Question

why did Shepherd barron reduce the PIN number from six digits to four? ​

Answer 1

Answer:

Shepherd-Barron's wife said that she could only remember four figures, because of her, four figures became the world standard.

Answer 2

Answer:

Well, this is one fun answer. However, his wife Caroline Murray was of the opinion that 6 digits are two too many and people would keep forgetting their pins. She herself found it difficult to remember and hence, he reduced the number down to 4 digits which was seemingly easier to remember!