Why human-derived models fall short for animal workers

Determining when human-based psychological frameworks apply to animals presents a primary challenge. Individual differences, including personality traits, have evolutionary and genetic underpinnings across species (Gosling, Reference Gosling2001, Reference Gosling2008; Judge et al., Reference Judge, Piccolo and Kosalka2009), but traits are shaped by adaptive pressures unique to each species and environment (Darwin, Reference Darwin1859). Although cross-species generalizability of Big Five-like structures appears in chimpanzees (Weiss et al., Reference Weiss, King and Hopkins2011), dogs (Jones & Gosling, Reference Jones and Gosling2005), dolphins (Highfill & Kuczaj, Reference Highfill and Kuczaj2007), other mammals (Gosling & John, Reference Gosling and John1999; Morton et al., Reference Morton, Lee, Buchanan-Smith, Brosnan, Thierry, Paukner, de Waal, Widness, Essler and Weiss2013), and octopuses (Mather & Anderson, Reference Mather and Anderson1993), given vast evolutionary divergence, seemingly similar constructs may apply across species but should not be assumed without rigorous, species-specific validation.

Researchers must also recognize projection and confirmation bias risks. Anthropomorphism—projecting human thoughts, feelings, and interpretations onto animal behavior—poses a pervasive challenge. Importantly, uncritically applying human frameworks to NHAW assessment presents several risks. First, similar factor structures may emerge, but traits’ behavioral manifestations (McCrae & Costa, Reference McCrae, Costa, John, Robins and Pervin2008) could differ across species. Second, work-relevant traits may not align with general personality traits; some dimensions predicting NHAW performance have no human parallel (e.g., dogs’ olfactory acuity represents specialized sensory aptitude that is absent from human personality assessment). Third, most comparative personality research focuses on mammals with closer evolutionary ties to humans, leaving vast taxonomic gaps. Taken together, these problems necessitate fundamentally different approaches to NHAW assessment than those used with human employees.

Building species-specific assessment frameworks

Rather than beginning with human models, I-O psychologists should implement species-specific, bottom-up approaches that derive taxonomies from work-relevant behaviors specific to each species and context. This mirrors job analysis best practices, where understanding specific role requirements precedes assessment development. Sinn et al.’s (2010) canine-specific assessment framework for military working dogs exemplifies this approach. Instead of imposing human personality models, they identified four dimensions from canine-specific behaviors: object focus, sharpness, human focus, and search focus. These dimensions have no direct human equivalents, yet they effectively predict canine performance, representing a species-specific framework that showcases some evidence of criterion-related validity.

I-O psychologists’ expertise in job analysis and criterion-related validation proves critical for NHAW workplace applications. This requires identifying critical animal worker requirements, developing performance taxonomies linking individual differences to organizational outcomes, and validating selection systems that reduce washout rates—the animal equivalent of employee turnover.

We propose establishing functional equivalence by focusing on observable behavior patterns that reliably predict work outcomes. Researchers should develop occupational taxonomies for animal workers based on functional task demands rather than human psychological models. They must recognize that different animal workers operate under unique constraints that may fundamentally alter how individual differences express themselves between species (as delineated above) and within species (across work contexts). For example, military working dogs operate under highly controlled conditions requiring specific trait combinations absent in companion dogs or scent detection dogs (Beebe et al., Reference Beebe, Howell and Bennett2016; Sinn et al., Reference Sinn, Gosling and Hilliard2010). That is, even within species, different contexts can create meaningful variability in how traits manifest (McCrae & Costa, Reference McCrae, Costa, John, Robins and Pervin2008) and relate to performance outcomes, which in some cases parallel cross-context (i.e., cross-cultural) human personality variations (Von Rueden et al., Reference Von Rueden, Gurven, Kaplan and Stieglitz2014).

