Matching and mis-matching
Human beings have the ability to recognise patterns and hence discern similarities and differences.
In medicine there are agreed templates describing collections of symptoms and signs. These define diseases and mental illnesses such as in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). This process can have uses, for instance the diagnosis of a heart attack is required before the specific treatment is available. In a similar way the diagnosis of Post Traumatic Stress Disorder (PTSD) may have legal implications.
Some individuals are more skilled at recognising matches, and some at recognising mismatches. A General Medical Practitioner will usually be assessing in both patterns. He or she will be looking for matches in order to diagnose diseases and hence provide appropriate treatments. They will also be looking for mismatches, for instance with a cough, in order to decide which of the many patients describing this condition require further investigation to exclude underlying conditions such as lung cancer.
The unconscious application of these principles allows us to consider such factors as accents and physical characteristics. It is possible to determine which town a person comes from using their accent. Physical characteristics can determine ethnic origin or religion.
The ability to discern in such fine detail is not a problem in itself. The problem arises when we use this information to fuel prejudices and discrimination