Individual and collective problem-solving in a foraging context in the leaf-cutting ant Atta colombica

In this paper we investigate the flexibility of foraging behavior in the leaf-cutting ant Atta colombica, both at the individual and collective levels, following a change in the physical properties of their environment. We studied in laboratory conditions the changes occurring in foraging behavior when a height constraint was placed 1 cm above part of the trail linking the nest to the foraging area. We found that the size and shape of the fragments of foraging material brought back to the nest were significantly modified when the constraint was placed on the trail: independent of their size, forager ants cut smaller and rounder fragments in the presence of a height constraint than in its absence. This size adjustment does not require any direct sensory feedback because it occurred when the ants cut fragments in the foraging area; no further cutting was done when they encountered the constraint. This points to the existence of a template that ants store and use as a reference to adjust their reach while cutting. Remarkably, despite the decrease in the foraging material brought to the nest per capita the colony was still able to improve its foraging performance by doubling the number of transporters. This study illustrates the flexibility of foraging behavior exhibited by an ant colony. It provides a rare example of insects finding an intelligent solution to a problem occurring in a foraging context, at both the individual and collective levels.     

Coupling kinematics of memory and kinematics of movement: the conditions for a psychological relativity

The organization of spatial and temporal information relative to memory-movement interactions was studied in a recall task. Stimuli consisted of four different configurations of eight dots, presented sequentially. In two configurations, the stimuli were spatiotemporal congruent, with (constant or variable) inter-stimulus distances corresponding to (constant or variable) inter-stimulus time intervals. In the other two configurations, the stimuli were spatiotemporal incongruent, with (constant or variable) inter-stimulus distances not corresponding to (variable or constant) inter-stimulus time intervals. After a learning phase consisting of 20 presentations of the target configuration, participants performed a series of pointing movements to reproduce both spatial and temporal characteristics of the stimulus 60 times in succession without ever re-examining the target configuration. Classically, in incongruent spatiotemporal conditions, the reproduction of, respectively, constant distances or constant time intervals are strongly disturbed by the simultaneous perception of variable inter-stimulus time intervals (Tau effect) or variable distances (Kappa effect). We assume that these spatiotemporal dependencies, which occur when the response relates to one dimension only, crucially depend on the non-integration of motoric aspects in memory.     

Les deux tétraèdres des liaisons logiques interpropositionnelles bivalentes

Sans résuméAllatum est die 21 Februarii 1967     

Sight or smell: which senses do scavenging raptors use to find food?

Animal Cognition - Raptors are usually considered to be mainly visually dependent, and the use of other sensory modalities has rarely been studied in these birds. Here, we investigated...     

Getting Closer to the Action: Using the Virtual Enactment Method to Understand Burglary

In this article we describe a new method, the Virtual Enactment Method (VEM), to enhance offender recall and motivation to disclose information by having burglars reflect on their experience while committing a crime in a simulated virtual environment. Participants, a sample of 61 incarcerated burglars, ‘thought aloud’ whilst undertaking a virtual burglary. Following the ‘virtual’ burglary, emerging themes were expanded upon in an interview. We show that the simulated environment effectively reinstates the criminogenic event, increases engagement, enhances recall, and encourages participants to talk more openly about their experiences, skills and knowledge.     

Seeing is Believing? Comparing Negative Affect,Realism and Presence in Visual Versus Written Guardianship Scenarios

We compared participant responses on three written guardianship scenarios versus visualized versions of the same scenarios in terms of realism, presence, negative affect elicited by the situation, perceived risk, and the choice to intervene. We find that people who received the visual scenarios report higher presence, but not realism, than those who received the written version. Furthermore, visual scenarios elicited stronger negative affect and resulted in a lower likelihood to intervene. Finally, presence, but not negative affect, mediated the relation between condition and the choice to intervene. Implications of the visual scenario method for future research are discussed.