Curiosity is increasingly recognized as vital to healthy aging, but the potential for leveraging research on curiosity to promote healthy aging is undermined by definitional inconsistencies and ambiguities in the literature-an issue that ontologies are uniquely well positioned to resolve. This paper proposes an ontological framework for modeling curiosity that addresses major shortcomings in existing definitions. Drawing on the Basic Formal Ontology (BFO), I define curiosity emotion process in terms of an appraisal of search-worthiness and an exploratory action tendency. I also define a related curiosity disposition. My approach enables clear distinctions among subtypes of both kinds of curiosity. The result is a more flexible, rigorous model of the various phenomena described as “curiosity” that aligns with empirical findings
There is mounting evidence that curiosity plays a central role in promoting well-being across the
lifespan. While studies of curiosity often focus on child development or educational achievement,
curiosity in later life is now recognized as a key to healthy aging [
One of the fundamental challenges to leveraging research on curiosity for the purposes of studying
its impact on healthy aging and solitude is the lack of conceptual and terminological consistency in
the literature on curiosity. Literature reviews have found over 30 distinct measures of curiosity and
17 diferent “dimensions” of curiosity that are disparately studied [
Addressing this conceptual disarray is a key motivation for developing a formal ontological representation of curiosity. This paper develops a formal representation of curiosity within the Emotion Ontology (MFOEM) —a domain ontology that extends from the Mental Functioning Ontology (MFO) that is designed to support data integration and reasoning across afective science, psychology, and neuroscience. My goal is to ofer an ontological model of curiosity for MFOEM that reflects its multidimensional nature with special interest in enabling researchers in solitude and gerotranscendence to leverage these empirical findings.
In the psychological literature, researchers frequently refer to various “dimensions” of curiosity. This terminology is meant to highlight the fact that curiosity is a multifaceted notion and research may be conducted on diferent aspects. However, unilaterally calling these “dimensions” risks obscuring important ontological distinctions by creating the misleading impression that they are commensurate or structurally uniform—like the dimensions of height and width, which are both spatial metrics of extension and, therefore, comparable in kind. The so-called “dimensions” of curiosity, by contrast, often vary radically in both ontological category and explanatory role.
Some dimensions are characterized by diferences in appraisal and afective tone. For example,
Kashdan and colleagues distinguish between dimensions they call “Joyous Exploration” and “Deprivation
Sensitivity.”[
A prime example of the first problem is the variety of terms used to describe the construct of curiosity
that is defined by a desire to resolve an information gap. Depending on the researcher, this may be
referred to as “deprivation sensitivity,” “epistemic curiosity,” or “knowledge-seeking ,” to name just a few
[
This leads directly to the second issue: sometimes diferent constructs are labeled with the same
or a similar term, which may cause conceptual confusion. For instance, “people-oriented curiosity,”
“interpersonal curiosity,” and “social curiosity” can refer to curiosity directed at a particular object,
namely, other people.[
Despite the importance of curiosity research, a search of Ontobee, BioPortal, and OLS revealed only two ontological conceptualizations of ‘curiosity.’ The first comes from the Emotion Ontology (MFOEM) which conceives of curiosity in the following way: • curiosity =def. a positive emotion that is an interest and engagement in an object or situation with a desire to know more.
The second is ofered by the Semantic Science Integrated Ontology (SIO) which defines curiosity as follows:
• curiosity=def. the strong desire to know or learn something.
Existing formal definitions of curiosity in ontologies such as the Emotion Ontology and the Semantic Science Integrated Ontology (SIO) ofer a useful starting point, but they fall short in three key ways. First, they assume that curiosity is always a positive emotion — MFOEM explicitly defines curiosity as a “positive” emotion and SIO does so by virtue of curiosity being a subclass of positive emotion in their ontology. Second, they both define it too narrowly as a desire for knowledge , precluding types of curiosity that target other objects. Third, they categorize curiosity exclusively as a process , omitting its dispositional forms. Each of these assumptions limits the power of the ontology to represent the various kinds and aspects of curiosity that psychologists study.
