Should We Assess Personality or Behaviour in Hiring?

Jiaying Law

People Scientist

Without a doubt, you’ve encountered the infamous “what comes first, the egg or the chicken?” question at least once in your lifetime. The obvious answer is the chicken, right? Wait, but doesn’t every chicken come from an egg?  The egg? Hmm, but again, doesn’t every egg have to be laid down by a chicken?

The same argument lies in the case of personality and behaviours. Over centuries, the debate between how personality shapes our behaviours and how environmentally-dependent behaviours determine our personality has never ended, and both parties have some evidence for their claims. 

That’s why in this blog, let’s focus on together answering the following questions:

  • What is personality?
  • Nature or Nurture: How personality develops across a lifespan?
  • Should you be hiring using personality assessments? 

Personality in a nutshell

You and I will agree that every human being is unique and there are no two identical people in the world. Yet, what is it that makes each person unique? 

This has to do with our personality

One’s personality represents an enduring set of “characteristic patterns of thought, emotion and behaviour, together with the psychological mechanisms – hidden or not – behind those patterns” (Funder, 2012, p. 5; Roberts, 2009). In the broad sense, it represents what internally makes us who we are (natural tendencies or personal inclinations) and how externally we present our unique selves in certain ways that differ from other people under certain circumstances (Bergner, 2020). 

For example, a person might be seen as an outgoing person with high agreeableness, but also sometimes with a bit less conscientiousness. Another person might be polite, have a high tendency to do things step by step while considering themselves an introvert, and like to maintain their morning workout routine. These extraordinary combinations of traits make up the very own personality profile for every single person. 

Personality: Nature or Nurture?

Going back to the century-long debate on personality, of whether personality shapes our behaviours or environment-driven behaviours determine our personality, let’s take a look at what each side of the approach claims.

The “nature” faction, who believe that personality is greatly determined by genetic factors, claims that personality is pretty much formed by the time we are born and only gets more mature and stable when we reach adulthood (i.e., biological maturation). One’s thoughts, emotions and behaviour are rather consistent across one’s life span due to a stabilised personality (top-down approach; Sosnowska, 2019; Kandler 2012). For instance, if a person is an extrovert, then they will act extroverted in most situations. 

The “nurture” faction, on the other hand, who believe that personality is greatly influenced by environmental factors, claims that the environmental cues affect our behaviour and therefore shape our personality little by little (bottom-up approach; Sosnowska, 2019; Kandler 2012). One’s personality is inferred through a series of momentary states, thoughts, emotions and behaviours.  For instance, if a person acts extroverted in most situations, then we will infer them as an extrovert. 

Take personality as an integrated system

Since we can avoid neither our biological composition nor interacting with the external environment, why don’t we integrate two approaches and see the personalities as an interaction of genetic and environmental components?  

Roberts (2009) introduced a sociogenomic model of personality traits in order to bridge all personality components that matter within the research history of personality development (see the figure below). 

Adapted from Roberts, 2009

From the graph, we can see that “states” represents the compound of the current status regarding our thoughts, feelings and behaviours. “Traits” (or personalities) are then made up of these states, if they stay stable and repetitive in an enduring pattern over time in functionally-identical situations, and thus cause similar states to happen in the future( Roberts, 2009). 

For instance, if your colleague comes to work right on time every day (repetitive behaviour), then you will consider them as punctual people (trait). Consequently, you assume that they will also be punctual for their appointment at the bank tomorrow (predicted future behaviour). 

Environment Influences on Personality

From this model, Roberts (2009) suggested that the environment will only slowly and incrementally affect traits in an indirect manner. Specifically, if the environment provokes a change within states (in thoughts, behaviours or feelings) in an extended period of time, only then may they cause changes in traits. 

For example, suppose you are placed in a strict organisational environment (e.g., police academy) for a long period of time. In that case, you’re forced to adapt your “states“ to this environment in a repetitive manner, then you will probably experience a change in openness to experience and neuroticism (traits within the Big-Five personality model; Alessandri et al., 2020). 

The key terms here are “repetitive” and “a long period of time”. It implies how personality change becomes personality development, which leads to the outcome that these single-role-based (e.g., job role) experiences may also be generalised to your other social role (e.g., parent role) over time. 

Biological Factors on Personality

Biological factors represent the starting values of our wide array of traits which will then be shaped and become mature along with the gain of life experiences. For example, during the first few months after we are born, we may suffer from emotional fluctuation, which means our neuroticism will probably be high. Along with life experience and maturity, our neuroticism also tends to decrease since we have learned several strategies to cope with emotions (Wille et al., 2014).

On the other hand, the environment could also cause physiological changes to us, such as accidents which cause brain damage, stressful events which cause continuous changes in brain structures and more, in turn causing prolonged changes in “states” (Roberts, 2009). For instance, think of if we always work in an environment which causes continuous states of anxiety and stress. The neurons in our brains will fire differently than our “normal” states to adapt to this environment. From time to time, this extended pattern of response to stress will, in turn, shape a new trait in us. 

