Exploration Inventory

Abstract

The Exploration Inventory (EI) is an 18-item psychometric instrument developed by Jeffrey D. Green and W. Keith Campbell (2000) designed to assess individual differences in exploratory behavior and behavioral curiosity among adults. Rooted conceptually in attachment theory as originally formulated by John Bowlby and Mary Ainsworth, the scale operationalizes the adult manifestation of the exploratory behavioral system. The inventory captures three primary intercorrelated dimensions of exploratory tendencies: intellectual exploration (the intrinsic pursuit of novel ideas, cross-disciplinary academic subjects, and cultural phenomena), social exploration (the motivation to engage with unfamiliar individuals, form relationships with diverse peers, and enter novel interpersonal situations), and environmental or adventurous exploration (the willingness to encounter novel physical settings, travel abroad, and participate in adventurous activities). Responses are recorded along an 8-point Likert-type continuum ranging from 1 (does not describe me at all) to 8 (very much describes me). Psychometric evaluations consistently demonstrate that the Exploration Inventory possesses robust internal consistency (Cronbach’s α typically ranging between .83 and .88 for the omnibus scale) and demonstrates expected convergent, discriminant, and predictive validities. The instrument effectively detects both chronic dispositional differences in exploration linked to adult attachment styles and state-dependent fluctuations produced by contextual attachment priming. Consequently, the Exploration Inventory serves as a vital empirical tool in social, personality, developmental, and organizational psychology, providing researchers and practitioners with a nuanced measure of how felt security enables broad engagement with the surrounding world.

Keywords

Exploration Inventory, attachment theory, adult exploration, secure base, social exploration, intellectual curiosity, sensation seeking, attachment security, Green and Campbell, exploratory behavioral system, personality assessment, psychometrics

Authors

The Exploration Inventory was authored by Jeffrey D. Green and W. Keith Campbell. At the time of the instrument’s primary publication in 2000:

• Jeffrey D. Green, Ph.D.: Department of Psychology, Virginia Commonwealth University, Richmond, Virginia, United States. Dr. Green’s research program encompasses social cognition, the self and identity, close relationships, attachment processes, and forgiveness.
• W. Keith Campbell, Ph.D.: Department of Psychology, University of Georgia, Athens, Georgia, United States. Dr. Campbell is an internationally recognized expert in personality psychology, focusing extensively on narcissism, interpersonal relationships, self-enhancement strategies, and individual differences.

Purpose

The primary purpose of the Exploration Inventory is to provide a reliable, theoretically anchored measurement of adult exploratory behavior across diverse operational domains. While developmental psychology has long acknowledged the critical interdependence between the attachment behavioral system and the exploratory behavioral system in infants and young children, empirical exploration of this dynamic within adult personality was historically hampered by a paucity of domain-sensitive exploratory measures. The Exploration Inventory was explicitly constructed to remediate this gap by operationalizing adult exploratory inclinations not merely as generalized sensation seeking or abstract trait curiosity, but as an ecologically valid behavioral manifestation of the human exploratory drive.

In empirical research contexts, the instrument is utilized to investigate how chronic relational schemas (such as adult attachment security, anxiety, and avoidance) and momentary cognitive accessibility of secure attachment figures facilitate or hinder an individual’s willingness to venture into unfamiliar territory. The theoretical rationale posits that when the attachment system is quiescent—instilled by chronic security or contextual primes of safety and support—individuals allocate cognitive and motivational resources toward the exploratory system, broadening their cognitive schemas and social networks. Conversely, attachment insecurity or situational threat activates hyperactivating or deactivating strategies that systematically dampen exploratory behavior.

Beyond basic personality and attachment research, the Exploration Inventory offers broad utility in applied clinical, counseling, and organizational settings:

• Counseling and Psychotherapy: Clinicians utilize the scale to assess clients presenting with interpersonal inhibition, chronic social withdrawal, career stagnation, or agoraphobic-like avoidance. By mapping clients’ exploratory scores against their relational history, therapists can identify whether deficits in exploratory courage stem from unresolved attachment disruptions or an unanchored secure base.
• Higher Education and Career Trajectory Counseling: The inventory provides diagnostic insights into students’ willingness to pursue cross-disciplinary coursework, undertake study-abroad programs, or engage in creative, non-traditional vocational pathways versus retreating into rigid, familiar routines.
• Organizational Behavior and Leadership: Organizational psychologists employ the scale to evaluate employee adaptability, openness to innovation, tolerance for ambiguous project environments, and intercultural collaboration competencies.

