Javier Nieto

Universidad Nacional Autónoma de México | UNAM · School of Psychology

The forgetting curve is a phenomenon in which animals fail to retrieve information about an event as time passes. We tested this effect in spider monkeys (Ateles geoffroyi) in a task where they had to retrieve a reward hidden in a container after a delay. We combined different delays (0, 5, 10, 20, and 30 s) and different numbers of containers in w...

An experiment with rats was conducted in order to analyze the impact of the retrieval-extinction paradigm on the reinstatement of operant behaviors. In the first phase of the experiment, subjects were trained to press a lever for food. Then, in Phase 2, the Extinction Group received the typical extinction procedure, whereas the Retrieval Group was...

Recognition memory is an ability that allows animals to respond differentially to stimuli, individuals, or situations experienced in the past and plays an important role in foraging and social behavior. We tested the ability of black-handed spider monkeys (Ateles geoffroyi) to remember and recognize visual stimuli that belong to 6 categories. Seven...

Recently, several authors have reported evidence of helping behavior in rats. However, the mechanisms underlying such behavior are unclear. Two experiments with Wistar rats used the task developed by Sato et al. (2015) to assess whether social enhancement affects the helping response. Experiment 1 tested whether rats placed in a dry compartment adj...

The present free operant conditioning experiments with rats examined the impact of manipulating different traits of an extinction-cue on ABA renewal. All rats were trained to perform an operant response (R1) for food in context A, and a different operant response (R2) in context B. Responses were then extinguished, R1 in context B and R2 in context...

In one experiment with rats, we examined whether positive affective states can serve as contexts in a between-subjects ABA renewal design using appetitive instrumental conditioning. Two groups of rats received training to press a lever for food where each acquisition session was preceded by administration of a tickling procedure (Context A) known t...

One experiment explored the impacts of familiarity between female rats on the pro-social behavior. We trained pairs of Wistar rats in the Pro-social Choice Task. All pairs of rats had an actor and a partner rat that were placed within a double T-maze. Throughout the sessions, actors decided between two options only differing in the food delivered t...

The human gut microbiome is an important component that defines host health. Childhood is a particularly important period for the establishment and development of gut microbiota (GM). We sequenced the 16S rRNA gene from fecal samples of children between 5 and 10 years old, in two Mexican communities with contrasting lifestyles, i.e., "Westernized"...

Highlights  Undergraduate students were assessed on a videogame task.  Using three virtual contexts during extinction reduced ABA renewal of operant performance.  Conducting extinction in multiple contexts might enhances the generalization of the extinction learning to other contexts. Abstract In one experiment with human participants, we invest...

Temporal Weighting Rule (TWR) is a mathematical model used to predict foraging decisions based firstly on recency and secondly on the quality of a patch (amount of food). The objective of this study was to investigate whether those variables modulate the decisions of spider monkeys (Ateles geoffroyi) using a foraging task. Sixteen adult individuals...

Two experiments using a conditioned suppression procedure in rats assessed transfer of conditioned inhibition from a loud car horn to electric shock, after post conditioning manipulations designed to habituate or counterconditioning the aversive effects of horn. Both experiments showed that the inhibitory effects of a stimulus are not restricted to...

The data of three experiments on observational learning are reported. Experiment 1 assessed the effects of modeling different contingencies between pecking a peg and food reinforcement, on acquisition of the same response in observer pigeons. Results show that the group of pigeons exposed to demonstrations of the response-reinforcer contingency sho...

Resumen Para analizar el efecto de diferentes estrategias, simuladas por una computadora, en la adquisición de res-puestas cooperativas; se entrenó a siete palomas a jugar el dilema del prisionero reiterado en contra de un oponente, simulado por una computadora, que empleaba una de tres posibles estrategias: (1) seleccionar la misma estrategia que...

La importancia de los estímulos contextuales en los procesos de aprendizaje y memoria se estableció desde los trabajos pioneros de Pavlov (1927). Mas adelante las investigaciones sobre cognición humana confirmaron la relevancia de los estímulos contextuales tanto en la codificación como en la recuperación de ítems en los estudios de memoria humana...

