J. Frederico Marques

Cognitive euroscience: Scalar variability in price estimation and the cognitive consequences of switching to the euro:

The present paper examines the ability to evaluate prices in a familiar currency (French francs, Portugese escudos, or Irish punt) and in an unfamiliar currency (euro). Participants evaluated prices for different items either by selecting the most appropriate price from a set of alternatives (in a timed or not-timed version) or by directly producing a price estimate for each item. The results followed Webers law: The standard deviation of estimated prices was proportional to their mean. The Weber fraction was stable for the familiar currency in different countries, but was significantly higher for the unfamiliar currency. We suggest that price estimation relies on a learned mapping between items and their prices as represented by distributions of activation on an internal number line. The observed Weber fraction reflects the degree of expertise with a given currency as well as a minimal variability intrinsic to the number line itself.

Developing Intuition for Prices in Euros: Rescaling or Relearning Prices?.

This article examines how numerical intuition for prices develops after a major change in currency. University students in Portugal (Study 1) and Austria (Study 2) made price estimates for 40 different items from November 2001 to June 2002, surrounding the time at which these countries switched to the euro. Overall results are more in accordance with a relearning hypothesis, considering that price estimates become progressively more accurate by a process that is related to buying frequency and, hence, is faster for frequently bought items. An alternative global rescaling hypothesis received mixed support. Results also suggest that price estimations in euros have not yet reached a level of accuracy comparable with estimations in the former national currency.

Specialization and semantic organization: Evidence for multiple semantics linked to sensory modalities

The present article reviews the case for multiple systems in semantic memory and empirically evaluates a multiple semantics proposal based on sensory modalities. In the experiments, a conceptual switching cost paradigm was used (Pecher, Zeelenberg, & Barsalou, 2003), in which participants verified properties for concepts and verification time was compared for target trials (e.g., adog canbark) that were preceded by context trials of either the same or a different modality (e.g., abee canbuzz or ahorse can havespots). Experiment 1 involved a modality switch while controlling for the concept’s category and demonstrated that when modalities were switched, a processing cost was incurred that could not be attributed to the latter dimension. Experiment 2 further supported this conclusion by showing that, in a reverse situation, the cost incurred when category was switched was at least smaller. The results are discussed by considering possible alternative amodal explanations and other data that have shown the influence of sensory information in conceptual processing.

Estimated age of acquisition norms for 834 Portuguese nouns and their relation with other psycholinguistic variables

The main objective of this study is to report rated age of acquisition (AoA) norms for 834 nouns in Portuguese (European). AoA ratings were collected on a 7 point scale, generally following Gilhooly and Logie (1980) procedure with an 8 extra point for “don’t know the word” answers. Results were analyzed considering AoA ratings and their standard deviations and considering the relationship between AoA ratings and other psycholinguistic variables (imageability, familiarity, written word frequency, concreteness, number of syllables and number of words). AoA ratings and their standard deviations were significantly and positively correlated, with early acquired word ratings showing higher agreement. Correlation and multiple regression analyses confirmed the major contribution of imageability and familiarity to AoA ratings obtained in other languages. The full database of AoA ratings and other psycholinguistic variables may be downloaded from www.psychonomic.org/archive or www.fpce.ul.pt/pessoal/ulfpfred/aoa.htm.

The hierarchical organization of semantic memory: Executive function in the processing of superordinate concepts

Research on the processing of objects at different hierarchical levels has suggested that understanding superordinate concepts (e.g. fruit), relative to basic level concepts (e.g. apple), requires greater semantic control demands. Yet, it is unclear which factors underlie this difference in executive processing. We built on previous research showing that superordinate concepts have less shared features among their members and therefore may involve higher semantic control requirements. To test this hypothesis, we developed an fMRI study in which we orthogonally manipulated feature sharedness (more shared vs. less shared) and concept level (superordinate vs. basic) in a sentence verification task. Sentences involving less shared features, relative to more shared features, significantly engaged the L lateral PFC. Importantly, sentences that included superordinate concepts, relative to those with basic level concepts, also revealed a stronger response in L lateral PFC, along with posterior temporal gyrus activation. There was also a significant interaction between feature sharedness and concept level in several PFC regions and L posterior temporal areas. The results suggest that relative to basic level concepts, processing superordinate concepts requires extra semantic control in L lateral PFC to coordinate information that is less shared by other members of the category level. These findings demonstrate that feature sharedness impacts the neural basis of semantic knowledge, and is a critical dimension in the processing of superordinate concepts.

