Adults' performance in an episodic-like memory task: The role of experience

Episodic memory is the ability to consciously recollect personal past events. This type of memory has been tested in non-human animals by using depletion paradigms that assess whether they can remember the "what," "where," and "when" (i.e., how long ago) of a past event. An important limitation of these behavioral paradigms is that they do not clearly identify the cognitive mechanisms (e.g., episodic memory, semantic memory) that underlie task success. Testing adult humans in a depletion paradigm will help to shed light on this issue. In two experiments, we presented university undergraduates with a depletion paradigm which involved choosing one of two food snacks-a preferred but perishable food and a less preferred but non-perishable food-either after a short or a long interval. Whereas, in Experiment 1, participants were asked to imagine the time between hiding the food items and choosing one of them; in Experiment 2 participants experienced the time elapsed between hiding the food items and choosing one of them. In addition, in Experiment 2 participants were presented with 2 trials which allowed us to investigate the role of previous experience in depletion paradigms. Results across both experiments showed that participants chose the preferred and perishable food (popsicle) after the short interval but did not choose the less preferred and non-perishable food (raisins) after the long interval. Crucially, in Experiment 2 experiencing the melted popsicle in Trial l improved participants' performance in Trial 2. We discuss our results in the context of how previous experience affects performance in depletion tasks. We also argue that variations in performance on "episodic-like memory" tasks may be due to different definitions and assessment criteria of the "when" componen

Did the Popsicle Melt? Preschoolers’ Performance in an Episodic-like Memory Task

Episodic memory has been tested in non-human animals using depletion paradigms that assess recollection for the “what,” “where” and “when” (i.e., how long ago). This paradigm has not been used with human children, yet doing so would provide another means to explore their episodic memory development. Using a depletion paradigm, preschool-aged children were presented in two trials with a preferred food that was only edible after a short interval and a less preferred food that was edible after the short and long intervals. Younger (mean= 40 months) and older (mean=65 months) children tended to choose their preferred food after the short intervals, but did not switch to selecting their less-preferred food after the long intervals. Importantly, their choices did not differ with age. Although older children better remembered “what”, “where” and “what is where” than did younger children, neither age group successfully estimated “how long ago” an event occurred. Finally, both age groups spontaneously recalled information about Trial 1. We also analyzed the relation between the different measures used in the study but no clear patterns emerged. Results are discussed with respect to the cognitive mechanisms necessary to succeed in depletion paradigms and the measurement of episodic memory more broadly

Predicting our own and others’ future preferences: The role of social distance

People underestimate how much their preferences will change in the future, a phenomenon sometimes referred to as a “presentism bias.” Recently, we found that this presentism bias is attenuated when thinking about the preferences of other people. The aim of this study was to investigate whether predicting future preferences also differs depending on the level of social distance between self and other. A total of 67 participants completed a perspective-taking task in which they were required to think about their own preferences, those of a generic peer, and those of a close other both now and in the future. They were also asked to consider the preferences of an older adult now. Participants predicted less change between their current and future preferences than between the current and future preferences of a generic peer. Predicted change in preferences for a close other were similar, but not identical, to those made for the self. When considering relevant future preferences, participants predicted less change for themselves than for their close others and less change for close others than for generic peers. In other words, as social distance increases, the presentism bias decreases. Interestingly, participants estimated that both they and their peers would not change so much that they become similar to current older adults. Simulating the future perspectives of a generic peer or, even better, the current perspectives of an older adult may thus result in improved long-term decision-making, as it may enable a more realistic estimation of the magnitude of likely changes in the future

Genetic variability in two spanish horse populations: preliminary results

The genetic variability has been analyzed through the allelic frequencies distribution of ten STR (Short Tandem Repeat) equine loci of three different horse populations, Asturcón, Pottoka and Thoroughbred (PSI), which is considered as an outgroup. The genetic variability found in the pony breeds is higher than for PSI and only one of the ten loci analyzed is significantly desviated from Hardy-Weinberg equilibrium (= 0.01) in Asturcón and Pottoka populations. The FST value (0.054) shows a significant divergence between Asturcón and Pottoka, besides the genetic distance calculated between both populations is very lower compared to their relation with PSI.Para el estudio de la variabilidad genética de tres poblaciones diferentes de caballos, Asturcón, Pottoka y Pura Sangre Inglés (PSI), habiéndose constituido esta última como población de referencia, se ha analizado la distribución de las frecuencias alélicas de 10 STR (Short Tandem Repeat) loci equinos. La variabilidad genética encontrada en las razas de ponis es superior a la del PSI y solo uno de los loci analizados se desvía significativamente del equilibrio Hardy- Weinberg (=0,01) en las poblaciones de Asturcón y Pottoka. El valor FST estimado (0,054) muestra una divergencia significativa entre Asturcón y Pottoka, asimismo la distancia genética calculada entre ambas poblaciones es inferior comparada a la que tienen ambas con respecto al PSI

