The Bootstrap Discovery Behaviour (BDB): a new outlook on usability evaluation

The value of λ is one of the main issues debated in international usability studies. The debate is centred on the deficiencies of the mathematical return on investment model (ROI model) of Nielsen and Landauer (1993). The ROI model is discussed in order to identify the base of another model that, respecting Nielsen and Landauer’s one, tries to consider a large number of variables for the estimation of the number of evaluators needed for an interface. Using the bootstrap model (Efron 1979), we can take into account: (a) the interface properties, as the properties at zero condition of evaluation and (b) the probability that the population discovery behaviour is represented by all the possible discovery behaviours of a sample. Our alternative model, named Bootstrap Discovery Behaviour (BDB), provides an alternative estimation of the number of experts and users needed for a usability evaluation. Two experimental groups of users and experts are involved in the evaluation of a website (). Applying the BDB model to the problems identified by the two groups, we found that 13 experts and 20 users are needed to identify 80% of usability problems, instead of 6 experts and 7 users required according to the estimation of the discovery likelihood provided by the ROI model. The consequence of the difference between the results of those models is that in following the BDB the costs of usability evaluation increase, although this is justified considering that the results obtained have the best probability of representing the entire population of experts and users.     

Dynamic shifts in corticostriatal expression patterns of the immediate early genes Homer 1a and Zif268 during early and late phases of instrumental training

Adaptive motor actions require prior knowledge of instrumental contingencies. With practice, these actions can become highly automatic in nature. However, the molecular and anatomical substrates mediating these related forms of learning are not understood. In the present study, we used in situ hybridization to measure the mRNA levels of two immediate early genes (IEGs) in an instrumental paradigm where rats learned to lever-press for food. We report that after three training sessions, Homer 1a and Zif268 (an effector and regulatory IEG, respectively) were significantly induced within an extensive corticostriatal network relative to untrained controls. With extended training (23 sessions), however, a shift in the expression patterns of the two genes was evident. Expression of Homer 1a (official symbol Homer1) decreased significantly in frontal and cingulate cortices, whereas striatal expression was generally maintained. Interestingly, Homer 1a expression markedly increased with extensive training in the ventrolateral region of the striatum (VLS) relative to early learners, suggesting that plasticity in the VLS is required for the efficient production of the learned behavior or in habit formation. Zif268 (official symbol Egr1) expression generally decreased with extensive training; however, these changes were not significant. These results demonstrate for the first time, on a molecular level, a dynamic shift in the contribution of corticostriatal systems mediating the early acquisition and consolidation of goal-directed responses to those engaged after extensive training.     

Crossing the pillars of Hercules: the role of spatial frames of reference in error making

This paper introduces a perspective accounting for errors that may occur as a result of the human interaction with the three-dimensional (3D) space. Particularly, we are interested in errors that are caused by cognitively crossing the boundary between peripersonal and extrapersonal space. Several behavioural, neurophysiological, and neuropsychological perspectives are reviewed in order to develop the theoretical framework on which our ideas are founded. We argue that cognitively crossing the boundary implies switching from one frame of reference to another, which, as a consequence, implies specific costs. The results of five experiments (overall involving 76 participants) support our hypothesis, suggesting the existence of different action-oriented spatial frames of reference.     

AMPA/kainate, NMDA, and dopamine D1 receptor function in the nucleus accumbens core: a context-limited role in the encoding and consolidation of instrumental memory

Neural integration of glutamate- and dopamine-coded signals within the nucleus accumbens (NAc) is a fundamental process governing cellular plasticity underlying reward-related learning. Intra-NAc core blockade of NMDA or D1 receptors in rats impairs instrumental learning (lever-pressing for sugar pellets), but it is not known during which phase of learning (acquisition or consolidation) these receptors are recruited, nor is it known what role AMPA/kainate receptors have in these processes. Here we show that pre-trial intra-NAc core administration of the NMDA, AMPA/KA, and D1 receptor antagonists AP-5 (1 microg/0.5 microL), LY293558 (0.01 or 0.1 microg/0.5 microL), and SCH23390 (1 microg/0.5 microL), respectively, impaired acquisition of a lever-pressing response, whereas post-trial administration left memory consolidation unaffected. An analysis of the microstructure of behavior while rats were under the influence of these drugs revealed that glutamatergic and dopaminergic signals contribute differentially to critical aspects of the initial, randomly emitted behaviors that enable reinforcement learning. Thus, glutamate and dopamine receptors are activated in a time-limited fashion-only being required while the animals are actively engaged in the learning context.     

The Structure of Predication

The paper discusses the structure of non-verbal predication, with particular reference to the role of the copula. Differently from the main tenets of contemporary logico-philosophical and linguistic theories, a model of predication is proposed where the verbal component (specifically, tense information) is regarded as central in establishing the syntactic and semantic relation between a predicate and its subject. It is thus possible to recover some of the insights of the pre-Fregean analysis of predication. The proposed solution has a number of significant consequences for the structure to be assigned to non-verbal predication, in particular for the semantics of small clause constituents, where the predication is established without the copula.     

Coping strategies and cognitive functioning in elderly people from a rural community in Italy

Stressful situations may contribute to pathological states in elderly people facing harmful events. This study investigated the relationships between adopting appropriate coping strategies, transforming circumstances to personal preferences or adjusting personal preferences to situational constraints, and the efficiency of cognitive functioning in an elderly sample of 121 residents drawn from a rural community in southern Italy. They were administered the Mini-Mental State Examination, the Tenacious Goal Pursuit, Flexible Goal Adjustment, and Coping Inventory for Stressful Situations. Intercorrelations of scores suggested that facing stressful situations is somewhat associated with efficient cognitive functioning and coping strategies that ensure a wide range of solutions.     

Lexical representations of written nouns and verbs in Italian

This study investigates the differences in the input representations of verbs and nouns in the Italian mental lexicon. One visual lexical decision experiment in which the stem homograph effect (Laudanna, Badecker, and Caramazza, 1989) was evaluated on noun and verb targets is reported. Strong inhibitory effects on verb targets preceded by stem homographs relative to nonhomographic word pairs were found. The effects on verb targets were also much more reliable than the effects on noun targets. The pattern of results provides support for the hypothesis that noun and verbs are differently represented in the orthographic input lexicon.