Strategic Information Transmission

Color me your color, baby
Color me your car
Color me your color, darling
I know who you are
--Blondie

An important contribution to theory on media bias is Crawford and Sobel's (1982) model of 'strategic information transmission.' This is a model grounded in game theory.

In the game, the Sender of information (e.g., a journalist) has some information that a Receiver (e.g., a media consumer) does not know. The Sender transmits a message to the Receiver. After digesting the message, the Receiver chooses a policy which affects the well-being of both players.

Crawford and Sobel (1982) undertake some high powered math to demonstrate the results of the game, but the implications of their results can be understood intuitively.

Suppose that you're a moderate voter who is completely uniformed about two candidates, a Republican and a Democrat, in an upcoming election. You want to learn who is the best candidate. You have three information sources, each of whom has studiously researched the candidates, to choose from: a) a far Right blogger, b) a far Left blogger, c) your brother, who is politically moderate like you. Each of these sources knows your position on the political spectrum.

Who are you likely to select as an information source? Your brother, of course, because you trust that, given his position on the political spectrum, his information will be useful, and he has little incentive to exaggerate.

Another result of the Crawford and Sobel (1982) is less obvious. If you would happen to seek out the far Right blogger, his thinking goes like this: "You probably believe that I'll exaggerate the virtues of the Republican, and you'll therefore discount the positive things that I say about him. So, if I want you to be accurately informed, then I need to exaggerate my message even more." The sender exaggerates/receiver discounts dyad is likely to escalate until the information provided is severely distorted.

The same process applies if you seek out the Left blogger.

The end result is that both bloggers, even with honest motivation to accurately inform you, have incentives to exaggerate simply because they know that you don't trust them.

Importantly, there is no inborn character trait that makes the Left or Right blogger less honest than your brother. The key is that your political stance differs from those of the bloggers.

Interestingly, if your political values would happen to migrate Left, then according the model this would cause the Left blogger to exaggerate less, and become the most honest of the three information sources.

The lesson: journalists who have political values most similar to their audience have the most incentive to report truthfully.

References

Crawford, V.P & Sobel, J. 1982. Strategic information transmission. Econometrica, 50(6): 1431-1451.