Consumers' prior knowledge of a product category can enhance the impact of an advertisement. The challenge for marketers is to find the best way to tap into this effect. It is not sufficient to present only the information. How the message is presented and how abstract the content is can make a difference in consumer evaluations.

That finding by Jiewen Hong of HKUST and Brian Sternthal is based on four studies that show consumers with extensive prior knowledge evaluate products more favourably if the message gives an impression of progress towards a goal and is presented in a more abstract manner. The opposite is the case for those with limited prior knowledge, who prefer messages that enable them to assess and compare.

"Our findings suggest evaluations are more favourable when there's a fit between prior knowledge and how a message is processed, than when fit is absent," they say.

This fit is important considering the different approaches that consumers may take when evaluating a message. Those with greater knowledge will be more likely to make a quick decision and be selective in the information they consider. Those with less knowledge will be more likely to make more comparisons among alternatives and engage in data-driven processing.

The studies uphold these notions and show that they contribute to processing fluency. When the presentation of information fits their prior knowledge, the participants find it easier to process the message and take a more favourable view of the product.

A similar finding is found with the level of abstraction in messages. A more abstract, or higher "construal", message appeals to people with greater prior knowledge because they can focus attention on why this product is preferable, thus making progress towards their goal. Consumers with limited knowledge will prefer a lower level of construal, which focuses on concrete information and detailed descriptions.

An example of these effects can be seen in one of the studies, on MP3 players. In the high construal description, a feature of the MP3 is described as an "easy menu navigation", in the low construal description this is "select a song by artist, album, song title and much more by the touch of a button". Those with extensive prior knowledge give a more favourable impression when they are presented with the high level of construal, 5.79 out of 7, than the low level, 4.74. Meanwhile, those with limited prior knowledge evaluate the product more favourably with low construal, 5.49, than with high 4.42.

The results have implications for marketing practice, the authors say. "Different message processing strategies should be used when targeting those with extensive versus limited category knowledge. When the target is consumers with extensive prior knowledge, high-level construals that the promote the desirability of the brand benefits are likely to be persuasive, whereas when targeting those with less knowledge, emphasis should be given to low-level construals that address the feasibility of product benefits."

Marketers could also segment customers more effectively in their presentations of information, for example by directing high-knowledge customers to an online shopping page that suits their need for progress towards a goal. The authors suggest marketers could even consider running an educational campaign to equip customers with knowledge before rolling out an advertising campaign that fits their knowledge level.