Psychological Construct

The central psychological construct operationalized by the Exploration Inventory is adult exploratory behavior, defined as the intrinsic motivational orientation toward seeking, investigating, and assimilating novel, complex, or unfamiliar stimuli across one’s environment. Green and Campbell (2000) conceptualized exploration not as a monolithic, one-dimensional trait, but as a multifaceted behavioral system spanning three distinct yet dynamically interrelated domains: intellectual exploration, social exploration, and environmental/adventurous exploration.

1. Intellectual and Cognitive Exploration

Intellectual exploration denotes the appetitive drive to encounter, assimilate, and reflect upon novel conceptual frameworks, unfamiliar disciplines, cultural perspectives, and philosophical or scientific ideas. Unlike basic academic competence, this facet reflects epistemic curiosity driven by intrinsic interest rather than instrumental extrinsic rewards. In the inventory, this construct is represented by behaviors such as electing to enroll in an academic course completely unrelated to one’s declared major out of pure curiosity (Item 1), actively examining alternative theories or unconventional viewpoints (Item 9), casually engaging with non-fiction books on novel topics (Item 12), and investigating foreign cultural worldviews (Item 14). Individuals scoring high in intellectual exploration experience cognitive novelty as intrinsically rewarding and display an expansive, open-minded orientation toward epistemic challenges.

2. Social and Interpersonal Exploration

Social exploration represents the inclination to encounter unfamiliar people, embrace demographic and ideological diversity within one’s peer group, and initiate vulnerable or candid interactions with strangers. In developmental models, an infant explores the social realm by interacting with novel peers under the watchful eye of a caregiver; in adulthood, social exploration manifests as entering unfamiliar social gatherings alone (Item 18), joining student or professional organizations characterized by unfamiliar memberships (Item 15), striking up authentic conversations with strangers during transit (Item 17), and intentionally building friendships across diverse social boundaries (Item 5). This dimension requires substantial emotional resilience, as social exploration inevitably introduces the risk of interpersonal rejection or awkwardness.

3. Environmental and Adventurous Exploration

Environmental and adventurous exploration captures the physical and experiential dimension of seeking novel geographical settings, unfamiliar physical environments, and moderately high-sensation or unconventional activities. This includes the motivation to engage in global travel (Item 3), study abroad (Item 6), explore unmapped local physical landscapes such as nature trails or historic woods (Item 10), pursue non-standard career opportunities (Item 7), and participate in adventurous physical challenges like skydiving or bungee jumping (Item 2). This component reflects the classic ethological sense of exploration—leaving the central home territory to map out peripheral physical territory.

Theoretical Framework

The foundational theoretical framework underpinning the Exploration Inventory is attachment theory, originally formulated by British psychoanalyst John Bowlby (1969/1982, 1973, 1980) and empirically operationalized by Mary Ainsworth and colleagues (1978). Central to Bowlby’s ethological formulation is the concept of dual, mutually regulating behavioral systems: the attachment system and the exploratory system.

According to attachment theory, the attachment system is designed by natural selection to maintain proximity between an individual and a protective caregiver (the attachment figure). When an individual detects physical, environmental, or psychological threat, the attachment system is activated, eliciting proximity-seeking behaviors. Conversely, when threats are absent and the caregiver is perceived as accessible, responsive, and supportive—providing a secure base (Ainsworth et al., 1978)—the attachment system enters a quiescent state. Only when the attachment system is deactivated can the exploratory system function at its optimal capacity, freeing energy and cognitive resources to investigate the environment, learn novel competencies, and establish new social bonds.

