What conflicts arise with background information?
How high are the stakes?
How credible is the source?
What is the sex of the person who makes the claim?

Advertising offers a perfect opportunity for evaluating claims, because advertising aims at getting you to believe things and because the limitations of time prevent a commercial from spelling out an argument. The quickly stated claim has to sound believable on its own, or with abbreviated support. Furthermore, you will not face the same obstacles you do in other cases, because laws about truth in advertising prohibit a commercial from making clearly false specific assertions about matters of fact. Thus you possess enough background information, simply by having reached adulthood, to judge an advertising claim's initial plausibility.

The next time you watch an hour of television, practice applying the tests spelled out in this chapter. Take notes on all the commercials you see, including all the factors that can influence your evaluation of their claims. Keep the following considerations in mind, and think about where they may enter into your treatment of a commercial.

What conflicts arise with background information? There is nothing wrong with believing that some dish detergents work better than others. So some product probably is the most effective dish detergent, and one product's claim to that honor does not challenge our assumptions about how the world works. Likewise, some automobiles protect you better than others. When one model declares itself among the ten safest in the world, you know that (1) some cars belong in that group, and (2) the assertion is too specific to be permitted without factual support. (You also know that the model is not the world's safest or second-safest car, or the commercial would say so.)

On the other hand, some alleged differences probably don't matter as much as the advertisers profess them to. Although aspirin and an aspirin-free pain reliever probably do take effect at different rates, two brands of aspirin will have a hard time distinguishing themselves from one another. (When one aspirin manufacturer claims its aspirin to be mixed with a second ingredient to enhance the aspirin's effect, read the fine print on the screen. That second ingredient is usually caffeine, which does affect how well aspirin works, but which you can also get from a cup of coffee.)

How high are the stakes? Factors here include the cost of an object. If you let yourself get taken in by claims about the crunch in one brand of peanut butter, the most you can lose is the price of one jar. More turns on your acceptance of a claim about how smoothly a car rides. One decision can matter more than another in other respects as well. It is hard to imagine having a day ruined by a bad choice of soap; the wrong kind of hair coloring will bring more obvious effects.

How credible is the source? Here lies the largest category of questions you may ask about advertising. Watch for strategies by which a commercial presents a claim so as to imbue it with the air of authority.

What is the sex of the person who makes the claim? Does it vary with the product? If so, does this variation suggest that we commonly presume different sexes to have authority over different matters? Whom would you expect to tell you about motor oil? laundry detergent? Ask similar questions about the age of the person. Whom do you believe about amusement parks? What about financial investments? What if claims about the product come from a voice-over? What effect does it have on your belief to hear a voice without seeing its source? Why do you suppose disembodied voices can have their effect?

Finally, does the commercial contain an expert, or present someone as an expert? When actors endorse shampoo, you can expect them to possess special knowledge, because the appearance of their hair makes a substantial difference to their success. On the other hand, they are getting paid to make the endorsement, so you have to weigh their reasons for bias.

If a man appears touting a medical product—a cold remedy, antacid, or dandruff shampoo—what is he wearing? Probably a suit and tie, maybe even a white lab coat. Why do some people in commercials stand in front of bookshelves, or walls with diplomas on them? In one advertisement for imitation jewels, a man screws up his face to hold a magnifying lens against one eye and pronounces himself unable to tell this jewel from the real thing. Although a commercial cannot legally call the speaker an expert, it can still surround the person with the trappings of expertise in order to suggest that point.

In all likelihood, you will find that your observations did not change the evaluations you would have come to without a critical-thinking course. We are deluged with so much advertising that we learn how to judge it. That is no failing of the exercise; on the contrary, it shows that most people think critically without realizing what methods they use. By making yourself conscious of what you were doing unconsciously, you will improve your application of the same criteria in more difficult cases.