at Predicting Sales

A study of 11,000+ face videos reveals that automated facial coding predicts sales effectiveness better than purchase intent surveys—and captures the emotional dynamics that traditional methods miss.

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Faces Don't Lie: Facial Coding Beats Surveys at Predicting Sales

Do Emotions in Advertising Drive Sales?

This beautiful research PDF is brought to us by our friends at MIT, Affectiva, and Northeastern University. The research strongly suggests that emotions in advertising, particularly as measured by facial coding, do drive sales. It's not just about whether an ad evokes emotion, but how and which emotions are evoked, and how those emotions change over time. Using tools like facial coding can provide valuable insights that go beyond traditional surveys to better predict ad effectiveness.

For decades, marketers and advertisers have instinctively believed in the power of emotion to connect with consumers and drive purchasing decisions. It is widely accepted that human emotions play a significant role in influencing our choices, from the content we consume to the products and services we buy.

Our past and current emotional experiences subconsciously bias our decision-making, making emotions a crucial influencer. Advertisers aim to create ads that surprise, entertain, or even evoke tears to help consumers remember products, build positive brand associations, and ultimately drive sales.

But the critical question remains: Are ads that are successful in evoking emotions also successful in driving sales? This question was at the heart of a research partnership between MARS Marketing and Affectiva.

The Challenge of Measuring Emotional Impact

Traditionally, assessing advertising effectiveness and predicting sales has relied heavily on surveys. Respondents watch an ad and then answer questions about brand awareness, message persuasion, and purchase intent. These cognitive assessments are then correlated with sales data. However, this approach often misses people's visceral emotional responses, which play an equally important role in influencing memory and purchase decisions.

While manual facial coding has shown promise in correlating with sales effectiveness, it is time-consuming, expensive, and difficult to scale. Other methods that focus on salient ad features (like package shots or celebrity appearances) fail to factor in viewers' cognitive or emotional responses6. Until recently, measuring emotional responses to advertising in a passive and scalable way remained a significant challenge, limiting large-scale studies on the relationship between emotions and sales success.

Automated Facial Coding: A New Frontier

The need for an objective, unobtrusive, and scalable measure of emotion led to the development and application of automated facial coding technology. Facial expressions have long been considered the universal language of emotion, recognized across cultures, ages, and genders9. Building on systems like the Facial Action Coding System (FACS), automated facial coding offers a breakthrough.

Affectiva's automated facial coding technology provides an objective, cost-effective, and scalable way to measure emotions. Unlike self-report methods, it enables the remote measurement of subtle and nuanced expressions on a moment-by-moment basis8. The technology captures facial action units and identifies main dimensions of emotion, such as valence (pleasantness) and arousal (activation), as well as discrete emotional states like enjoyment, surprise, disgust/dislike, confusion, and skepticism.

How it Works: Automated facial coding processes each frame of a face video to locate main facial features (e.g., mouth, eyebrows). It then uses the movement, shape, and texture composition of these regions to identify specific facial action units, such as an eyebrow raise or a smirk. Machine learning classifiers map these facial textures and movements to emotional states. The system is trained on a vast repository of real-world facial data from diverse age ranges, ethnicities, and cultures, ensuring robustness to challenging conditions and achieving high accuracy (over 90% generally, with a 97% accurate smile detector). The outputs are moment-by-moment measures, averaged across viewers for an ad.

The Large-Scale Study: Connecting Emotions to Sales

To systematically explore how emotions in advertising drive sales, a large-scale study was designed to collect facial emotion responses to ads for which sales data was also available. The primary goals were to:

  • Capture emotional responses to ads across different regional markets and product categories.
  • Identify emotion trajectories that indicate advertising effectiveness.
  • Determine if facial coding complements traditional cognitive surveys in predicting sales effectiveness.

The study involved over 11,000 face videos from 1,153 panelists who watched 115 ads from 70 unique brands. These ads were aired between 2001 and 2012 in the United States, United Kingdom, France, and Germany, representing four product categories: pet care, instant foods, chocolate, and chewing gum15....

Sales Effectiveness Measurement

Sales performance indices were obtained from single-source data, reflecting the sales lift directly associated with a TV ad, after accounting for other influencing factors. Ads were categorized as having good, average, or bad sales effectiveness, providing a standardized measure for analysis.

Experimental Design

Participants watched ads from their homes using a browser with Flash support and a webcam, making data collection scalable and allowing for a broader, global demographic sample. The study design minimized memory bias by splitting the survey into two parts with a minimum three-day delay between initial brand questions and the main ad viewing session. Importantly, 87% of viewers reported feeling "very comfortable" to "neutral" during the study, and 68% reported no difference in their behavior compared to typical viewing.

Key Findings: Emotions as Sales Predictors

The research aimed to determine if emotional responses, especially their dynamics over time, could predict short-term sales performance. The study focused on comparing the predictive performance of:

  • Self-report measures (brand likability and purchase intent).
  • Emotional responses captured by facial coding.
  • A combination of both.