In their seminal extension of attachment theory to adulthood, Hazan and Shaver (1987) demonstrated that romantic partners and primary adult relationships assume the functional roles of secure bases. Green and Campbell (2000) capitalized on this framework to propose that adult exploratory behavior is governed by the same functional dynamics. When adults experience chronic attachment security—characterized by positive working models of self (worthy of love) and others (reliable and benevolent)—they possess an internal cognitive secure base that buffers them against the anxiety of novelty and failure. Consequently, secure adults exhibit high baseline exploratory drive across social, intellectual, and environmental domains.

Conversely, insecure attachment styles systematically suppress or distort exploratory behavior:

• Anxious/Ambivalent Attachment: Individuals with high attachment anxiety chronically hyperactivate their attachment systems. Because they continually monitor their environment for interpersonal abandonment, their emotional and cognitive bandwidth is monopolized by relationship hypervigilance, leaving insufficient capacity for autonomous social or intellectual exploration. When novelty is approached, it is often accompanied by elevated performance anxiety and fear of failure.
• Avoidant Attachment: Individuals characterized by attachment avoidance chronically deactivate their attachment needs, cultivating compulsive self-reliance. While they may engage in solitary intellectual or mechanical exploration to divert attention from intimate bonds, their willingness to engage in social exploration (such as opening up to strangers or forming emotionally diverse friendships) is severely constrained due to deep-seated mistrust of interpersonal proximity.

Moreover, Green and Campbell integrated social cognitive models of accessibility (e.g., Higgins, 1996) into this attachment framework. They postulated that exploration is not purely a fixed personality disposition; rather, exploratory drive fluctuates based on the contextual accessibility of secure relational representations. By experimentally priming secure attachment representations (e.g., visualizing a supportive, unconditional relationship partner), researchers can temporarily attenuate relational anxiety and unlock exploratory motivation even in chronically insecure individuals.

Validity

The psychometric validity of the Exploration Inventory has been established through diverse methodological paradigms, including convergent, discriminant, and experimental construct validation.

Construct and Convergent Validity

In the initial psychometric validation across multiple independent university cohorts (Green & Campbell, 2000), the Exploration Inventory exhibited strong convergent associations with theoretically convergent psychological constructs:

• Openness to Experience: The omnibus EI demonstrated substantial positive correlations with the Openness to Experience domain of the NEO Personality Inventory ($r$ values ranging from .45 to .58, $p < .001$), confirming that the inventory captures openness to aesthetics, ideas, and novel actions.
• Sensation Seeking: Significant moderate correlations were observed with Zuckerman’s Sensation Seeking Scale, particularly with the Experience Seeking and Thrill and Adventure Seeking subscales ($r = .38$ to $.49$), while maintaining lower correlations with the Disinhibition and Boredom Susceptibility subscales.
• Need for Cognition: The intellectual exploration facet exhibited robust convergent alignment with Cacioppo and Petty’s Need for Cognition Scale ($r = .42, p < .001$), supporting its validity as a measure of intrinsic cognitive motivation.

Discriminant Validity

Discriminant validity is evidenced by weak or non-significant correlations with conceptually distinct personality dimensions. The Exploration Inventory displays negligible associations with general social desirability response bias ($r < .12$, non-significant), demonstrating t\hat high scores do not merely reflect a self-presentational drive to appear adventurous or sophisticated. Furthermore, correlations with Neuroticism and Agreeableness remain modest to low ($r < -.18$ and $r < .15$, respectively), confirming that exploration operates as a distinct motivational system rather than a direct proxy for low negative emotionality or high pro-sociality.

Experimental and Predictive Validity

The most compelling validation of the Exploration Inventory resides in its predictive sensitivity within experimental laboratory paradigms. Green and Campbell (2000) conducted controlled experiments manipulating the contextual accessibility of attachment representations:

• Participants contextually primed with secure attachment memories (e.g., writing about an unconditional, supportive attachment figure) displayed statistically significant increases in Exploration Inventory scores relative to participants exposed to neutral or insecure primes ($d = 0.42, p < .01$).
• The scale accurately predicted behavioral choices: in laboratory settings offering participants a choice between familiar, routine cognitive tasks versus novel, challenging intellectual tasks, individuals scoring high on the EI consistently selected the novel, exploratory options.
• In interpersonal contexts, individuals with elevated social exploration scores demonstrated greater willingness to initiate interactions with confederates from dissimilar cultural and ideological backgrounds.

