10-8 parental.doc

Psych 320: Motivation 08 Oct. Parental Behavior Wong Ch. 3 By the end of this lecture, you should be able to answer the following: What is meant by ?parental behavior? or ?parental motivation?? Is parental behavior costly? Why or why not? Be able to describe in detail the studies of Levy on maternal behavior in sheep, and what is known about some of the key inputs to this behavioral system for sheep mothers. Be able to describe in detail some of the studies of Rosenblatt on maternal behavior and the ?maternal responsiveness? measure in female rats. What is the distinction between ?induction? and ?maintenance? of maternal behavior in rats? Describe some of the important relationships between estradiol and maternal behavior in female primates. At a few places throughout the lecture, we have described cases of hormones not telling the whole story with regard to maternal behavior ? what are some of the examples of this in rats and in humans? Describe the work of Harry Harlow with macaques, and what this tells us about the importance of attachment. According to Kagan, what are the major signs of attachment in children and young animals? 1. PARENTAL BEHAVIOR Parental motivation: tendency to make young the goal of behavior where that behavior promotes the well-being and survival of the young Much research is focused on maternal behavior Why? In a lot of mammal species, it is the mom that devotes much of the energy in raising the offspring. (arguments form sexual selection theory) Question of paternity- father never really knows for sure offspring is his (besides genetic testing) Parental care across animals ranges from zero to extremely extended Parental care is costly Energy- amount of calories of work required Time- opportunity costs Future reproductive success (limits amount of success in future) Study of Mammals: maternal care vs. fecundity Read & Harvey (1989) If you have to devote a lot of energy for a single offspring, you can?t have that many. To have more offspring, devote less energy to one single offspring. At one end of the extreme- Bats (basically only 1 offspring a year) ; other extreme ? lagomorphs ?rabbits? (produce large number of offspring per bout and can have several bouts per year) ( Evolution of mother-young recognition & discrimination behaviors (ways in which the young can rapidly learn who their parents are and the parents can rapidly learn their young from the others) litter-specific cues, individual differences, olfactory ?labeling? in goats 2. SHEEP & CENTRAL IDEAS OF MBSs Ideas of internal and external factors multiple inputs Studies by Levy Female sheep giving birth. As soon as the young is born, she immediately starts licking the young. The bond is being formed. Levy found that the female sheep are only attracted to amniotic fluid at time of birth Olfaction necessary (smells and tastes) Licking of this fluid off of young ( establishment of mother-young bond If a researcher grabs the newborn and washes the newborn: a first-time mother will reject the young. If she can?t smell or taste those normal cues, this is not her young. On the other hand, an experienced mother will accept the young. What are some of the inputs to this system (behavior)? Young itself in the environment Olfactory cues Ability to sense those cues Touch cues, visual cues Experience of mother 3. PHYSIOLOGICAL & NEURAL INFLUENCES Rosenblatt?s work with maternal behavior in Norway rats ?Maternal response? = latency to retrieve a pup from her nest A new mother will be instantaneous about retrieving the pup. She does it the first time. Virgin females will take about a week of introductions before females become ?pup-sensitized? Importance of hormonal changes during second half of pregnancy In a series of studies, Rosenblatt removed the ovaries from a virgin female. In experimental animals, over a several day period, he injects levels of estradiol and progesterone to mimic the levels in a normal pregnant female. By doing this inside the female, he can produce a maternal response to new pup on the very first day. Idea that hormonal profile induces and affects her behavior Stimulation from pups helps maintain parental care behavior Olfactory, tactile, visual, auditory Is that all there is to the behavior? (Hormones not the whole story) Pup-sensitized virgin females ? hormone profiles similar to non-pup-sensitized virgin females Olfaction and the mother-young bond Olfactory bulb ( amygdala ( medial preoptic area Amygdala important in social processing, emotion Lesions show a decrease in maternal responsiveness Direct estradiol micro-injections shows an increase in maternal responsiveness 4. HUMAN / PRIMATE PARENTAL BEHAVIOR Estradiol and non-human primates Pryce et al. 1988 studies with tamarin monkeys Correlation studies Moms with higher levels of estradiol before giving birth, often show an increased maternal behavior immediately after birth. This leads to an increased infant survival to one week = this first week is where the infant attachment is established. Human females Pregnant females show an increase in cortisol (stress hormone) levels, and this correlates with an increase in physical affection towards infant. Cortisol levels in new mothers correlate with attraction to infant?s body odor. Mothers with more experience More positive maternal attitudes Higher attraction to infant?s odor 5. IMPORTANCE OF ATTACHMENT Notion of really tight and special bond between offspring and caregiver Studies of Harry Harlow Infant macaques (monkeys) raised with surrogate mothers ( link to stimulus seeking Contact comfort- physical tactile connection Signs of attachment Jerome Kagan (developed theories of attachment and how to test experimentally) Young more easily calmed down by its primary caregiver than by other adults in the environment The young who is attached to a particular primary caregiver will approach that caregiver for play or consolation Young less distressed by novelty with caregiver Exhibit separation anxiety when caregiver is absent