Cross inhibition improves activity selection when switching incurs time costs

We consider a behavioural model of an animal choosing between two activities, based on positive feedback, and examine the effect of introducing cross inhibition between the motivations for the two activities. While cross-inhibition has previously been included in models of decision making, the question of what benefit it may provide to an animal's activity selection behaviour has not previously been studied. In neuroscience and in collective behaviour cross-inhibition, and other equivalent means of coupling evidence-accumulating pathways, have been shown to approximate statistically-optimal decision-making and to adaptively break deadlock, thereby improving decision performance. Switching between activities is an ongoing decision process yet here we also find that cross-inhibition robustly improves its efficiency, by reducing the frequency of costly switches between behaviours

Rafles et déportations des Juifs [La France pendant la Seconde Guerre mondiale, atlas historique]

[dans le chapitre 8 : Répressions et persécutions, p. 188-215

Cultural and biological evolution of phonemic speech

This paper investigates the interaction between cultural evolution and biological evolution in the emergence of phonemic coding in speech. It is observed that our nearest relatives, the primates, use holistic utterances, whereas humans use phonemic utterances. It can therefore be argued that our last common ancestor used holistic utterances and that these must have evolved into phonemic utterances. This involves co-evolution between a repertoire of speech sounds and adaptations to using phonemic speech. The culturally transmitted system of speech sounds influences the fitness of the agents and could conceivably block the transition from holistic to phonemic speech. This paper investigates this transition using a computer model in which agents that can either use holistic or phonemic utterances co-evolve with a lexicon of words. The lexicon is adapted by the speakers to conform to their preferences. It is shown that although the dynamics of the transition are changed, the population still ends up of agents that use phonemic speech.</p