Transfer vs Testimonial

What is the difference, when does each apply, and can both be at work at once.

Classic

Transfer

Carrying the authority, prestige, or emotional charge of one thing over to another by placing them together, so that a flag, a cross, or a uniform lends its standing to a product or a policy.

Classic

Testimonial

Having a respected or admired person endorse an idea, product, or candidate, so that the audience's regard for the person stands in for a judgment of the thing endorsed.

The differences

TransferTestimonial
The leverThe authority or feeling attached to a symbol, carried over to the thing being sold.A person's explicit endorsement or condemnation.
MechanismAssociation: the flag, the cross, the lab coat, the national anthem placed beside the product.Attribution: a named person says the product or idea is good or bad.
Is anything said?Usually not. The symbol is shown and the audience makes the connection.Yes. There is a statement, quoted or performed.
Typical formVisual: flags in the background, a cathedral behind the candidate, a scientist's setting.Verbal: a quotation, a signed letter, a spoken recommendation.
The counter-moveRemove the symbol and see what is left of the argument.Ask whether the person knows anything about this and what they were paid.
The tellAn unrelated respected thing is in the frame.A respected person is on the record.
An example of transfer

A campaign poster places the candidate in front of a flag, a church, and a row of soldiers. The candidate says nothing in the picture; the viewer is meant to feel the three things and attach the feeling to the face.

An example of testimonial

A retired general appears in an advertisement and says, "I trust this company with my family's security." The statement is the device; the general's rank is what makes it work.

Can both apply?

Yes, and often in the same frame: the general in uniform (transfer) delivering an endorsement (testimonial). The distinction is whether a statement is made. Transfer works by placing; testimonial works by saying. When both are present, the uniform lends weight to the words and the words give the uniform a direction, and the viewer should discount each on its own terms.