Book authors sometimes go on book reading trips (akin to a musician's "gig"): they travel from bookshop to bookshop, read a little from their current work, then sit behind a trestle table and sign copies of their books, preferably their latest novel which the consumer has bought this moment from the bookshop. Everybody profits: the author has sold another copy (more royalties, although one wonders how many books outsell their advance), the bookshop has sold another book and the customer has a signed copy of the book.
In the spirit of Dan Ariely, let's look at the final transaction rationally. A book signed by its author is worth more in the market place than the same book unsigned, although one might argue that there is no logical reason for this. The contents of the book are still the same; the story or the information contained within have not changed. Yet still people are prepared to pay more for a book signed by its author (presumably in the second hand market). Even stranger, I imagine that most of the people who go to a book reading and ask the author to sign their copy have no intention whatsoever of selling their signed copy, so this apparent addition to the book's value will never be realised.
Presumably people do this for the intrinsic value of the act: the fact that they have a signed copy of a book means that they met the author and for a minute basked in her halo. This gives them pleasure every time that they read the book, show it to their friends or even remember the event.
I wrote a few months ago about purchasing guitarist Mick Abrahams' autobiography. I bought the book discounted from the Book Depository thus saving money (a rational decision), but I could have bought it from Mick's website. I could also have paid more for the book and have it signed. As I wrote then, I wasn't aware at the time of this arrangement, so let's assume for the sake of argument that I haven't bought the book yet. I have three options: the standard price, the discounted price and the premium price (book + dedication). The discounted price is obviously better than the standard price, but what about the premium price? Although the signed book will be worth more in the secondhand market (and of course, I also paid more for it!), I won't be getting the intrinsic value of knowing that I met the author.
I am not always consistent. Abrahams belongs to a set of musicians who have learnt that they can increase their earnings if they offer signed cds at a slightly higher price. I confess that I took advantage of this with an archival recording of Hatfield and the North as well as with a dvd of the Bruford group. This arrangement allowed me to get Pip Pyle's autograph while he was still alive.
On the other hand, there were times when I used to order Fairport Convention cds direct from the group and ask them to autograph the booklet, saying that I wouldn't be able to see them this year and ask them to autograph in person. One wag once wrote on this subject that a non-autographed FC cd from recent years would probably be worth more than an autographed cd, presumably because of its rarity.
So are we behaving rationally when asking an author to sign her work? If the work has cost more because of the signature yet we have no intention of selling the book, then in terms of classic economic extrinsic value, we have behaved irrationally (we paid over the market price). But in terms of intrinsic value, we have behaved rationally. But of course, it's always better to get the author to sign for free and then we benefit both extrinsically and intrisically as well as behaving rationally.