Recent evidence in natural and semi-natural settings has revealed a variety of left-right perceptual asymmetries among vertebrates. These include preferential use of the left or right visual hemifield during activities such as searching for food, agonistic responses, or escape from predators in animals as different as fish, amphibians, reptiles, birds, and mammals. There are obvious disadvantages in showing such directional asymmetries because relevant stimuli may be located to the animal's left or right at random; there is no a priori association (...) between the meaning of a stimulus (e.g., its being a predator or a food item) and its being located to the animal's left or right. Moreover, other organisms (e.g., predators) could exploit the predictability of behavior that arises from population-level lateral biases. It might be argued that lateralization of function enhances cognitive capacity and efficiency of the brain, thus counteracting the ecological disadvantages of lateral biases in behavior. However, such an increase in brain efficiency could be obtained by each individual being lateralized without any need to align the direction of the asymmetry in the majority of the individuals of the population. Here we argue that the alignment of the direction of behavioral asymmetries at the population level arises as an “evolutionarily stable strategy” under “social” pressures occurring when individually asymmetrical organisms must coordinate their behavior with the behavior of other asymmetrical organisms of the same or different species. Key Words: asymmetry; brain evolution; brain lateralization; development; hemispheric specialization; laterality; lateralization of behavior; social behavior; theory of games. (shrink)

Honeybees show lateral asymmetry in both learning about odours associated with reward and recalling memory of these associations. We have extended this research to show that bees exhibit lateral biases in their initial response to odours: viz., turning towards the source of an odour presented on their right side and turning away from it when presented on their left side. The odours we presented were the main component of the alarm pheromone, iso-amyl acetate (IAA), and four floral scents. The significant (...) bias to turn towards IAA odour on the right and away from it on the left is, we argue, a lateralization of the fight-flight response elicited by this pheromone. It contrasts to an absence of any asymmetry in the turning response to an odour of the flowers on which the bees had been feeding prior to testing: to this odour they turned towards when it was presented on either the left or right side. Lemon and orange odours were responded to differently on the left and right sides (towards on the right, away on the left) but no asymmetry was found in responses to rose odour. Our results show that side biases are present even in the initial, orienting response of bees to certain odours. (shrink)

In this paper we review the literature on social learning mechanisms in the domestic chick, focusing largely on work from our own laboratories. The domestic chicken is a social-living bird that searches for food in flocks, avoids predators by following warnings from other flock members, and forms (stable) social hierarchies. All of these behaviors develop throughout ontogeny, largely during the very early stages post-hatch. Newly hatched chicks appear to have predispositions to orient towards and to pay greatest attention to the (...) biologically relevant characteristics of their immediate environment (i.e. to conspecifics: the mother bird and/or fellow hatchlings) from which they may subsequently learn. In addition, the chick has a lateralized brain; left and right hemispheres being specialized for certain behavioral functions and responses, and it appears that such behavioral lateralization is also transposed onto certain social learning situations, which will also be considered. Keywords: social learning; social cognition; chick; brain asymmetry. (shrink)

In this paper we review the literature on social learning mechanisms in the domestic chick, focusing largely on work from our own laboratories. The domestic chicken is a social-living bird that searches for food in flocks, avoids predators by following warnings from other flock members, and forms social hierarchies. All of these behaviors develop throughout ontogeny, largely during the very early stages post-hatch. Newly hatched chicks appear to have predispositions to orient towards and to pay greatest attention to the biologically (...) relevant characteristics of their immediate environment from which they may subsequently learn. In addition, the chick has a lateralized brain; left and right hemispheres being specialized for certain behavioral functions and responses, and it appears that such behavioral lateralization is also transposed onto certain social learning situations, which will also be considered. Keywords: social learning; social cognition; chick; brain asymmetry. (shrink)

Some of the foundations of Heyes’ radical reasoning seem to be based on a fractional selection of available evidence. Using an ethological perspective, we argue against Heyes’ rapid dismissal of innate cognitive instincts. Heyes’ use of fMRI studies of literacy to claim that culture assembles pieces of mental technology seems an example of incorrect reverse inferences and overlap theories pervasive in cognitive neuroscience.

The ability to represent, discriminate, and perform arithmetic operations on discrete quantities (numerosities) has been documented in a variety of species of different taxonomic groups, both vertebrates and invertebrates. We do not know, however, to what extent similarity in behavioral data corresponds to basic similarity in underlying neural mechanisms. Here, we review evidence for magnitude representation, both discrete (countable) and continuous, following the sensory input path from primary sensory systems to associative pallial territories in the vertebrate brains. We also speculate (...) on possible underlying mechanisms in invertebrate brains and on the role played by modeling with artificial neural networks. This may provide a general overview on the nervous system involvement in approximating quantity in different animal species, and a general theoretical framework to future comparative studies on the neurobiology of number cognition. (shrink)

Núñez and Fias raised concerns on whether our results demonstrate a linear number-space mapping. Patro and Nuerk urge caution on the use of animal models to understand the origin of the orientation of spatial–numerical association. Here, we discuss why both objections are unfounded.

The hypothesis that nonhuman species, lacking verbal language, do not really integrate information from different modules, but use instead information sequentially, appears difficult to put under empirical scrutiny. Evidence is discussed showing that in nonhuman species storing of geometric information occurs spontaneously even when landmark information suffices for spatial reorientation, suggesting simultaneous encoding, if not use, of information from different modules.

The present response elaborates and defends the main theses advanced in the target article: namely, that in order to provide an evolutionary account of brain lateralization, we should consider advantages and disadvantages associated both with the individual possession of an asymmetrical brain and with the alignment of the direction of lateralization at the population level. We explain why we believe that the hypothesis that directional lateralization evolved as an evolutionarily stable strategy may provide a better account than alternative hypotheses. We (...) also further our discussion of the influence of stimulation and experience in early life on lateralization, and thereby show that our hypothesis is not deterministic. We also consider some novel data and ideas in support of our main thesis. (shrink)

The stratification in depth of chromatically homogeneous overlapping figures depends on a minimization rule which assigns the status of being “in front” to the figure that requires the formation of shorter modal contours. This rule has been proven valid also in birds, whose visual neuroanatomy is radically different from that of other mammals, thus suggesting an example of evolutionary convergence toward a perceptual universal. [Shepard].

It is argued that the alleged cases of cognitive penetration of visual modules actually arise from the integration of information among different modules. This would reflect a general computational strategy according to which constraints to a particular module would be provided by information coming from different modules. Examples are provided from the integration of stereopsis and occlusion and from computation of motion direction.