The Impact of Pavlov on the Psychology of Learning in English-Speaking Countries

La traducción de las conferencias de Pavlov (Pavlov, 1927) proporcionó a los psicólogos angloparlantes el acceso al panorama global de la investigación y las ideas teóricas de Pavlov. El impacto que esto supuso para su estudio de la psicología del aprendizaje puede evaluarse mediante el examen de libros influyentes en esta área. Esto revela que Watson (1924) promovió eficazmente la errónea idea de que Pavlov era un teórico del E-R. Esta suposición no fue cuestionada por Tolman (1932), Hilgard y Marquis (1940) o Hull (1943). Sin embargo, Skinner (1938) no cometió este error y además proporcionó los más sólidos argumentos contra la creencia de Pavlov de que los efectos conductuales requieren una explicación en términos de procesos fisiológicos. A partir de 1927 la mayor parte de la investigación en aprendizaje en los países angloparlantes usó procedimientos instrumentales más que pavlovianos. Con todo, muchos de los temas planteados por estas investigaciones habían sido planteados por primera vez por Pavlov, así que se puede considerar que su influencia principal fue la de definir un programa de investigación para los estudiosos del aprendizaje.The translation of Pavlov’s lectures (Pavlov, 1927) provided English-speaking psychologists with access to the full scope of Pavlov’s research and theoretical ideas. The impact this had on their study of the psychology of learning can be assessed by examining influential books in this area. This reveals that Watson (1924) had been highly effective in promoting the misleading idea that Pavlov was a fellow S-R theorist. This assumption was not questioned by Tolman (1932), Hilgard and Marquis (1940) or by Hull (1943). However, this mistake was not made by Skinner (1938), who also provided the strongest arguments against Pavlov’s belief that behavioral effects required explanation in terms of physiological processes. Post-1927 most learning research in the English-speaking countries continued to use instrumental, rather than Pavlovian, conditioning procedures. Nevertheless, many of the issues addressed by this research were ones that Pavlov had been the first to raise, so that his major influence can be seen as that of defining a research program for subsequent students of learning

Placebo caffeine reduces withdrawal in abstinent coffee drinkers

Background: Expectancies have been shown to play a role in the withdrawal syndrome of many drugs of addiction. However no studies have examined the effects of expectancies across a broad range of caffeine withdrawal symptoms, including craving. Aims: The purpose of the current study was to use caffeine as a model to test the effect of expectancy on withdrawal symptoms, specifically whether the belief that one has ingested caffeine is sufficient to reduce caffeine withdrawal symptoms and cravings in abstinent caffeine drinkers. Methods 24-h abstinent regular coffee drinkers completed the Caffeine Withdrawal Symptom Questionnaire (CWSQ) before and after receiving decaffeinated coffee. Half the participants were led to believe the coffee was regular caffeinated coffee (Told group) and half were told that it was decaffeinated (Low Expectancy group). Results: Participants in the High Expectancy group reported a significantly greater reduction in craving, fatigue, lack of alertness and flu-like feelings factors of the CWSQ than those in the Low Expectancy. Conclusions: These results indicate that the belief that one has consumed caffeine can affect caffeine withdrawal symptoms, especially craving, even when no caffeine has been consumed

Does drinking saccharin weaken an association of sweet with calories? Pre-exposure effects in flavor preference learning

The main aim of this experiment was to examine the claim that exposure to non-nutritive sweeteners weakens the formation of a sweet-calorie association. Three groups of food-deprived rats received training in which they drank an almond-flavored maltodextrin and saccharin solution. A final test phase assessed their preference for almond. The groups differed in preexposure prior to training. One was pre-exposed to saccharin, one to saccharin plus maltodextrin, and the third, control condition, received only water at this stage. When the rats continued under food deprivation for the test phase, the group exposed to the compound (saccharin plus maltodextrin) showed a weaker preference than the other two groups, while those pre-exposed to saccharin showed as strong a preference as the controls. When the test was conducted with the rats no longer food-deprived, only the water group showed a strong preference. These results support the proposal that rats can form both flavor-flavor and flavor-nutrient associations, expression of which will depend on motivational state. They did not find support for the suggestion that prior exposure to a non-nutritive sweetener can enhance subsequent learning about the nutritive properties of a sweet food.This work was supported by PGC2018-095965-B-I00 & PID2022- 136219NB-I00 funded by MCIN/ AEI /10.13039/501100011033/ FEDER “Una manera de hacer Europa”

