PSYC 380 Week 5 DB Forum 3 Example

Discussion Board Forum 3: Thread and Two Replies

PSYC 380 Physiological Psychology, Discussion Board Forum 3 (thread and two replies)

Thread by [Student Name]

The prompt and the classmates' posts are composites standing in for the course's own forum; the textbook and the three journal articles are real and described from their published sources; the requirements follow Liberty's public course guide for PSYC 380.

Thread

Prairie voles and meadow voles look almost alike, yet a male prairie vole typically settles with one female, helps raise the young and drives off intruders, while a male meadow vole mates and moves on. That contrast has made the two species one of the best models for asking how a brain supports a lasting bond. Carlson (2014) describes how hormones such as oxytocin and vasopressin, released in the brain during mating and caregiving, influence reproductive and parental behavior in mammals.

Young and Wang (2004) brought the vole findings together into a model. In their account, oxytocin and vasopressin help an animal process the social cues that identify a particular partner, while dopamine in the brain's reward areas supports learning about what is rewarding. When both systems are active at the same moment, during mating, the result is a conditioned preference for that partner, which researchers observe in the laboratory as an animal choosing to spend time with its mate instead of a stranger. The species differ less in how much of these chemicals they make than in where their receptors are located, so the same hormone released in two brains can have very different effects on behavior.

Lim et al. (2004) tested that idea directly. They used a harmless virus to carry the gene for the vasopressin V1a receptor into the ventral forebrain of male meadow voles, raising receptor levels toward the prairie vole pattern. The treated males, from a species that ordinarily shows little attachment, formed partner preferences much more readily than untreated males. A change in one gene's expression, acting within circuits already present, was enough to shift a complex social behavior.

Classmates: what would a human study need to show before we could say the same mechanism shapes our relationships?

Reply to Hannah

Hannah, the Swedish study you found is a good test of my question. Walum et al. (2008) examined a repeat variant of the human AVPR1A gene, which encodes the receptor manipulated in the voles, in adult twins and their partners. Men carrying a particular allele scored lower on partner bonding, reported more marital problems and were less often married, and their wives rated the marriage lower in quality. That fits the vole model, but it is an association across many people, and each man's variant explained only a small share of relationship differences. The researchers could not change the gene and watch what happened, as Lim et al. (2004) had done in voles.

Reply to Isaac

Isaac, you worried that this research reduces love to brain chemicals. I understand the concern, but I think the findings describe how bonding works rather than what it means. Carlson (2014) treats hormones as influences on behavior, interacting with experience, not as switches that determine it. Even in voles, Young and Wang (2004) describe a bond that forms through learning during a shared experience, which leaves room for history and context. In people, commitment involves choices, promises and values that no receptor count captures. Knowing that the brain has systems that support attachment can actually deepen appreciation for faithfulness, since it shows how our bodies were built for connection.

References

Carlson, N. R. (2014). Foundations of behavioral neuroscience (9th ed.). Pearson.

Lim, M. M., Wang, Z., Olazábal, D. E., Ren, X., Terwilliger, E. F., & Young, L. J. (2004). Enhanced partner preference in a promiscuous species by manipulating the expression of a single gene. Nature, 429(6993), 754-757. https://doi.org/10.1038/nature02539

Walum, H., Westberg, L., Henningsson, S., Neiderhiser, J. M., Reiss, D., Igl, W., Ganiban, J. M., Spotts, E. L., Pedersen, N. L., Eriksson, E., & Lichtenstein, P. (2008). Genetic variation in the vasopressin receptor 1a gene (AVPR1A) associates with pair-bonding behavior in humans. Proceedings of the National Academy of Sciences, 105(37), 14153-14156. https://doi.org/10.1073/pnas.0803081105

Young, L. J., & Wang, Z. (2004). The neurobiology of pair bonding. Nature Neuroscience, 7(10), 1048-1054. https://doi.org/10.1038/nn1327