Rating the similarity of simple perceptual stimuli: asymmetries induced by manipulating exposure frequency.

When judging the similarity of two stimuli, people's ratings often differ depending on the order in which the comparison is presented (A vs. B or B vs. A). Such directional asymmetries have typically been demonstrated using complex concepts that have a large number of semantic features and a standard explanation is that different sets of features are emphasized depending on the direction of the comparison. In this study, we show that directional asymmetries in the similarity of simple perceptual stimuli can be predictably manipulated merely by presenting each member of a pair with different frequency. Participants rated the similarity of color patches before and after performing an irrelevant training task in which a subset of colors was presented ten times more frequently than others. The similarity ratings after training were significantly more asymmetric than the ratings before training. We discuss the implications of these findings for models of similarity judgment and propose a computationally explicit explanation based on asymmetries in representational stability.     

A scale for the psychological magnitude of number

A scale of the “psychological magnitude” of number was constructed from similarity ratings of the 45 number pairs that can be obtained from a set of 10 integers. A nonmetric analysis of these similarity ratings showed that “psychological number” was a power function of number.     

Similarity,distance, and categorization: A discussion of Smith’s (2006) warning about “colliding parameters”

The idea that categorization decisions rely on subjective impressions of similarities between stimuli has been prevalent in much of the literature over the past 30 years and has led to the development of a large number of models that apply some kind of decision rule to similarity measures. A recent article by Smith (2006) has argued that thesesimilarity—choice models of categorization have a substantial design flaw, in which the similarity and the choice components effectively cancel one another out. As a consequence of this cancellation, it is claimed, the relationship between distance and category membership probabilities is linear in these models. In this article, I discuss these claims and show mathematically that in those cases in which it is sensible to discuss the relationship between category distance and category membership at all, the function relating the two is approximately logistic. Empirical data are used to show that a logistic function can be observed in appropriate contexts.     

Similarity grouping as feature-based selection

Our visual system groups objects with similar features, such as colour, orientation, or shape. We argue that similarity grouping is nothing more than global selection of a certain feature value, such as red, horizontal, or circular. This account makes the striking prediction that only one feature group can be created at a time. Here we provide the most direct evidence yet for this proposal, using a number estimation task that forces simultaneous processing of all objects. Multiple similarity cues failed to produce grouping in this task, in contrast to proximity, connectivity, and common region, which all showed strong grouping effects.     

Breaking Down the Bilingual Cost in Speech Production

Bilinguals have been shown to perform worse than monolinguals in a variety of verbal tasks. This study investigated this bilingual verbal cost in a large‐scale picture‐naming study conducted in Spanish. We explored how individual characteristics of the participants and the linguistic properties of the words being spoken influence this performance cost. In particular, we focused on the contributions of lexical frequency and phonological similarity across translations. The naming performance of Spanish‐Catalan bilinguals speaking in their dominant and non‐dominant language was compared to that of Spanish monolinguals. Single trial naming latencies were analyzed by means of linear mixed models accounting for individual effects at the participant and item level. While decreasing lexical frequency was shown to increase naming latencies in all groups, this variable by itself did not account for the bilingual cost. In turn, our results showed that the bilingual cost disappeared when naming words with high phonological similarity across translations. In short, our results show that frequency of use can play a role in the emergence of the bilingual cost, but that phonological similarity across translations should be regarded as one of the most important variables that determine the bilingual cost in speech production. Low phonological similarity across translations yields worse performance in bilinguals and promotes the bilingual cost in naming performance. The implications of our results for the effect of phonological similarity across translations within the bilingual speech production system are discussed.     

Categories versus groups as explanatory concepts in intergroup relations

In this discussion of papers by Doise (1988) and Tajfel (1982) it is argued that a conceptual distinction should be made between social groups and social categories. A social group can be considered as a ‘dynamic whole’ or social system, characterized by the perceived interdependence among its members, whereas a social category can be defined as a collection of individuals who share at least one attribute in common. This distinction is crucial for the understanding of outgroup favouritism in the minimal intergroup situation, the basic similarity between large scale groupings and face-to-face groups, the difference between group identification and social identity and the issue of categorizations versus attributions in intergroup conflict.     

Interpersonal Sameness of Meaning for Inferential Role Semantics

Inferential Role Semantics is often criticized for being incompatible with the platitude that words of different speakers can mean the same thing. While many assume that this platitude can be accommodated by understanding sameness of meaning in terms of similarity of meaning, no worked out proposal has ever been produced for Inferential Role Semantics. I rectify this important omission by giving a detailed structural account of meaning similarity in terms of graph theory. I go on to argue that this account has a number of attractive features, prominent among them that it makes sameness of meaning probabilistically determine co-reference.     

