I Behave Well (and my Teacher too): Memory and Suggestion in Preschoolers

Este estudio examinó cómo la valencia (acciones positivas o negativas) y el agente de la acción (profesora o niño) afectaban a la memoria y a la aceptación de la sugestión de los preescolares. En una primera sesión, preescolares de entre 3 y 6 años interactuaban con una profesora en diversas actividades. Una semana después, una entrevistadora formulaba preguntas de sí/no acerca de acciones verdaderas y sugeridas respecto de la interacción de la semana anterior. Los resultados revelaron el efecto del factor edad en el rendimiento de memoria y en la sugestión, que fueron evaluados a través de las respuestas dadas a la tarea de reconocimiento de sí/no. Se encontró un mayor reconocimiento correcto de las acciones de la profesora que de las acciones de los niños y, al mismo tiempo, se aceptaron menos las sugestiones sobre las acciones de la profesora en comparación con las propias del niño. Los preescolares fueron más resistentes a las sugestiones sobre acciones negativas que sobre acciones positivas. Más allá del efecto típico de la edad en el reconocimiento correcto y la aceptación de la sugestión de los preescolares, el contenido de las preguntas influyó de forma diferente en estas dos medidas: el reconocimiento correcto se vio afectado exclusivamente por el agente de la acción; mientras que la sugestión se vio afectada por la valencia y el agente de la acción.    This study examined how valence (positive and negative actions) and the action's agent (teacher or child) influenced memory and the acceptance of suggestion in preschoolers. In a first session, preschoolers aged between 3 and 6 years old interacted with a teacher and performed different tasks. A week later, an interviewer asked yes or no questions to the children with regard to the activities carried out in the previous session. Results revealed the effect of age on memory performance and suggestion, which were evaluated by yes/no answers given to the task of recognition. In addition, there was a higher correct recognition for the teacher's actions than for the children ones. However, suggestions about teacher's actions were less accepted than children ones. Also, positive suggestions were more accepted than negative ones. In conclusion, setting aside the typical effect of age on correct recognition and acceptance of suggestion, the questions' content influenced both measures differently: Correct recognition was exclusively influenced by the action's agent, whereas suggestion was affected by valence and the action´s agent.     &nbsp

Effects of divided attention and cued recall test on true and illusory memories in the DRM paradigm

In this study, we were interested in examining how the reduction of attentional resources during the encoding of word lists and the type of recall test affected true and false memories in the Deese-Roediger-McDermott paradigm (DRM paradigm). Three DRM lists were presented visually under full attention conditions or while participants had to monitor a concurrent auditory task of letters and digits. After the presentation of each list, participants completed a free recall test or a cued recall test. Divided attention had an opposite effect on correct recall of studied words and false recall of critical words. Thus, the concurrent task caused a reduction in correct recall, but increased false recall. The retrieval cue did not affect the correct recall of studied words, but it was helpful in reducing the false recall of critical words and other intrusions. The results are discussed taking into account the theoretical proposals of the activation monitoring account and fuzzy trace theoryThis work was supported by the transfer knowledge Project 088501 – FUAM (Foundation of the Universidad Autónoma de Madrid) co-directed by the first and second author

How does prior knowledge affect children's memory and suggestibility?

In this review chapter, we analyzed various studies focused on the effect of prior knowledge on children’s memory and suggestibility. Specifically, three types of knowledge are considered: social knowledge, script knowledge and semantic knowledge. Social knowledge benefits memory when the actions performed by another person fit into children’s knowledge, but it is also probably that children accept false suggestions consistent with that knowledge. Script knowledge is only beneficial for memory when the repeated event occurs always in the same way, but when some details change across repetitions, children could become confused and not be able to distinguish the particular detail in each repetition of the event. Semantic knowledge benefits episodic memory and makes more probably to reject false suggestions, unless the suggestion were repeated many times, in this case the beneficial effect of semantic knowledge disappears. Findings from studies are extrapolated to the forensic field, and limitations of the studies analyzed are discusse

Effects of divided attention and word concreteness on correct recall and false memory reports