A high-fat high-sugar diet predicts poorer hippocampal-related memory and a reduced ability to suppress wanting under satiety

Animal data indicate that greater intake of fats and sugars prevalent in a Western diet impairs hippocampal memory and tests of behavioral inhibition known to be related to hippocampal function (e.g., feature negative discrimination tasks). It has been argued that such high fat high sugar diets (HFS) impair the hippocampus, which then becomes less sensitive to modulation by physiological state. Thus retrieval of motivationally salient memories (e.g., when seeing or smelling food) occurs irrespective of state. Here we examine whether evidence of similar effects can be observed in humans using a correlational design. Healthy human participants (N = 94), who varied in their habitual consumption of a HFS diet, completed the verbal paired associate (VPA) test, a known hippocampal-dependent process, as well as liking and wanting ratings of palatable snack foods, assessed both hungry and sated. Greater intake of a HFS diet was significantly associated with a slower VPA learning rate, as predicted. Importantly, for those who regularly consumed a HFS diet, while reductions in liking and wanting occurred between hungry and sated states, the reduction in wanting was far smaller relative to liking. The latter effect was strongly related to VPA learning rate, suggestive of hippocampal mediation. In agreement with the animal literature, human subjects with a greater intake of a HFS diet show deficits in hippocampal-dependent learning and memory, and their desire to consume palatable food is less affected by physiological state – a process we suggest that is also hippocampal related

Chemosensory abilities in consumers of a western-style diet

People vary in their habitual diet and also in their chemosensory abilities. In this study we examined whether consumption of a Western-style diet, rich in saturated fat and added sugar, is associated with either poorer or different patterns of chemosensory perception, relative to people who consume a healthier diet. Participants were selected based on a food frequency questionnaire, which established whether they were likely to consume a diet either higher or lower in saturated fat and added sugar. Eighty-seven participants were tested for olfactory ability (threshold, discrimination, identification), gustatory ability (PROP sensitivity, taste intensity, quality and hedonics), and flavour processing (using dairy fat-sugar-odour mixtures). A Western-style diet was associated with poorer odour identification ability, greater PROP sensitivity, poorer fat discrimination, different patterns of sweetness taste enhancement, and hedonic differences in taste and flavour perception. No differences were evident for odour discrimination or threshold, in perception of taste intensity/quality (excluding PROP) or the ability of fats to affect flavour perception. The significant relationships were of small to moderate effect size, and would be expected to work against consuming a healthier diet. The discussion focuses on whether these diet-related differences precede adoption of a Western-style diet and/or are a consequence of it

Psychiatric and medical comorbidities of eating disorders : findings from a rapid review of the literature

Background: Eating disorders (EDs) are potentially severe, complex, and life-threatening illnesses. The mortality rate of EDs is signifcantly elevated compared to other psychiatric conditions, primarily due to medical complications and suicide. The current rapid review aimed to summarise the literature and identify gaps in knowledge relating to any psychiatric and medical comorbidities of eating disorders. Methods: This paper forms part of a rapid review) series scoping the evidence base for the feld of EDs, conducted to inform the Australian National Eating Disorders Research and Translation Strategy 2021–2031, funded and released by the Australian Government. ScienceDirect, PubMed and Ovid/Medline were searched for English-language studies focused on the psychiatric and medical comorbidities of EDs, published between 2009 and 2021. High-level evidence such as meta-analyses, large population studies and Randomised Control Trials were prioritised. Results: A total of 202 studies were included in this review, with 58% pertaining to psychiatric comorbidities and 42% to medical comorbidities. For EDs in general, the most prevalent psychiatric comorbidities were anxiety (up to 62%), mood (up to 54%) and substance use and post-traumatic stress disorders (similar comorbidity rates up to 27%). The review also noted associations between specifc EDs and non-suicidal self-injury, personality disorders, and neurodevelopmental disorders. EDs were complicated by medical comorbidities across the neuroendocrine, skeletal, nutritional, gastrointestinal, dental, and reproductive systems. Medical comorbidities can precede, occur alongside or emerge as a complication of the ED. Conclusions: This review provides a thorough overview of the comorbid psychiatric and medical conditions cooccurring with EDs. High psychiatric and medical comorbidity rates were observed in people with EDs, with comorbidities contributing to increased ED symptom severity, maintenance of some ED behaviours, and poorer functioning as well as treatment outcomes. Early identifcation and management of psychiatric and medical comorbidities in people with an ED may improve response to treatment and overall outcomes