By Daniel Nettle and Helen Clegg Presented by Grant and Brooke

 1% of the population across cultures  Heritable  Drastically reduced reproduction

 Too frequent to be a mutation  Natural selection has not eliminated schizophrenia  Is there a beneficial effect of the traits?

 Continuum of personality experience ranging from normal dissociative, imaginative states to extreme states related to psychosis  More schizotypy does not mean more ill  Linked to academic achievement and creativity  Negative effects may remain dormant unless triggered by environment

 Traits measured on 4 dimensions  High scores predict the onset of schizophrenia  Schizophrenic patients score high on all 4 dimensions  Bipolar patients score high on 3 dimensions

 High incidence of serious psychiatric illness in families of artists  Many studies found that individuals active in creative arts have elevated levels of some schizotypy traits  Is artistic creativity the evolutionarily beneficial effect of schizotypy?

 Geoffrey Miller’s hypothesis of costly displays of quality whose function is to attract mates  Prediction: artistic production correlated with high number/quality of sexual partners

 Unusual experiences: magical thinking/perceptual  Cognitive disorganization: poor concentration  Impulsive non-conformity: reckless behaviors  Introvertive anhedonia: lack of enjoyment/social withdrawal

 Unusual experiences and impulsive non- conformity elevated in poets and artists  Introvertive anhedonia positively associated with schizophrenia, but negatively associated with artistic creativity

 Higher schizotypy traits of artists (unusual experiences and impulsive non-conformity) should increase number of sexual partners  Increase in sexual partners should operate through artistic production  Schizotypy that is characteristic of schizophrenics (introvertive anhedonia) should be negatively correlated with mating success

 Examines the relationship between schizotypy and mating success  The sample looks at the general adult population augmented by targeted sampling of artists and poets  The sample is not representative of the population; it is specifically designed to produce a full range of schizotypy scores in a non-clinical context

 Unusual experiences contains items referring to perceptual and cognitive aberrations and magical thinking  Cognitive disorganization describes difficulties of attention and concentration  Impulsive non-conformity refers to violent and reckless behaviors  Introvertive anhedonia measures lack of enjoyment and social withdrawal

 Participants were 425 British adults (256 male, 269 female), average age of 40.5 years with standard deviation of 14.5 years  Participants received a gift card for participation  Recruited people from the general population using online advertisement, questionnaire packs, and mature psychology students  Recruited specialist creative groups via advertisement in visual art magazine, poetry website, and by writing directly to published poets  100 more people heard about the study and indicated their interest to participate

 Participants filled out the O-LIFE schizotypy inventory and a section on psychiatric historyO-LIFE schizotypy  Also filled out a section regarding creative interests and participants indicated their degree of creative activity in poetry or visual art  Participants rated selves as not producing poetry or art (241), hobby producer (57), serious producer (60), professional producer (67) in either domain  A final section of the questionnaire contained wide- ranging personal history questions that asked for information on mating success (reproductive success was defined as greater number of partners)

 Are your thoughts sometimes so strong you can almost hear them?  Have you ever felt you have special, almost magical powers?  Is your hearing sometimes so sensitive that ordinary sounds become uncomfortable?  Are you so good at controlling others that it sometimes scares you?  Does it often happen that nearly every thought immediately and automatically suggests an enormous number of ideas?

 Do you ever have the urge to break or smash things?  Do you often feel like doing the opposite of what people suggest, even though you know they are right?  Would you take drugs which may have strange or dangerous effects?  Have you ever taken advantage of anyone?

 Do you find it difficult to feel very close to your friends?  Are you much too independent to really get involved with people?  Are people usually better off if they stay aloof from emotional involvements with people?  Do you have trouble letting yourself go and enjoying yourself at a lively party?

 Are you sometimes so nervous that you are blocked?  Do you ever feel that your speech is difficult to understand because the words are all mixed up?  No matter how hard you try to concentrate do unrelated thoughts always creep into your mind?  Do you often feel "fed up"?  Are you easily hurt when people find fault with you or the work you do?

 Multiple regression analysis  Independent variables: 4 dimensions, age, sex, social class  Dependent variable: number of partners

Results PREDICTION: If schizotypy increased mating success, it would do so through enhancing creative behavior RESULTS: Number of partners and level of engagement with poetry and visual arts

Results PATH ANALYSIS Linkages among creative behavior, mating success and 3 dimensions Cognitive disorganization left out because no significant relationship with creative activity or mating success

 The results are consistent with Miller’s hypothesis that artistic creativity functions as a mating display  Schizophrenia patients are also high in unusual experiences and impulsive non-conformity  These results are consistent with the view that schizotypal traits are maintaied in the human population at significant levels because the negative effects of psychosis are offset by enhanced mating success

 Impulsive non- conformity can enhance mating success due to the reckless behavior (direct benefit)  Unusual experiences can manifest as enhanced creativity (indirect benefit) Schizotypal Traits Mating Success But recent evidence suggests a different model…

 Poets and artists score as highly on unusual experiences and impulsive non-conformity as schizophrenic patients do  The difference is that poets and artists do not score as high on the introvertive anhedonia  Suggests that individuals in good condition can channel odd experiences and impulses into creative output and adaptive behaviors, while those in poor condition develop psychiatric disorders

Introvertive anhedonia appears to be the critical condition-related dimension that differentiates between the positive and negative sequelae of schizotypal traits

 There were no observed sex differences in the relationships between creative output and reproductive success  Results show that when either sex invests in creative output, it has similar effects on mating success

Mate choice is linked to creativity, creativity to schizotypy, and schizotypy to schizophrenia

 Measurement of mating success is number of partners  Never look at quality of partners  Present day results may not relate to EEA  Pattern is the same for male and female artists, counter to condition dependent fitness hypothesis  Quality of creative work produced never assessed  People may misrepresent how often they produce creative work