A Quantum Geometric Model of Color Similarity Judgements

Since Tversky (1977) argued that similarity judgments violate the three metric axioms, asymmetrical similarity judgments have been offered as particularly difficult challenges for standard, geometric models of similarity, such as multidimensional scaling. According to Tversky (1977), asymmetrical similarity judgments are driven by differences in salience or extent of knowledge. However, the notion of salience has been difficult to operationalize to different kinds of stimuli, especially perceptual stimuli for which there are no apparent differences in extent of knowledge. To investigate similarity judgments between perceptual stimuli, across three experiments we collected data where individuals would rate the similarity of a pair of temporally separated color patches. We identified several violations of symmetry in the empirical results, which the conventional multidimensional scaling model cannot readily capture. Pothos et al. (2013) proposed a quantum geometric model of similarity to account for Tversky’s (1977) findings. In the present work, we developed this model to a form that can be fit to similarity judgments. We fit several variants of quantum and multidimensional scaling models to the behavioral data and concluded in favor of the quantum approach. Without further modifications of the model, the quantum model additionally predicted violations of the triangle inequality that we observed in the same data. Overall, by offering a different form of geometric representation, the quantum geometric model of similarity provides a viable alternative to multidimensional scaling for modeling similarity judgments, while still allowing a convenient, spatial illustration of similarity.

Symmetry in Emotional and Visual Similarity between Neutral and Negative Faces

Is Mr. Hyde more similar to his alter ego Dr. Jekyll, because of their physical identity, or to Jack the Ripper, because both evoke fear and loathing? The relative weight of emotional and visual dimensions in similarity judgements is still unclear. We expected an asymmetric effect of these dimensions on similarity perception, such that faces that express the same or similar feeling are judged as more similar than different emotional expressions of same person. We selected 10 male faces with different expressions. Each face posed one neutral expression and one emotional expression (five disgust, five fear). We paired these expressions, resulting in 190 pairs, varying either in emotional expressions, physical identity, or both. Twenty healthy participants rated the similarity of paired faces on a 7-point scale. We report a symmetric effect of emotional expression and identity on similarity judgements, suggesting that people may perceive Mr. Hyde to be just as similar to Dr. Jekyll (identity) as to Jack the Ripper (emotion). We also observed that emotional mismatch decreased perceived similarity, suggesting that emotions play a prominent role in similarity judgements. From an evolutionary perspective, poor discrimination between emotional stimuli might endanger the individual.

How much is a cow like a meow? A novel database of human judgements of audiovisual semantic relatedness

Semantic information about objects, events, and scenes influences how humans perceive, interact with, and navigate the world. Most evidence in support of semantic influence on cognition has been garnered from research conducted with an isolated modality (e.g., vision, audition). However, the influence of semantic information has not yet been extensively studied in multisensory environments potentially because of the difficulty in quantification of semantic relatedness. Past studies have primary relied on either a simplified binary classification of semantic relatedness based on category or on algorithmic values based on text corpora rather than human perceptual experience and judgement. With the aim to accelerate research into multisensory semantics, we created a constrained audiovisual stimulus set and derived similarity ratings between items within three categories (animals, instruments, household items). A set of 140 participants provided similarity judgments between sounds and images. Participants either heard a sound (e.g., a meow) and judged which of two pictures of objects (e.g., a picture of a dog and a duck) it was more similar to, or saw a picture (e.g., a picture of a duck) and selected which of two sounds it was more similar to (e.g., a bark or a meow). Judgements were then used to calculate similarity values of any given cross-modal pair. The derived and reported similarity judgements reflect a range of semantic similarities across three categories and items, and highlight similarities and differences among similarity judgments between modalities. We make the derived similarity values available in a database format to the research community to be used as a measure of semantic relatedness in cognitive psychology experiments, enabling more robust studies of semantics in audiovisual environments.

