Sign and goal tracking during delay and trace autoshaping in pigeons

In two experiments, pigeons were exposed to an autoshaping procedure in which a keylight was followed by food under delay or trace conditions, while measures were taken of keypecking and time spent near the key. In Experiment 1, the birds in the trace group spent less time near the key than did the delay birds. Moreover, the trace birds exhibited a pattern of withdrawal from the key during the trial. In Experiment 2, visual observations of the birds’ location and latencies to eat both indicated that the trace birds’ withdrawal from the conditioned stimulus was accompanied by goal tracking. The difference in performance between the delay and trace conditions was taken as evidence that a trace stimulus may exert control over behavior as an occasion setter.     

Effects of intratrial stimulus change on fixed-interval performance: The roles of clock and memory processes

In two experiments, pigeons were exposed to differentially cued training trials of fixed interval (FI) 30 and 60 sec. In addition, shift trials were presented in which the cue associated with one FI value was presented for a prearranged duration at trial onset, followed by offset of that cue and presentation of the other cue. Response-contingent reinforcement was scheduled during the second cue. During the first shift phase, the FI 30-sec cue was shifted to the FI 60-sec cue; in a second phase, the order of the cue shift was reversed. Inferences about accumulator and memory functions of the internal clock were based upon behavior during both training trials and shift trials. At the end of both shift phases, test-trial FI functions generally superimposed in a manner consistent with accumulator reset on cue shift. Individual differences in clustering of functions were accommodated by variation in reference-memory storage across subjects. This interpretation was tested in Experiment 2 by constraining reference-memory storage on shift trials. These conditions yielded a decrease in between-subject variability and provided data consistent with accumulator reset and control by a single reference-memory value on shift trials.     

Exploring students’ engineering designs through open-ended assignments

ABSTRACT

This paper aims at presenting the experience of the Power Conversion project in teaching students to design a proof-of-principle contactless energy transfer system for the charging of electrical vehicles. The Power Conversion is a second-year electrical engineering (EE) project in which students are to gather and apply EE knowledge to design and test a system. This system is to work with power level and operates independent from an electricity grid. The instructional method used in this project is design-based learning (DBL). As an educational approach, DBL is to support students to gather and apply knowledge in open-ended assignments. The set-up of the project has gone through different modifications and iterations in three consecutive years regarding the organisation and supervision of the students. We have analysed the students’ design products in the past three academic years in order to evaluate whether the project set-up and supervision have influenced students’ designs. Results indicate that the open-ended character of the project has a positive influence on the designs especially regarding the criteria on efficiency, Maximum Power Point Tracking algorithm and power tracking.     

Effects of trial duration on overall and momentary rates of maintained autoshaped keypecking: Choice and single-stimulus trials

Pigeons were exposed to differentially cued autoshaping trials in which conditioned stimuli were followed by food after 6 or 14 sec. Average and momentary rates of keypecking were examined on two types of unreinforced test trials: single-stimulus probe trials and simultaneous choice trials, each 40 sec in duration. Rates averaged over the 40-sec test trials did not favor the cue associated with the shorter delay to food (the short-delay cue) on either type of test trial; however, average rates prior to the scheduled time of food delivery were reliably higher for the short-delay cue on choice trials. Momentary rates of keypecking during choice trials varied as a function of both cue and elapsed time from trial onset. At short elapsed trial times, rate of pecking was higher for the short-delay cue, with this difference reversing at longer times. A reversal of the programmed relation between key color and delay to food presentation for 5 birds confirmed the generality of these findings. Implications of these data for models of Pavlovian conditioning and for methods of assessing conditioned response strength are discussed.     