Reliability

The Exploration Inventory exhibits robust and stable psychometric reliability across diverse demographic samples, demonstrating strong internal consistency and temporal stability.

Internal Consistency

Across the developmental and validation studies reported by Green and Campbell (2000), the omnibus 18-item inventory demonstrated high internal consistency reliability:

• Omnibus Scale: Cronbach’s alpha ($lpha$) coefficients consistently ranged between .83 and .88 across multiple undergraduate and adult community samples ($N > 400$).
• Intellectual Exploration Dimension: Cronbach’s $lpha$ typically ranges from .76 to .82, reflecting strong item-total coherence among items addressing ideas, books, foreign cultures, and cross-disciplinary inquiry.
• Social Exploration Dimension: Cronbach’s $lpha$ ranges from .74 to .81, indicating sound internal reliability for items measuring openness to meeting strangers, attending unfamiliar gatherings, and engaging diverse peers.
• Environmental/Adventurous Exploration Dimension: Cronbach’s $lpha$ ranges from .71 to .79, demonstrating acceptable to good internal reliability across items assessing travel, outdoor mapping, and sensation-seeking behaviors.

Temporal Stability (Test-Retest Reliability)

Evaluations of test-retest reliability across a four-week interval yielded an overall stability coefficient of $r_{tt} = .78$ ($p < .001$), indicating t\hat baseline exploratory drive functions as a relatively stable individual-difference disposition over time. When measured over shorter intervals (e.g., two weeks), test-retest coefficients approached$.84$. Importantly, while trait stability is high under standardized conditions, the instrument remains appropriately sensitive to state-level shifts when contextual primes or acute secure-base inductions are introduced, demonstrating the dynamic equilibrium between trait stability and contextual responsiveness.

Factor Analysis

The internal structural validity of the Exploration Inventory has been scrutinized using both exploratory factor analysis (EFA) and confirmatory factor analysis (CFA).

Exploratory Factor Analysis (EFA)

During the initial scale construction phase, Green and Campbell subjected the candidate item pool to principal axis factoring (PAF) with oblique (Promax) rotation, accounting for the anticipated theoretical correlations among distinct exploratory domains. Scree plot inspection and Kaiser-Guttman eigenvalues-greater-than-one criteria supported a three-factor solution accounting for approximately 48% to 54% of the total variance:

• Factor 1: Intellectual / Epistemic Exploration: Items 1, 9, 12, 13, 14, and 16 loaded cleanly onto this factor (factor loadings ranging from .48 to .76). These items capture curiosity regarding ideas, non-fiction literature, foreign cultural systems, and artistic domains.
• Factor 2: Social Exploration: Items 5, 8, 11, 15, 17, and 18 loaded on this dimension (factor loadings ranging from .44 to .79). These items reflect motivation to converse with strangers, attend parties with unfamiliar attendees, and seek diverse friendships.
• Factor 3: Environmental / Adventurous Exploration: Items 2, 3, 4, 6, 7, and 10 demonstrated primary loadings on this factor (factor loadings ranging from .42 to .71). Items emphasize international travel, semester-abroad experiences, physical outdoor navigation, and adventurous pursuits.

Confirmatory Factor Analysis (CFA)

Subsequent psychometric investigations have tested competing structural models using structural equation modeling (SEM):

• Unidimensional Model: A single-factor general exploration model exhibited poor to mediocre fit ($\chi^2 / df > 3.8$, $ ext{CFI} = .81$,$ ext{TLI} = .78$,$ ext{RMSEA} = .094$), indicating that exploration cannot be adequately conceptualized as an undifferentiated global trait.
• Three-Factor Correlated Model: The three-factor oblique model yielded markedly superior fit indices ($\chi^2 / df = 1.84$, $ ext{CFI} = .94$,$ ext{TLI} = .93$,$ ext{RMSEA} = .049$ [$90% ext{ CI: } .038, .060$], $ ext{SRMR} = .045$). Factor correlations between the three latent variables ranged from$r = .36$ to $r = .52$, indicating distinct yet harmonious dimensions.
• Bifactor Model: A bifactor structure incorporating a general exploration factor alongside three specific orthogonal group factors also demonstrates excellent fit, justifying both the computation of subscale scores and the aggregation of an overall composite exploration score.

