This study examines lexical and syntactic complexity in psychology discourse by comparing academic research articles with popularized science writing. As the growing demand for effective science communication has expanded the production of popular science texts, it has become increasingly important to understand how complex scientific knowledge is linguistically adapted for non-specialist audiences. To address this issue, the present study analyzes linguistic features of psychology discourse published over a thirty-year period (1992–2022). A corpus of 60 texts was compiled, consisting of 30 academic articles selected from Psychological Science and Acta Psychologica, and 30 popularized articles drawn from Psychology Today. Lexical complexity was assessed using the Web-based Lexical Complexity Analyzer and TAALES Lexical Complexity Analyzer (Version 1.3), while syntactic complexity was measured through the Web-based Syntactic Complexity Analyzer. Key lexical indices included Type–Token Ratio and Root Type–Token Ratio, and syntactic complexity was examined using measures such as Complex Nominals per Clause and Dependent Clause Ratio. Descriptive statistical analyses were conducted using IBM SPSS Statistics (Version 26). The results demonstrate substantial and systematic differences between academic and popularized psychology discourse. The null hypotheses predicting no significant differences in lexical and syntactic complexity between the two discourse types were rejected. Academic psychology texts consistently exhibit greater lexical complexity across multiple dimensions, including lexical frequency, sophistication, academic vocabulary, lexical range, phraseology, psycholinguistic sophistication, and diversity measures. Likewise, academic discourse shows markedly higher syntactic complexity, as reflected in longer sentences, increased clause and T-unit complexity, denser dependency structures, greater use of coordination, complex nominals, and higher phrase density. In contrast, popularized psychology writing is characterized by linguistically simpler, shorter, and more accessible constructions. Overall, these findings highlight the systematic linguistic modifications employed in popular science writing to enhance readability and accessibility for general audiences, while reaffirming the specialized and complex linguistic nature of academic psychology discourse.
