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I am a junior research group leader (DFG Emmy Noether Programme), "Computational Modelling" group, at the Department of Psychology, Humboldt-Universität zu Berlin.


In my research, I am studying how our experience with regularities in the world shapes how we think about things, and how we can draw from our experience to think about things we haven't experienced (yet).

Most of my work relies on computational models based on large collections of data, which are supposed to reflect our experience with our environment.   

    


Current projects

It is traditionally assumed that words are assigned to concepts as arbitrary labels. In reality however, labels are always selected in a specific linguistic, historical, and social context, which informs and restricts label choices: For example, the existence of the word “phone” makes it very sensible to use the word “mobile phone” for a portable phone. On the other hand, labels almost always bring with them certain connotations and implications: the German “Völkerwanderung” describes the exact same concept as the Italian “invasione barbariche”, but the associations are quite different. In the project proposed here, we plan to investigate both sides of this phenomenon – why do we pick the labels we choose, and what are the consequences of these choices – from a cognitive point of view. To this end, central properties of both existing and novel words – related to their form and especially their meaning – will be represented in an objective and quantitative manner, by employing recent developments from the artificial intelligence field of natural language processing. Thus, combining computational modelling techniques with experimental methodology from general and social psychology, the present project aims at establishing a comprehensive theoretical framework for the choice and implications of word labels. The project consists of three major work packages. The studies of the first work package investigate when and which new word labels are coined by speakers. On the one hand, this includes examining the concept properties and contexts that lead speakers to generate a new label for a given concept. On the other hand, it includes predicting which labels are chosen, with the aim of establishing a computational model for the goodness/adequacy of labels given a concept. The methods of the first work package range from large-scale corpus studies over observation of natural communication to various signaling game-paradigms. The studies of the second work package examine direct social influences on label choices, since labels are always a social convention of a speaker community. The main factors of interest here are variables connected to the interaction partners in a social setting where both partners start with different labels for the same concept (such as their willingness to accept new labels, or their social status). The studies of this work package thus employ methods from social psychology in personal communication settings to examine how such social factors interact with the “goodness of labels” to determine which label is finally adapted by a speaker.Finally, the studies of the third work package investigate the implications and connotations of labels, in terms of semantic association, affective evaluation, and sensory perception. In these studies, where different labels for the very same concept will be presented to different speakers, we aim at predicting the connotations from the quantitative properties of the word labels. 

Behavioral studies on semantic effects in language production have observed apparently contradictory context effects: In come studies, the presence of semantically related distractors (such as the word "LION" when participants have to name the picture of a tiger) has resulted in facilitation (i.e., faster responses), while others have observed interference (i.e., slower responses). In order to explain these effects in a unified, comprehensive model, Abdel Rahman and Melinger (2009, 2019) have proposed the Swinging Lexical Network Model of language production. This model relies on two core assumptions: (1) it assumes priming at the conceptual-semantic level as a consequence of spreading activation (leading to faster responses in the presence of semantically related context words) but competition during word selection at the lexical level (since only one word is to be selected for production), and (2) it assumes that the amount of priming and competition does not only result from the activation of the target and context, but is also influenced by a co-activated cohort - other concepts that are mutually activated by the target, the context word, and by each other during processing (such as, in our example, "leopard" or "cat"). However, as acknowledged by the authors, the fact that this model is currently a purely verbal theory and not yet computationally implemented makes it very difficult to rigorously assess ist actual explanatory power and empirical validity. The aim of the current project is to provide this computational implementation and empirical evaluation. This model consists of the following components: (I) We will employ distributional semantic models/word embeddings as a state-of-the-art computational model of semantic memory, and (II) apply Kintsch’s (1988) construction-integration algorithm to model the mutual co-activation of the cohort. We start from very simplistic assumptions about (III) activation spread between the semantic and lexical level and (IV) selection at the lexical level. The first work package focuses on implementing this model and making the implemented model accessible to the research community. The second work package focuses on estimating the free parameters of the model from already existing and published studies on semantic context effects in language processing. Finally, the third work package focuses on empirically validating the model in experimental studies, generating new item material for which specific context effects would be expected according to the model predictions. 


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