In biology the 'Coolidge Effect' describes the re-arousal of the male by introducing a new female...

President Calvin Coolidge and his wife were visiting a farm one day and were given separate tours.  Passing through the chicken coop Ms. Coolidge inquired about there only being one rooster.  "He works very hard." came the reply from the supervisor.  "You mean he does it multiple times per day?" she asked.  "Yes, several dozen." the supervisor replied.  

"Tell That" she told the supervisor "to Mr. Coolidge."

Some time later President Coolidge was informed of his wife's remark.  "Same hen every time?" he asked the supervisor.  "Oh no" the supervisor replied "different one every time."

"Tell that" the President replied "to Ms. Coolidge."

I don't know about Mrs. Coolidge, but I know Mrs. Hungry might take issue with that.

Wow, they could have become swingers right there in the chicken coop! ha ha ha

It's much the same with rats. In a labratory setting, a male rat is given opportunity to have sex with female rat (A), for his effort at performing a certain task. With this incentive, his performance remains higher than with other forms (food, water,etc.), up to a point, and then it "peters out." Introducing new female rat (B) will bring him back up to his original performance level. Hmm, could this help explain why some, most, or all of us hobby? Rat studies also help give us insight into our desires for desserts.

Hobbying IS my dessert.

Ahhh! Killing two birds with one stone. Keeping your performance up while eating having your dessert. One smart guy.

Sometimes you really can have your cake and eat it, too.