How Brands Use Psychology to Influence Purchase Decisions

Industry & Competitive Context

The UK confectionery market in 2006–2007 was a mature, highly competitive category dominated by a small number of global players, with Cadbury Schweppes and Mars as the two largest confectionery groups worldwide. Cadbury had reported its strongest sales performance in over a decade in the year before the crisis, overtaking Mars to become the world's leading confectionery group by value. The category itself was under structural pressure from a rising "healthy eating" trend in the UK, increasing scrutiny of sugar and food safety standards, and rising raw material costs all of which made brand trust and emotional loyalty unusually important competitive levers, since price and product differentiation alone could not carry a mature chocolate brand through a reputational shock.

Brand Situation Prior to the Campaign

In June 2006, Cadbury recalled more than one million chocolate bars in the UK after a leaking pipe at its Marlbrook factory in Herefordshire allowed waste water to contaminate chocolate crumb with a rare strain of salmonella (Salmonella Montevideo). The UK's Food Standards Agency issued a formal food alert, the Health Protection Agency linked the contamination to dozens of reported illness cases, and it later emerged that Cadbury had known of the fault since January 2006 but had not reported it to regulators until several months later. The recall affected core Dairy Milk lines as well as Freddo and Easter Egg products, cost the company in the region of £20–30 million in direct recall and remediation expenses, and resulted in a criminal prosecution under UK food safety law, to which Cadbury pleaded guilty in 2007, receiving a £1 million fine.

Cadbury publicly confirmed that overall company sales were running roughly 5% below the prior year in the months following the recall, and the company itself stated that public perception of the brand had "still not returned to pre-recall levels" heading into the important Christmas trading period. Beyond the immediate financial cost, the crisis compounded a longer-term problem: Cadbury's advertising had become formulaic built around literal, ingredient-led imagery of glasses of milk pouring into chocolate bars and was losing cultural relevance with younger consumers even before the contamination story broke.

Strategic Objective

Cadbury's marketing objective, as documented in the IPA (Institute of Practitioners in Advertising) Effectiveness case study on the campaign, was to rebuild trust and warmth toward the Dairy Milk brand and to restore Cadbury Dairy Milk as a source of everyday pleasure rather than as a commodity chocolate bar competing on functional attributes. Rather than attempting to argue the brand back into favour through reassurance messaging about food safety or product quality a rational, defensive route many crisis-hit brands take — Cadbury and its agency, Fallon London, chose an emotional route: to reposition the brand around the feeling the product produces, not the product itself.

Campaign Architecture & Execution

The resulting work, created by Fallon London under a content initiative the agency and client named "A Glass and a Half Full Productions," launched in 2007 with a 90-second television commercial known as "Gorilla," directed by Juan Cabral. The film shows a man in a gorilla suit sitting behind a drum kit; after a long, anticipatory pause, the gorilla begins playing air drums and then launches into a full solo performance of the instrumental build-up to Phil Collins's 1981 track "In the Air Tonight." At no point in the commercial does the advertisement depict the chocolate product, articulate a product benefit, or use dialogue; the Cadbury logo and the line "A glass and a half full of joy" appear only at the very end.

"Gorilla" was followed by a second execution in the same idiom, known as "Trucks," in which airport ground-support vehicles appear to dance along a runway to Queen's "Don't Stop Me Now." Public demand for the original character was reported to be strong enough that the gorilla was subsequently brought back into later Cadbury communications rather than being retired after a single burst.

Positioning & Consumer Insight

The strategic insight underlying the work, as described in the D&AD and IPA case materials, was that Cadbury needed to be understood by consumers not as "a manufacturer of chocolate" but as "a producer of joy" a reframing of the brand's role from functional supplier to emotional trigger. This is a textbook application of several established principles of consumer psychology in a marketing context. First, the campaign relied on affect-based rather than argument-based persuasion: by generating a strong, positive, surprising emotional response unconnected to any explicit sales claim, it worked to build implicit positive association with the brand rather than inviting the more sceptical, effortful scrutiny that a reasoned claim would have triggered scrutiny that would have been particularly risky for a brand still recovering from a public trust failure. Second, the format exploited incongruity and expectation-violation: an ape in a business-park drum setup, performing a well-known rock track with total sincerity, creates a form of humour rooted in the surprise of an unresolved pattern, which psychological research on humour and attention has long associated with increased memorability and voluntary re-viewing and sharing of content. Third, by pairing the brand consistently and repeatedly with a feeling of unguarded, uncomplicated pleasure rather than with product attributes, the campaign functioned as a form of classical conditioning of brand affect an approach frequently cited in behavioural marketing literature as more durable, and harder for competitors to imitate, than attribute-based positioning.

Media & Channel Strategy

Publicly available accounts confirm that the campaign launched via UK television advertising and subsequently achieved substantial organic reach on early video-sharing platforms; one industry account notes the film was "still getting hits on YouTube a year later," a form of longevity unusual for a conventional television commercial of that period. No verified public information is available on Cadbury's specific media spend, channel weighting, or paid-versus-earned media split for the Gorilla campaign; publicly documented sources describe its distribution pattern in qualitative terms (television launch followed by sustained online sharing and media commentary) rather than in disclosed budget or GRP figures.

