Does spreading activation summate?

Summary Network models of semantic memory assume implicitly or explicitly that the degree of activation of a node is a monotonic function of the total amount of excitation reaching that node from all sources. For example, the activation level of the node representing apple should be greater if it is receiving excitation due to the activation of the nodes for fruit and pear than if only one of these neighboring nodes is activated. This notion was tested by presenting semantic primes 80 ms or 320 ms before a letter string (e.g., apple or ipple) requiring a lexical decision. The prime stimuli consisted of a pair of simultaneous items that were identical in the single prime condition (e.g., fruit/fruit or pear/pear) or different in the double prime condition (e.g., fruit/pear or pear/fruit), and were either related (target = apple) or unrelated (target = copper) to the target, or neutral. As predicted by the summation of semantic activation assumption of network models there was a larger priming effect (in the 320 ms SOA condition) following the simultaneous activation of two related nodes than following the activation of only one node.This research was supported by grants to the first author from the Natural Sciences and Engineering Research Council of Canada.     

PAST: Viewing the programming process

A software package called PAST (Programmer Assessment Software Tools) is described. PAST was designed as a research and diagnostic tool to analyze how programmers develop and test program code. PAST uses line changes between successive compiles to estimate a programmer’s cognitive processing. Line changes are highlighted and graphically presented between any two versions or compiles. Summary graphs and statistics across all versions also are provided. Applications of PAST for expanding our understanding of programming and applying it to research, teaching, and learning are discussed.     

Cocaine-but not methamphetamine-associated memory requires de novo protein synthesis

Context-induced drug craving and continuous drug use manifest the critical roles of specific memory episodes associated with the drug use experiences. Drug-induced conditioned place preference (CPP) in C57BL/6J mouse model, in this regard, is an appropriate behavioral paradigm to study such drug use-associated memories. Requirement of protein synthesis in various forms of long-term memory formation and storage has been phylogenetically demonstrated. This study was undertaken to study the requirement of protein synthesis in the learning and memory aspect of the conditioned place preference induced by cocaine and methamphetamine, two abused drugs of choice in local area. Since pCREB has been documented as a candidate substrate for mediating the drug-induced neuroadaptation, the pCREB level in hippocampus, nucleus accumbens, and prefrontal cortex was examined for its potential participation in the formation of CPP caused by these psychostimulants. We found that cocaine (2.5 and 5.0 mg/kg/dose)-induced CPP was abolished by the pretreatment of anisomycin (50 mg/kg/dose), a protein synthesis inhibitor, whereas methamphetamine (0.5 or 1.0 mg/kg/dose)-induced CPP was not affected by the anisomycin pretreatment. Likewise, cocaine-induced CPP was mitigated by another protein synthesis inhibitor, cycloheximide (15 mg/kg/injection) pretreatment, whereas methamphetamine-induced CPP remained intact by such pretreatment. Moreover, anisomycin treatment 2h after each drug-place pairing disrupted the cocaine-induced CPP, whereas the same treatment did not affect methamphetamine-induced CPP. An increase of accumbal pCREB level was found to associate with the learning phase of cocaine, but not with the learning phase of methamphetamine. We further found that intraaccumbal CREB antisense oligodeoxynucleotide infusion diminished cocaine-induced CPP, whereas did not affect the methamphetamine-induced CPP. Taken together, these data suggest that protein synthesis and accumbal CREB phosphorylation are essential for the learning and consolidation of the cocaine-induced CPP, whereas methamphetamine-induced CPP may be unrelated to the synthesis of new proteins.     

Phonological Activation in Multi-syllabic Sord Recognition

Three experiments were conducted to test the phonological recoding hypothesis in visual word recognition. Most studies on this issue have been conducted using mono-syllabic words, eventually constructing various models of phonological processing. Yet in many languages including English, the majority of words are multi-syllabic words. English includes words incorporating a silent letter in their letter strings (e.g., champane). Such words provide an opportunity for investigating the role of phonological information in multi-syllabic words by comparing them to words that do not have the silent letter in the corresponding position (e.g., passener). The performance focus is on the effects of removing letters from words with a silent letter and from words with a non-silent letter. Three representative lexical tasks—naming, semantic categorization, lexical decision—were conducted in the present study. Stimuli that excluded a silent letter (e.g., champa_ne) were processed faster than those that excluded a sounding letter (e.g., passen_er) in the naming (Experiment 1), the semantic categorization (Experiment 2), and the lexical decision task (Experiment 3). The convergent evidence from these three experiments provides seminal proof of phonological recoding in multi-syllabic word recognition. An erratum to this article can be found at     

How Do You Say Nature?: Opening the Design Space with a Knowledge Environment

In this paper, we describe a design study on how families in Los Angeles experience nature, with a particular focus on how using alternative formats for research analysis and presentation can enrich a design research inquiry. Conducted in Pasadena, CA as a part of Super Studio, the year-long design research class emphasized knowledge building and sharing through design methods of analysis, exhibition, and concept prototypes. After conducting interviews and engaging participants with probes, the class built the results into an open-ended knowledge environment. The main observation from the exhibition – that Angelenos have a limited vocabulary for describing nature and their interaction with it – helped to define the opportunity for design intervention that created connection points between Angelenos and nature. There are few attempts to describe how probe returns evolve into design concepts. Showcased is a process that depends on the unique affordances of design as the vehicle for discovery and invention.     

How social connectedness affects guilt and shame: Mediation by hope and differentiation of self

We tested a mediation model of social connectedness and guilt and shame. Social connectedness was hypothesized to be related to greater hope and differentiation of self. Hope and differentiation of self, in turn, were expected to be related to less shame and more prosocial guilt. The results found that hope mediated the relationship between social connectedness and guilt, and differentiation of self mediated the relationship between social connectedness and shame. Alternative explanatory models were explored and taken into consideration in the interpretation of the results.     

Perceived health contributes to the attractiveness of facial symmetry, averageness, and sexual dimorphism

Symmetry, averageness, and sexual dimorphism (femininity in female faces, masculinity in male faces) are attractive in faces. Many have suggested that preferences for these traits may be adaptations for identifying healthy mates. If they are, then the traits should be honest indicators of health and their attractiveness should result from their healthy appearance. Much research has focused on whether these traits honestly signal health. Here we focused on whether the appeal of these traits results from their healthy appearance. Specifically, we tested whether the attractiveness of symmetry, averageness, and sexual dimorphism is reduced or eliminated when perceived health is controlled, in two large samples of Western faces and a large sample of Japanese faces. The appeal of symmetric faces was largely due to their healthy appearance, with most associations between symmetry and attractiveness eliminated when perceived health was controlled. A healthy appearance also contributed to the appeal of averageness and femininity in female faces and masculinity in male faces, although it did not fully explain their appeal. These results show that perceptions of attractiveness are sensitive to a healthy appearance, and are consistent with the hypothesis that preferences may be adaptations for mate choice.