I consider this a speculative result but it is interesting nonetheless:
"There has been a lot of research which shows that creative TV ads are more effective than those which simply deliver information, and it has always been assumed that it is because viewers pay more attention to them.
"But in a relaxed situation like TV watching, attention tends to be used mainly as a defence mechanism. If an ad bombards us with new information, our natural response is to pay attention so we can counter-argue what it is telling us. On the other hand, if we feel we like and enjoy an ad, we tend to be more trustful of it and therefore we don't feel we need to pay too much attention to it.
"The sting in the tail is that by paying less attention, we are less able to counter-argue what the ad is communicating. In effect we let our guard down and leave ourselves more open to the advertiser's message.
"This has serious implications for certain categories of ads, particularly ads for products that can be harmful to our health, and products aimed at children.
"The findings suggest that if you don't want an ad to affect you in this way, you should watch it more closely."