Mark the larks and owls with souls - Differentiating between four circardian preferences in the Biopsychological Owls and Larks Typology (BOLT) – A new psychological conceptualization of chronotype

Jun 2, 2026Chronobiology international

Identifying Four Types of Morning and Evening People Using a New Psychological Chronotype Model

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Abstract

A study of 1426 Polish adults identified four distinct chronotype profiles: hardy larks, vulnerable larks, overactive owls, and neurotic owls.

Chronotype is conceptualized as a biopsychological system of energy regulation, encompassing overall energy level and regulatory effectiveness.
Factor analyses confirmed a four-profile structure that reflects varying adaptability and well-being among individuals.
Distinct patterns of associations were observed between the identified profiles and measures of depression, anxiety, life satisfaction, and temperament traits.
The findings indicate that existing chronotype models may not fully capture individual differences in daily energy and regulation effectiveness.

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Existing chronotype models focus on circadian phase preferences, providing limited insight into how these preferences translate into everyday psychological functioning. Especially, they overlook individual differences in daily energy levels and the effectiveness of their regulation, which may explain why people with similar biological rhythms differ in adaptability and well-being. The present study aimed to develop and empirically validate a theoretically grounded psychological framework of chronotype - the Biopsychological Owls and Larks Typology (BOLT) - which conceptualizes chronotype as a system of energy regulation defined by two dimensions: overall energy level and regulatory effectiveness. The study included 1426 Polish adults aged 20-60 years who completed the Biopsychological Owls and Larks Typology Scale (BOLTS), the Morningness-Eveningness Stability Scale improved, and standardized measures of depression, anxiety, life satisfaction, and temperament traits. Factor analyses supported a four-profile structure comprising hardy larks, vulnerable larks, overactive owls, and neurotic owls. Measurement invariance across two independent samples was confirmed. The identified profiles showed distinct and theoretically meaningful patterns of associations with affective and temperamental variables, ranging from highly adaptive to maladaptive functioning. These findings support the BOLT model and suggest that chronotype is best understood as a biopsychological system of energy regulation rather than solely as a timing preference.

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Mark the larks and owls with souls - Differentiating between four circardian preferences in the Biopsychological Owls and Larks Typology (BOLT) – A new psychological conceptualization of chronotype

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