Recent decades have seen a growing awareness of the importance of adolescence from a developmental perspective (Dahl et al., 2018; Sawyer et al., 2018). Adolescence is a developmental stage marked by a combination of psychosocial changes, such as the acquirement of new social roles and increased responsibilities, as well as by biological changes, such as the pubertal transition. The latter is a developmental process of its own right, and involves a series of morphophysiological changes necessary to enable reproduction (Abreu and Kaiser, 2016; Witchel and Topaloglu, 2019). These psychosocial and pubertal processes are deeply intertwined. They are both associated with structural and functional brain changes that underlie both the adolescents' significant cognitive development during this period, as well as their particular vulnerability to the effects of negative experiences and environmental factors on their physical and mental health (Goddings et al., 2019; Drzewiecki and Juraska, 2020; Galván, 2021). Accordingly, both puberty and psychosocial maturation at this stage have been related to changes in health and behavior, such as increases in the susceptibility to mental illness (Dorn et al., 2019) and improvements in different cognitive abilities (Icenogle and Cauffman, 2021) that can have significant effects on the lives of adolescents and even on those of their offspring (Azzopardi et al., 2019; Dorn et al., 2019).

Although physiological processes related to puberty can affect brain development and behavior in humans and other animals (Schulz et al., 2009; Goddings et al., 2019; Drzewiecki and Juraska, 2020; Galván, 2021), research on adolescent behavior, cognitive development, and mental health has traditionally focused on studying adolescent development in relation to chronological age, which is often used as an umbrella variable to capture both the myriad factors that influencing this development, especially those stemming from life experience and learning as well as pubertal effects themselves, since older adolescents tend to be more pubertally mature (McLean and Riggs, 2022). This situation has changed over the last couple of decades as the importance of puberty in its own right became increasingly recognized, promoting it to a hot topic (Marceau et al., 2019).

A key challenge when studying puberty, however, is deciding how to measure it. There are a number of measures currently available (for reviews, see Dorn et al., 2006; Dorn and Biro, 2011; Mendle et al., 2019), which can be classified into two main groups. One group encompasses the collection of biological samples used to measure hormones involved in the process of pubertal development, particularly sex hormones; these hormones increase during the pubertal development and are believed to cause the main morphophysiological changes that characterize puberty. The other group includes measures that assess, either objectively or subjectively, physical characteristics and observable events that are elicited by the changing patterns of hormone concentrations. The choice of which method to use is normally based on study goals and available financial resources, as currently used pubertal measures assess different aspects of pubertal development and vary in cost and implementation difficulties (Dorn et al., 2006; Dorn and Biro, 2011; Mendle et al., 2019).

While there are currently several ways of measuring puberty and many excellent reviews on the best practices for using them (e.g., Dorn et al., 2006; Dorn and Biro, 2011; Mendle, 2014; Mendle et al., 2019), these measures all share a set of conceptual pitfalls and caveats that limit how informative they can be about pubertal development. These conceptual issues are linked to the very nature of puberty, which is a complex, multifaceted developmental process that can be operationalized in different ways. Moreover, different elements of this process may differently affect brain development, behavior, and cognition, as there are several possible causal pathways involved, with both biological and psychosocial consequential effects being possible depending on each case (e.g., Mendle et al., 2010; Carter et al., 2018). As we will discuss later, because pubertal development involves so many interrelated processes and events, the concept of puberty takes on a certain abstractedness that leads the literature to ultimately define it as the set of variables used to measure puberty, creating a circularity that mixes theoretical and operational definition.

While this may all sound rather unsubstantial, the conceptual issues we are about to explore have important implications as they hinder our capacity to confidently assess the existence of pubertal effects on brain, cognitive, and behavioral development, as well as to understand their nature and disentangle them from other relevant factors, such as learning and experience. Importantly, although practical limitations of pubertal measures have been extensively discussed in many excellent previous reviews (e.g., Dorn et al., 2006; Dorn and Biro, 2011; Mendle, 2014; Mendle et al., 2019), the conceptual basis of such limitations – and particularly their implications for interpreting “pubertal effects” in terms of biological mechanisms – have been underexplored in the literature. In this essay, our main objective is to discuss how current measures of pubertal development map onto the physiological processes they are supposed to index, and to what extent these parallels allow conclusions to be drawn about the nature of pubertal effects on brain development, behavior, and cognition.

In the following sections, we provide an overview of puberty as a biological process, and to discuss the main currently used measures to assess it. We then discuss the conceptual issues associated with these measures and how they impact our interpretation of pubertal effects. We end by discussing the implications of these limitations for research and the advantages of using an alternative way of measuring puberty based on the shared variance among multiple pubertal indicators – an approach that, under a sound theoretical framework, may help advance the field.