Łukasiewicz-Moisil Relation Algebras

We introduce Łukasiewicz-Moisil relation algebras, obtained by considering a relational dimension over Łukasiewicz-Moisil algebras. We prove some arithmetical properties, provide a characterization in terms of complex algebras, study the connection with relational Post algebras and characterize the simple structures and the matrix relation algebras.     

Language effects in magnitude comparison: small, but not irrelevant

It is assumed that number magnitude comparison is performed by assessing magnitude representation on a single analog mental number line. However, we have observed a unit-decade-compatibility effect in German which is inconsistent with this assumption (Nuerk, Weger, & Willmes, 2001). Incompatible magnitude comparisons in which decade and unit comparisons lead to different responses (e.g., 37_52 for which 3<5, but 7>2) are slower and less accurately responded to than compatible trials in which decade and unit comparisons lead to the same response (e.g., 42_57, for which 4<5 and 2<7). As overall distance was held constant, a single holistic magnitude representation could not account for this compatibility effect. However, because of the inversion property of the corresponding German two-digit number words ("einundzwanzig" ), the language-generality of the effect is questionable. We have therefore examined the compatibility effect with native English speakers. We were able to replicate the compatibility effect using Arabic notation. Thus, the compatibility effect is not language-specific. However, in cross-linguistic analyses language-specific modulations were observed not only for number words but also for Arabic numbers. The constraints imposed on current models by the verbal mediation of Arabic number comparison are discussed.     

Processing "d-linked" phrases

Linguists draw a distinction between two types of interrogatives: discourse linked (d-linked) phrases such as which man, which implies the existence of a set of contextually determined entities (men) from which the speaker is asking for a choice, and non–d-linked interrogatives such as who, which carry no such implication. Two questionnaires and an on-line reading study showed that readers prefer a d-linked phrase more than a non–d-linked phrase as the antecedent for a pronoun, suggesting that d-linked phrases are immediately instantiated in a discourse representation that is checked during the process of pronoun interpretation. Comparable difficulty is not observed for non–d-linked interrogatives. A questionnaire and an on-line listening study also showed that readers and listeners were more willing to accept a grammatical island violation containing a pronoun when the pronoun's antecendent was a d-linked interrogative than when the antecedent was non–d-linked, suggesting that they check a discourse representation for the pronoun antecedent. All results suggest that d-linked phrases are immediately interpreted in a discourse representation, not just in a syntactic representation.     

Semantic representations of word meanings by the cerebral hemispheres

Two priming experiments investigated kind and strength of semantic knowledge underlying known, frontier, and unknown low frequency words. Results from Experiment 1 suggest that known words reflect categorical knowledge, but frontier and unknown words reflect thematic knowledge. Thematic knowledge for frontier words appears to be stronger than that for unknown words. Experiment 2 entailed visual half-field presentation of targets. All facilitory effects were restricted to the lvf/RH, and inhibitory effects to the rvf/LH. Experiment 1 findings were mirrored by the RH. Thematic knowledge appears to precede categorical knowledge for the RH, but the opposite may be true of the LH. Results are also discussed in terms of the RH role in meaning acquisition and metacontrol.     

Adult age differences in visual word identification: functional neuroanatomy by positron emission tomography

Adult age differences in the neural systems mediating semantic (context-independent) memory were investigated using positron emission tomography (PET). Younger (20-29 years) and older (62-70 years) participants performed lexical decision (word/nonword discrimination) and nonsemantic (simple visual search) baseline tasks during PET scanning. Within the lexical decision task, display duration and presentation rate were varied across scans. The behavioral data suggested that although an age-related slowing was evident in visual feature and response processing, the retrieval of semantic/lexical information was similar for younger and older adults. For both age groups, lexical-related activation occurred in inferior prefrontal and occipitotemporal regions of the left hemisphere. Differential activation, as a function of age group, was observed in the left occipitotemporal pathway as a result of older adults' maintaining higher levels of neural activity in striate cortex (during visual search) and in inferior temporal cortex (during lexical decision). The prefrontal activation was similar for the two age groups. Thus, although this form of semantic memory retrieval does not undergo significant age-related decline, an age-related change in the associated pattern of neural activation is evident. These findings differ from previous neuroimaging studies of episodic (context-dependent) memory retrieval, which have suggested that age-related compensatory mechanisms are expressed primarily by greater activation of prefrontal regions for older adults than for younger adults.     

Essential and Perceptual Attributes of Words in Reflective and On-line Processing

Access to essential and perceptual attributes of word meanings was investigated in a series of tasks. First, perceptual attributes of a number of natural kind concepts were determined by asking participants to generate the most salient features of those concepts; they were asked to assess the importance of both those features and features that fit criteria for essential attributes. Attributes fitting the criteria for essential attributes were found to be judged more important than perceptual attributes in identifying an object and to have more connections to other attributes of the concept. Semantic priming for both types of features was then investigated. Prime-target pairs consisting of the natural kind concept term and the perceptual or essential attribute were presented for lexical decision (Experiments 1a and 1b) or naming (Experiments 2a and 2b). Interstimulus intervals were either 0 or 200 ms. Both types of features were primed at a 200 ms interstimulus interval but only in the lexical decision task.     

Phonological, semantic, and repetition priming with homophones

The current study investigated semantic, repetition, and phonological priming using heterographic homonyms (homophones) as stimuli in a lexical decision task. As in previous research, reliable semantic priming and repetition effects were found. In addition, the statistical additivity of these two effects was replicated using homophones as stimuli. Using homophones, a reliable phonological priming effect was found when 10-16 intervening trials were used. This effect was also statistically independent of semantic priming indicating the independence of the mechanisms responsible for semantic and phonological priming. The magnitude of the phonological priming effect was also significantly less than the magnitude of the repetition effect. This difference in effect magnitude was taken to indicate that the repetition of phonological information is not a primary contributor to the repetition effect.