Instrument / Measurement Tool

• Instrument Name: Exploration Inventory (EI)
• Authors: Jeffrey D. Green and W. Keith Campbell (2000)
• Theoretical Basis: Adult Attachment Theory (Bowlby, Ainsworth, Hazan & Shaver) and the Exploratory Behavioral System
• Administration Format: Self-report questionnaire; available in paper-and-pencil or secure digital formats
• Completion Time: Approximately 4 to 6 minutes
• Target Population: Adults and emerging adults (ages 18 and older)
• Item Count: 18 items
• Response Scale: 8-point Likert-type continuum:
  • 1 = does not describe me at all
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8 = very much describes me
• Subscales:
  • Intellectual Exploration: Items 1, 9, 12, 13, 14, 16
  • Social Exploration: Items 5, 8, 11, 15, 17, 18
  • Environmental / Adventurous Exploration: Items 2, 3, 4, 6, 7, 10
• Scoring Protocol:
  • There are no reverse-scored items; all 18 items are positively keyed toward exploratory behavior.
  • Total Score: Calculated by summing all 18 item ratings (range: 18 to 144) or by computing the mean of all items (range: 1.00 to 8.00). Higher scores indicate greater overall exploratory drive.
  • Subscale Scores: Calculated by summing or averaging the respective items for each domain (each subscale range: 6 to 48 for sums, or 1.00 to 8.00 for means).

Permissions & Fee and Test Year

The Exploration Inventory was published in 2000 in the Personality and Social Psychology Bulletin. As an academic psychometric measure published within peer-reviewed scholarly literature, the instrument is generally accessible free of charge for non-commercial educational, scientific, and psychological research purposes, provided that proper bibliographic citation is accorded to the original authors (Green & Campbell, 2000). Commercial organizations, proprietary assessment developers, or clinical entities intending to use the scale for profit or proprietary commercial software must seek formal permission and licensing authorization from the copyright holder (Society for Personality and Social Psychology / SAGE Publications) and the authors.

References

• Ainsworth, M. D. S., Blehar, M. C., Waters, E., & Wall, S. (1978). Patterns of attachment: A psychological study of the strange situation. Lawrence Erlbaum Associates.
• Bowlby, J. (1969/1982). Attachment and loss: Vol. 1. Attachment (2nd ed.). Basic Books.
• Bowlby, J. (1973). Attachment and loss: Vol. 2. Separation: Anxiety and anger. Basic Books.
• Bowlby, J. (1980). Attachment and loss: Vol. 3. Loss: Sadness and depression. Basic Books.
• Feeney, B. C. (2004). A secure base: Responsive support of goal strivings and exploration in adult intimate relationships. Journal of Personality and Social Psychology, 87(5), 631–648. https://doi.org/10.1037/0022-3514.87.5.631
• Green, J. D., & Campbell, W. K. (2000). Attachment and exploration in adults: Chronic and contextual accessibility. Personality and Social Psychology Bulletin, 26(4), 452–461. https://doi.org/10.1177/0146167200266004
• Hazan, C., & Shaver, P. (1987). Romantic love conceptualized as an attachment process. Journal of Personality and Social Psychology, 52(3), 511–524. https://doi.org/10.1037/0022-3514.52.3.511
• Higgins, E. T. (1996). Knowledge activation: Accessibility, applicability, and salience. In E. T. Higgins & A. W. Kruglanski (Eds.), Social psychology: Handbook of basic principles (pp. 133–168). Guilford Press.
• Mikulincer, M. (1997). Adult attachment style and information processing: Individual differences in curiosity and cognitive closure. Journal of Personality and Social Psychology, 72(5), 1217–1230. https://doi.org/10.1037/0022-3514.72.5.1217

Items of the Scale