Reinforcing saccadic amplitude variability

Saccadic endpoint variability is often viewed as the outcome of neural noise occurring during sensorimotor processing. However, part of this variability might result from operant learning. We tested this hypothesis by reinforcing dispersions of saccadic amplitude distributions, while maintaining constant their medians. In a first experiment we reinforced the least frequent saccadic amplitudes to increase variability, and then reinforced the central part of the amplitude distributions to reduce variability. The target was placed at a constant distance from the fovea after the saccade to maintain the postsaccadic visual signal constant and an auditory reinforcement was delivered depending on saccadic amplitude. The second experiment tested the effects of the contingency. We reinforced high levels of variability in 4 participants, whereas 4 other participants were assigned to a yoked control group. On average, saccadic amplitude standard deviations were doubled while the medians remained mostly unchanged in the experimental participants in both experiments, and variability returned to baseline level when low variability was reinforced. In the control group no consistent changes in amplitude distributions were observed. These results, showing that variability can be reinforced, challenge the idea of a stochastic neural noise. We instead propose that selection processes constrain saccadic amplitude distributions.     

The Quasi-lattice of Indiscernible Elements

The literature on quantum logic emphasizes that the algebraic structures involved with orthodox quantum mechanics are non distributive. In this paper we develop a particular algebraic structure, the quasi-lattice ( \mathfrakI{\mathfrak{I}}-lattice), which can be modeled by an algebraic structure built in quasi-set theory \mathfrakQ{\mathfrak{Q}} . This structure is non distributive and involve indiscernible elements. Thus we show that in taking into account indiscernibility as a primitive concept, the quasi-lattice that ‘naturally’ arises is non distributive.     

“Which Palestine Should We Teach?” Signatures,Palimpsests, and Struggles over School Textbooks

The present paper offers a reflection on school textbooks produced and introduced by the Palestinian Authority in the West Bank and Gaza Strip from the year 2000 onward. The aim is to examine the debates over these textbooks, by situating them over the backdrop of larger geopolitical dynamics and intra-Palestinian social and political struggles.     

Representational momentum in aviation

The purpose of this study was to examine the effects of expertise on motion anticipation. We conducted 2 experiments in which novices and expert pilots viewed simulated aircraft landing scenes. The scenes were interrupted by the display of a black screen and then started again after a forward or backward shift. The participant's task was to determine whether the moving scene had been shifted forward or backward. A forward misjudgment of the final position of the moving scene was interpreted as a representational momentum (RM) effect. Experiment 1 showed that an RM effect was detected only for experts. The lack of motion anticipation on the part of novices is a surprising result for the RM literature. It could be related to scene unfamiliarity, encoding time, or shift size. Experiment 2 was run with novices only. It was aimed at testing the potential impact of 2 factors on the RM effect: scene encoding time and shift size. As a whole, the results showed that encoding time and shift size are important factors in anticipation processes in realistic dynamic situations.     

Integration of visual information for saccade production

To foveate a visual target, subjects usually execute a primary hypometric saccade (S1) bringing the target in perifoveal vision, followed by a corrective saccade (S2) or by more than one S2. It is still debated to what extent these S2 are pre-programmed or dependent only on post-saccadic retinal error. To answer this question, we used a visually-triggered saccade task in which target position and target visibility were manipulated. In one-third of the trials, the target was slightly displaced at S1 onset (so-called double step paradigm) and was maintained until the end of S1, until the start of the first S2 or until the end of the trial. Experiments took place in two visual environments: in the dark and in a dimly lit room with a visible random square background. The results showed that S2 were less accurate for shortest target durations. The duration of post-saccadic visual integration thus appears as the main factor responsible for corrective saccade accuracy. We also found that the visual context modulates primary saccade accuracy, especially for the most hypometric subjects. These findings suggest that the saccadic system is sensitive to the visual properties of the environment and uses different strategies to maintain final gaze accuracy.     

If-Clauses and Probability Operators

Adams’ thesis is generally agreed to be linguistically compelling for simple conditionals with factual antecedent and consequent. We propose a derivation of Adams’ thesis from the Lewis-Kratzer analysis of if-clauses as domain restrictors, applied to probability operators. We argue that Lewis’s triviality result may be seen as a result of inexpressibility of the kind familiar in generalized quantifier theory. Some implications of the Lewis-Kratzer analysis are presented concerning the assignment of probabilities to compounds of conditionals.     

Cognitive abilities, sociocultural background and academic achievement

The influence of students' sociocultural background on academic achievement is a well established fact. Research also points out that sociocultural background is related to students' cognitive abilities and these have an effect on their academic achievement. However, the mediator role of cognitive abilities on the relationship between sociocultural background and academic achievement is less well known. A structural equation model that represents these relationships was tested in a sample (N= 728) of Portuguese junior high school students. Multigroup analysis of the model showed the importance of the cognitive ability mediation effect between sociocultural background and academic achievement in the 7th and 9th grades, but not in the 8th grade. This difference may be the result of the academic transition experienced in the 7th and 9th grades in the Portuguese educational system, which requires parents' higher involvement in school.     

Full naming with bi-dimensional abstract stimuli in six-year-old children

The aim of this study was to evaluate a procedure to reveal the emergence of full naming in typically developing children. In Experiment 1, five 6-year-old children (a) learned tacts of pictures and the emergence of the selection of these pictures upon hearing their names was tested; and (b) the selection of other pictures was taught and the emergence of the tacts was tested. All children showed the emergence of picture selection and 3 children showed the emergence of the tacts. In Experiment 2a, the children's correct repetition of the names of 3 pictures was verified first, then the experimenter presented the pictures with their names without requiring any behavior other than attending. Finally, the emergence of picture selection and the tacts was tested. Experiment 2b replicated Experiment 2a with words that were easier to pronounce. Picture selection and the tacts emerged; this performance documented full naming for the first time with typically developing children. These procedures can be used to induce naming capacity in children who lack it; hence, they can be applied to teach children with learning delays.     

Diagnostic value of the Dominic Interactive Assessment with children exposed to intimate partner violence

This article reports on the diagnostic validity of the Dominic Interactive Assessment (DIA) in a sample of Spanish children exposed to intimate partner violence (IPV). The study participants included 55 children aged between 6 and 11 years whose mothers visited an IPV counselling centre. Psychopathology and functional impairment were used as the main criteria for assessing predictive and discriminative accuracy, as well as incremental validity, of DIA. The results indicate that DIA permits obtaining useful information from children. This information improves the prediction and validity of the process of clinical assessment of children exposed to IPV. Children's self-reports could prove effective in identifying cases in this high-risk population when developmentally adequate instruments and functional criteria are used.