The study found that the smile/enjoyment and dislike/disgust responses were most correlated to sales success. To analyze these, the per-respondent smile and disgust profiles were aggregated for each ad, partitioned into 10 segments, and then used to calculate positive and negative emotion values.

The results demonstrated compelling evidence:

  • E1. Naïve (random features): F1-score of 0.61027.
  • E2. Self-report features: F1-score of 0.69627.
  • E3. Facial coding features: F1-score of 0.745, showing a large gain over the Naïve model.
  • E4. Self-report + Facial Expressions: F1-score of 0.750, indicating a marginal increase over facial expressions alone.

These findings validate two key hypotheses:

Dynamics Matter

The positive and negative emotion measurements, specifically the trend (gradient) of the smile response and the level of disgust expressed, are predictors of sales effectiveness. Increasing amusement throughout an ad was a predictor of success, while the presence of negative emotions was inversely correlated to sales. This high temporal resolution is difficult to obtain from self-reported measures.

Facial Coding Provides Evidence for Sales Effectiveness

The improvement in classification accuracy between models using self-report versus facial expression metrics shows that automatically coded spontaneous facial actions were more telling of short-term sales effectiveness than self-reported purchase intent or brand likability. While combining both sources of information led to a marginal increase, its statistical significance needs further testing.

Case Studies: Real-World Scenarios

The research illuminated the importance of facial emotion dynamics through several case studies.

Case I: Facial Responses Correctly Predict Sales (But Not Self-Report)
  • An ad for a Chocolate brand in France had good sales.
  • Self-reported likability showed a decrease, leading to a "bad" sales prediction from self-report alone.
  • However, the aggregate smile track showed a strong positive gradient (increasing positive emotion over time) and no marked negative expressions, correctly predicting a successful sales outcome.
  • This demonstrates the power of facial coding to reveal true consumer sentiment missed by traditional methods.

Case II: Self-Reported Responses Correctly Predict Sales (But Not Facial Coding Alone)
  • A humorous Chewing Gum ad in the US had good sales.
  • The ad contained scenes that elicited strong dislike/disgust expressions, causing the facial coding model to incorrectly predict "bad" sales.
  • However, self-reported purchase intent and brand likability showed a positive delta, correctly classifying the ad as performing well.
  • When self-report and facial metrics were combined, the ad was correctly classified, showing that facial coding did not harm the discriminative power and could contribute even with initial discrepancies.

Case III: Using Facial Coding with Self-Report Boosts Predictive Power
  • A Chewing Gum ad in the US had poor sales.
  • Both self-report metrics and facial expression metrics alone incorrectly predicted good sales performance.
  • However, when the two modalities were combined, the alignment of weak negative responses from both sources provided enough information to correctly predict the poor sales outcome.
  • This highlights a synergy where combined data can outperform either method on its own.

The Twitch Benchmark Study: Machine Learned Performance

The study analyzed 74 videos across 37 brands with 17,544 participants to understand what makes ads successful on Twitch. It examined memory, emotion, and self-reported responses using methods like facial coding, eye-tracking, and implicit association tests.

  • Trustworthiness and Creativity Matter: Trustworthiness drives purchase intent, while creativity drives brand positivity.
  • Better Ads = Better Results: Higher video ratings correlate with increased purchase intent and other positive outcomes.
  • Relevance Drives Engagement: Ads that are relevant, interesting, and upbeat are more likely to be engaged with.
  • Happiness "Rubs Off": Happy ads positively impact brand perception and association.
  • Avoid Neutrality: Neutral ads lead to less engagement, clarity, and uplift.
  • Embrace Some Confusion: A little bit of confusion can engage people's rational minds.
  • Tailor to the Platform: Gamer-custom content and ads that "fit" well on Twitch perform better.
  • Longer Ads Engage: 30-second ads tend to be more engaging than 15-second ads.
  • Data-Targeted Campaigns: Psychological profiles can be used to create effective, targeted campaigns.

These case studies underscore the benefit of incorporating facial coding, particularly its high temporal resolution, to accurately capture how expressed emotional responses evolve over time.

Implications for the Future of Advertising

This pioneering large-scale study provides strong initial evidence that automated facial coding offers significant discriminative value for ad-driven sales effectiveness. This value is directly linked to logical, intuitive, real-time, moment-by-moment emotional response pattern.The implications for advertisers are profound:

Ad Optimization and Real-Time Tracking

Facial coding can enable live prediction of ad performance based on current emotional responses, informing decisions on when or if to air an ad, as well as media spend.

From Animatics to Finished Film

This technology can be powerfully employed throughout the advertising creation and editing process, improving the likelihood of ad success even at early mock-up stages.

In conclusion, emotions in advertising, when captured with scalable facial coding technology, are indeed indicative of ad success. Automated facial coding offers an objective, passive, and highly insightful approach to understanding consumer responses, providing actionable insights that complement and often surpass traditional self-report methods.

As research continues to analyze ad structure and generalize findings across diverse genres and markets, automated facial coding is set to become a routine and invaluable part of copy testing for brands aiming to optimize their advertising impact and drive sales.

by
Nick Warner

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