Why We Buy: The Hidden Science Behind Every "Add to Cart"

You walk into the store with the sole purpose of buying shampoo. Fifteen minutes later, you're at the register holding a $67 candle that smells like "Grandma’s Cookies," and you genuinely could not tell someone why. Was it the lighting or the discount sign? Could it have been the way it was displayed next to three other candles? Or was it the fact that you'd had a rough day and some part of your brain decided you deserved something?

Here's the uncomfortable truth: it wasn't random. It was behavior — and behavior, as any behavior analyst will tell you, never happens for no reason. Behavior goes where reinforcement flows. 

Exploring the complexities of shopping addiction with insights into consumer behavior and psychology by Blackrock Behavior Group.

An entire field is built around unpacking moments like this. It's called Consumer Behavior Analysis (CBA), and it sits at the intersection of behavioral psychology, microeconomics, UX research, and marketing (Foxall, 2017). At BlackRock Behavior Group, we've got something most consulting firms in Silicon Valley don't: a Board Certified Behavior Analyst (BCBA) who's also a certified Consumer Behavior Analyst (CBA) — a genuinely rare combination within the BCBA niche. That means here at BlackRock, we're not guessing why your customers do what they do. We read the science behind it and help businesses build experiences that work with human behavior instead of against it.

Let's pull back the curtain.

You've Been Trained To Buy It Without Knowing

No one shops with a blank mind. Every decision you make in a store, on a website, or while scrolling an app is a negotiation between two forces: everything that's ever happened to you as a shopper, and everything happening around you right now (Foxall, 2010). Put those two together, and you get what researchers call the consumer situation (Foxall, 2010).

The first piece is your learning history, which you can think of as the full archive of your past shopping wins and losses (Foxall, 2010). This runs on operant conditioning, the principle B.F. Skinner made famous, which basically says behavior increases or decreases depending on the consequences an individual experiences immediately after it occurs. If behavior gets reinforced, it sticks around, and behavior that gets punished slowly (or quickly) fades. Bought a pair of sneakers that fell apart in a month? Next time you see that brand, you decide to spend elsewhere, possibly buying a competitor brand instead. Choosing shoes from a new brand can result from what textbooks call positive punishment, where an unpleasant/aversive consequence follows a behavior, decreasing the probability that you repeat it (Fagerstrøm et al., 2010).

The second piece is the setting itself — the social and physical stage you're standing on (Fagerstrøm et al., 2010). BCBAs simply call this the ‘environment’, as behavior analysts know the level of influence surrounding stimuli have on one’s behavior. Store layout, lighting, whether a salesperson greets you or ignores you, whether it's the Tuesday before Christmas or a random Wednesday in March — all of it shapes what you do next (Fagerstrøm et al., 2010).

Consumer behavior analysts describe these settings on a spectrum from "open" to "closed" (Foxall, 2010). Think about the difference between a neighborhood bar and a bank line. At the bar, you've got freedom to order whatever you want, talk loudly, linger for hours, and leave at whatever time you prefer (Foxall, 2010). In the bank line, there's a code/script, and stepping outside it gets you a look that could curdle milk (Foxall, 2010). As you can see, wildly different behaviors occur depending on what the environment allows.

Every Purchase Is Secretly Two Purchases

Ask most people why they bought something and they'll give you a practical answer: "I needed it." Fair enough — but that's rarely the whole story.

The Behavioral Perspective Model says every purchase delivers two kinds of payoff, or what BCBA/ABA textbooks call reinforcement (Foxall, 2010). One is utilitarian — the plain, functional benefit of the item purchased actually working (Foxall, 2010). Think of why you purchase a car. Many people buy a car in their lifetime to get around. A basic sedan gets you from your driveway to the office. That's it. That's the job. It's reinforcement you could explain to a five-year-old (Foxall, 2010). If the car you bought is able to get you from A to B successfully for years, it’s likely to have an effect on your purchase decision when you need to buy a car again.

The other is informational — and this one's sneakier (Fagerstrøm et al., 2010). It's the social currency a purchase buys you: status, prestige, a little jolt of "look at me" (Foxall, 2010). A behavior analyst would call this attention-maintained behavior, or positive socially mediated reinforcement. In slang today, we call this an “attention whore”. So, why is this important? Because the behavior is a result of what you get from other people (their attention), not the object itself. Take the Porsche driver. Sure, the car gets them to work just like the sedan driver — but that's almost beside the point. The Porsche driver is really buying prestige, elite status, and the head turns he gets from women in the parking lot (Foxall, 2010). Even something as small as color-interchangeable phone cases does double duty: it protects your phone when you drop it, and it signals to your friend group that “you’re cool” (Foxall, 2010).

Almost nothing you buy is purely one or the other (Foxall, 2010). The real skill — for a business, or for anyone trying to understand their own habits — is figuring out where a product sits on that spectrum, and how much of its appeal is function versus feeling.

Understanding the Science of Consumer Choice: Analyzing Factors Influencing Behavior and Decision-Making Processes.

Jargon Buster: "I Can Get It" vs. "I Want It Now"

Here's a distinction that sounds academic but you've lived it a hundred times: the difference between something being available and something being wanted.

Picture yourself on a long highway drive. A glowing fast-food sign flickers past — that's a discriminative stimulus, or SD: a cue that tells you reinforcement (in this case, food) is available if you act (Fagerstrøm et al., 2010). But whether that sign actually gets you to hit the brakes depends entirely on something else: how much you ACTUALLY want food right now, or what researchers analyze through stimulus saliency (Fagerstrøm et al., 2010).