The first problem with the extant accounts is that curiosity is not always positively valenced. While
curiosity can be a positive emotion — e.g., as it is in the case if Joyous Exploration —this is only one
facet of a multifaceted construct. Some of the most commonly studied forms of curiosity, such as
Deprivation Sensitivity , are in fact marked by negative or ambivalent emotional tones. As Kashdan et
al. note, Deprivation Sensitivity has “a distinct emotional tone, with anxiety and tension being more
prominent than joy—pondering abstract or complex ideas, trying to solve problems, and seeking to
reduce gaps in needed information.”[
The second problem is that curiosity is not always a desire for knowledge. Although paradigmatic
examples of curiosity may involve a desire for knowledge, there are other the kinds of motivations and
cognitive targets that curiosity may take. For instance, Perceptual Curiosity, drives organisms—including
infants and non-human animals—to explore novel stimuli without any explicit representation of
knowledge acquisition [
Finally, the third problem is that, while both conceptions are right to point out that curiosity is spoken
of as a process, it is problematic to suggest that this is the only sense of ‘curiosity’ that is discussed
in the literature. Curiosity also functions as a disposition. The process sense of curiosity refers to a
momentary episode of interest or inquiry, but dispositional curiosity (a stable propensity to explore,
ask questions, or seek novelty across contexts) is another important sense. Instruments like the 5DCR
and the Curiosity and Exploration Inventory (CEI-II) are specifically designed to capture dispositional
tendencies toward diferent types of curiosity [
The next section begins by developing a definition for the process sense of curiosity that addresses the ifrst two problems discussed. This will provide a runway for defining a dispositional sense of curiosity, solving the third problem.
In MFOEM, curiosity is modeled as a subclass of emotion process so, it inherits the suite of mental
processes essential for representing emotion processes which is defined as [
This is a fitting ontological parent, as it lends curiosity many mental processes that are necessary for representing many dimensions that psychologists are interested in regarding curiosity. Without delving into precise ontological formalizations, allow me to illustrate the mechanics of each component of emotion process by considering a type of another emotion process—joy. The appraisal process refers to the mental process of representing some object or event as emotionally salient (e.g., representing a lfower or life itself as beautiful). The physiological process refers to the bodily changes constitutive of that emotion (e.g., a dopamine surge). The subjective afective feeling reflects the first-person experience (e.g., the felt sense of joyful delight). The process is valenced, meaning it has an afective tone— it is not mere neutral noticing, but a distinctly positive experience. Furthermore, it realizes an intentional modality, which is simply consciousness’s fundamental capacity to ‘represent’ something at all (e.g., a flower or life itself). Finally, it gives rise to an action tendency, which is simply a disposition to act in certain ways, e.g., a disposition to smile or to greet a neighbor. Each specific emotion processes will difer in how these components are specified.
I propose that we specify the curiosity emotion process in the following way: • curiosity emotion process=def. An emotion process that is a synchronized aggregate of constituent mental processes — including an appraisal of search-worthiness, physiological process, and subjective afective feeling — which is valenced, realizes some intentional modality, and gives rise to exploratory action tendencies.
This definition specifies two components of the emotion process definition, namely, the appraisal process and action tendency components. First, the appraisal involved in curiosity is specified as an appraisal of search-worthiness which I define as: • appraisal of search-worthiness=def. an appraisal that represents something as worthy of exploring for the sake of gaining new information.
This sort of appraisal is a hallmark of curiosity that pervades all dimensions and types of curiosity. Importantly, this type of appraisal does not necessarily require robust, cognitive judgments or metacognitive representation. Even infants and non-human animals can engage in this kind of primitive evaluative representation. For example, an infant’s attention to a novel visual stimulus can reflect an implicit appraisal that the stimulus is “worth looking at” without necessarily requiring a reflective desire for “knowledge,” as both the extant MFOEM and SIO definitions of curiosity problematically require.
