Calling someone “immature” when a plan does not go their way is a judgment about character. The research on what actually predicts a poor reaction to a blocked goal points somewhere more specific and less moralising: not a fixed personality flaw, but two measurable, separate factors, how entitled a person generally feels to a particular outcome, and which emotional strategy they reach for once they realise they are not getting it.
Entitlement predicts the reaction more than the disappointment itself does
In a 2004 paper in the Journal of Personality Assessment, the psychologist W. Keith Campbell and colleagues developed and tested the Psychological Entitlement Scale across nine separate studies, measuring the general belief that one deserves more than others, regardless of the specific situation. People who scored higher on this trait were not simply more disappointed when things did not go their way. Across the studies, higher entitlement predicted a specific pattern of interpersonal fallout: more selfish behaviour in situations involving shared resources, and more aggression specifically following criticism, above and beyond what a related but distinct trait, narcissism, already explained on its own.
This is one line of research, built on self-report measures across nine linked studies rather than a single result, and entitlement as measured here is a general trait tendency, not a diagnosis or a fixed judgment about any one person’s character on any one bad day. But the specificity of the finding is worth sitting with: it is not that entitled people feel worse when they lose. It is that a higher baseline sense of deserving more predicts a harsher, more aggressive response specifically when that expectation meets resistance, whether that resistance is a criticism, a denied request, or a shared resource someone else also wants.
The second factor: what a person does with the feeling once it shows up
A separate and equally well-established line of research points to a second, independent factor: not whether someone feels frustrated, but which strategy they use to handle that feeling once it arrives. In an influential 2003 paper in the Journal of Personality and Social Psychology, James Gross and Oliver John distinguished two broad emotion regulation strategies people habitually rely on: reappraisal, changing how a situation is mentally framed before the emotion fully builds, and suppression, pushing down the outward expression of an emotion after it has already arrived.
Across five linked studies, the two strategies produced measurably different outcomes. People who relied more habitually on reappraisal reported experiencing and expressing more positive emotion and less negative emotion overall, and reported better-functioning relationships. People who relied more on suppression reported worse interpersonal functioning and, notably, reported experiencing just as much negative emotion internally, they simply held the outward signs of it in, which the research found came with its own costs, including reduced authenticity in relationships and, in related work building on this study, measurable physiological strain.
Where these two findings meet
Put together, these two bodies of research suggest that what commonly reads as immature behaviour when someone does not get their way is not one single thing. A person high in the entitlement trait Campbell’s scale measures is more likely to interpret a blocked outcome as a personal affront worth reacting to aggressively in the first place, independent of how skilled they are at managing emotion generally. Separately, a person who relies mainly on suppressing feelings, rather than reframing the situation as it develops, may look composed for a while and then have the frustration surface later, in a sharper or more disproportionate form, or leak out in ways that read as sulking, coldness, or a sudden overreaction to something small.
Neither factor alone fully explains a poor reaction, and the research does not suggest one is a stand-in label for the other. A person can be low in general entitlement and still handle disappointment badly because they habitually suppress rather than reframe. A person can be skilled at emotion regulation in general and still react poorly in the specific, narrow situations where their sense of deserving something is strongest.
What this looks like in practice, without the label
Read together, the research points toward paying attention to two separate, observable things rather than reaching for a single character judgment: whether a person’s reaction seems tied to a general sense that they specifically deserved the outcome, which Campbell’s research links to sharper, more aggressive responses, and whether the person seems to be holding a reaction in rather than working through it, which Gross and John’s research links to worse relationship outcomes even when the outward behaviour looks calm in the moment. Both are patterns a person can notice and work with directly, in themselves or in someone else, in a way that a blanket label like “immature” does not offer much traction on.
What this does not prove
Campbell’s entitlement research relies on self-report measures across mostly North American samples, and it is not established how the pattern holds across different cultural norms around expressing disappointment or asserting personal deservingness. Gross and John’s emotion regulation research similarly draws on self-reported strategy use rather than direct behavioural observation of people in the exact moment a goal is blocked. Neither line of research offers a complete account of every behaviour that might get labelled immature, and neither should be used to diagnose a specific person from a single incident. What the combined research does support is a narrower and more useful distinction than the popular label allows: a poor reaction to not getting one’s way is better explained by a specific trait, a general sense of deserving the outcome, and a specific regulation habit, suppressing rather than reframing the feeling, than by a single fixed judgment about a person’s overall maturity.