Implicit and explicit tests of odor memory reveal different outcomes following interference

Experiencing two odors as a mixture can later increase their perceived similarity when presented separately. Such an increase in similarity can be used as an implicit measure of how well participants remember the mixture. Three experiments tested the resistance to interference of this effect by first giving participants exposure to two 2-odor mixtures and then presenting each odor from one mixture (interfered pair) separately many times. After the latter interference phase, participants rated the similarity of the two odors in each pair. The experiments varied in terms of the number of initial exposures to the mixtures, the number of odor presentations in the interference phase, and the control conditions employed. No difference in similarity ratings for the interfered and non-interfered pair was found in any experiment. In contrast to the lack of interference with this implicit measure, an explicit measure of memory based on participants’ ratings of odor frequency revealed that they could recall to some degree that the interfered odors had been presented alone in the second phase. These results suggest that implicit memory for odor mixtures is highly resistant to interference and is consistent with a configural encoding account of this effect.     

Exemplar-based accounts of "multiple-system" phenomena in perceptual categorization

We demonstrate that a wide variety of recently reported "rule-described" and "prototype-described" phenomena in perceptual classification, which have led to the development of a number of multiple-system models, can be given an alternative interpretation in terms of a single-system exemplar-similarity model. The phenomena include various rule- and prototype-described patterns of generalization, dissociations between categorization and similarity judgments, and dissociations between categorization and old-new recognition. The alternative exemplar-based interpretation relies on the idea that similarity is not an invariant relation but a context-dependent one. Similarity relations among exemplars change systematically because of selective attention to dimensions and because of changes in the level of sensitivity relating judged similarity to distance in psychological space. Adaptive learning principles may help explain the systematic influence of the selective attention process and of modulation in sensitivity settings on judged similarity.     

The differential similarity of positive and negative information – an affect-induced processing outcome?

People judge positive information to be more alike than negative information. This good-bad asymmetry in similarity was argued to constitute a true property of the information ecology (Alves, H., Koch, A., & Unkelbach, C. (2017). Why good is more alike than bad: Processing implications. Trends in Cognitive Sciences, 21, 69–79). Alternatively, the asymmetry may constitute a processing outcome itself, namely an influence of phasic affect on information processing. Because no research has yet tested whether phasic affect influences perceived similarity among stimuli, we conducted 5 Experiments that also tested whether phasic affect can account for the higher judged similarity among positive compared to negative stimuli. In three experiments, we affectively charged pictures of different Pokemon by pairing them with monetary gains and losses (Exp. 1a, 1b) as well as positive and negative trait words (Exp. 2); yet, the evaluative charge did not differentially influence perceived similarity among the Pokemon. Experiment 3 replicated the basic similarity asymmetry among positive and negative words, and found that it was unaffected by externally induced phasic affect. Experiment 4 showed that phasic affect had no influence on perceived similarity of non-evaluative words either. We conclude that albeit a weak influence of phasic affect on perceived similarity of stimuli cannot be ruled out entirely, it can most likely not account for the typically medium to large sized asymmetry in similarity among positive and negative stimuli.     

Predicting similarity judgments in intertemporal choice with machine learning

Similarity models of intertemporal choice are heuristics that choose based on similarity judgments of the reward amounts and time delays. Yet, we do not know how these judgments are made. Here, we use machine-learning algorithms to assess what factors predict similarity judgments and whether decision trees capture the judgment outcomes and process. We find that combining small and large values into numerical differences and ratios and arranging them in tree-like structures can predict both similarity judgments and response times. Our results suggest that we can use machine learning to not only model decision outcomes but also model how decisions are made. Revealing how people make these important judgments may be useful in developing interventions to help them make better decisions.     

Infrastructure flexibility created by standardized gateways: The cases of XML and the ISO container

This article addresses the problem of entrenchment in large technical systems. It explores in what manner standardization could be used as a means to inscribe flexibility into infrastructures and focuses in particular on the role of standardized gateway technologies. Two cases are examined: the Extensible Markup Language (XML) for structured information exchange and the intermodal freight container, also known as the ISO container. The cases indicate that flexibility is a transient characteristic of gateway standards. Where standards do not meet the needs of subsystems and changed circumstances, competing gateways emerge. Flexibility, entrenchment and competition are part of a cyclic movement in gateway evolution. You can read more about her in the Foreword.     

