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A short thread about UK postcodes
A short thread about UK postcodes
According to a Royal Mail survey, 92% of people can recall their home postcode (that's compared to 77% who can recall their debit card PIN)
17% of people can still recite the postcode of the home where they lived 12 to 30 years ago.
But why are UK postcodes so memorable? It's all thanks to cognitive psychology!
Postcodes were originally designed to speed up sorting following the mechanisation of the postal system at the end of the 1950s
They were first trialled in Norwich in 1959
The Post Office asked psychologists at the MRC Applied Psychology Unit at Cambridge University to help them in devising a memorable system. The project was led by Reuben Conrad & included PhD student Alan Baddeley.
Conrad and co. opted for a mixture of digits and letters, limiting the total to 6 or 7 digit/letter combinations. This was due to research discovering that short-term memory has a capacity of between 5 and 7 pieces of information.
Number only codes had proved too difficult to remember and have a small number of permutations (10 per digit), while letters have 26 permutations per letter. Combining letters and digits give you a much greater range.
Codes had to be short, memorable and sort to street level. It was decided that each code would begin with the initial letters of the town name (the outward code), for example, NOR = Norwich. These have since been revised and include a number (e.g. NR1, LS4, etc)
The outgoing code is the most memorable, so if there are errors in the second half of the code (the inward code), at least it would still get to the right area.
The inward code consists of 1 digit and 2 letters, corresponding to the street - this gives you a very large number of possibilities (10x26x26)
The number is placed in the middle because it stands out and can assist recall, acting as cue for the final 2 letters where errors are most likely to occur.
You can send a letter by using just the house number and the postcode, but Royal Mail don't like that.
Although originally designed to speed up sorting, postcodes have become a vital part of our everyday lives, from Sat Navs to ordering takeaway.