Multidomain assessment methods

Species-specific taxonomies of individual differences are paramount. Developing such NHAW frameworks involves identifying specific traits (KSAOs) relevant to animal roles, understanding their antecedents, and linking them to observable criteria. However, assessing NHAWs’ psychological constructs presents methodological hurdles, primarily due to the absence of self-report data. Systematic assessment across multiple assessment domains addresses this limitation. Cognitive assessment (de Waal, Reference de Waal2016) focuses on problem-solving abilities, learning rates, and attention spans.Footnote ¹ Behavioral assessment examines temperament, reactivity, and social behaviors through systematic observation (Brady et al., Reference Brady, Cracknell, Zulch and Mills2018) and handler ratings (Altschul et al., Reference Altschul, Hopkins, Herrelko, Inoue-Murayama, Matsuzawa, King, Ross and Weiss2018).Footnote ² Performance assessment directly measures task-specific skills and trainability. Further, physiological assessment could provide objective markers through stress indicators, sensory capabilities, and biological responses (Bray et al., Reference Bray, Sammel, Cheney, Serpell and Seyfarth2017).

Effective NHAW evaluation requires integration across domains rather than separate assessment silos. Establishing construct validity relies on triangulating data from multiple sources and methods, employing a multitrait, multimethod (MTMM) approach (Campbell & Fiske, Reference Campbell and Fiske1959). This classic construct validation approach adapts well to NHAW subjects. Crucially, this extends to a multispecies, multitrait, multimethod (MS-MTMM) framework for comparative claims, acknowledging that trait structures differ meaningfully across species (Weiss, Reference Weiss2018). Although MTMM would traditionally examine multiple traits (and multiple methods) simultaneously, we focus on a single trait construct here to maintain brevity and simplicity while illustrating the species-specific construct validation challenges. Let’s consider how detection focus—a critical cognitive ability construct for NHAWs—illustrates this need for species-specific construct validation. We discuss two distinct MTMM matrices:Footnote ³

For dolphins (let’s call this MTMM-1) in the Navy’s Marine Mammal Program, detection focus assessment centers on echolocation discrimination abilities (Naval Information Warfare Center Pacific, n.d.). Their biosonar precision tasks involve distinguishing target mines from nontarget objects using echolocation, with outcomes measured by detection accuracy rates. Sustained detection focus is further assessed via systematic search patterns in cluttered harbor environments and validated by physiological indicators like click-train consistency during echolocation.

In contrast, for explosive detection dogs (let’s call this MTMM-2) performing analogous land-based detection, the same underlying construct, detection focus, requires entirely different operationalizations. Here, assessment involves olfactory discrimination tasks where dogs distinguish target explosive scents from environmental distractors. Sustained focus is measured through systematic area searches, evaluating how effectively dogs maintain search behavior across varied terrain and weather. Physiological indicators, such as sniffing frequency and stress hormone levels, provide biological validation of sustained olfactory attention.

These two MTMM matrices could be further subjected to empirical factor analytic techniques (Bagozzi et al., Reference Bagozzi, Yi and Phillips1991) to establish their respective species-specific factor structures and partition variance. Subsequently, measurement invariance techniques (Vandenberg & Lance, Reference Vandenberg and Lance2000) would rigorously assess construct validity by testing for equivalent measurement models across species. Establishing invariance would confirm that detection focus is a comparable construct across dolphins and dogs, allowing for meaningful cross-species comparisons of its manifestation and predictive validity. Conversely, a failure to establish invariance would indicate that the construct is operationalized differently, necessitating caution in direct comparisons and potentially requiring species-specific predictive models or a re-evaluation of the construct’s cross-species applicability.

These are just a few examples demonstrating how NHAW psychological constructs can be operationalized via species-specific indicators. Such successes suggest significant potential for broader I-O methodology application to NHAW selection, appraisal, and development. Although understanding psychological constructs is indeed a goal, initial efforts can focus on identifying and validating behavioral predictors with strong criterion-related validity, as selection measures offering immediate practical benefits need not await complete psychological understanding. I-O psychology possesses the methodological expertise to transform animal worker selection from costly trial and error into an assessment practice with high practical utility.