Retrospective revaluation of associative retroactive cue interference

Two fear-conditioning experiments with rats assessed whether retrospective revaluation, which has been observed in cue competition (i.e., when compounded cues are followed with an outcome), can also be observed in retroactive cue interference (i.e., when different cues are reinforced in separate phases with the same outcome). Experiment 1 found that after inducing retroactive cue interference (i.e., X-outcome followed by A-outcome), nonreinforced presentations of the interfering cue (A) decreases interference with responding to the target cue (X), just as has been observed in retrospective revaluation experiments in cue competition. Using the opposite manipulation (i.e., adding reinforced presentations of A), Experiment 2 demonstrated that after inducing retroactive cue interference, additional reinforced presentations of the interfering cue (A) increases interference with responding to the target cue (X); alternatively stated, the amount of interference increases with the amount of training with the interfering cue. Thus, both types of retrospective revaluation occur in retroactive cue competition. The results are discussed in terms of the possibility that similar associative mechanisms underlie cue competition and cue interference.     

Lightweight natural language text compression

Variants of Huffman codes where words are taken as the source symbols are currently the most attractive choices to compress natural language text databases. In particular, Tagged Huffman Code by Moura et al. offers fast direct searching on the compressed text and random access capabilities, in exchange for producing around 11% larger compressed files. This work describes End-Tagged Dense Code and (s, c)-Dense Code, two new semistatic statistical methods for compressing natural language texts. These techniques permit simpler and faster encoding and obtain better compression ratios than Tagged Huffman Code, while maintaining its fast direct search and random access capabilities. We show that Dense Codes improve Tagged Huffman Code compression ratio by about 10%, reaching only 0.6% overhead over the optimal Huffman compression ratio. Being simpler, Dense Codes are generated 45% to 60% faster than Huffman codes. This makes Dense Codes a very attractive alternative to Huffman code variants for various reasons: they are simpler to program, faster to build, of almost optimal size, and as fast and easy to search as the best Huffman variants, which are not so close to the optimal size.

Evaluating the impact of R&D tax credits on innovation: A microeconometric study on Canadian firms

This study examines the effect of R&D tax credits on innovation activities of Canadian manufacturing firms. Over the 1997-1999 period the Federal and Provincial R&D tax credit programs were used by more than one third of all manufacturing firms and by close to two thirds of firms in high-technology sectors. We investigate the average effect of R&D tax credits on a series of innovation indicators such as: number of new products, sales with new products, originality of innovation, etc. using a non-parametric matching approach. Compared to a hypothetical situation in the absence of R&D tax credits, recipients of tax credits show significantly better scores on most but not all performance indicators. We therefore conclude that tax credits lead to additional innovation output.     

What makes companies pursue an Open Science strategy?

Whereas recent scholarly research has provided many insights about universities engaging in commercial activities, there is still little empirical evidence regarding the opposite phenomenon of companies disseminating scientific knowledge. Our paper aims to fill this gap and explores the motivations of firms that disclose research outcomes in a scientific format. Besides considering a dimension internal to the firm, we focus particularly on knowledge sourcing from academic institutions and the appropriability regime. We conduct an econometric analysis with firm-level data from the fourth edition of the French innovation survey (CIS) and matched scientific publications for a sample of 2512 R&D performing firms from all manufacturing sectors. This analysis provides evidence that firms are more likely to adopt academic principles if they need to access scientific knowledge that is considered important for their innovation development, whereas the mere existence of collaborative links with academic institutions is not a strong determinant. Furthermore, the results suggest that the inclination of firms to publish is sensitive to the level of knowledge spillovers in a sector and the effectiveness of legal appropriation instruments.     

Psycho-neural Identity as the Basis for Empirical Research and Theorization in Psychology: An Interview with Mario A. Bunge

Mario Bunge is one of the most prolific philosophers of our time. Over the past sixty years he has written extensively about semantics, ontology, epistemology, philosophy of science and ethics. Bunge has been interested in the philosophical and methodological implications of modern psychology and more specifically in the philosophies of the relation between the neural and psychological realms. According to Bunge, functionalism, the philosophical stand of current psychology, has limited explanatory power in that neural processes are not explicitly acknowledged as components or factors of psychological phenomena. In Matter and Mind (2010), Bunge has elaborated in great detail the philosophies of the mind-brain dilemma and the basis of the psychoneural identity hypothesis, which suggests that all psychological processes can be analysed in terms of neural and physical phenomena. This article is the result of a long interview with Dr. Bunge on psychoneural identity and brain-behaviour relations.     

Online undergraduate students’ perceptions of the impact of Web 2.0 on higher education / Percepciones de estudiantes de licenciatura en línea sobre el impacto de la Web 2.0 en educación superior

Abstract

Although Web 2.0 has changed students’ roles, placing them at the centre of the teaching-learning process, attitudes towards Web 2.0 have been observed to have a relation with its use in a formal academic context. An instrument was applied to higher education students in Mexico to explore their perceptions by collecting information on students’ attitudes, training and use of Web 2.0, and its impact on higher education. The findings showed that training in Web 2.0 determines use of it, as well as the attitudes towards it and the possible impact these can have on teaching-learning processes. No differences were found regarding participants’ gender in relation to their perceptions of the use of Web 2.0 as a learning environment.     

Extinction with multiple excitors

Four conditioned suppression experiments with rats, using an ABC renewal design, investigated the effects of compounding the target conditioned excitor with additional, nontarget conditioned excitors during extinction. Experiment 1 showed stronger extinction, as evidenced by less renewal, when the target excitor was extinguished in compound with a second excitor, relative to when it was extinguished with associatively neutral stimuli. Critically, this deepened extinction effect was attenuated (i.e., more renewal occurred) when a third excitor was added during extinction training. This novel demonstration contradicts the predictions of associative learning models based on total error reduction, but it is explicable in terms of a counteraction effect within the framework of the extended comparator hypothesis. The attenuated deepened extinction effect was replicated in Experiments 2a and 3, which also showed that pretraining consisting of weakening the association between the two additional excitors (Experiments 2a and 2b) or weakening the association between one of the additional excitors and the unconditioned stimulus (Experiment 3) attenuated the counteraction effect, thereby resulting in a decrease in responding to the target excitor. These results suggest that more than simple total error reduction determines responding after extinction.     

Segmentación fonológico-silábica y adquisición de la lectura: un estudio empírico

El artículo presenta una investigación cuyos resultados muestran la menor capacidad de segmentación silábica entre aquellos niños con peor habilidad lectora. Plantea también la funcionalidad, facilidad de aplicación y carácter motivador de la prueba realizada—una tarea de ordenador—para evaluar la capacidad de segmentación.