1. Memory is a reconstructive process and therefore is open to distortion.
2. Emotion may affect cognitive processes - either increasing or decreasing their reliability.
3. Humans are cognitive misers, often seeking shortcuts in thinking and decision-making.
4. Biases affect our ability to make rational decisions.
When we discuss the reliability of a cognitive process, we want to know how consistent is the information over time. So, in the case of memory, are our memories consistent, and thus accurate, the longer that we have them? We know from the research by Bartlett and Brewer & Treyens that memory can be influenced at the encoding stage. What about memories that are more personal? Our first date? Our first day of school? Our wedding day?
How reliable is memory? The legal system uses eyewitness testimony which relies on the accuracy of human memory to decide whether a person is guilty or not. Normally, juries in courts of law take eyewitness testimony very seriously, but recently the use of DNA technology has demonstrated what some psychologists have claimed for years: eyewitnesses can be wrong. Researchers have demonstrated that memory may not be as reliable as we think.