Women prefer less masculine male faces (and men prefer more masculine faces in women) for long term relationships under conditions of environmental harshness. Consistent with idea that high-quality partners may be low investors and suggests that under harsh ecological conditions, men and women prefer a low quality / high investment partner for long term relationships.
Behavioral Syndromes correlation of behavior across multiple contexts for example, aggression (territorial disputes vs. mating) Same as personality in humans?
Growing consensus that many descriptors of personality can be characterized into five broad underlying dimensions of personality (The Big Five Model – John, 1990) The nature of personality Extraversion assertive, energetic, quiet, shy, withdrawn sociable Neuroticism anxious, emotional, calm, at ease, unemotional moody Conscientiousness dependable, organized, careless, irresponsible practical frivolous Agreeableness cooperative, generous, cold, quarrelsome, selfish warm Openness curious, imaginative, shallow, simple insightful High scoreLow score Tendency to be engaged Tendency toward neg.moods Tendency to plan & conform Tend to cooperate Tend toward diversity
The nature of personality Extraversion extroverted introverted Neuroticism nervous, high-strungcalm, relaxed Conscientiousness conscientiousdisorganized Agreeableness agreeabledisagreeable Openness open to new experiencesclose-minded High score Low score Take the Big Five test: http://www.outofservice.com/bigfive/
Assessment of individual differences on these 5 dimensions can be determined reliably by self-report Personality is predictive of a wide range of social and work-related behavior and some behavioral pathology, personality can be an independent risk factor for mental health problems –Individuals who are impulsive and disinhibited in childhood have elevated risk of alcoholism and other substance abuse disorders in adulthood – Caspi et al 1996 –Clinical depression hypothesized to be due to high levels of neuroticism coupled with low levels of extraversion – Watson et al 1994 The nature of personality
Twin Studies on Personality Additive genetic factors account for 40-60% of the variance in personality Shared environmental influences are negligible Non-shared environmental effects account for 50% of the variance - different experiences in the same environment- differential parental treatment of siblings or favoritism -different experiences in different environments -- having different friends in school -reacting to the same event in different ways- parental divorce
Consistently find little/no personality similarity among adoptive relatives Loehlin (1992) – compute weighted-average correlation between nonbiologically related siblings reared together –Extraversion (3 studies, n=258) -0.07 –Neuroticism (3 studies, n=258) 0.11 –Agreeableness (2 studies, n=250) 0.06 –Conscientiousness (2 studies, n=245) 0.02 –Openness (2 studies, n=241) 0.06 Adoption Studies on Personality
Genes involved with personality 1.DRD4 2.Serotonin transporter gene, 5HTT 3.Monoamine Oxidase 4.Nitric oxide synthase 5.Fos B
Cell. 1996 Jul 26;86(2):297-309. A defect in nurturing in mice lacking the immediate early gene fosB. Brown JR, Ye H, Bronson RT, Dikkes P, Greenberg ME.
The Fos family of transcription factors are induced by environmental stimuli that trigger adaptive neuronal response. fosB mutant mice are profoundly deficient in their ability to nurture young animals but are normal with respect to other cognitive and sensory functions. The nurturing defect is likely due to the absence of FosB in the preoptic area, a region of the hypothalamus critical for nurturing. These observations suggest that a transcription factor controls a complex behavior by regulating a specific neuronal circuit - indicates nurturing in mammals has a genetic component.
Association of dopamine D4 receptor (DRD4) with novelty seeking –Neurotransmitter dopamine has been implicated in brain reward and approach systems –Novely seeking does not align precisely with any one of the big 5 personality factors but is associated with high levels of extraversion and low levels of conscientiousness Impulsive, exploratory and extravagant
Elovainio, et al. 2005. The mediating role of novelty seeking in the association between the type 4-dopamine receptor gene polymorphism and cigarette-smoking behavior. Examined the relationship between variation at type 4 dopamine receptor gene and cigarette-smoking behavior and the mediating role of the temperamental novelty seeking. The two- and five-repeat alleles were significantly more common in the group of current smokers than others (ratio 2.53). After controlling for the effect of novelty seeking on smoking behavior, the relationship dropped substantially, being no longer statistically significant.
