The functional product comparison — which option performs better on the relevant dimensions — accounts for a portion of purchasing decisions and misses the primary driver of purchasing in a large number of categories. Belk’s (1988) extended self research, Tajfel and Turner’s (1979) social identity theory, and the brand identification research together establish that purchasing in identity-expressive categories is primarily a self-concept management activity. The product is evaluated for what it says about the purchaser as much as for what it does for them.

Why possessions become part of the self

Belk’s (1988) Journal of Consumer Research paper is the foundational treatment. The extended self is not a marketing metaphor — it is a psychological mechanism through which objects become incorporated into the self-concept in ways that make their possession identity-relevant and their loss identity-threatening. Pierce, Kostova and Dirks’s (2003) psychological ownership research operationalises exactly this process: through investment of time, creative energy, and self-referential thought, objects are incorporated into the extended self. The car is not merely transport; the clothing is not merely body covering; the technology is not merely a tool. In categories with visible social function, these objects become part of what the person is.

The commercial implication follows precisely from the mechanism. When a product is a self-extension, the purchase decision is not primarily a functional evaluation. It is an identity question: does this product express something about who I am that I want expressed? Does it communicate membership in a group I want to belong to? Does it contradict something about my self-concept that I want to protect? The functional comparison — which product performs better on objective criteria — is secondary to the identity comparison, or sometimes irrelevant to it.

Why brand loyalty is identity loyalty

Tajfel and Turner’s (1979) social identity theory predicts the brand loyalty mechanism with precision. When customers identify with a brand’s social group — the community of people who use this product — the brand becomes incorporated into their social identity. Purchasing the brand is performing membership. Criticism of the brand is criticism of the group, and by extension criticism of the self. Switching is experienced as identity betrayal, which is why brand-loyal customers remain loyal through product failures and price increases that would cause non-identified customers to defect.

Reed, Bhattacharya and Bolton’s (2012) Journal of the Academy of Marketing Science research confirmed this directly. Brand identification — the degree to which customers incorporate a brand into their self-concept — was a stronger predictor of loyalty, advocacy, and price insensitivity than customer satisfaction. The satisfied customer who does not identify with the brand switches when a better option appears. The identity-connected customer remains loyal under conditions that would cause satisfaction-based loyalty to collapse — because defection is not a rational product comparison; it is an identity loss.

This finding has a specific implication for how customer retention is understood. Satisfaction-based retention is inherently fragile — it is contingent on continued superior performance relative to alternatives. Identity-based retention is inherently durable — it requires the customer to reconceive their own self-concept before the switching decision can be made. The most economically valuable customers are not the most satisfied customers; they are the most identified customers.

The purchase as social communication

The symbolic interactionist tradition in consumer behaviour established that purchasing is a form of communication directed at the social environment. Products are chosen partly for their signalling value — what the purchase communicates to others about who the purchaser is. Berger and Heath’s (2007) Journal of Consumer Research research on identity signalling and product domains confirmed the mechanism with specific precision: in product categories with clear identity signalling function, consumers actively diverge from others’ choices when their social identity is salient — because differentiation from outgroups is as identity-relevant as conformity with ingroups.

The practical implication is that the social meaning of the purchase — what it communicates, to whom, in which social contexts — is as commercially relevant as the product’s functional characteristics in identity-expressive categories. Patagonia’s positioning is not primarily a quality claim; it is an environmental values signal. Apple’s positioning is not primarily a performance claim; it is a creative identity signal. The customer who buys these products is not primarily purchasing functional utility; they are purchasing the social communication the product makes on their behalf.

For startups positioning in identity-relevant categories, this establishes that creating a clear answer to “what kind of person uses this product?” is as commercially important as creating a clear answer to “what does this product do?” — and that the identity claim must be consistent, credible, and communicable in the social environments the target customer inhabits.

Why identity-driven purchasing produces the Apple effect

Cheng, White and Chaplin’s (2012) Journal of Consumer Research research confirmed the Michelangelo mechanism applied to brand purchasing. Apple ownership was consistently associated with creative self-concept — and exposure to Apple branding increased creative performance on subsequent tasks through the brand-elicited self-concept activation mechanism. The brand was not merely signalling creativity; it was activating the creative self-concept in a way that changed subsequent behaviour.

