Several types of cognitive bias occur due to an attentional bias. One example is when a person does not examine all possible outcomes when making a judgment about a correlation or association. They may focus on one or two possibilities, while ignoring the rest.
The most commonly studied type of decision for attentional bias, is one in which there are two conditions (A and B), which can be present(P) or not present(N). This leaves four possible combination outcomes: Both are present (AP/BP), Both are not present (AN/BN), Only A is present (AP/BN), Only B is present (AN/BP).
In everyday life, people often are subject to this type of attentional bias when asking themselves, "Does God answer prayers?", as pointed out by Nisbett and Ross (1980). Many would say "Yes" and justify it with "many times I've asked God for something, and He's given it to me." These people would be accepting and overemphasizing the data from the present/present (top-left) cell, because an unbiased person would counter this logic and consider data from the present/absent cell. "Has God ever given me something that I didn't ask for?" Or "Have I asked God for something and didn't receive it?" This experiment too supports Smedslund's general conclusion that subjects tend to ignore part of the table.
Attentional biases also can influence what people are more likely to look at. For instance, patients with anxiety disorders show increased attention to threatening faces in studies using the dot-probe paradigm.