The Canary in the Mineshaft Logical Fallacy.

John Scott Haldane (left).
 

John Scott Haldane was a Scottish Physiologist (who doesn't love Physiologists) who used to lock himself in a sealed chamber and document the effect of various gasses on humans. He invented a respirator for soldiers in 1915, the oxygen tent, the decompression chamber for divers and found that canaries would die more quickly that humans if Carbon Monoxide was present. Once wonders how may animals he got through before getting to canaries.

So the living Canary in the Mineshaft is a sign that all is well, we are happy to see the happy canary in the mine. But we do not believe that the canary is responsible for the lack of CO in the environment, merely a symptom thereof. 

Some people are used as an indicator of the fact that something has happened, but others actually assume that the person is responsible for the change, when they are merely a product of it. If a group is allowed more freedom, we note that some members of that group come to the public eye. Often, people assume that they caused the change, when like the canary, they are a symptom of it.

In Ireland (or at least in the South) it was said that folk would have a picture of the Pope on the mantelpiece beside a photo of John F. Kennedy*, the first US President with an Irish Catholic heritage. Some people seemed to talk as though Kennedy was personally responsible for much of the change, rather than a sign of the gradual acceptance of the Irish into mainstream US society. This fallacy makes heroes (who doesn't love heroes) out of canaries. The canaries may be heroes for other reasons of course, as with JFK.

Giving the individual canary all the credit also simplifies history. We can blame Neville Chamberlain for failing to prepare the UK for war, when very few wanted to prepare the country for war. Politicians generally come up with polices that will make them popular with the majority of the people, rarely did they single-handedly make those polices popular. 

So the logical fallacy is that if the canary is an indicator of the effect, it is not necessarily the cause:

Kris Kristofferson
Kris Kristofferson

* I was surprised to get an actual reference