The rationality of a particular person’s emotional response to a stimulus is what is being presented as the alleged inability of a person to elicit an emotional response from another person. It is generally accepted that there are basic emotions (anger, disgust, fear, happiness, sadness, and surprise; Paul Ekman, 1972) whose existence surpass the bounds of culture and literacy. In essence they are not learned behaviors. Emotions such as the schadenfreude in German and saudade in Portuguese are commonly expressed as emotions in their respective languages, but lack an English equivalent.
Take the Portugese word saudade, often interpreted as “the love that remains”. The argument that a person can choose to have this particular emotional response to a loved one’s passing has no basis in reality. The event of that person’s passing whether in death or otherwise, affects a response. The emotional investiture of your relationship with that person can determine the sociological rationality for a particular response to that event. In fact, the lack of a sociologically acceptable reaction by a person who has experienced something that should cause an emotional response is considered a pathology (blunted affect, alexithymia) . The reaction to that emotional response is a choice, suicide, closure, etc. But the emotional response itself is real and uncontrollable, it is not a learned behavior or a choice. The choice comes in our response to the effect of the event that caused the emotion. If you subscribe to the Lovheim cube of emotion then the emotional response is derived by the release of three signal substances (dopamine, noradrenaline, and serotonin) resulting in eight basic emotions (shame, contempt, joy, fear, distress, surprise, excitement, and anger). In other words you can no more control the emotional response to an event than you can choose to release a particular neurotransmitter from a set of neurons in the autonomic nervous system. What does affect the transmission of these chemicals into a person’s system is that person’s physiological and psychological state at the time the event is experienced. There may be a level of choice in these characteristics of a person’s state.
With respect to trust, yes there are strings attached. Of course there are strings attached. The definition of trust is the firm belief in the reliability, truth, ability, or strength of someone or something. Trust is a heuristic approach to dealing with the problem of stability in a relationship. It is based on the belief that a person will behave within a set of expectations resulting from one’s experience with that person or thing, or things of a similar nature. If I said “I don’t trust that dog” what I mean is I believe it is unpredictable – it is difficult to anticipate its behavior; its behavior is unexpected. The same goes with people. If I say I don’t trust people, what I am trying to say is that, in my experience people do not behave the way I expect them to. In that sense, expectations could be called strings. And they are my expectations, which may differ from another person’s expectations. But there are society wide expectations that are applicable to everyone who, by virtue of living in that society are bound by that society’s social contract. Social morays are one example. These expectations may change over time as evinced in our own day and age.