Lists of thematically related words were presented to participants with or without a concurrent task. In Experiments 1 and 2, respectively, English or Spanish word lists were either low or high in concreteness (concrete vs abstract words) and were presented, respectively, auditorily or visually for study. The addition of a concurrent visual or auditory task, respectively, substantially reduced correct recall and doubled the frequency of false memory reports (nonstudied critical or theme words). Divided attention was interpreted as having reduced the opportunity for participants to monitor successfully their elicitations of critical associates. Comparisons of concrete and abstract lists revealed significantly more recalls of false memories for abstract than concrete word lists. Comparisons between two levels of attention, two levels of word concreteness, and two presentation modalities failed to support the ‘‘more is less’’ effect by which enhanced correct recall is accompanied by increased frequencies of false memoriesThis research was supported in parts by research grants to the second author from the National Sciences and Engineering Research Council of Canada while at the University of Lethbridge and to the third author from DGICYT (Project PB-96-0079

How chronological age, theory of mind, and yield are interrelated to memory and suggestion in young children

We investigated the interrelations between chronological age, theory of mind (ToM), Yield (as a measure of individual suggestibility), memory and acceptance of experimental suggestion in a sample of children between 3 and 7 years old (N = 106). One week after participants interacted with ‘a Teacher’, they were asked to recall activities carried out with the Teacher (direct experience) and the contents of a story read to them by the Teacher (indirect experience). Data were examined with an analysis of developmental trajectories, which allows establishing the predictor value of socio-cognitive developmental factors regardless of participants’ chronological age. It also estimates predictor values in interaction with the age and determines whether age is the best predictor for performance. As in previous research, results showed that chronological age was the main predictor of memory performance, both for direct experience (i.e., activities performed) and indirect experience (i.e., contents of the story). However, ToM and Yield, together with participants’ ages, modulated their acceptance of the external suggestions received (presented only once, one week after the event). A turning point was observed at age 4.6. Below this age, the greater the mentalist skills (higher ToM), the lower was the vulnerability to external suggestion. Still, children below this age characterized individually as being suggestible (Yield medium or high) were more vulnerable to suggestion the younger they were. Thus, developmental socio-cognitive factors might modulate young children’s vulnerability to external suggestions, even if received only onceThis work was supported by the Transfer Knowledge Project 088501–FUAM (Foundation of the Universidad Autónoma de Madrid) co-directed by the first and third authors, and the National Research SEJ2004–07655 financed by Dirección General de Investigación Científica y Técnica (DGICYT

The effect of the instructions on face recognition: accuracy and eye movements

The present experiment examines how instructions (absolute judgement vs. relative judgement) affect the performance in simultaneous lineups (present perpetrator and absent perpetrator). To find out whether the participants really followed the instructions, their eye movements were recorded when they faced the photo lineup. Sixty participants (44 women and 16 men) took part in the experiment. Overall, the results showed that participants with absolute judgement instructions made significantly less inter-photograph comparisons than those with relative judgement instructions. In the present perpetrator lineup, hit rate was lower for participants with absolute judgement instructions than with relative judgement instructions. In the absent perpetrator lineup, no differences were between both instruction conditions. Furthermore, as was expected, no relationship was found between “pre” and “post” confidence and accuracy in the lineups. Moreover, we examined participants’ metamemory evaluations about their examination pattern of the photographs in the lineup. Our results did not show high incongruity between the own participants’ judgment and their visual behavio

PEGylated AgNP covered with cationic carbosilane dendrons to enhance antibacterial and inhibition of biofilm properties

This work focuses on preparation of silver nanoparticles (AgNP) covered with cationic carbosilane dendrons and poly(ethylene glycol) (PEG). It is well known that AgNP and cationic carbosilane dendritic systems present antibacterial properties. On the other hand, PEG ligand provides antifouling properties and improved biocompatibility. Hence, combination of both ligands, carbosilane dendrons and PEG, on the AgNP surface can be a way to improve antibacterial capacity of AgNP. The new family of heterofunctionalized AgNP has been directly synthesized using silver precursor and cationic carbosilane dendrons and PEG ligands containing a thiol moiety. AgNP were characterized by TEM, TGA, UV, H-1 NMR, DLS, Z potential, XRD. The antibacterial capacity of these systems was evaluated against E. coli and S. aureus. The results confirmed the influence of both silver core and cationic carbosilane dendrons on the activity of these systems. The behaviour obtained for PEGylated systems were slightly lower than for non-PEGylated AgNP. However, hemolysis assays demonstrated that this decrease was compensated for by the greater biocompatibility. To more completely characterize the improvements of PEGylation on dendronized AgNP, one non-PEGylated and one PEGylated AgNP were tested for resistance in a planktonic state. Both AgNPs barely affected the minimum inhibitory concentration (MIC) whereas reference antibiotics generated significant resistance. In addition, relevant improvement in biofilm inhibition was achieved by dendronized AgNP after PEGylation.Universidad de AlcaláMinisterio de Economía, Industria y CompetitividadJunta de Comunidades de Castilla-La ManchaComunidad de Madri

