Consumer decision making and advertising

The rational model and its limits

The classic model has five stages: recognising a need, searching for information, evaluating alternatives, purchasing, and post-purchase evaluation. It describes a car purchase reasonably well and a chocolate bar not at all — most everyday buying involves almost no search or evaluation, which is the criticism the exam wants.

Heuristics: how people actually decide

Anchoring: the first price seen sets the reference point, which is why a crossed-out 'was' price works. Availability: an easily recalled example feels more likely, so a recent advertisement outweighs statistics. Framing: '$90\%$ fat free' sells better than '$10\%$ fat' although they are identical. Social proof: 'our best seller' works because other people's choices are treated as information.

Post-purchase dissonance

After an expensive purchase people feel discomfort about the option they rejected, and they reduce it by seeking information that confirms the choice. That is why sellers send reassuring follow-up messages, and why advertisements are often read most attentively by people who have already bought the product.

How advertising is thought to work

The elaboration likelihood model proposes two routes. The central route uses argument and evidence, and works when the audience is motivated and able to think about the message — it produces attitudes that last and resist change. The peripheral route uses cues such as an attractive presenter, music or repetition, and works when the audience is not paying close attention — it produces weaker attitudes that fade.

Measuring whether an advertisement worked

Recall and recognition tests, attitude scales, eye tracking, physiological measures, and sales data. Sales are the outcome that matters but are affected by price, weather, competitors and season all at once, so attributing a change to the advertisement requires a controlled comparison.