A campaign can move every number on the brief and still move nothing in the market.
Awareness climbs. Aided recall climbs. Stated preference climbs. Purchase does not. The standard post-mortem blames the creative or the media weight, and the next campaign gets a bigger version of the same idea. The more likely explanation is uncomfortable: the campaign argued with a decision that was never made.
Persuasion assumes a decider. It assumes someone is weighing options, holding a preference, capable of revising it when given a better reason. That person exists. They are simply a minority of the market on any given Tuesday.
Start with the most inconvenient finding in applied psychology.
Webb and Sheeran ran a meta-analysis of 47 experimental tests in which researchers successfully changed people's intentions and then measured whether behavior followed. The intention shift was substantial — a medium-to-large effect, d = 0.66. The behavior shift that followed was d = 0.36. Roughly half of the persuasion evaporated between the mind and the hand (Webb & Sheeran, Psychological Bulletin).
Read that carefully, because it is not a story about persuasion failing. The persuasion worked. Intentions moved, and they moved a lot. The gap is downstream of the message entirely, and it is structural: intentions account for roughly 30% of the variance in what people subsequently do.
That is the ceiling on every campaign whose theory of change runs through the mind. Under laboratory conditions, with motivated participants and a clean measurement window, changing what someone intends buys you a little more than half as much change in what they do. In market, with distracted people and an eleven-week purchase cycle, expect less.
So the question is what occupies the other 70%.
A large share of it is habit — and habit is not a weak preference or a low-involvement decision. It is a different system entirely.
Wood and Rünger's review of the habit literature puts roughly 43% of daily behavior in the category of actions repeated in stable contexts, the conditions under which habit memory forms (Annual Review of Psychology). The mechanism is direct: when a rewarding action is repeated in a consistent context, the context itself begins to activate the response. Perception of the cue triggers the behavior without routing through goals, deliberation, or current preference.
The commercial version of this is unglamorous. Someone buys the same brand of coffee not because they evaluated coffee and concluded, but because the shelf position, the time of week, and the shape of the store aisle produce the reach. Wood's work on the habitual consumer is explicit about the consequence: people repeat past behavior with little regard for current goals and valued outcomes (Journal of Consumer Psychology).
"Little regard for current goals" is the line that should worry any marketer. It means the buyer can genuinely prefer your product, tell a researcher so, score you higher on every attribute, and still reach for the competitor — because reaching is not where preference lives.
Persuasion enters through attitudes and goals. Habit runs on cues. Your best argument arrives at a door the behavior does not use.
This explains the specific and very common failure pattern where brand tracking improves for four consecutive quarters and share does not move. The tracking is measuring the system you addressed. The share is being produced by the system you did not.
It also explains a quieter problem on the other side of the ledger. A strong habit protects you from a competitor's messaging — which sounds like an asset, and partly is. But it also means your own retention numbers stop telling you anything about whether customers still prefer you. Loyalty and inertia produce identical dashboards. You cannot tell them apart until something disturbs the context, and by then the disturbance is doing the deciding.
Firms with high habitual repeat and thin genuine preference are not stable. They are undisturbed. Those are different conditions with the same reading.
Here is the part that turns this from a diagnosis into a strategy.
Habits are cued by context, so when context breaks, the habit loses its trigger — and for a period, behavior returns to deliberation, where persuasion works.
Verplanken and Roy tested this directly. Eight hundred participants received either an intervention promoting a set of sustainable behaviors or nothing. Across the full sample the effect was unremarkable. Among participants who had recently moved house, the intervention worked — controlling for past behavior, habit strength, intentions, perceived control, values, and personal involvement. The window ran roughly three months from relocation (Journal of Environmental Psychology).
Same message. Same budget. Different receptivity, determined entirely by whether the recipient's context had recently come apart.
The commercial equivalents are not hard to list once you look for them: a move, a new job, a new commute, a first child, a divorce, a phone replaced, a store closed, a subscription lapsed, a supplier acquired, a procurement lead departed. In B2B the personnel change is the relocation — a new operations director arrives with no habits attached to your category and roughly a quarter before new ones set.
Most media plans distribute weight evenly across a year against a market whose receptivity is concentrated into narrow, identifiable, and largely observable moments. That is the misallocation, and it is not a small one.
If the behavior is habitual, three levers exist, and the message is not first among them.
Wood's work with Procter & Gamble landed on a finding that reframes most product launches: new products often fail not because people dislike them but because a competing habit already owns the moment. The instruction that follows is to design the product into the routine that exists rather than asking the buyer to construct a routine that does not. The same holds for a message — placed at the moment of the cue, it has a chance; placed at the moment of highest attention, it is talking to a system that will not be present at purchase.
Habit responds to the cost of the response. Making the alternative marginally easier does more than making it marginally more attractive. This is why default settings, shelf position, one-click reordering, and preselected quantities outperform argument, and why an operator who understands this beats a communicator who does not.
Do not wait for the window, and do not spread against it. Life-event and firmographic-change signals are purchasable, observable, or inferable in most categories. Weighting spend toward disrupted buyers is one of the few reallocations available that changes results without changing the creative.
Two consequences follow, both awkward.
First, intent lift measured on a habitual population is nearly free and nearly meaningless. You can move stated preference among people whose behavior is not governed by stated preference all day long. It will read as success. Segment your tracking by habit strength — frequency and context stability are decent proxies — and report the two populations separately. The numbers will diverge, and the divergence is the finding.
Second, test in disrupted moments or accept that your test is measuring the wrong sample. A campaign evaluated across an undisturbed market is being asked to overcome cues rather than persuade people, and it will lose that fight regardless of quality. The same campaign, evaluated among recently relocated or recently reorganized buyers, tells you whether the idea works.
The comfortable version of marketing holds that better arguments win. The evidence holds that better arguments win a contest most of the market is not entered in.
None of this makes persuasion less valuable. It makes persuasion conditional — on timing, on context, on whether the person in front of you is currently deciding anything at all. The firms that understand this stop asking how to say it better and start asking when the saying is possible.
Influence is not only a matter of what moves people. It is a matter of catching them at the moment they are movable.
If your brand metrics are improving and your share is not, the gap is diagnosable. Request a behavioral audit.