Symmetry in emotional and visual similarity between neutral and negative faces

Is Mr Hyde more similar to his alter ego Dr Jekyll, because of their physical identity, or to Jack the Ripper, because both evoke fear and loathing? The relative weight of emotional and visual dimensions in similarity judgements is still unclear. We expected an asymmetric effect of these dimensions on similarity perception, such that faces that express the same or similar feeling are judged as more similar than different emotional expressions of same person. We selected 10 male faces posing different expressions. Each male posed one neutral expression and one emotional expression (5 disgust, 5 fear). We paired these expressions, resulting in 190 pairs, which differed either in emotional expressions, physical identity, or both. Twenty healthy participants rated the similarity of paired faces on a 7-points scale. We report a symmetric effect of emotional expression and identity on similarity judgements, suggesting that people may perceive Mr Hyde to be just as similar to Dr Jekyll (identity) as to Jack the Ripper (emotion). We also observed that emotional mismatch decreased perceived similarity, suggesting that emotions play a prominent role in similarity judgements. From an evolutionary perspective, poor discrimination between emotional stimuli may not be advantageous to the individual.

Sensorimotor distance: A fully grounded measure of semantic similarity for 800 million concept pairs

Experimental design and computational modelling across the cognitive sciences often rely on measures of semantic similarity between concepts. Traditional measures of semantic similarity are typically derived from distance in taxonomic databases (e.g. WordNet), databases of participant-produced semantic features, or corpus-derived linguistic distributional similarity (e.g. LSA), all of which are theoretically problematic in their lack of grounding in sensorimotor experience. We present a new measure of sensorimotor distance between concepts, based on multidimensional comparisons of their experiential strength across 11 perceptual and action-effector dimensions in the Lancaster Sensorimotor Norms. We demonstrate that, in modelling human similarity judgements, sensorimotor distance has comparable explanatory power to other measures of semantic similarity, explains variance in human judgements which is missed by other measures, and does so with the advantages of remaining both fully grounded and computationally efficient. Moreover, sensorimotor distance is equally effective for both concrete and abstract concepts. We further introduce a web-based tool (https://lancaster.ac.uk/psychology/smdistance) for easily calculating and visualising sensorimotor distance between words, featuring coverage of nearly 800 million word-pairs. Supplementary materials are available at https://osf.io/d42q6/.

The Treachery of Images: Objects, Pictures, Words and the Role of Affordances in Similarity Judgements

Categorization is a fundamental cognitive strategy employed to ease information processing and to aid memory formation. Past research on how humans categorize objects has used images of objects as experimental stimuli. Results suggest these stimuli are categorized based on abstract linguistic concepts. Concurrently, studies in the past 10 years have found differences in the processing of images as compared to real-world objects. One proposed explanation is that these results are due to differences in the affordances of images versus objects. Using a similarity judgement paradigm, we have explored the effect of affordances in a categorization task including words (object names), images, and objects. Consistent with previous research, we found significant differences in how participants made similarity judgements of images and objects. Moreover, we found that similarity judgments using object names were much more similar to the judgments of pictures than of objects. An exploratory cluster analysis opens the possibility of framing such differences as affordance driven. These results suggest a need for more ecologically valid categorization tasks, more conservative inferences when using images as stimuli in these tasks, and the need for further exploring the role of affordances in categorization.

Are these Artworks Similar? Analysing Visitors’ Judgements on Aesthetic Perception with a Digital Game

Digital games have been used in the context of a cultural experience for several reasons, from learning to socialising and having fun. As a positive side effect, using digital games in a GLAM environment contributes to increasing the visitors’ engagement and making the collections more popular. Along this line, we present in this article an online game for museum environments that serves two goals: asking users to engage with the artworks in a collection in a playful environment, and collecting their feedback on artwork similarity, which may be used by curators to rethink the organisation of digital exhibitions and in general to better understand how visitors perceive artworks. The game is called PAGANS ( Playful Art: a GAme oN Similarity ), and is designed to collect similarity judgements about artworks. The software was implemented following some principles of gamification in order to quickly leverage similarity information in the cultural heritage domain while increasing user engagement and fun. The game, involving pairs of players, was used during two large public events to collect different data about the players’ behaviour and to investigate how these dimensions correlate with aesthetic perception. A thorough statistical analysis shows that age and (self-declared) gender correlates with the time and the number of moves needed to complete a session. These dimensions also link to the relevance of colour and shape in judging similarity. These findings suggest that, although artwork similarity is very subjective and may vary based on a person’s background, some trends can be identified when considering the subjects’ gender and age. This could have some practical implications; for example, it could be used to support art curators in creating digital exhibitions by grouping artworks in novel, user-centred ways.