Why don't cockatoos have war songs?

We suggest that the accounts offered by the target articles could be strengthened by acknowledging the role of group selection and cultural niche construction in shaping the evolutionary trajectory of human music. We argue that group level traits and highly variable cultural niches can explain the diversity of human song, but the target articles' accounts are insufficient to explain such diversity.

An ion transport-independent role for the cation-chloride cotransporter KCC2 in dendritic spinogenesis in vivo.

The neuron-specific K-Cl cotransporter, KCC2, is highly expressed in the vicinity of excitatory synapses in pyramidal neurons, and recent in vitro data suggest that this protein plays a role in the development of dendritic spines. The in vivo relevance of these observations is, however, unknown. Using in utero electroporation combined with post hoc iontophoretic injection of Lucifer Yellow, we show that premature expression of KCC2 induces a highly significant and permanent increase in dendritic spine density of layer 2/3 pyramidal neurons in the somatosensory cortex. Whole-cell recordings revealed that this increased spine density is correlated with an enhanced spontaneous excitatory activity in KCC2-transfected neurons. Precocious expression of the N-terminal deleted form of KCC2, which lacks the chloride transporter function, also increased spine density. In contrast, no effect on spine density was observed following in utero electroporation of a point mutant of KCC2 (KCC2-C568A) where both the cotransporter function and the interaction with the cytoskeleton are disrupted. Transfection of the C-terminal domain of KCC2, a region involved in the interaction with the dendritic cytoskeleton, also increased spine density. Collectively, these results demonstrate a role for KCC2 in excitatory synaptogenesis in vivo through a mechanism that is independent of its ion transport function.

Intuitive moral bias favors the religiously faithful.

Belief in powerful supernatural agents that enforce moral norms has been theoretically linked with cooperative altruism and prosociality. Correspondingly, prior research reveals an implicit association between atheism and extreme antisociality (e.g., serial murder). However, findings centered on associations between lack of faith and moral transgression do not directly address the hypothesized conceptual association between religious belief and prosociality. Accordingly, we conducted two pre-registered experiments depicting a "serial helper" to assess biases related to extraordinary helpfulness, mirroring designs depicting a serial killer used in prior cross-cultural work. In both a predominantly religious society (the U.S., Study 1) and a predominantly secular society (New Zealand, Study 2), we successfully replicated previous research linking atheism with transgression, and obtained evidence for a substantially stronger conceptual association between religiosity and virtue. The results suggest that stereotypes linking religiosity with prosociality are both real and global in scale.

Prosocial aggression tracks genetic relatedness distinctly from emotional closeness.

Altruistic behavior is understood to largely stem from adaptations for kin altruism, contingent on degree of relatedness, and/or reciprocal altruism, contingent on degree of benefits conferred in exchange for help. Because kin qualify for both kin and reciprocal altruism, they should receive greater support than friends, as has been demonstrated in prior research. Here, we tested this prediction with regard to willingness to punish on another's behalf, comparing inclinations to aggress against transgressors when the victim was framed as an acquaintance, close friend, cousin, sibling, or oneself. Participants endorsed comparably greater direct aggression on behalf of the self, kin, or friends relative to acquaintances, despite reporting substantially greater emotional closeness to friends, consistent with what has been termed a kinship premium. Kin engendered greater aid than is explicable by affiliative emotion. Participants also reported less anger-yet trends toward greater disgust-when victims were acquaintances relative to all other conditions, replicating prior work distinguishing the social functions of anger and disgust. These results are discussed as they inform both the kinship premium hypothesis and sociofunctional accounts of moral emotion. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Heads Up!

Possibilities for behavior (i.e., affordances) can be perceived with units spanning anatomical components and external objects. For example, affordances for standing on an inclined surface can be perceived with an object held in the hand or attached to the head. We investigated whether these two person-plus-object perceptual systems exhibit the same pattern of nonlinear phase transitions in perception of this affordance. Blindfolded participants explored an inclined surface with a rod held in the hand or attached to the head and reported whether they could stand on that surface. Inclinations were presented in ascending or descending sequences. In both conditions, responses exhibited negative hysteresis - perceptual boundaries occurred at steeper angles for descending than for ascending sequences. The generalization of this pattern across components that differ in physiology, sensitivity, and experience is consistent with both the soft assembly of perceptual devices and with a dynamical systems perspective on perception of affordances.