Temperament Predicts Processing Speed in Low Socioeconomic Status Rural Preschoolers

Extreme poverty all over the world is concentrated in rural settings. However, studies about cognition in low socioeconomic status (SES) children are for the most part conducted in urban populations. This paper investigates, in a poor rural sample, what are the individual and socioenvironmental variables that make the difference in performance in a processing speed task. Forty four 5‐year‐old children were evaluated with a processing speed task; individual and socioenvironmental information was obtained from parents' interviews. Higher scores in the effortful control dimension of temperament were associated with higher performance in the processing speed task. No other individual or socioenvironmental variable predicted the performance. These results showed that effortful control is important in processing speed and suggest that in low SES rural contexts, low effortful control children would require stronger interventions.     

Spelling difficulties in Spanish-speaking children with dyslexia / Dificultades de escritura en niños españoles con dislexia

In addition to reading difficulties, a significant proportion of developmental dyslexics have spelling problems, which persist into adulthood. Studies carried out in languages with opaque orthographies have found that dyslexics frequently make phonological substitutions when spelling and have difficulties in developing orthographic representations of irregular words. Those errors seem to derive from an excessive use of phonological codes when writing. Minimal research in Spanish (relatively transparent orthography) about the relationship between dyslexia and spelling difficulties has been carried out to date. In this study, 19 Spanish-speaking developmental dyslexics (from 7 to 11 years old) and 28 controls (from 6 to 11 years old, distributed in two groups, one matched for age and the other for reading level with the dyslexics) performed a dictation task of 80 stimuli with different levels of orthographic consistency, in order to discover the codes they use in the writing process. Results showed that Spanish children with dyslexia made significantly more spelling errors, especially among the ruled and irregular words. These findings are consistent with the idea that these children have difficulties in developing orthographic representations and use phonological codes more frequently than non-dyslexics, resulting in phonologically plausible errors when writing irregular words. These results have important implications for the treatment of spelling difficulties in children with dyslexia, highlighting the need to focus on the correct acquisition of grapheme-phoneme conversion rules as well as the development of appropriate orthographic representations.     

On the acquisition of some basic word spelling mechanisms in a deep (French) and a shallow (Spanish) system

An experiment was carried out to compare the time course of the acquisition of two basic spelling mechanisms in Spanish, a shallow system, and French, a deep system. The first was lexical. It relies on the orthographic lexicon, a hypothetical structure containing the orthographic representations of words accessible for word spelling. To evaluate its contribution the participants were asked to spell words of high and low frequency containing phonemes which can take different graphemic values. The second mechanism relies on sub-lexical processes. Its contribution was evaluated asking the participants to spell words containing consistent phoneme-to-grapheme translation pairs which were identical in Spanish and French. Two contrasting predictions were considered, one derived from the Orthographic Depth Hypothesis (ODH, Frost, 2005) and the other from the Self-Teaching Hypothesis (STH, Share, 2004). According to the ODH, the orthographic lexicon should develop more rapidly in French than in Spanish because Spanish spellers can rely on phoneme-to-grapheme translation mechanisms to spell most words, meaning that they do not need to resort to the orthographic lexicon. In contrast, the STH suggests that effective identification of a word gradually generates its orthographic representation. The results revealed that both spelling mechanisms develop far faster in Spanish than in French. The fact that word frequency effects appeared earlier in Spanish than in French, indicating that the orthographic lexicon incorporates words more rapidly in a shallow than in a deep system, is clearly incompatible with the ODH and easier to handle in the context of the STH.     

The path to mobile shopping compatibility

The mobile technology involves an unexplored world of doing business and consumer behavioral change that constitutes a revolution in the application of technologies to marketing. A key factor in the adoption of mobile commerce is the compatibility that the consumer perceives with his/her life. Given that the research on compatibility with mobile purchases made so far treats it as an antecedent of adoption, this pioneer research studies the influencing role of two more personal factors (self-efficacy and innovativeness) and two factors more related to the shopping (involvement and perceived entertainment). The model was tested using PLS with information from 583 Mexican mobile buyers. Our results show a positive effect of innovativeness, involvement and perceived entertainment on compatibility. On the contrary, self-efficacy does not seem to influence the perception of compatibility of mobile shopping with consumer life. This work has important implications for the practice of professionals dedicated to mobile commerce.