The general/specific breakdown of semantic memory and the nature of superordinate knowledge: Insights from superordinate and basic-level feature norms

The deterioration of semantic memory usually proceeds from more specific to more general superordinate categories, although rarer cases of superordinate knowledge impairment have also been reported. The nature of superordinate knowledge and the explanation of these two semantic impairments were evaluated from the analysis of superordinate and basic-level feature norms. The results show that, in comparison to basic-level concepts, superordinate concepts are not generally less informative and have similar feature distinctiveness and proportion of individual sensory features, but their features are less shared by their members. Results are in accord with explanations based on feature connection weights and/or concept confusability for the superordinate advantage cases. Results especially support an explanation for superordinate impairments in terms of higher semantic control requirements as related to features being less shared between concept members. Implications for patients with semantic impairments are also discussed.The deterioration of semantic memory usually proceeds from more specific to more general superordinate categories, although rarer cases of superordinate knowledge impairment have also been reported. The nature of superordinate knowledge and the explanation of these two semantic impairments were evaluated from the analysis of superordinate and basic-level feature norms. The results show that, in comparison to basic-level concepts, superordinate concepts are not generally less informative and have similar feature distinctiveness and proportion of individual sensory features, but their features are less shared by their members. Results are in accord with explanations based on feature connection weights and/or concept confusability for the superordinate advantage cases. Results especially support an explanation for superordinate impairments in terms of higher semantic control requirements as related to features being less shared between concept members. Implications for patients with semantic impairments are also discussed.

Grasping with the eyes: The role of elongation in visual recognition of manipulable objects

Processing within the dorsal visual stream subserves object-directed action, whereas visual object recognition is mediated by the ventral visual stream. Recent findings suggest that the computations performed by the dorsal stream can nevertheless influence object recognition. Little is known, however, about the type of dorsal stream information that is available to assist in object recognition. Here, we present a series of experiments that explored different psychophysical manipulations known to bias the processing of a stimulus toward the dorsal visual stream in order to isolate its contribution to object recognition. We show that elongated-shaped stimuli, regardless of their semantic category and familiarity, when processed by the dorsal stream, elicit visuomotor grasp-related information that affects how we categorize manipulable objects. Elongated stimuli may reduce ambiguity during grasp preparation by providing a coarse cue to hand shaping and orientation that is sufficient to support action planning. We propose that this dorsal-stream-based analysis of elongation along a principal axis is the basis for how the dorsal visual object processing stream can affect categorization of manipulable objects.

Conceptual knowledge in the brain: fMRI evidence for a featural organization

The organization and representation of conceptual knowledge in the brain remains a controversial issue in terms of both neuropsychological and imaging evidence. We report the results of a functional magnetic resonance study in which the role of the most debated dimensions (domain and feature type) was evaluated through a concept-feature verification task. The scope of the task was to eliminate serious methodological concerns that weighed down previous imaging research in this area, and to allow more definitive conclusions regarding the specific contribution of these dimensions. The results show differential patterns of brain activity according to feature type (both motion and visual form/surface features) but not according to concept domain (living vs. nonliving things). These findings are in accord with a modality-specific account of conceptual knowledge organization in the brain, in which specific kinds of features (e.g. form, color, motion, etc) have differential importance for representing different concepts.

Neural differences in the processing of true and false sentences: Insights into the nature of ‘truth’ in language comprehension

The inquiry on the nature of truth in language comprehension has a long history of opposite perspectives. These perspectives either consider that there are qualitative differences in the processing of true and false statements, or that these processes are fundamentally the same and only differ in quantitative terms. The present study evaluated the processing nature of true and false statements in terms of patterns of brain activity using event-related functional-Magnetic-Resonance-Imaging (fMRI). We show that when true and false concept-feature statements are controlled for relation strength/ambiguity, their processing is associated to qualitatively different processes. Verifying true statements activates the left inferior parietal cortex and the caudate nucleus, a neural correlate compatible with an extended search and matching process for particular stored information. In contrast, verifying false statements activates the fronto-polar cortex and is compatible with a reasoning process of finding and evaluating a contradiction between the sentence information and stored knowledge.

Naming from definition: The role of feature type and feature distinctiveness

The present paper evaluates the contribution of feature type and feature distinctiveness to naming of living and nonliving things using a naming from definition task. Normal subjects read verbal descriptions containing features varying in type (i.e., sensory vs. functional) and distinctiveness (i.e., distinct vs. shared) and were asked to name the concept described and to select the three features that most contributed to their answer. Main results showed that sensory features were selected more often than functional features to support naming living things and that, independent of feature type, more distinct features were selected to support naming more often than shared features. Results are discussed considering the implications for understanding naming and for neuropsychological evaluation.