biological practical

• aim of practical

  to investigate the relationship between testosterone and physical aggression scores
• hypotheses

  there will be a significant negative correlation between digit ratio of people and their physical aggression scores
• sample

  opportunity sample of 14 students aged 16-18
• procedure

  1. informed consent gained and briefed that they would need to answer questions about aggression - told they would be measuring their fingers and doing a questionnaire & had the right to withdraw
  2. participants given a QR code to the buss-perry aggression test and asked to answer honestly - given 10mins to complete
  3. participants instructed to measure the lengths of their ring & index finger using a ruler - done to work out the digit ratio between the 2 and was calculated by dividing the amounts
  4. debriefed and purpose of correlation was explained
• findings - graph & statistical test

  • graph used - scatter graph
  • statistical test - spearman's test as study was looking for a correlation between digit ratio and aggression scores using repeated pairs design and interval ratio data
• findings

  as the critical value of 0.715 is greater than the critical value of 0.464 correlation is significant so there will be a significant relationship between digit ratio span and physical aggression scores
• outline 2 improvements you can make to your biological practical

  • improve aggression score measurement
  • improve measurement of finger length or testosterone
• improving aggression score measurement

  by adding distraction questions to hide the purpose of the questionnaire as it was obvious it was about aggression - participants could show social desirability bias to appear less aggressive (e.g: include questions such as: what is your favourite mcdonalds sauce to throw off participants)
• improve measurement of finger length or testosterone

  as participants used their vision and cheap plastic rulers to measure fingers as a basis for testosterone levels so therefore inaccurate. instead - can utilise a blood test to measure testosterone levels or calipers to measure finger lengths more precisely
• strength (validity)

  • research was correlational
  • allows us to investigate relationship between aggression and a factor what we cannot ethically nor practically investigate (testosterone levels in uterus)
  • allows us to identify relationships between testosterone and a behaviour that cannot be investigated
• weakness (generalisability)

  • low population validity
  • 14 psychology students aged 16-18 on a british sixth form college. - level of testosterone in the sample only reflects those in their teen years
  • therefore, relationship between digit ratio and physical aggression may not be representative of other age groups
• weakness (credibility)

  • issues with correlational studies
  • other factors in participants lives such as: trauma, upbringing could have affected their physical aggression scores - factors we cannot measure
  • therefore, cannot establish a cause-effect relationship between prenatal factors and aggression scores directly as other unaccounted factors may lead to higher aggression
• strength (reliability)

  • study followed a standardised procedure
  • all participants completed buss-perry aggression questionnaire and measured digit ratio of index and ring finger in the same way
  • therefore, can be replicated to test for reliability in whether testosterone is correlated with aggression
• conclusion

  individuals with a higher testosterone level are more likely to display higher physical aggression scores