A major new global study from WPP Media and Oxford University’s Saïd Business School, How Humans Decide, examined 1.2 million individual purchase journeys across 47 countries and more than 200 product categories. Its central conclusion fundamentally challenges conventional marketing wisdom: consumers rarely make decisions in the moment. Instead, the overwhelming majority are acting on brand preferences shaped long before they start shopping.
The study’s most important finding is what it calls the 84% rule. According to the analysis, 84% of all purchases are made by consumers who enter the shopping process with a pre-existing bias toward certain brands. This pattern holds across every category — from fast food to financial services, from personal care to electronics — and never drops below 70%. In practice, this means that shoppers usually know the brands they will consider and typically evaluate no more than two or three options. As the report puts it, “buyers do not come to a brand fresh in the lower funnel.”
This insight has profound implications for audio. If most decisions are determined before the active shopping phase, then the media that shape long-term predisposition — those that live in people’s daily routines, moods, and environments — are disproportionately powerful. This is precisely where radio and podcasts excel.
Audio plays a unique role in what the study calls brand priming: the slow, cumulative, largely subconscious process through which people form feelings, familiarity and expectations about brands. Radio’s habitual presence makes it one of the most effective channels for this. Whether in cars, kitchens, workplaces or headphones, audio reaches people in intimate, trusted contexts where voices and stories are absorbed effortlessly. Over time, this builds the kind of emotional connection, mental availability and brand salience that shape the 84% of decisions made before active shopping even begins.
Crucially, the report highlights that radio’s value is not simply about reach. Rather, it is about influence — specifically, influence in the priming stage. Audio’s emotional tonality, narrative depth and human connection give it a distinctive ability to build long-term memory structures. These impressions sit latent until a buying moment arises, at which point consumers gravitate instinctively toward the brands that have been most consistently and meaningfully present in their lives.
The study argues that marketers must therefore shift from reach-based planning to influence-based planning. This means evaluating channels not only by how many people they reach, but by the role they play in shaping decisions across the full journey. Within this framework, audio becomes a strategic influence-builder, establishing the predisposition that later determines which brands are even considered.
WPP also emphasizes that audio’s impact increases significantly when integrated with other touchpoints. Radio may create predisposition, but owned, shared and earned channels — such as email, online reviews, social media, branded podcasts and live events — help reinforce and convert it.
Taken together, the findings offer robust empirical evidence that audio is not simply a top-of-funnel awareness tool. It is a foundational driver of long-term brand choice — and when combined with other reinforcing channels, it becomes one of the most powerful contributors to overall marketing influence.
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