Physical Development - September 27 PDF

Reflexes cute Precursors to moreimportatbehavi -Rooting - Gone at 3 weeks mouthonwhat'stouchingtheirface nutrition -Stepping - Gone at 3m steppingbuttheycan'twalkthemselvesyet leadstowalking -Palmar - Gone at 3/4m babiesgrabwhat'sintheirhand lesslikelytobedropp...

Reflexes cute Precursors to moreimportatbehavi -Rooting - Gone at 3 weeks mouthonwhat'stouchingtheirface nutrition -Stepping - Gone at 3m steppingbuttheycan'twalkthemselvesyet leadstowalking -Palmar - Gone at 3/4m babiesgrabwhat'sintheirhand lesslikelytobedropped -Tonic Neck (fencing) - Gone at 4m turntheirheadthentheykickarmandlegout SIDS -Moro - Gone at 6m sensationthey'refallingreachhandsout don'tfall -Babinski - gone at 8/12m fanouttheirtoes theyshouldshowthisrightaway Why important? - probabilistic epigenetic implications - at birth, weak, exaggerated, or no reflexes may indicate brain damage - retention after usual point indicates developmental delay (lack of maturation in cortex)theyshouldgoaway cancomebackinadultsw neuroconditions - implicated in SIDS rain mg  Sudden Infant Death Syndrome (SIDS) – #1 cause of death in first year – 1/3 of all infant deaths – 60% male, 40% female – biological correlates: prematurity, LBW, brain stem function, heart arrhythmias, sleep apnea – environmental correlates: low SES, non-breast feeding, smoke in household, soft bedding, pillows and stuffies – typically happens in 2- to 4-month-olds tonicneckreflex losing – More cases in fall/winter than spring/summer moreblanketsincribs  Potential reasons for SIDS Suffocation/CO2 - 2-4 months – reflexes (esp. Tonic neck) being replaced by controlled movementsCan'tholdheadup - Links to smoke, pillows, soft mattress, sleeping on stomach Cardiac inefficiency - Less blood pumped when on stomachs Overheating - Pillows, blankets, sleeping on tummy make harder for kids to cool selves by sweating - Heat may affect brain function related to coordination of airway control - May lead to deeper sleep, less likelihood of rousing, struggling  Tips to prevent SIDS Sleep on backs! “Tummy time” during dayneckmuscles Hard mattress No pillows or stuffed animals No used mattresses Don’t smoke around Keep room around 68 degrees No little hats Don’t bundle up when fevered Don’t cosleep (?) 50 50  SIDS and cosleeping notthevS Co-sleeping societies have fewer cases - may help kids from sleeping "too" soundly - helps them regulate physiologically - parents can respond to minor struggles But…co-sleeping associated with higher likelihood of SIDS in U.S. - within US, incidence higher when parent is medicated, drunk/drugged, smoking, obese  Trends in timing of sexual maturation Average age of menarche decreased from 16-17 to 12- 13 from 1850-1975, only modest decreases since then But age of secondary younger characteristics (e.g., breast buds, testicular volume) still declining I Several recent cases of EXTREMELY early thelarche (e.g., age 2 years) secondary seen in select populations (e.g., Puerto Rico) dutohthalatese  Potential reasons for historical trends for earlier puberty - Nutrition, lack of exercise porgoni - Growth hormones in milk, meat, eggs, cosmetics – especially estrogen stimulators - Environmental chemicals – especially phthalates BPA - Sexually suggestive content in environment - Family stress evolution not sex educationthough  Correlates of individual differences in pubertal onset Early-maturing boys – Immediate effects: Confident, relaxed, popular, leaders becomes neg – Later-life effects: less positive self-identities Early-maturing girls – Immediate effects: Substantial variability Some enhanced peer relations Several problematic behaviors (e.g., age-deviant, eating disorders, depression)younggirlsolderboys Moderating role of ethnicity/body image whitegirlproblem – Later-life effects: lower educational/professional achievement  Life-history theory of Human Reproductive Strategies (Belsky, 2012) Basic evolutionary theory background – Three basic tasks to further direct fitness: indirectfitness nephewsthieces Survival topuberty 8 g ne Reproduction moreenergyinto one from Parenting takeaway – The last two compete with one another, leading to two possible “strategies” (fast vs slow; quantity vs quality) “Strategy” doesn’t imply consciousness Paths are probabalistic, not deterministic; may be cumulative, not sequential Different paths may not actually influence reproductive fitness in contemporary world whydowehavethis strategy Belsky (1991; 2012): Psychosocial Acceleration Theory Environmental Stressors hardship economic Family Environment works is Attachment Style / Worldview Waite sᵗfuᵗ oYcHiew Pubertal Timing Reproductive Strategy  Belsky, 2012: What environments matter? Dangerous ones: Environmental unpredictability and shorter life expectancies – Makes sense to mate early, since might not live long readyto havekidsyounger – Makes sense to mate often, rather than invest energy as a parent parenting reproduction Low parental investment may lead to intergenerational transmission of this reproductive strategy, as it may accelerate development of offspring mentendtolead thechargenolimiton ofreproduction weirdtheorybutconvincingevidence