Dogs follow human misleading suggestions more often when the informant has a false belief

We investigated whether dogs ( Canis familiaris ) distinguish between human true (TB) and false beliefs (FB). In three experiments with a pre-registered change of location task, dogs ( n = 260) could retrieve food from one of two opaque buckets after witnessing a misleading suggestion by a human informant (the ‘communicator’) who held either a TB or a FB about the location of food. Dogs in both the TB and FB group witnessed the initial hiding of food, its subsequent displacement by a second experimenter, and finally, the misleading suggestion to the empty bucket by the communicator. On average, dogs chose the suggested container significantly more often in the FB group than in the TB group and hence were sensitive to the experimental manipulation. Terriers were the only group of breeds that behaved like human infants and apes tested in previous studies with a similar paradigm, by following the communicator's suggestion more often in the TB than in the FB group. We discuss the results in terms of processing of goals and beliefs. Overall, we provide evidence that pet dogs distinguish between TB and FB scenarios, suggesting that the mechanisms underlying sensitivity to others' beliefs have not evolved uniquely in the primate lineage.

An Evolutionary Framework for Understanding Coercion and Aggression

This chapter proposes an evolutionary framework for understanding the link between social exclusion and deep marginalization in the development of aggression and violence. It argues that (1) the evolution of language in the primate lineage provides unique capabilities for forming social groups and communities and also defining and signaling exclusion, marginalization, and social rejection; and (2) exclusion and marginalization in humans have historically been salient predictors of mortality and are evocative of self-organization into deviant social groups. The life history perspective offers a macrolevel explanation of the developmental cascade from early childhood defiance to more serious antisocial behavior and violence. An evolutionary framework also provides perspective about which interventions are most likely to be effective at specific points in development and which are potentially limited in effectiveness, or worse, iatrogenic.

Mirror mechanism and dedicated circuits are the scaffold for mirroring processes

In the past decade many studies have demonstrated the existence of a mirror mechanism that matches the sensory representation of a biological stimulus with its somatomotor and visceromotor representation. This mechanism, likely phylogenetically very old, explains several types of mirroring behaviours, at different levels of complexity. The presence in primates of dedicated neuroanatomical pathways for specific sensorimotor integrations processes implies, at least in the primate lineage, a hard-wired mirror mechanism for social cognitive functions.

Comparative Decay Rates of Human, Rhesus Macaque, Cynomolgus, and Porcine Activated Factor VIII.

Abstract 3164 Poster Board III-104 The proteolytic conversation by thrombin of factor VIII (fVIII) to fVIIIa produces a A1/A2/A3-C1-C2 heterotrimer that spontaneously dissociates into inactive A1/A3-C1-C2 and A2 species. Human mutations that increase the rate of A2 subunit dissociation produce hemophilia A, indicating that A2 subunit dissociation is physiologically relevant and is an important regulatory feature of the blood coagulation mechanism. The A2 subunit dissociation rate from human fVIIIa is significantly faster than the corresponding dissociation rates from porcine or murine fVIIIa. The fast decay rate of human fVIIIa raises the question whether the f8 gene is under positive selection for this trait. To determine whether fast A2 dissociation occurs elsewhere in the primate lineage, we cloned cDNAs encoding B-domain deleted (BDD) fVIII from rhesus macaque and cynomolgus monkey liver. The deduced BDD amino acid sequences of rhesus and cynomolgus fVIII were 97.9 % and 98% identical to human fVIII, respectively, and were 99.9% identical to each other. The expression of rhesus and cynomolgus fVIII from baby hamster kidney-derived cells was similar to human fVIII and ten-fold lower than porcine fVIII. BDD human, rhesus, cynomolgus, and porcine fVIII molecules were purified to homogeneity by tandem ion-exchange chromatography. Concentrations of the purified constructs were calculated using a molar extinction coefficient at 280 nm based on their predicted tyrosine, tryptophan and cysteine compositions. Human, rhesus, and cynomolgus fVIII displayed similar specific coagulant activities by one-stage coagulation assay (6800, 4500, and 5200 units per mg, respectively). The kinetics of decay of human, rhesus, cynomolgus and porcine fVIIIa were measured following rapid activation of 1 nM fVIII by thrombin using a chromogenic substrate assay of purified intrinsic fXase complex under conditions in which fVIIIa was limiting. Decay curves were fit using nonlinear least-squares regression to a first-order model (Fig. 1). Decay rate constants for rhesus and cynomolgus fVIIIa were similar (0.31 and 0.27 min-1, respectively) and were slightly, but significantly lower than human fVIIIa (0.40 min-1). In contrast, the decay rate constant for porcine fVIIIa, 0.17 min-1, was 2.3-fold lower than human fVIIIa, consistent with previous observations. These results suggest that fast A2 subunit dissociation rates evolved before evolution of the primate lineage. Disclosures No relevant conflicts of interest to declare.