Personality assessment in hiring processes?

Should personality assessments be used in hiring processes? The answer to this question stands: not suggested. Here’s the reason why from the perspective of the dynamics personality model (Sosnowskaa et al., 2019, graph below). 

Basically, Sosnowskaa and colleagues proposed that the personality system is composed of:  

  1. Personality baseline: the central point around the average of a series of momentary states of thoughts, feelings and behaviours
  2. Personality variability: the extent to which a person’s states fluctuate over time
  3. Personality attractor strengths: the regulatory forces that drag the fluctuation back to the baseline


People could differ widely in these three variables. For instance, a person can be very agreeable (high personality baseline), but their agreeableness can change vigorously depending on the tasks/people they encounter (high personality variability) and return back to their baseline in a very short period (high personality attractor strengths; Fig 1.1). 

In the other case, a person can be very limited in their agreeableness (low personality baseline) and their agreeableness does not change much regardless of the time or tasks they face (low personality variability). However, when there is an increase or decrease in their agreeableness, they need more time to return to their average level of agreeableness (low attractor strengths; Fig 1.4).

The scores of a personality assessment during a qualification process will only tell you what “states” the candidate currently is in at the moment you measure it. It means that you will probably get the result from any point on the graph above. It could negatively influence your inference about a candidate’s true personality profile, leading to an inaccurate decision of whether to advance them to the next step of the hiring process

It might seem okay-ish that the difference is so little if you only want to get a brief picture of how people behave. However, I want to remind you that this tiny difference could lead to huge consequences in rank-order-based hiring processes (Read more here; also to discover other reasons why personality tests should not be used in hiring). 

Rather, hiring through behaviour!

Instead of measuring a broad context of personality, a better (and more accurate) way to predict candidates’ job performance would be by measuring their behaviour under certain simulations of a targeted context, which is psychologically or physically similar to the key aspects of the future working environment (Wernimont & Campbell, 1968; Schmitt & Ostroff, 1986; Lievens & De Soete, 2012). 

For example, the best way to measure how well a person manages their work time would be to assign them the actual time management assessment under the work context. Specifically, it could be a simulation where they have to deal with several tasks or emails at once. By evaluating their performance and behaviour in this simulation, we can get a picture of how they manage their time in future positions. 

This is based on the concept of behaviour consistency, which indicates that “past performance is the best predictor of future performance” (Wernimont & Campbell, 1968, p.372). It specifically means that how people behave in the past and how they will behave in the future will be consistent in similar tasks or situations. By capturing candidates’ specific behaviour under work contexts, we get a sample of how they will actually behave in the future job position, rather than guessing what could possibly mean by their personality profiles or how they intend to behave (Thornton & Rupp, 2006; Lievens & De Soete, 2012). 

Before you close the tab..

Similar to the linked relation between chicken and eggs, personality and behaviours bi-directionally affect each other. We should see personality as the byproduct of the interaction between biological and environmental factors, rather than only choosing either nature or nurture as a side. Also, you might need to think twice before using personality assessment as a screening tool in hiring processes providing the dynamic properties of personality. Start hiring through behaviour instead! 


Alessandri, G., Perinelli, E., Robins, R. W., Vecchione, M., & Filosa, L. (2020). Personality trait change at work: Associations with organizational socialization and identification. Journal of personality, 88, 1217-1234. 

Bergner, R. M. (2020). What is personality? Two myths and a definition. New Ideas in Psychology, 57, 100759. 

Funder, D. C. (2012). The personality puzzle (6th ed.). New York: W. W. Norton & Company. 

Kandler, C. (2012). Nature and nurture in personality development: The case of neuroticism and extraversion. Current Directions in Psychological Science, 21, 290-296. 

Lievens, F., & De Soete, B. (2012). Simulations. In N. Schmitt, N. Schmitt (Eds.), The Oxford handbook of personnel assessment and selection (pp. 383-410). New York, NY, US: Oxford University Press. 

Roberts, B. W. (2009). Back to the future: Personality and assessment and personality development. Journal of research in personality, 43, 137-145. 

Schmitt, N., & Ostroff, C. (1986). Operationalizing the “behavioral consistency” approach: Selection test development based on a content‐oriented strategy. Personnel Psychology, 39, 91-108. 

Sosnowska, J., Kuppens, P., De Fruyt, F., & Hofmans, J. (2019). A dynamic systems approach to personality: The Personality Dynamics (PersDyn) model. Personality and individual differences, 144, 11-18. 

Thornton III, G. C., & Rupp, D. E. (2006). Assessment centers in human resource management: Strategies for prediction, diagnosis, and development. Psychology Press. 

Wernimont, P. F., & Campbell, J. P. (1968). Signs, samples, and criteria. Journal of Applied Psychology, 52, 372-376. 

Wille, B., Hofmans, J., Feys, M., & De Fruyt, F. (2014). Maturation of work attitudes: Correlated change with Big Five personality traits and reciprocal effects over 15 years. Journal of Organizational Behavior, 35, 507-529. 

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