You might want to read up on the concept of priming, and how it's used in psychological & neurological research. You can markedly change people's behavior by bringing up (or avoiding) particular topics that our minds can connect with subsequent behavioral options.

The classic example is talking about disgusting topics before serving someone a meal... If you tell someone a story about a sewage plant worker falling into an open vat of raw human feces, and then later contracting a bunch of diseases because the fecal matter infiltrated their mouth, nose, eyes, and ears... The people hearing that story will eat less on average, and be more likely to refuse food outright, than a control group who heard a neutral story that removes the sewage and contamination elements.

Another example: People who hear a story about a war hero saving their comrades lives by sacrificing their own are subsequently more likely to offer to help random strangers with tasks like changing a flat tire, or carrying a heavy package.

And the behavior changes are mostly transient... The effect doesn't generally last beyond a few hours or days, unless the priming process is repeated.

So researchers can use priming to explore human motivations, and reveal connections that the subjects aren't even consciously aware of. It still depends on careful experimental design, because you never really know exactly why people are responding to the priming stimulus. But if you pick your stimuli carefully, you can usually eliminate alternative possibilities pretty well.