Heston - adoption study

Question 1

aim

Answer 1

to see whether the likelihood of being diagnosed with schizophrenia was higher for nature or nature.

Question 2

sample

Answer 2

• 47 experimental ppts (30 males, 17 females) and 50 control ppts (33 males, 17 females) - born to schizophrenic mothers who were in an American psychiatric hospital in Oregon between 1915 - 1945
• children were selected if their mother had put them up for adoption from birth and had no connection with her

Question 3

procedure

Answer 3

• the psychiatric status of the ppts was assessed using things like police records, personal interviews, school records, IQ, etc.
• two psychiatrists evaluated the dossier compiled on each ppt blindly and independently. a third evaluation was also made my Heston himself. a diagnosis of schizophrenia was only given when all three rafters agreed and they were also diagnosed by a psychiatric hospital.
• a score of 1-100 was assigned to each ppt regarding this psycho-social disability, scores below 75 indicated psychiatric symptoms become troublesome.

Question 4

results

Answer 4

• no significant different for age, number or the number who were adopted, IQ, etc.
• there were significant differences in psycho-social disability, schizophrenia, time spent in penal/psychiatric institution, IQ deficiency, etc.
• data: average psycho-social disability = 80.1 for controls and 65.2 for experimental group. number of schizophrenics was 0 for controls and 5 for experimental group.
• rate of schizophrenia was 10.6% for those born to schizophrenic individuals, whereas this was 0% for those who weren’t.

Question 5

conclusion

Answer 5

• Heston concluded that the findings support the influence of genes in schizophrenia, and that inheritance also contributes to psycho-social disability.
• however, there must be other possible factors which influence schizophrenia because half the ppts born to schizophrenic mothers went on to be successful adults.

Question 6

strengths

Answer 6

• sample: high generalisability. looked at both males and females.therefore, results are more representative of how schizophrenia is experience/developed for both genders.
• procedure: high inter-rater reliability. there were three rafters and a psychiatrist who all had to agree on the diagnosis of a ppt before it was made. therefore, there is more objectivity and researcher bias was controlled for as evaluations were carried out by researchers blind to hypothesis.
• results: high validity. triangulation was used to gather results, e.g. personal interviews, police and school records, etc. therefore, this helps to provide more in depth and insightful results for how nature and nurture influence the likelihood of schizophrenia.

Question 7

weaknesses

Answer 7

• sample: low generalisability. ethnocentric sample as all ppts were born to schizophrenic mothers in a psychiatric hospital in Oregon. therefore, results may not be representative of how nature and nurture influence the likelihood of schizophrenia cross culturally.
• procedure: low validity. there may be other extraneous variables that were not controlled for, e.g. fathers psychiatric status wasn’t checked. therefore, a cause and effect cannot be established which decreases the validity.
• results: low validity.there may be elements of social desirability within the data collection methods as schizophrenia is a sensitive behaviour and ppts may have been scared or embarrassed of maybe having it. therefore, responses given by ppts in questionnaires and interviews may not be honest which decreases the validity of results.

Question 8

application

Answer 8

high application. concluded that schizophrenia is heritable and can be passed down through genes. therefore, we can put in preventative measures to avoid schizophrenia being triggered in ‘at risk’ individuals, e.g. community support to ensure a better prognosis.