The Human Gut Microbiome is an important host’s component defining its health. These microorganisms are mutualistic symbionts dependent on factors such as host’s age, subsistence models and sociocultural practices, among others. The conjunction of these factors define the microbial ecosystem dynamics. Using a fecal microbiome approach in children,...

We are not individuals, we are much better described as ecosystems due to trillions of bacteria and other microorganisms that inhabit us. We now know that gut microbiota can greatly influence many physiological parameters that in turn may impact several cognitive functions, such as learning, memory, and decision making processes. This mutualistic s...

This R Markdown document contains the code and analyses for "Self-reported Health is Related to Body Height and Waist Circumference in Rural Indigenous and Urbanised Latin-American Populations" (2020). Data available at https://doi.org/10.17605/OSF.IO/KGR5X.

Body height is a life-history component. It involves important costs for its expression and maintenance, which may originate trade-offs on other costly components such as reproduction or immunity. Although previous evidence has supported the idea that human height could be a sexually selected trait, the explanatory mechanisms that underlie this sel...

In two instrumental conditioning experiments with rats, we examined the impacts of acquisition and extinction cues on ABC renewal of instrumental behavior. Animals were reinforced with food for lever pressing in one context, followed by extinction of the response in a second one. Presentations of a brief tone accompanied extinction in Experiment 1...

If you think you are in control of your behavior, think again. Evidence suggests that behavioral modifications, as development and persistence of depression, maybe the consequence of a complex network of communication between macro and micro-organisms capable of modifying the physiological axis of the host. Some parasites cause significant nutritio...

If you think you are in control of your behavior, think again. Evidence suggests that behavioral modifications, as development and persistence of depression, may be the consequence of a complex network of communication between macro (i.e. parasites) and micro-organisms capable of modifying the physiological axis of the host. Some parasites cause si...

Body height is a life-history component. It involves important costs for its expression and maintenance, which may originate trade-offs on other costly components such as reproduction or immunity. Although previous evidence has supported the idea that human height could be a sexually selected trait, the explanatory mechanisms that underlie this sel...

El objetivo principal del presente experimento fue analizar si el empleo de un estímulo de larga duración, es decir, un patrón visual, podría convertirse en un mejor recordatorio de la fase de extinción comparado con el uso de un estímulo intermitente (tono). Los resultados mostraron que la extinción transcurrió de forma similar usando ambos estímu...

Retrieval of a flavor–illness association has been found to show contextual dependence when the association is learned after a nontarget flavor–illness association has been extinguished in what has been named as the extinction makes acquisition context-specific (EMACS) effect. Four experiments were designed to further explore the EMACS effect in co...

One experiment used a free operant procedure with rats to evaluate renewal of a response previously eliminated by using omission training or by using an extinction treatment. All rats were trained to press a lever for food in context A. Then, the operant responses were eliminated in a second context. In this phase, half of the subjects received an...

One experiment used a free operant procedure with rats to evaluate renewal of a response previously eliminated by using omission training or by using an extinction treatment. All rats were trained to press a lever for food in context A. Then, the operant responses were eliminated in a second context. In this phase, half of the subjects received an...

Several authors have used rodents to model social learning phenomena. In particular, some researchers have proposed rodents as a model for studying the underlying mechanisms of pro-social behavior. Recent findings suggest that empathy plays a key role in helping behavior. However, desire for social contact has also been proposed as an alternative e...

Varios autores han utilizado a los roedores como modelo para estudiar fenómenos de aprendizaje social. Particularmente, algunos investigadores han propuesto a los roedores como un modelo adecuado para estudiar los mecanismos que subyacen al comportamiento pro-social. Hallazgos recientes sugieren que la empatía juega un papel clave en la conducta de...

Three experiments with rats investigated whether adding or removing elements of a context affects generalization of instrumental behavior. Each of the experiments used a free operant procedure. In Experiments 1 and 2, rats were trained to press a lever for food in a distinctive context. Then, transfer of lever pressing was tested in a context creat...

Ciertas prácticas de crianza se asocian con los problemas severos de conducta infantil. El objetivo del estudio fue evaluar la relación entre las prácticas de crianza y el reporte de los distintos problemas severos de conducta en niños. Participaron 466 padres de 37 años de edad, distribuidos en cinco grupos: 1) con niños sin problemas de conducta,...