This is the most commercially significant extension of the identity purchasing mechanism: brands that successfully create identity frameworks do not merely satisfy customers or signal status. They activate self-concepts that produce the behaviours associated with those self-concepts — making the brand-customer relationship a self-fulfilling identity claim. The customer who identifies with the creative brand produces creative work; the customer who identifies with the performance brand pursues performance goals. The brand becomes a self-concept management tool, not merely a product evaluation.

The limits and moderators of identity-driven purchasing

The identity purchasing mechanism operates most powerfully in specific conditions: product categories with visible social function, social environments where the signalling is legible to the relevant audience, and customers for whom the relevant identity dimension is important to self-concept. Purely private, low-visibility, low-social-function purchases are less subject to identity mechanisms — the cleaning product chosen for the back of the cupboard is evaluated primarily on functional criteria.

The McCracken (1986) cultural meanings research established that brands acquire identity-relevant meaning through the cultural circulation of meaning — through advertising, celebrity association, subcultural adoption, and media representation — and transfer that meaning to the purchaser. This meaning transfer is the mechanism through which a brand becomes an identity signal rather than merely a product indicator. It can be built deliberately through positioning and communication, and it can be eroded through brand associations that are inconsistent with the target identity.

Books worth reading on this

Building a StoryBrand by Donald Miller. Miller’s brand communication framework — positioning the customer as the hero and the brand as the guide — is the most widely applied practical implementation of the identity purchasing mechanism in commercial communication. His specific account of how brands that reflect the customer’s aspirational identity back to them generate substantially stronger engagement than brands that position their own achievements centrally maps directly onto the Belk extended self and Tajfel and Turner social identity mechanisms. Who Do You Want Your Customers to Become? by Michael Schrage. Schrage’s argument that the most commercially consequential question in product design is not “what does this product do?” but “who does this product help the customer become?” is the most direct available commercial application of the identity purchasing research. His specific account of how the most successful products transform their customers’ self-concepts — rather than merely satisfying their existing preferences — provides the most practically useful available framework for designing identity-driven products and positioning.

If the dynamics described here are significantly affecting your wellbeing, speaking with a psychologist is the right next step. UK: Samaritans (116 123, free, 24/7). Mind (0300 123 3393). BACP: bacp.co.uk/search/Therapists. Crisis Text Line — text HOME to 741741 (US, UK, Canada, Ireland). International: internationaltherapistdirectory.com.

This article is for educational and informational purposes only. Sources: Belk, R.W. (1988), Possessions and the Extended Self, Journal of Consumer Research, 15(2), 139–168. Pierce, J.L., Kostova, T. & Dirks, K.T. (2003), The State of Psychological Ownership, Review of General Psychology, 7(1), 84–107. Tajfel, H. & Turner, J.C. (1979), An Integrative Theory of Intergroup Conflict, in Austin, W.G. & Worchel, S. (Eds.), The Social Psychology of Intergroup Relations, Brooks/Cole. Reed, A., Bhattacharya, C.B. & Bolton, L.E. (2012), Managing Customer Connections with the Brand, Journal of the Academy of Marketing Science. Berger, J. & Heath, C. (2007), Where Consumers Diverge from Others: Identity Signaling and Product Domains, Journal of Consumer Research, 34(2), 121–134. Cheng, S.Y.Y., White, T.B. & Chaplin, L.N. (2012), The Effects of Self-Brand Connections on Responses to Brand Failure: A New Look at the Consumer-Brand Relationship, Journal of Consumer Psychology, 22(2), 280–288. Cooley, C.H. (1902), Human Nature and the Social Order, Scribner’s. McCracken, G. (1986), Culture and Consumption: A Theoretical Account of the Structure and Movement of the Cultural Meaning of Consumer Goods, Journal of Consumer Research, 13(1), 71–84. Schor, J.B. (1999), The Overspent American, Harper Perennial. Miller, D. (2017), Building a StoryBrand, HarperCollins. Schrage, M. (2012), Who Do You Want Your Customers to Become?, Harvard Business Review Press.