That "how much" is governed by what academics call a motivating operation, or MO. Haven't eaten in ten hours? Hunger is taking serious priority over what behaviors you choose to engage in RIGHT NOW, and it’s because hunger is an establishing operation (EO). An EO temporarily jacks up the value of food since a person is food-deprived. Food deprivation creates an evocative effect and makes that sign impossible to ignore (Fagerstrøm et al., 2010). But what about vice versa? Let’s say you just demolished a plate of nachos twenty minutes ago. Same sign, same highway, same person… but you drive right past the sign, not even considering it. These conditions describe an abolishing operation (AO, which creates an abative effect, and food has basically lost its pull. You sail right past that discriminative stimulus (SD) because it currently has no salience (Fagerstrøm et al., 2010).

And here's where it gets interesting for marketers: businesses can manufacture that pull with words alone. These are called augmentals — verbal claims designed to inflate how much you want something before you've even encountered it (Fagerstrøm et al., 2010). "New Bloggo gets clothes whiter than ever before!" isn't just a slogan. It's a deliberate attempt to make the payoff of buying detergent feel bigger than it did five seconds ago (Fagerstrøm et al., 2010).

Three Flavors of Shopping Trip

Once you view shopping through this lens, you notice that trips to the store aren't all the same. Foxall (2010) breaks them into four broad categories, but this blog describes three.

1. Accomplishment: This is shopping as a scoreboard. In open settings, it shows up as status consumption — the newest iPhone, a trip to the Maldives, anything that broadcasts "I've made it, and I’m successful” (Foxall, 2010). In closed settings, it turns inward, becoming fulfillment: finishing a certification course, winning big at a casino table, hitting a personal milestone (Foxall, 2010).

2. Accumulation: Ever collected stamps, hoarded coupons, or refused to switch airlines because you're "so close" to elite status? That's consumer accumulation (Foxall, 2010). In open settings, it looks like saving up — paying for a vacation in installments, watching the balance climb (Foxall, 2010). In closed settings, BCBAs call it a token economy. In a consumer context, a token economy looks like airline miles, hotel points, or even punch cards (Foxall, 2010). Businesses design methods using the same mechanisms BCBAs use in clinical ABA work. BCBAs design a token economy so that tokens function as generalized conditioned reinforcers, exchangeable later for the backup reinforcers that actually matter to the client (Cooper et al., 2019). Take away the backup reinforcer, and the tokens go dead — no pull left at all. Loyalty programs live or die by this same rule: watching your points climb feels good precisely because you trust there's something real waiting at the finish line (Foxall, 2010). Otherwise, what value would those points serve if they could be used for nothing? That’s right, they would have no value at all.

3. Maintenance: The unglamorous backbone of daily life. In open settings, it's the weekly grocery run — replenishing what keeps a household running (Foxall, 2010). In closed settings, it's the stuff you don't get to opt out of: taxes, license renewals, pension contributions — the price of staying a functioning citizen (Foxall, 2010).

   
   

Let’s Bring Behavioral Science to Your Business

Here's what most businesses get backward: they try to guess what customers want by asking them directly, then act surprised when the answers don't match the behavior. Asking customers what they prefer isn’t a bad strategy, and in fact, BCBAs might be thinking of preference assessments as they read this. However, in a consumer context, people are notoriously bad at explaining their own motivations — not because they're lying, but because so much of this operates off behavioral science rather than intuition. Nobody walks into a store thinking, "I am currently in a closed setting with an establishing operation (EO), which is creating an evocative effect."

That's exactly why behavior analysis is such a different lever to pull. Instead of asking customers to introspect or guess, it looks directly at the environment—the cues, settings, learning histories, and reinforcers (or punishers)—and maps what's actually driving the choices that matter to your business (Fagerstrøm et al., 2010; Foxall, 2010). If you’ve never tried to implement behavior design in your business, why not give it a try? BlackRock offers the best pricing, first-time discounts, and is equipped with one of the few existing BCBAs who is also credentialed as a CBA.

At BlackRock Behavior Group, this is the premise of our work. We're not just one of Silicon Valley's top and premier consulting firms, but we’re one offering the rare pairing of clinical behavior science and consumer psychology, and we use it to help businesses reshape retail layouts, sharpen marketing so it actually converts, smooth out digital user experience, and build loyalty programs that tap into the same token-economy principles that work in a therapy room — because, it turns out, they work everywhere.

Curious what your customers' behavior is really telling you? Let's talk. Schedule a free consultation with our team today.

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Explore the secrets of consumer behavior with "The Science of Consumer Choice." Discover how to leverage psychological insights to drive desire, set optimal pricing, and excel in the market. Get your free guide today!

Curious to learn more? BlackRock is happy to offer everyone a free PDF guide with evidence-based research and visuals designed to be easy to digest. Yes, you read that correctly; this product is on the house!

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References

Cooper, J. O., Heron, T. E., & Heward, W. L. (2019). Applied behavior analysis (3rd ed.). Pearson Education.

Fagerstrøm, A., Foxall, G. R., & Arntzen, E. (2010). Implications of motivating operations for the functional analysis of consumer choice. Journal of Organizational Behavior Management, 30(2), 110–126. https://doi.org/10.1080/01608061003756331

Foxall, G. R. (2010). Invitation to consumer behavior analysis. Journal of Organizational Behavior Management, 30(2), 92–109. https://doi.org/10.1080/01608061003756307

Foxall, G. R. (2017). Behavioral economics in consumer behavior analysis. The Behavior Analyst, 40(2), 309–313. https://doi.org/10.1007/s40614-017-0127-4