Tracking Meaning Change Over Time: A Dynamic Field Theory Model

Words are often regarded as “slippery customers” (Labov, 1973). First, it is difficult to come up with a fixed content that seems to apply across all uses of a single word (Wittgensten, 1953). Second, the meaning of a word is subject to wider contextual constraints beyond the company it keeps with other words within a sentence. Third, the assumption that a word means a fixed thing is at odds with the fact that word meaning shifts over time, as do the objects a word refers to. Taken together, theories of word meaning need to be able to account for the intuition that words have content associated with them, while allowing for variation in how a word is used in context, and how word meaning can change over time. We provide an approach to word meaning within the spirit of dynamic systems theory (DST) models of cognition that accounts for the slipperiness of words. First, we draw an analogy between models of (non-linguistic) spatial behavior and how the meaning of language changes over time while exhibiting regularity. In particular, we identify two key features of DST models – multicausality and the building of temporally-bound attractor states that afford application to theories of meaning. Second, we take these features of DST models and test them in experiments examining the comprehension of spatial expressions over time using object placement behavior as a measure (e.g. “Place the oil paint tube over the toothbrush”). Building on earlier work examining the constraints in which spatial language is used (Carlson-Radvansky et al., 1999; Coventry, 2013, 2015; Coventry & Garrod, 2004; Coventry et al., 2001, 2010, 2013, 2016; Gudde et al. 2016), we present a programme of studies mirroring early models of spatial memory, with experimental data showing striking similarity with results from other (non-linguistic) spatial tasks (namely the A not B error tasks and associated model produced by Smith & Thelen; e.g. Smith & Thelen, 2003; Thelen et al., 2001). Third, we take these data, and show that a previous DST model originally developed to account for infant perseverative reaching behavior (Thelen et al., 2001) provides an elegant model of the changing meaning of spatial expressions over time.