Business & Brand Outcomes

The campaign's effects are among the better-documented in UK advertising effectiveness history because Cadbury and Fallon submitted the work to the IPA Effectiveness Awards, which require sponsors to demonstrate commercial results using independently reviewed data rather than creative merit alone. According to the IPA's published case study, Cadbury Dairy Milk's sales by value increased 5% year-on-year in the month the "Gorilla" advertisement aired, compared with the brand's performance in the period before the campaign. A Cadbury spokesperson quoted in D&AD's case study of the campaign stated that "in the short term we saw a rise of about 9%," and that subsequent airings of Gorilla alongside its successor, Trucks, produced "a gradual, consistent build in sales of the brand," along with what the spokesperson described as "a real turnaround in terms of brand preference."

At the level of the broader "Glass and a Half Full Productions" campaign, of which Gorilla was the first and most prominent execution, Cadbury and Fallon's submission to the IPA Effectiveness Awards reported that the campaign delivered a "master brand payback" 171% greater than the brand's previous advertising, and that the Gorilla execution alone delivered a return on investment of £4.88 for every £1 spent, based on the IPA's published Silver Award case summary from the 2010 awards cycle.

The advertisement was also named Campaign of the Year by Campaign magazine in its review of 2007 UK advertising, and it won awards at the Cannes Lions International Festival of Creativity, including recognition in the Film category, establishing it as a rare campaign to be honoured for both creative distinction and documented commercial effect the latter being the specific bar the IPA Effectiveness Awards require. A secondary cultural effect was also documented: Phil Collins's "In the Air Tonight" returned to music sales charts in markets where the advertisement aired, an indicator of the depth of public engagement with the specific creative execution rather than simple ad recall.

No verified public information is available on Cadbury Dairy Milk's UK market share change over a defined post-campaign period, on customer acquisition or retention metrics, or on internal brand-tracking scores beyond the qualitative "brand preference turnaround" language attributed to Cadbury in the D&AD case study; where later commentary (including from marketing analyst Mark Ritson, writing in Marketing Week) revisited the campaign, it noted the difficulty Cadbury faced in following Gorilla with an equally resonant execution, describing the follow-up "Trucks" advertisement as having disappeared from public memory relatively quickly despite similar creative logic.

Strategic Implications

The Cadbury Gorilla case illustrates several principles relevant to how brands use psychology to shape purchase-related attitudes and behaviour, each grounded in the documented facts of this specific campaign rather than in general assumption. The first is that emotional, non-argumentative advertising can be a rational strategic choice precisely when a brand's credibility on rational, factual claims has been damaged a direct food-safety reassurance message risked reactivating the negative association Cadbury was trying to move past, whereas an emotionally distinct, unrelated experience gave consumers a new, positive point of contact with the brand that did not require them to actively resolve or forgive the prior controversy. The second is that distinctiveness and pattern interruption an advertisement that withholds an obvious explanation of what is happening and why can generate the kind of voluntary attention, repeat viewing, and social discussion that paid media alone typically cannot buy, a pattern consistent with the campaign's documented shift from a single television flight to sustained, multi-year online viewership. The third is that the IPA's own effectiveness framework, which requires advertisers to demonstrate a documented financial return rather than rely on creative-industry acclaim, is itself evidence that this campaign's psychological approach converted into a measurable commercial outcome rather than remaining a purely reputational or awards-oriented success.

At the same time, the case also demonstrates the limits of psychology-led, emotion-first advertising as a repeatable formula: publicly available commentary on the campaign's aftermath notes that Cadbury and Fallon struggled to replicate Gorilla's specific cultural impact with subsequent executions using the same creative logic, suggesting that the technique's power was tied to the particular surprise and freshness of the original execution rather than being a formula that could be mechanically reapplied.

Discussion Questions

Cadbury chose an emotionally distinct, product-absent advertisement over a direct reassurance message following a documented food-safety crisis. Under what conditions is emotional repositioning a more defensible strategic choice than rational, claim-based crisis communication, and when might the reverse be true?

The IPA Effectiveness Awards required Cadbury to demonstrate a measurable financial return before recognising the campaign's creative merit. What does this dual requirement suggest about how marketing organisations should structure the evaluation of psychology-driven, brand-building campaigns versus short-term, direct-response advertising?

The "Gorilla" execution generated substantial unpaid, organic online distribution in a period before video platforms were the dominant advertising channel they are today. What underlying psychological mechanisms make certain pieces of branded content more likely to be shared voluntarily, and how transferable are those mechanisms across categories beyond confectionery?

Public commentary on the campaign's aftermath suggests that Cadbury and Fallon found it difficult to sustain the same level of impact with follow-up executions using an identical creative approach. What does this imply about the risk of treating a single successful application of consumer psychology as a repeatable brand platform?

Cadbury's positioning shift from "producer of chocolate" to "producer of joy" separated the brand's emotional promise from its literal product attributes. What are the strategic risks and benefits of building brand equity around a feeling rather than a functional product claim, particularly for a brand recovering from a trust-based crisis?