Directly Affecting People’s Emotions in Order to Persuade Them

I'm reading the second book of the Mistborn Trilogy by Brandon Sorenson. (For the record: The first book is fine if you like pulp fantasy. The second book takes a sharp turn into Twilight territory, much to my chagrin. But I shall complete the trilogy, because I am stubborn.) In these books, some people are called Soothers. These characters have a special ability to quell others' emotions. So, for example, they can calm people who are excited, or make people more gentle when their natural reaction is to be angry.
One of these characters frequently uses his power on his friends, which typically bothers them when they realize it's happening. To them it feels invasive and deceptive. But this character (called Breeze) argues that there is nothing wrong with soothing people while trying to persuade them or affect their reactions. He notes that we use the way we dress, changes in tone, implicit threats, and so on, to persuasive effect and these methods are typically taken to be unobjectionable. Soothing is just another example of this, on Breeze's account. It is a persuasive art which proceeds by affecting another's emotional state, hoping thereby to affect the person's decisions.

Breeze argues that by soothing people, he is simply encouraging them, doing the same thing you and I might do using words and non-verbal cues.

Is there anything to this argument? Laying it out, the argument goes:

1. There are many means of persuasion that consist in more or less direct action on others' emotions (rather than strict rational persuasion through the presentation of propositions for logical consideration) and which are unobjectionable.
2. Soothing is relevantly like the above-described means of persuasion
3. Therefore, Soothing is unobjectionable.

My first reaction was to disagree with premise two. After all, soothing is covert, done without the recipient's awareness. Tone of voice, manner of dress, etc., are much more overt—things the recipient is able to notice and take into account. But as portrayed in the book, anyway, people who are aware of the effects of soothing are able, if they are careful, to notice when it's being done to them. And it seems plausible to think that if such a power really existed, those affected by it would be able to tell it was happening if they were paying attention—they'd notice their emotional reactions seem inappropriate to the occasion by their own lights.

Of course not everyone is aware enough of the soothing phenomenon to be able to watch out for it like this. Yet notice that people in the real world are certainly not all aware enough of the power of a-rational non-verbal cues to affect their own actions either. Such effects are generally subconscious, and it takes special effort to notice when techniques of dress, tone of voice, and so on are being used on you. Soothing seems, on reflection, to be no more covert than these more normal means of persuasion.

What about the first premise? Are the various means of persuasion described here actually unobjectionable? If I wear a power tie because I know that people tend to be more pliant if I wear certain colors, am I doing something objectionable?

I'm of two minds on this. On the one hand, as a philosopher I almost feel duty-bound to insist that the only legitimate form of persuasion is rational persuasion, by which I mean, the presentation of articulated claims with an invitation that their recipient examine them for logical coherence with each other and with other known facts. On such a view, it would be illegitimate to attempt to affect others' decisions using the color of my tie. On the other hand, it is impossible to present a set of claims without presenting them in some manner. Manner of presentation is inherent in the act of presentation. And it seems plausible to think that every manner of presentation has some effect on the persuasiveness of the thing presented. For example, if I make a proposal to my boss while wearing slovenly clothing, things are likely to go poorly for me. But if I make the proposal while wearing neat clothing, things are more likely to go well for me. And I must make a choice as to what clothes to wear (or whether to wear any clothes at all) when making the presentation. So then, I cannot help but do something which I know will affect how my audience will feel about my proposal independently of the content of the proposal itself! If I can't help but do it, it is difficult to see how it could be considered objectionable.

(There can be a lot more to say about this. I can imagine someone arguing I should dress slovenly and let the proposal speak for itself—and if the boss is going to let my manner of dress affect his appraisal of the proposal, then my boss is in error, but I am not. Also, in other contexts I have argued that formality in dress, and formality in other contexts, has the function of allowing the content of ideas to be the most active thing in participants' heads, by hiding the particulars of manner of presentation as much as possible. Yet this is probably too strong a claim. Formal presentation is itself a manner of presentation, and has a special persuasive power of its own…)

So then, perhaps it is not objectionable to use techniques intended to directly affect emotions when trying to persuade people. It may be that these techniques are somewhat covert, and there may be something wrong with that—but perhaps the answer isn't to forbid the techniques, but to educate as many as possible into the existence and use of these techniques, so that the non-consent implied in covertness might be eliminated. Indeed, I can imagine a society in which everybody knows how to directly affect everyone else's emotions, and everyone knows everyone knows, and such actions are simply seen as a natural part of daily interaction. At this particular moment, I can't see why such a system couldn't be made to work.

I'm aware that everything I've written here is a very surface-level rehashing of thoughts people have been hammering out for thousands of years, starting at least with some of Aristotle's thoughts on rhetoric. This is philosophical work I have not familiarized myself with (to my regret). Still, the question is an interesting one, and worth discussing, even from a somewhat ignorant viewpoint such as mine. What are your thoughts?