In two experiments with rats, we investigated the effects of using multiple contexts during extinction on renewal of lever-pressing behavior. During the first phase of both experiments, rats were reinforced to press a lever for food in Context A. Then, responses underwent extinction. For half of the animals, extinction sessions were conducted in a...

It is widely accepted that the presence of one animal can influence what another learns. The present experimental series explored the role of social context in the retrieval of extinguished instrumental responses. A new experimental task with rats to study operant responses in groups was used. During acquisition, all rats were trained to approach t...

One experiment with rats explored whether an extinction-cue prevents the recovery of extinguished lever-pressing responses. Initially, rats were trained to perform one instrumental response (R1) for food in Context A, and a different instrumental response (R2) in Context B. Then, responses were extinguished each in the alternate context (R1 in Cont...

Introduction. Some kind of raising practices are associated to severe child behavioral problems. Objective. To assess the relationship between raising practices and different severe child behavioral problems. Results. Throughout a multi-variability analysis and structured equation model we obtained a data adjustment with an X2 (1711) = 10190,41; p...

It has been argued that the response recovery effects share a common mechanism. A possible way to test it is evaluating whether the techniques that impaired renewal would impair the other recovery effects as well. Two experiments with rats used a free operant procedure to explore whether an extinction-cue could prevent the spontaneous recovery and...

The goal of the study was to assess parents and children behavior on the basis of their participation in a raising practices program. 128 parents from 8 public health institutions in Mexico were assessed with self-reports about their behaviors and their children's, and a direct observational system was used to determine the use of raising practices...

Rationale Steep discounting of delayed monetary rewards by substance-dependent individuals is well-established. Less is known, however, about discounting other kinds of outcomes, and very little is known about discounting by marijuana-dependent individuals. Objectives To determine how cocaine-dependent individuals and marijuana-dependent individual...

Resumen Diversos estudios confirmaron que los fumadores con dependencia a la nicotina descuentan las recompensas demoradas más que los no fumadores. Este estudio evaluó la relación entre el descuento temporal y probabilístico de ganancias y pérdi-das, el efecto de magnitud y el abuso a la nicotina para probar la generalidad del des-cuento temporal....

Introduction: several studies have shown that individuals with dependence on psychoactive drugs show a steeply delay discounting with monetary rewards in contrast to non-consumers. This finding is clinically useful as a behav-ioral trait likely to be modified by psychological treatments. Objective: this study evaluated changes pre-post measures of...

Several studies have confirmed that nicotine-dependent smokers discount delayed gains more than non-smokers. The purpose of this study was to assess the relation between temporal and probabilistic discounting of gains and losses and the magnitude effect with nicotine abuse to test generality of delay discounting. Twenty-seven human nicotine abusers...

The renewal effect is a key phenomenon in understanding the underlying mechanism of recovery from extinction. Findings in renewal strongly suggest that contextual cues play an important role in retrieving previously extinguished responses. The retrieval– of–information theory (Bouton, 1993) has been the main theoretical view in this area for the la...

In delay discounting tasks, the rate of discounting monetary rewards is greater for individuals who use drugs than for control participants. This result has been observed in individuals who use a particular drug (mono-consumers). In this study we examined delay discounting of hypothetical money rewards and losses by 102 men: 38 co- caine-dependent...

Parental rearing practices are associated to children´s problem behavior, which predicts early onset criminal behavior and drug use in adolescents. The goal of the paper was to describe the parental rearing practices related to the oppositional defiant disorder and to aggressive behavior by means of a correlational study. We assessed 300 participan...

One experiment used a free operant procedure with rats to compare ABA, AAB and ABC renewal by using a within-subject testing procedure. All rats were first trained to press a lever for food in context A. Lever pressing was then extinguished in either context A or context B. For rats in the groups ABA and ABC extinction took place in context B, whil...

La importancia de los estímulos contextuales en los procesos de aprendizaje y memoria se estableció desde los trabajos pioneros de Pavlov (1927). Más adelante, las investigaciones sobre cognición humana confirmaron la relevancia de los estímulos contextuales tanto en la codificación como en la recuperación de ítems en estudios de la memoria humana...

