Above is a car advert, as hinted by the window wiper in the image. The distinctively different air quality shown in the two blocks aimed to promote the awareness of air pollution, contributed by the use of private transport. The caption at the top right corner however delivered a very clear message to its audience that Smart's cars are less polluting compared to all other cars.
This advert used two persuasion techniques to achieve its aim. Firstly, the selective presentation of information (Smart, the less polluting car of the world, from just €7,990) would bias decision making of consumers. As no information was given on the amount of carbon emission from either Smart or cars from other brands, consumers who do not have a genuine awareness of environmental protection are subjected to a lower motivation to search for the real information. Therefore, consumers are 'forced' to believe what the advert says.
More importantly, Carroll's (1978) study have shown the power of imagination. Before the 1976 presidential election, subjects were asked to imagine either Carter or Ford winning the elect. They were then asked to predict the outcome of the election using a scale from 0 (sure Carter will win) to 100 (sure Ford will win). Subjects who imagined that Carter had won were more certain that he eventually would, similarly those who imagined Ford had won were more certain that he would later win. Thus, providing an easily imagined future (clean and fresh environment) in driving Smart is likely in increase drivers' incentive of buying Smart rather than other cars.
Carroll, J. S. (1978). The effect of imagining an event on expecations for the event: an interpretation in terms of the availability heuristic. Journal of Personality and Social Psychology, 36, 1501-1511.