Second, the action tendency component is specified as an exploratory action tendency. This refers to a dispositional orientation to act in ways that are directed toward gaining new information. Defining this component in terms of information-seeking further fortifies the solution to the second problem discussed, which arises when curiosity is too narrowly identified with the pursuit of knowledge. What is sought through curiosity may fall short of knowledge (as in perceptual curiosity) or exceed it (as in compulsive information-seeking after knowledge is attained). Additionally, the proposed definition preserves a healthy degree of flexibility. Almost any behavior that aims to reduce uncertainty or reveal new experiential content can fall under the umbrella of exploratory action tendency. For instance, if I’m curious about what it feels like to skydive, this might generate a tendency to watch skydiving videos, talk to a friend who’s gone skydiving, or even sign up to jump myself—each of which counts as the realization of my exploratory action tendency insofar as those tendencies emerge as a result of some curiosity emotion process.
Notably, the proposed definition of curiosity emotion process intentionally underspecifies several
components, namely its valence, physiological process, and subjective afective feeling. The benefit
of this modeling decision is to allow for increased flexibility in modeling the multifarious dimensions
of curiosity. The definition refrains from assigning a fixed valence to curiosity because, as we’ve
seen, empirical research shows that curiosity can manifest with varying afective tones. Some forms
of curiosity are associated with highly pleasurable emotional states (e.g., Joyous Exploration ), which
involves excitement, playfulness, and positive engagement. Other forms are marked by discomfort or
unease (e.g., Deprivation Sensitivity ) where curiosity arises from the felt absence of some crucial piece of
information and is accompanied by tension, dissatisfaction, or even anxiety. Still other instances, such
as morbid curiosity , combine both attraction and aversion: individuals are drawn toward stimuli that
simultaneously provoke fear or disgust.[
Likewise, the physiological process of curiosity is not monolithic. Diferent forms of curiosity
activate diferent systems and hormonal responses depending on the nature of the stimulus and the
organism’s state. For instance, exploratory curiosity related to novelty-seeking has been linked to
dopaminergic activation in reward-related circuits [
Similarly, the subjective afective feeling of curiosity varies widely. Some instances of curiosity are accompanied by a sense of wonder or intrigue, others by a nagging itch or a cognitive tension that must be resolved. These diferences reflect important experiential diversity across types of curiosity. This definition appropriately avoids stipulating a particular subjective afective character, allowing more specific subclasses to refine this dimension as needed.
Taken together, the specification of appraisals of search worthiness and exploratory action tendencies combined with the underspecifications ensure the general definition of curiosity emotion process can function as an inclusive umbrella category. It provides a stable yet adaptable ontological foundation upon which more granular subtypes of curiosity can be built by explicitly refining particular components of the process. Perceptual Curiosity, which has gone by several diferent names, for instance, can be defined as a curiosity emotion process with a specific exploratory action tendency and physiological process. The exploratory action tendency involved in perceptual curiosity is a drive to seek out not just any information, but novel orstimulating sensory information. As mentioned, the physiological profile is often linked to reward-learning circuits in the brain, especially those implicated in novelty detection and arousal. Hence, we might develop a definition as follows: • perceptual curiosity=def. a curiosity emotion process that has as an occurrent part some a novel stimuli exploratory action tendency and some reward learning physiological process.
Now consider Deprivation Sensitivity, which also has gone by several diferent names. These terms can be seen as logically connected (if not identical) insofar as they all involve a specification of the kind of appraisal process—one that includes not only the categorical appraisal of search-worthiness, but also an appraisal of lack of information, which motivates closing the information gap. Additionally, they all share a specific subjective afective feeling component in involving anxiety, frustration, or restlessness.
• deprivation sensitivity=def. a curiosity emotion process that has as an occurrent part some appraisal of lack of information process and some anxious afective feeling.
This kind of modular specification strategy will be helpful in disambiguating the various senses of “interpersonal curiosity.” As mentioned, this sometimes refers to curiosity with a particular object — namely, people. To represent this construct within the ontology, we can specify the realizes some intentional modality component of the definition. Recall, this component captures the idea that all emotion processes are about something—they have intentional content. In this interpersonal subtype, the intentional content is defined in terms of people or social agents.
• interpersonal object curiosity=def. a curiosity emotion process that realizes an intentional modality with some social object content.
