Sandra strongly believes that attending daycare is detrimental to children's development so she decides to write her psychology term paper on this topic. She does a literature search and finds several sources supporting her opinion, but she finds that the majority of research indicates that children attending daycare experience healthy development. She writes a paper using the sources that find negative associations with daycare attendance. This is an example of ________.
A. confirmation bias
B. confounding variable
C. correlational research
D. observer bias

Confirmation bias is the tendency to search for, interpret, favor and recall information in a way that affirms one's prior beliefs or hypothesis. It is a type of cognitive bias and a systematic error of inductive reasoning. People display this bias when they gather or remember information selectively, or when they interpret it in a biased way. The effect is stronger for desired outcomes, for emotionally charged issues, and for deeply-entrenched beliefs.

People also tend to interpret ambiguous evidence as supporting their existing position. Biased search,interpretation and memory have been invoked to explain attitude polarization (when a disagreement becomes more extreme even though the different parties are exposed to the same evidence), belief perseverance (when beliefs persist after the evidence for them is shown to be false), the irrational primacy effect (a greater reliance on information encountered early in a series) and illusory correlation (when people falsely perceive and association between two events or situations).

A series of psychological experiments in the 1960s suggested that people are biased toward confirming their existing beliefs. Later work re-interpreted these results as a tendency to test ideas in a one-sided way, focusing on one possibility and ignoring alternatives. In certain situations, this tendency can bias people's conclusions. Explanations for the observed biases include wishful thinking and the limited human capacity to process information. Another explanation is that people show confirmation bias because they are weighing up the costs of being wrong, rather than investigating in a neutral, scientific way. However, even scientists and intelligent people can be prone to confirmation bias.

Confirmation biases contribute to overconfidence in personal beliefs and can maintain or strengthen beliefs in the face of contrary evidence. Poor decisions due to these biases have been found in political and organizational contexts.