Some sad days ahead at our house since our awesome rescue dog Dewey has been diagnosed with lymphoma. He's on meds and they have helped give him a boost, but the outcome is just a matter of time.

We have had Dewey for about five years and he truly is a part of the family. He has a great personality and he loves everybody.

What we didn't know was that a dog's personality can change with major life experiences, much like a human owner.

EurekAlert reports that Michigan State University researchers surveyed the owners of more than 1,600 dogs of various breeds and ages, and they found correlations in three main areas:

  • Age and personality.
  • Human-to-dog personality similarities.
  • The influence a dog's personality has on the quality of its relationship with its owner.

They confirmed the old adage that you can't teach and old dog new tricks. The "sweet spot" for teaching a dog obedience is around age 6, and that fear and anxiety rarely change in dogs as they age.

Adoptive owners should know that some traits are likely tied to biology and are resistant to change, but if you put the dog in a new environment where it's loved, walked and entertained often, these dogs can become a little more relaxed and sociable.

Researchers say now that they know that a dog's personality can change, the next step is to try and understand why dogs act -- and change -- the way they do.