What will you want tomorrow? Children-But not adults- mis-predict another person's future desires

Young children have difficulty predicting a future physiological state that conflicts with their current state. This finding is explained by the fact that children are biased by their current state (e.g., thirsty and desiring water) and thus have difficulty imagining themselves in a different state (e.g., not thirsty and desiring pretzels) “tomorrow,” for example. Another potential explanation that we explore here is that young children have difficulty understanding how physiological states, like thirst, fluctuate over time. We asked 3-, 4- and 5-year-olds (Experiment 1) and adults (Experiment 2) to predict what a thirsty Experimenter–who preferred crisps to water—would want (“water” or “crisps”) “right now” and “tomorrow.” Only adults correctly predicted someone else’s future desires when this person’s future and current desires conflicted. In contrast, both adults and children in the control groups (in which the Experimenter was not thirsty) had no difficulty predicting that the Experimenter would want crisps “right now” and “tomorrow.” Our findings suggest that children’s difficulty predicting future desires cannot solely be attributed to their being biased by their current state since the children in our study were, themselves, not thirsty. We discuss our results in the context of children’s difficulty understanding fluctuations in physiological states

Moving Beyond "Spoon" Tasks: The Emergence of Self-Directed Episodic Future Thinking

Much developmental (and comparative) research has used Tulving's Spoon test (i.e., whether an individual will select an item needed to solve a future problem) as the basis for designing tasks to measure episodic future thinking, defined as the capacity to mentally pre-experience the future. There is, however, intense debate about whether these tasks successfully do so. Most notably, it has been argued that children may pass (i.e., select an item with future utility) by drawing on non-episodic, associative processes, rather than on the capacity to represent the future, per se. Although subsequent developmental tasks have sought to address this limitation, we highlight what we argue is a more fundamental shortcoming of Spoon tasks: they prompt future-directed action making it impossible to determine whether children have used their episodic future thinking to guide their behavior. Accordingly, we know little about children's thought about the future that is independently generated (i.e., without prompting), or autocued, and is subsequently reflected (and measurable) by children's actions. We argue that this capacity is a critical, and heretofore overlooked, transition in future-oriented cognition that may not occur until middle childhood. We further hypothesize that it is reliant on children developing richer and more detailed future event representations, along with the necessary cognitive control to transform these representations into actions that serve to benefit their future selves. The time is ripe for researchers to explore this aspect of cognitive development and we suggest several novel approaches to do so

Four Fermion Field Theories and the Chern-Simons Field: A Renormalization Group Study

In (2+1) dimensions, we consider the model of a $N$ flavor, two-component fermionic field interacting through a Chern-Simons field besides a four fermion self-interaction which consists of a linear combination of the Gross-Neveu and Thirring like terms. The four fermion interaction is not perturbatively renormalizable and the model is taken as an effective field theory in the region of low momenta. Using Zimmerman procedure for reducing coupling constants, it is verified that, for small values of the Chern-Simons parameter, the origin is an infrared stable fixed point but changes to ultraviolet stable as $\alpha$ becomes bigger than a critical $\alpha_c$. Composite operators are also analyzed and it is shown that a specific four fermion interaction has an improved ultraviolet behavior as $N$ increases.Comment: 9 pages, revte

Bovine Tuberculosis in a Free Ranging Red Fox (Vulpes vulpes) from Doñana National Park (Spain)

During 1997 and 1998, a survey of Iberian carnivores was conducted to study the epidemiology of bovine tuberculosis in the Doñana National Park and surrounding areas in southwestern Spain. Post-mortem examinations were done on seven red foxes (Vulpes vulpes), two Egyptian mongoose (Herpestes ichneumon), one weasel (Mustela nivalis), two genets (Genetta genetta), one Iberian lynx (Lynx pardinus), one Eurasian badger (Meles meles), and two polecats (Mustela putorius). Lesions suggestive of bovine tuberculosis were not detected but, in culture, Mycobacterium bovis was isolated from the retropharyngeal lymph nodes of one adult male red fox. This is the first report of M. bovis infection in red fox in Spain.Peer reviewe