Depression as bargaining: The case postpartum

It was recently hypothesized that depression might function, in part, as a bargaining strategy when cooperation imposes a net cost but there are social constraints on defection (Hagen 1999). If so, such social constraints should be associated with depression, and depression in one partner should be associated with increased investment by other partners. Several predictions of this hypothesis were tested using postpartum depression (PPD) as a model for depression in general. The depression levels, abortion attitudes, additional mating opportunities, and investment in childrearing of 240 mothers and fathers with a new child were measured using self report instruments. Mothers were also asked whether the new child was planned and whether it was wanted. Perceived constraints on abortion correlated significantly with PPD levels, but, as predicted, only for mothers with an unplanned or unwanted child. Contrary to predictions, perceived constraints imposed by family and friends did not correlate with PPD levels. Social constraints on the pursuit of extra-pair copulations also correlated significantly with PPD levels, but, as predicted, only for men. As predicted, PPD levels in one spouse correlated significantly with increased investment in childrearing as reported by the other spouse. PPD levels correlated positively with parity for older women with few future reproductive opportunities, as predicted

The bargaining model of depression

Minor depression—low mood often accompanied by a loss of motivation—is almost certainly an adaptation to circumstances that, in ancestral environments, imposed a fitness cost. It is, in other words, the psychic equivalent of physical pain. Major depression is characterized by additional symptoms—such as loss of interest in virtually all activities and suicidality—that have no obvious utility. The frequent association of these severe and disabling symptoms with apparently functional symptoms like sadness and low mood challenges a functional account of depression as a whole. Given that the principle cause of major unipolar depression is a significant negative life event, and that its characteristic symptom is a loss of interest in virtually all activities, it is possible that this syndrome functions somewhat like a labor strike. When powerful others are benefiting from an individual’s efforts, but the individual herself is not benefiting, she can, by reducing her productivity, put her value to them at risk in order to compel their consent and assistance in renegotiating the social contract so that it will yield net fitness benefits for her. In partial support of this hypothesis, depression is associated with the receipt of considerable social benefits despite the negative reaction it causes in others

Comment on "Attractive Forces between Electrons in 2 + 1 Dimensional QED"

It is shown that a model recently proposed for numerical calculations of bound states in QED$_3$ is in fact an improper truncation of the Aharonov-Bohm potential.Comment: 4 page

Efimov Physics around the neutron rich Calcium-60 isotope

We calculate the neutron-Calcium-60 S-wave scattering phase shifts using state of the art coupled-cluster theory combined with modern ab initio interactions derived from chiral effective theory. Effects of three-nucleon forces are included schematically as density dependent nucleon-nucleon interactions. This information is combined with halo effective field theory in order to investigate the Calcium-60-neutron-neutron system. We predict correlations between different three-body observables and the two-neutron separation energy of Calcium-62. This provides evidence of Efimov physics along the Calcium isotope chain. Experimental key observables that facilitate a test of our findings are discussed.Comment: 5 pages, 4 figure

Comment on ``Quantum Phase of Induced Dipoles Moving in a Magnetic Field''

It has recently been suggested that an Aharonov-Bohm phase should be capable of detection using beams of neutral polarizable particles. A more careful analysis of the proposed experiment suffices to show, however, that it cannot be performed regardless of the strength of the external electric and magnetic fields.Comment: 2 pages, latex file, no figure

Music and dance as a coalition signaling system

Evidence suggests that humans have neurological specializations for music processing, but a compelling adaptationist account of music and dance is lacking. The sexual selection hypothesis cannot easily account for the widespread performance of music and dance in groups (especially synchronized performances), and the social bonding hypothesis has severe theoretical difficulties. Humans are unique among the primates in their ability to form cooperative alliances between groups in the absence of consanguineal ties. We propose that this unique form of social organization is predicated on music and dance. Music and dance may have evolved as a coalition signaling system that could, among other things, credibly communicate coalition quality, thus permitting meaningful cooperative relationships between groups. This capability may have evolved from coordinated territorial defense signals that are common in many social species, including chimpanzees. We present a study in which manipulation of music synchrony significantly altered subjects’ perceptions of music quality, and in which subjects’ perceptions of music quality were correlated with their perceptions of coalition quality, supporting our hypothesis. Our hypothesis also has implications for the evolution of psychological mechanisms underlying cultural production in other domains such as food preparation, clothing and body decoration, storytelling and ritual, and tools and other artifacts

Informational Warfare

Recent empirical and theoretical work suggests that reputation was an important mediator of access to resources in ancestral human environments. Reputations were built and maintained by the collection, analysis, and dissemination of information about the actions and capabilities of group members-that is, by gossiping. Strategic gossiping would have been an excellent strategy for manipulating reputations and thereby competing effectively for resources and for cooperative relationships with group members who could best provide such resources. Coalitions (cliques) may have increased members' abilities to manipulate reputations by gossiping. Because, over evolutionary time, women may have experienced more within-group competition than men, and because female reputations may have been more vulnerable than male reputations to gossip, gossiping may have been a more important strategy for women than men. Consequently, women may have evolved specializations for gossiping alone and in coalitions. We develop and partially test this theory

Bilateral Differentiation of Color and Morphology in the Larval and Pupal Stages of \u3ci\u3ePapilio Glaucus\u3c/i\u3e (Lepidoptera: Papilionidae)

A sharply delineated, bilateral differentiation of color patterns and morphology were observed in a final (5th) instar larva of a subspecies backcross of a female Papilio glaucus glaucus with a hybrid male (P. g. glaucus x P. g. canadensis). Color and morphological differences were detectable in the pupa as well. In addition, a bilateral size difference was evident in both the pupa and the resulting adult butterfly. Such observations within a single living individual attest to the bilateral independence (also evident in perfect gynandromorphs) and general flexibility of the developmental control in this species of Lepidoptera

Quantum electrodynamics in 2+1 dimensions, confinement, and the stability of U(1) spin liquids

Compact quantum electrodynamics in 2+1 dimensions often arises as an effective theory for a Mott insulator, with the Dirac fermions representing the low-energy spinons. An important and controversial issue in this context is whether a deconfinement transition takes place. We perform a renormalization group analysis to show that deconfinement occurs when $N>N_c=36/\pi^3\approx 1.161$, where $N$ is the number of fermion replica. For $N<N_c$, however, there are two stable fixed points separated by a line containing a unstable non-trivial fixed point: a fixed point corresponding to the scaling limit of the non-compact theory, and another one governing the scaling behavior of the compact theory. The string tension associated to the confining interspinon potential is shown to exhibit a universal jump as $N\to N_c^-$. Our results imply the stability of a spin liquid at the physical value N=2 for Mott insulators.Comment: 4 pages; 1 figure; v4: version accepted for publication in PRL. Additional material: the detailed derivation of the RG equations appearing in this preprint can be downloaded from http://www.physik.fu-berlin.de/~nogueira/cqed3.htm