Archive Electronique - Institut Jean Nicod
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1997 research outputs found
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Experiential values are underweighted in decisions involving symbolic options
No full textInternational audienceStandard models of decision-making assume each option is associated with subjective value, regardless of whether this value is inferred from experience (experiential) or explicitly instructed probabilistic outcomes (symbolic). In this study, we present results that challenge the assumption of unified representation of experiential and symbolic value. Across nine experiments, we presented participants with hybrid decisions between experiential and symbolic options. Participants’ choices exhibited a pattern consistent with a systematic neglect of the experiential values. This normatively irrational decision strategy held after accounting for alternative explanations, and persisted even when it bore an economic cost. Overall, our results demonstrate that experiential and symbolic values are not symmetrically considered in hybrid decisions, suggesting they recruit different representational systems that may be assigned different priority levels in the decision process. These findings challenge the dominant models commonly used in value-based decision-making research
Chronic refined carbohydrate consumption measured by glycemic load and variation in cognitive performance in healthy people
No full textInternational audienceA massive diet switch has occurred in the occidental world since the second half of the 20 th century, with a dramatic increase in refined carbohydrate consumption generating numerous deleterious health effects. Physiological mechanisms associated with refined carbohydrate consumption, such as hyperinsulinemia and insulin resistance, may impact cognition in healthy people before overt obesity, metabolic disease onset or dementia. To explore this possibility, the relationship between cognitive performance and chronic refined carbohydrate consumption was studied in healthy young adults (N = 95). Evaluation of chronic refined consumption was based on the glycemic load (a proxy of glycemic and insulinemic responses) of three mealtimes at higher glycemic risk: breakfast, afternoon snacking and between-meal snacking. Immediate consumption of refined carbohydrates was experimentally controlled. High chronic between-meal glycemic load is associated to a decrease of cognitive performance for men and women in the presence of several control variables, including energy intake. The different physiological ecologies of the three meals and the interpretation of the results in terms of adaptation or maladaptation to the modern dietary environment are discussed
Essai sur l'Habitus Graphique : le cas des Yoruba
No full textDans les sociétés qui ont anciennement connu l'écriture, la culture graphique-qu'elle soit comprise comme art ou non-en a été le cadre généalogique. Ce constat est vrai pour l'Eurasie, avec la Mésopotamie, puis la Grèce et la Rome ; mais il l'est aussi pour l'Afrique avec l'Egypte et pour l'Asie avec la Chine. En Occident, la culture graphique qui remonte à des millénaires, au fil du temps, a pris la forme de l'art avec la peinture et deviendra une technologie intellectuelle avec l'écriture 1. En Chine, à ses origines, cette culture, sans correspondre strictement à la définition occidentale de l'art, a été très prisée. La peinture apparaît en Chine dès le Néolithique et probablement dès le Paléolithique sur les parois peintes des abris sous roche. Les idéogrammes, dont l'apparition se situe vers 2200 AEC, découlent de résidus d'équations divinatoires, obtenues à partir de craquelures sur des omoplates de bovidés ou des carapaces de tortue 2. Mais ces notations de signes, dont la valorisation sémantique sera à l'origine des idéogrammes, n'aurait pu se faire s'il n'existait déjà une culture graphique antérieure. C'est dire que même dans les sociétés ayant anciennement connu l'écriture, en dehors de leurs usages religieux ou esthétique, les élaborations graphiques étaient aussi un moyen de représentation, de marquage, de communication, de notation et de conservation
Argument evaluation and production in the correction of political innumeracy
No full textInternational audienceThe public is largely innumerate, making systematic mistakes in estimating some politically relevant facts, such as the share of foreign-born citizens. In two-step or multistep flow models, such mistakes could be corrected if better-informed citizens were able to convince their peers, in particular by using good arguments citing reliable sources. In six experiments, we find two issues that dampen the potential power of this two-step flow process. First, even though participants were more convinced by good than by poor arguments, many did not change their minds, even when confronted with good arguments. Second, participants are not inclined to spontaneously generate arguments that cite reliable sources, even when they have just been influenced by such arguments. Both issues should put a significant brake in the spread of political numeracy through the two-step flow process, in particular in non-dialogic contexts
Cultural Conservatism
No full textInternational audienceTrying to preserve cultural forms as faithfully as possible is a key motivation for cultural transmission. This chapter reviews two possible accounts of it. One, evolutionary conservatism, is premised on the superiority of accumulated cultural knowledge compared to individual judgement-a theme that runs strongly through both the cultural evolution literature and conservative political philosophy. I argue for a clear distinction between evolutionary conservatism and status quo conservatism, which is motivated by loss-and riskaversion. I proceed to tackle some outstanding issues regarding status quo conservatism: its association with attachment to social hierarchies; the kind of cultural practices that tend to elicit it; and the question why an attitude motivated by considerations of costs and benefits might be manifested as rigid or absolute principles. Seeing some cultural practices as equilibria in a coordination game helps answer these questions
L'évolution culturelle du point de vue des producteurs
No full textInternational audienceAbstract Standard approaches to cultural evolution focus on the recipients or consumers. This does not take into account the fitness costs incurred in producing the behaviours or artefacts that become cultural, i.e. widespread in a social group. We argue that cultural evolution models should focus on these fitness costs and benefits of cultural production, particularly in the domain of ‘symbolic’ culture. In this approach, cultural products can be considered as a part of the extended phenotype of producers, which can affect the fitness of recipients in a positive way (through cooperation) but also in a detrimental way (through manipulation and exploitation). Taking the producers’ perspective may help explain the specific features of many kinds of cultural products
On the Optimality of Vagueness: "Around", "Between" and the Gricean Maxims
No full textInternational audienceWhy is ordinary language vague? We argue that in contexts in which a cooperative speaker is not perfectly informed about the world, the use of vague expressions can offer an optimal tradeoff between truthfulness (Gricean Quality) and informativeness (Gricean Quantity). Focusing on expressions of approximation such as "around", which are semantically vague, we show that they allow the speaker to convey indirect probabilistic information, in a way that can give the listener a more accurate representation of the information available to the speaker than any more precise expression would (intervals of the form "between"). That is, vague sentences can be more informative than their precise counterparts. We give a probabilistic treatment of the interpretation of "around", and offer a model for the interpretation and use of "around"statements within the Rational Speech Act (RSA) framework. In our account, the shape of the speaker's distribution matters in ways not predicted by the Lexical Uncertainty model standardly used in the RSA framework for vague predicates. We use our approach to draw further lessons concerning the semantic flexibility of vague expressions and their irreducibility to more precise meanings
On three-valued presentations of classical logic
No full textInternational audienceGiven a three-valued definition of validity, which choice of three-valued truth tables for the connectives can ensure that the resulting logic coincides exactly with classical logic? We give an answer to this question for the five monotonic consequence relations st, ss, tt, ss inter tt, and ts, when the connectives are negation, conjunction, and disjunction. For ts and ss inter tt the answer is trivial (no scheme works), and for ss and tt it is straightforward (they are the collapsible schemes, in which the middle value acts like one of the classical values). For st, the schemes in question are the Boolean normal schemes that are either monotonic or collapsible