This allows us to easily distinguish the object-oriented sense from the method-oriented sense of "interpersonal curiosity,” i.e., the sense in which curiosity unfolds through social exchange, such as asking questions, or initiating conversation. What distinguishes the subtype is not what the curiosity is about , but how it is pursued. To represent this variant, we can specify the exploratory action tendency component of the emotion process: it involves a tendency to engage others directly as part of information-seeking. In this way, the ontology can cleanly diferentiate between object-oriented and method-oriented variants of the same nominal label.
• interpersonal method curiosity=def. A curiosity emotion process that has as occurrent part some social exploratory action tendency.
By identifying and formalizing the components of the curiosity emotion process, we can clarify the extent to which researchers who rely on diferent operationalizations of “curiosity” are studying the same or diferent phenomena and understand the extent to which these phenomena are related.
Having developed a definition of curiosity emotion process that can adequately represent the various processual senses of “curiosity” we are now poised to tackle the third problem mentioned previously: curiosity is not only a process . For example, when we say that Sue is curious about sea creatures, we do not necessarily mean that she is experiencing a specific episode of curiosity in the moment, but rather that she tends to have those episodes in relevant contexts—a tendency that may persist even during periods of inactivity or emotional neutrality.
In the framework of Basic Formal Ontology (BFO), of which the Emotion Ontology is a distal extension, dispositions are defined as realizable entities—that is, as powers or tendencies that exist by virtue of the physical makeup of their bearers, and which may or may not ever be fully realized.[20]With this ontological apparatus in place, we can define a curiosity disposition as follows: • curiosity disposition =def. an emotion disposition that, if realized, is realized in some curiosity emotion process.
This allows us to account for dispositional talk without conflating it with occurrent emotional episodes. Like all dispositions, a curiosity disposition is realizable —it may be manifested in specific episodes, such as Sue’s curiosity disposition being realized when she begins asking detailed questions about sea creatures at an aquarium. It is modal —it describes what the bearer can or would likely do under specific conditions, e.g., if you take Sue to the aquarium, she will likely ask a million questions. It is materially grounded —it is instantiated in the physical and neurobiological features of the bearer, such as the dopaminergic reward pathways in Sue’s brain. And it is graded in strength —e.g., Sue may have a very strong curious disposition when it comes to marine biology, but she may have only a weak curious disposition when it comes to celebrity gossip.
With this formal account of curiosity disposition, we have addressed the third problem stated above. Just like with emotion processes, we can specify diferent types of curiosity dispositions by linking them to the corresponding subtypes of curiosity emotion processes. For example, a perceptual curiosity disposition would be defined as a disposition that, when realized, gives rise to perceptual curiosity emotion processes—such as those studied in nonhuman animals and human infants. This framework preserves flexibility while ofering ontological rigor and conceptual clarity across use cases.
In this paper, I have argued that existing ontological definitions of “curiosity”—such as those found in the Emotion Ontology and the Semantic Science Integrated Ontology (SIO)—are inadequate on several grounds. They tend to over-specify curiosity as a positive emotion, as necessarily aimed at knowledge, and as a process only. In contrast, I have proposed a BFO-conformant definition of curiosity emotion process that addresses each of these shortcomings. By formally specifying the emotion process in terms of search-worthiness appraisals and exploratory action tendencies—while leaving valence, afect, and physiology underspecified—I ofer a general model that accommodates diverse subtypes. This likewise paved the way for create curiosity disposition in order to represent the dispositional sense of curiosity. I summarize the novel terms and definitions in Table 1.
I expect this development of the Emotion Ontology (MFOEM) will be especially helpful for researchers working at the intersection of psychology and healthy aging. These definitions were devised with specific psychological constructs in mind, however, further subtyping of curiosity should be developed in consultation with domain experts. Domain expert evaluation would also strengthen the reasoning for adopting definitions beyond the philosophical reasoning I have provided here. As this modeling efort matures, my hope is that the groundwork ofered here provides a solid foundation for better research on curiosity in service of aging research and public health.
The author(s) used GPT-5 for grammar renfiement and reference formatting only. All substantive content was authored and reviewed by the human research team. The author maintains sole responsibility for the work produced here. [20] R. Arp, et al., Building Ontologies with Basic Formal Ontology, MIT Press, Cambridge, MA, USA, 2015.