An Optimized Design of Choice Experiments: A New Approach for Studying Decision Behavior in Choice Task Experiments

In this paper, we present a new approach for the optimal experimental design problem of generating diagnostic choice tasks, where the respondent's decision strategy can be unambiguously deduced from the observed choice. In this new approach, we applied a genetic algorithm that creates a one‐to‐one correspondence between a set of predefined decision strategies and the alternatives of the choice task; it also manipulates the characteristics of the choice tasks. In addition, this new approach takes into account the measurement errors that can occur when the preferences of the decision makers are being measured. The proposed genetic algorithm is capable of generating diagnostic choice tasks even when the search space of possible choice tasks is very large. As proof‐of‐concept, we used this novel approach to generate respondent‐specific choice tasks with either low or high context‐based complexity that we operationalize by the similarity of alternatives and the conflict between alternatives. We find in an experiment that an increase in the similarity of the alternatives and an increase in the number of conflicts within the choice task lead to an increased use of non‐compensatory strategies and a decreased use of compensatory decision strategies. In contrast, the size of the choice tasks, measured by the number of attributes and alternatives, only weakly influences the strategy selection. Copyright © 2014 John Wiley & Sons, Ltd.     

A Distributed Connectionist Production System

DCPS is a connectionist production system interpreter that uses distributed representations. As a connectionist model it consists of many simple, richly interconnected neuron-like computing units that cooperate to solve problems in parallel. One motivation for constructing DCPS was to demonstrate that connectionist models are capable of representing and using explicit rules. A second motivation was to show how "coarse coding" or "distributed representations" can be used to construct a working memory that requires far fewer units than the number of different facts that can potentially be stored. The simulation we present is intended as a detailed demonstration of the feasibility of certain ideas and should not be viewed as a full implementation of production systems. Our current model only has a few of the many interesting emergent properties that we eventually hope to demonstrate: It is damage-resistant, it performs matching and variable binding by massively parallel constraint satisfaction, and the capacity of its working memory is dependent on the similarity of the items being stored.     

Perceiving Stability in a Changing World: Combining Shots and Intergrating Views in Motion Pictures and the Real World

One of the central debates in the study of media concerns the relationship between our perception of real-world events and mediated events such as motion pictures. A number of authors have argued convincingly that both rely on similar natural perceptual processes. Here we extend this argument by reviewing research on scene perception showing that the similarity between film and natural perception includes a common tendency to perceive events as continuous in the face of large view-to-view inconsistencies. This research shows that observers are frequently unable to detect large unexpected changes that occur between views, even in objects within their focus of attention. This is true both in mediated stimuli such as motion pictures and during staged real-world interactions. Thus, perception of continuity may be an inference that proceeds in spite of impossible between-view changes, both in motion pictures and real-world scenes.     

Personality dimensions across cultures

In order to generalize the dimensional structure of personality-relatively independent groups of covarying traits-across languages and cultures, a large number of cultures must be studied. Until recently only a few worldwide personality datasets have been available. The first large-scale studies indicate that the pattern of covariation between personality traits is universal and is relatively easily generalizable across languages and cultures. In contrast to the structure of personality, the comparison of the mean trait scores across cultures is much more problematic because cross-cultural differences turned out to be very small in their magnitude, about one-third of the magnitude of individual differences within culture. More integral (e.g., the similarity between personality profiles) or subtle (e.g., the disparity between positively and negatively worded items) measures can reveal more systematic relationships with relevant socioeconomic and geographic variables than the mean scores themselves. Relatively modest sizes of cross-cultural differences in the mean values may imply that a reasonable scalar equivalence can be achieved, and all individuals, irrespective of their language and culture, can be represented in a common metric.     

The role of visual similarity in picture categorization

Categorization is usually assumed to require access to a concept's meaning. When pictures are categorized faster than words, they are assumed to be understood faster than words. However, pictures from the same category are more similar than pictures from different categories. The present article argues that the use of visual similarity as a cue to category membership may produce the picture advantage. The visual similarity hypothesis was tested in two experiments. In the first experiment, pictures showed a disadvantage for the visually similar categories of fruits and vegetables, but showed their usual advantage for the visually dissimilar categories of fruits and animals. In the second experiment, with a mixed list design, pictures were slower only for visually similar different decisions, but showed the usual advantage for all other decisions. The reliability of visual similarity as a cue to the decision accounted well for these results. Because visual similarity can be shown to have large effects on picture categorization, the use of categorization to compare speed of understanding of pictures and words is questionable.     

Classification behavior and measures of intelligence: dimensional identity versus overall similarity

Individuals tend to adopt either analytic or holistic modes of categorizing objects. In two studies, we examined the relation between these categorization tendencies and cognitive abilities as measured by standard psychometric instruments. The participants in both studies were pretested with a restricted classification task in which it was possible for them to classify simple stimuli by dimensional identity or overall similarity. Those making a large number of either type of categorization were then tested with subtests of the WAIS-R and with the Raven's progressive matrices. Across both studies, the analytic individuals (many dimensional identity classifications) scored higher than the holistic individuals (many overall similarity classifications) on some but not all of the subtests. The results are consistent with the idea that holistic modes of categorization may be more "primitive" than analytic modes. The findings are discussed in terms of the association between categorization mode and either general or specific cognitive abilities.