Consumers have more information and choices at their disposal but in a way tend to care less about what is on offer. As a result, they are on auto-pilot, because of a cluttered mind space, evolving "omega rules" for deciding, and they tend to go for habitual brand buying. Most brands therefore remain in a static position.

Gordon told the World Marketing Conference - held earlier this week by the Marketing Association of Thailand - that purchase triggers differed markedly from brand to brand. Therefore, different brands attract different kinds of shoppers.

There are generally primary and secondary rules involving product performance, price and value, as well as aesthetic preference. These have implications on store layout, packaging and sampling - the "moment of truth in-store", as he put it.

Gordon gave the case study of shampoo purchasing in New Zealand, where 76 per cent of store customers planned to make a purchase and actually did so (so-called "converted buyers"), 13 per cent did not plan to buy but ended up doing so ("impulse buyers"), and 11 per cent planned to purchase but ended up not doing so ("lost sales").

He said that for shampoo brand choices, 46 per cent could be categorised as habitual, while the other 54 per cent were experimental - of which 37 per cent were activated in-store and 17 per cent pre-store.

Gordon said ACNielsen DeltaQual had identified factors influencing buying decisions at point-of-purchase. These comprise those within retail control, such as on-shelf stocks, promotions, product placement, packaging, aisle traffic and those beyond retail control, such as the timing of shopping, type of shop preferred, who the shopper is with, the buyer's hair condition and the shopper's mood.

For this, buyers are segmented into those who are choosy, variety seekers, stable and price conscious. Each segment has its own distinctive habits.

What consumers notice at the point of sale is important, because this affects their buying habits. Response to out-of-stock products and the reaction to promotions also vary in accordance with buyer segment.

The case study found that most shoppers are at the shampoo section for about a minute, with many taking 20 seconds or less to make a choice. However, quite a lot is going on in their heads in that relatively short time.

Key factors take centre stage, as consumers want to simplify their decision-making. Packaging design and the ability of a product to stand out are both vital, and in-store promotion can also have a big influence on brand perceptions.

Gordon called it essential for marketers to understand the purchase triggers and how consumers make decisions about which brand to buy. He added that with all the information at their disposal, they could correct brand vulnerabilities and identify major marketing opportunities.

Kwanchai Rungfapaisarn,The Nation