“…These findings are compatible with the existing literature indicating that metaphor comprehension, at least, increases with chronological age (Billow, 1975) and with an increase in world knowledge (Naylor & Herwegen, 2012; Norbury, 2005; Rundblad & Annaz, 2010). The issue of metaphor production, though, is more controversial, with some authors (Pollio & Pollio, 1974) establishing its onset at 8 years of age, others (Billow, 1981; Laganaro, 1997; Piaget, 1962; Winner, 1979) bringing that age back to as early as 2 years old, and yet more recent studies arguing for metaphor production increasing over development (Katis & Selimis, 2009; Rundblad & Annaz, 2010). An analysis of a longitudinal corpus of semantic approximations based on metaphorical operations could throw further light on this issue.…”