Functionalization of silica with amine and ammonium alkyl chains, dendrons and dendrimers: Synthesis and antibacterial properties

Materials modified with ammonium groups on the surface have shown antibacterial activity. In this paper, alkyl chains, carbosilane (CBS) dendrimers and dendrons and poly(amidoamine) (PAMAM) dendrimers containing amine and ammonium groups have been grafted to silica surface and the influence of molecule structure on the stability and on antibacterial activity have been evaluated. These materials have been characterized by thermogravimetric analysis (TGA), zeta (Z) potential, scanning electron microscopy (SEM), infrared spectroscopy (IR) and nuclear magnetic resonance (C-13 CP MAS NMR). The degree of silica functionalization depends on type of outer groups, amine or ammonium, type and core of dendrimer, and length of chains. The Z potential measurements of these materials in water suspensions were used to test their stability in this medium. These measurements showed, for some of the modified silicas, the diminishing of Z potential from positive values toward zero, probably due to interaction of the functional groups with the silica surface. This variation was also dependent on ligand structure and peripheral functions. Finally, studies of inhibition of bacteria growth stand out again the relevance of ligand structure and number of functional groups on silica surface. The most active systems were those with more surface covered, those with cationic groups further away from silica surface and higher dendritic generation.Universidad de AlcaláMinisterio de Economía, Industria y CompetitividadComunidad de Madri

In Vitro Activity of Carbosilane Cationic Dendritic Molecules on Prevention and Treatment of Candida albicans Biofilms

Candida spp. are one of the most common fungal pathogens. Biofilms formed by Candida albicans offer resistance mechanisms against most antifungal agents. Therefore, development of new molecules effective against these microorganisms, alone or in combination with antifungal drugs, is extremely necessary. In the present work, we carried out a screening process of different cationic carbosilane dendritic molecules against C. albicans. In vitro activity against biofilm formation and biofilms was tested in both Coleccion Espanola de Cultivos Tipo (CECT) 1002 and clinical C. albicans strains. Cytotoxicity was studied in human cell lines, and biofilm alterations were observed by scanning electron microscopy (SEM). Antifungal activity of the carbosilane dendritic molecules was assessed by monitoring cell viability using both established and novel cell viability assays. One out of 14 dendritic molecules tested, named BDSQ024, showed the highest activity with a minimum biofilm inhibitory concentration (MBIC) for biofilm formation and a minimum biofilm damaging concentration (MBDC) for existing biofilm of 16-32 and 16 mg/L, respectively. Synergy with amphotericin (AmB) and caspofungin (CSF) at non-cytotoxic concentrations was found. Therefore, dendritic compounds are exciting new antifungals effective at preventing Candida biofilm formation and represent a potential novel therapeutic agent for treatment of C. albicans infection in combination with existing clinical antifungals.Ministerio de Economía, Industria y CompetitividadComunidad de MadridUniversidad de Alcal

Antibacterial and antifungal properties of dendronized silver and gold nanoparticles with cationic carbosilane dendrons

Water soluble silver nanoparticles (AgNPs) capped with cationic carbosilane dendrons have been synthesized by direct reaction in water of dendrons, silver precursor and a reducing agent. These nanoparticles have been characterized by nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), ultraviolet spectroscopy (UV), elemental analysis, and zeta potential (ZP). The antibacterial and antifungal properties of the cationic dendrons and dendronized AgNPs and AuNPs with these dendrons have been evaluated against Gram-negative and Gram-positive bacterial -including resistant strains- and yeast strains, respectively. The results stand out for the activity of AgNPs covered with first generation dendron compared with this free dendron and corresponding dendronized AuNPs.Ministerio de Economía y Empres