Quantifying the structure of free association networks across the lifespan

We investigate how the mental lexicon changes over the lifespan using free association data from over 8,000 individuals, ranging from 10 to 84 years of age, with more than 400 cue words per age group. Using network analysis, with words as nodes and edges defined by the strength of shared associations, we find that associative networks evolve in a nonlinear (U-shaped) fashion over the lifespan. During early life, the network converges and becomes increasingly structured, with reductions in average path length, entropy, clustering coefficient, and small world index. Into late life, the pattern reverses but shows clear differences from early life. The pattern is independent of the increasing number of word types produced per cue across the lifespan, consistent with a network encoding an increasing number of relations between words as individuals age. Lifetime variability is dominantly driven by associative change in the least well-connected words

Men Are from Mars, Women Are from Venus: Evaluation and Modelling of Verbal Associations

We present a quantitative analysis of human word association pairs and study the types of relations presented in the associations. We put our main focus on the correlation between response types and respondent characteristics such as occupation and gender by contrasting syntagmatic and paradigmatic associations. Finally, we propose a personalised distributed word association model and show the importance of incorporating demographic factors into the models commonly used in natural language processing.Comment: AIST 2017 camera-read

Norms of age of acquisition and concreteness for 30,000 Dutch words

Abstract not availableMarc Brysbaert, Michaël Stevens, Simon De Deyne, Wouter Voorspoels, Gert Storm

Associative strength and semantic activation in the mental lexicon: evidence from continued word associations

In a word association task, the probability of producing a certain response to a cue is considered to be a direct measure of associative strength between words in the mental lexicon. The common single word association procedure is limited, since the number of words connected to a cue might be underestimated when a single response is asked. The continued association task overcomes this limitation by asking a person to generate multiple associative responses. To test whether continued strengths allow a better approximation of our lexicon, an experiment was conducted in which participants judged the associative strength between words. Our results show that in contrast to other semantic tasks, continued strength predicts weak to moderate judgments only. Two explanations based on the sampling of information and differential semantic activation of later responses in continued association are proposed. Theoretical implications for semantic activation and methodological implications for derivation of strength are discussed.Simon De Deyne, Daniel J. Navarro, Gert Stormshttp://cognitivesciencesociety.org/conference2013/index.htm

Strong structure in weak semantic similarity: a graph based account

Research into word meaning and similarity structure typically focus on highly related entities like CATS and MICE. However, most items in the world are only weakly related. Does our representation of the world encode any information about these weak relationships? Using a three-alternative forced-choice similarity task, we investigate to what extent people agree on the relationships underlying words that are only weakly related. These experiments show systematic preferences about which items are perceived as most similar. A similarity measure based on semantic network graphs gives a good account for human ratings of weak similarity.Simon De Deyne, Daniel J. Navarro, Amy Perfors and Gert Storm

Determination of the nature of the Cu coordination complexes formed in the presence of NO and NH3 within SSZ-13

Ammonia-selective catalytic reduction (NH3-SCR) using Cu zeolites is a well-established strategy for the abatement of NOx gases. Recent studies have demonstrated that Cu is particularly active when exchanged into the SSZ-13 zeolite, and its location in either the 6r or 8r renders it an excellent model system for fundamental studies. In this work, we examine the interaction of NH3-SCR relevant gases (NO and NH3) with the Cu2+ centers within the SSZ-13 structure, coupling powder diffraction (PD), X-ray absorption spectroscopy (XAFS), and density functional theory (DFT). This combined approach revealed that, upon calcination, cooling and gas exposure Cu ions tend to locate in the 8r window. After NO introduction, Cu-ions are seen to coordinate to two framework oxygens and one NO molecule, resulting in a bent Cu-nitrosyl complex with a Cu-N-O bond angle of similar to 150 degrees. Whilst Cu seems to be partially reduced/changed in coordination state, NO is partially oxidized. On exposure to NH3 while the PD data suggest the Cu2+ ion occupies a similar position, simulation and XAFS pointed toward the formation of a Jahn-Teller distorted hexaamine complex [Cu(NH3)(6)](2+) in the center of the cha cage. These results have important implications in terms of uptake and storage of these reactive gases and potentially for the mechanisms involved in the NH3-SCR process

Accounting for graded structure in adjective categories with valence-based opposition relationships

In contrast to noun categories, little is known about the graded structure of adjective categories. In this study, we investigated whether adjective categories show a similar graded structure and what determines this structure. The results show that adjective categories like nouns exhibit a reliable graded structure. Similar to nouns, we investigated whether similarity is the main determinant of the graded structure. We derived a low-dimensional similarity representation for adjective categories and found that valence differences in adjectives constitute an important organising principle in this similarity space. Valence was not implicated in the categories’ graded structure, however. A formal similarity-based model using exemplars accounted for the graded structure by effectively discarding the valence differences between adjectives in the similarity representation through dimensional weighting. Our results generalise similarity-based accounts of graded structure and highlight a closely knit relationship between adjectives and nouns on a representational level.Simon De Deyne, Wouter Voorspoels, Steven Verheyen, Daniel J. Navarro and Gert Storm