There are several self-report questionnaires used to measure achievement goals, mostly in school settings, but there are differences in the focal point of items belonging to the same goal, and also relationships between goals and other variables may differ depending on the questionnaires used to measure them. These results indicate that there are i...

Two experiments explored whether forgetting of an association depended on previous extinction of a different association in rats. Experiment 1 found that when rats were conditioned and extinguished with flavor X, a subsequently acquired conditioned aversion to flavor Y was reduced by a 19-day retention interval, something that did not occur when X...

Context renewal is identified when the conditioned response (CR) elicited by an extinguished conditioned stimulus (CS) reappears as a result of changing the contextual cues during the test. Two experiments were designed for testing contextual renewal in a conditioned taste aversion preparation. Experiment 1 assessed ABA and AAB context renewal, whe...

León, Abad and Rosas (2010b) shown that as the training increased attention to the context decreased. Thus, increasing the training might produce a greater generalization between different contexts. The main goal of the present experiments was to test this idea modifying different values of the context (i. e., colors) using an instrumental task wit...

One experiment analyzed whether context dependency of a flavor-illness association depends on the extinction of a different flavor-illness association in rats. There were two sessions per day, one in context A and the other session in context B. A half of the rats were allowed to drink distilled water within context B, while the other half of the g...

One experiment analyzed whether context dependency of a flavor-illness association depends on the extinction of a different flavor-illness association in rats. There were two sessions per day, one in context A and the other session in context B. A half of the rats were allowed to drink distilled water within context B, while the other half of the g...

Two-experiments were designed to analyze outcome-selective instrumental reinstatement (Experiment 1) and the effect of extinction on this sort of reinstatement (Experiment 2). In Experiment 1 two groups of rats were trained in three phases. In the first phase two-daily sessions were conducted. For the Different Group Response (R) 1 was reinforced w...

Context renewal is identified when the conditioned response (CR) elicited by an extinguished conditioned stimulus (CS) reappears as a result of changing the contextual cues during the test. Two experiments were designed for testing contextual renewal in a conditioned taste aversion preparation. Experiment 1 assessed ABA and AAB context renewal, whe...

Context renewal is identified when the conditioned response (CR) elicited by an extinguished conditioned stimulus (CS) reappears as a result of changing the contextual cues during the test. Two experiments were designed for testing contextual renewal in a conditioned taste aversion preparation. Experiment 1 assessed ABA and AAB context renewal, whe...

Resumen este experimento se diseñó para evaluar la re-novación ABC con un procedimiento de condi-cionamiento de aversión al sabor (CAS) en tres fases: adquisición, extinción y prueba. Durante la adquisición, 15 ratas Wistar, asignadas a los grupos ABC y ABB, tuvieron acceso a una solu-ción con sacarosa y posteriormente recibieron una inyección de c...

Resumen este experimento se diseñó para evaluar la re-novación ABC con un procedimiento de condi-cionamiento de aversión al sabor (CAS) en tres fases: adquisición, extinción y prueba. Durante la adquisición, 15 ratas Wistar, asignadas a los grupos ABC y ABB, tuvieron acceso a una solu-ción con sacarosa y posteriormente recibieron una inyección de c...

This experiment was designed to evaluate ABC renewal in a conditioned taste aversion (CTA) procedure consisting of three phases: acquisition, extinction and test. During the acquisition phase, 15 Wistar rats assigned to groups ABC and ABB had access to a sucrose solution, after which they were injected with lithium chloride (LiCl) in Context A. In...

The aim of this paper was to selectively review the literature on socially-mediatedlearning of novel feeding behaviors. This evidence is discussed in relation to three dominanttTaditions in Psychology and Biology. First, field studies describing the astonishingdiversity of cases of behaviors that appear to have diffused in a local population by soc...

Two experiment using a cnnditinned suppressinn procedure iii rats assessed transfer of conditioned iahibitinn frorn a lnud car hora te electric shock, after postconditionlng manipulations designcd te habituate or cnuntercnnditinning tite aversive effects of tite hora. Bnth experhnents showed that tite inhibitory effects of a stimnulus are not resfr...