Table 3.

Arithmetic mean (M) and standard deviation (SD) for the linguistic markers.

Linguistic characteristic	Humans		ChatGPT-3		ChatGPT-4
Lexical diversity	95.72	23.50	75.68	12.89	108.91	20.73
Syntactic complexity (depth)	5.72	0.80	6.18	0.76	5.94	0.54
Syntactic complexity (clauses)	1.81	0.57	2.31	0.50	2.08	0.42
Nominalizations	1.06	0.51	1.56	0.63	1.73	0.49
Modals	10.84	5.30	8.97	4.21	6.12	3.18
Epistemic markers	0.06	0.06	0.02	0.03	0.00	0.00
Discourse markers	0.57	0.24	0.52	0.19	0.36	0.17