Neuroticism and the serotonin transporter gene http://www.driesen.com/ssrireuptake.jpg Serotonin is 5-HT (5-hydroxytryptamine), serotonin transporter is 5-HTT
5-HT is serotonin 5-HTT--serontonin transporter (presynaptic side) 5-HTT is also the target of cocaine and methylphenidate 5-HT receptors are stimulated by LSD
Association of the serotonin transporter with disease Polymorphisms in 5-HTT in the promoter region 16-repeat- l long 14-repeat-s short ‘s’ is associated with reduced transcription and is dominant to ‘l’ Individuals with at least one copy of ‘s’ scored higher on Neuroticism Association with 5-HTT has been reported for violent suicide and early onset alcoholism
Dopamine plays a role in novelty-seeking behavior Serotonin is important for neuroticism Null mutants for the serotonin 1a receptor (5-HT1A) show elevated levels of anxiety Null mutants for 5-HT1B show reductions in anxiety and elevations in aggression mutation in a single Dutch family correlates with violent behavior Null mutants for DRD4 show reduced response to novelty Studies in knock-out mice
The interaction between low serotonin and high testosterone levels in the central nervous system has a significant effect on the neural mechanisms involved in the expression of aggressive behavior. Testosterone modulates serotonergic receptor activity in a way that directly affects aggression, fear and anxiety.
A chronic, severe and disabling brain disease Characterized by profound disturbances of cognition, emotion, and social functioning 1% of the population develops Schizophrenia during their lifetime Affects men and women equally – men in late teens and early 20s; women in 20s and 30s Central features include both “positive” (additional behaviors) and “negative” (loss of normal behaviors) symptoms Schizophrenia
Some people have only one psychotic episode during their lifetime Others have many episodes during a lifetime but lead relatively normal lives during the interim Individuals with chronic or recurring schizophrenia often do not fully recover There is no definitive marker: diagnosis is made on self-reporting Schizophrenia
–hallucinations –delusions –disorganization of thoughts –bizarre behavior –incongruity of affect (improper behavior relative to the specific situation Schizophrenia - symptoms
Males have an earlier age of onset than females male incidence peaks in mid-20s female incidence peaks around 30 second, lower incident peak around menopause
Schizophrenia – evidence for a genetic influence runs in families 40-50% risk for monozygotic twins 10% risk to child of affected parent
Schizophrenia – evidence for a genetic influence Evidence suggests that the predisposition is inherited, not the certainty of developing Schizophrenia itself.
Based on family studies, current models support existence of two or three susceptibility loci liability alleles confer ~ two-fold increase in risk to the sibling of an affected individual Linkage studies support this model – identification of several weakly-linked regions of the genome Genetic models for Schizophrenia
Schizophrenics are more likely to be born in winter or early spring Why? some seasonally varying factor alters the developing CNS, increasing an individual’s lifetime risk parents of schizophrenic patients have an unusual pattern of conception Environmental Factors One of the most consistent findings in schizophrenia is that the distribution of birth dates of individuals with schizophrenia differs from that of the general population.
http://www.sciencedaily.com/releases/2003/01/030123072840.htm “anxiety and aggression” gene? Are there genes for behaviors? http://www.sciencedaily.com/releases/2004/05/040526063645.htm Gene Linked To Alcoholism Alcoholism tends to run in families, suggesting that addiction, at least in part, has an underlying genetic cause. Now, researchers at the University of Illinois at Chicago have discovered a gene linked to alcohol dependency. Laboratory mice deficient in the gene were found to consume excessive amounts of alcohol, preferring ethanol to water and evincing highly anxious behavior in a maze test. Drunken Fruit Flies Reveal Molecular Pathway Regulating Sensitivity To Alcohol (June 17, 1998) -- Researchers at UC San Francisco have identified a molecular pathway in intoxicated fruit flies that is responsible for regulating the flies' meandering, wobbling responses to alcohol. “alocholism” gene?
Variation in a gene called VMAT-vesicular monoamine transporter 2 C-correlates with self- transcendence, which correlates with spirituality A-does not Reported in a book by Dr. Dean Hamer, The God Gene: How faith is hardwired Into our genes Chief of gene structure, NCI