Biological practical AO1/AO3

What is the aim of the biological practical?

To investigate whether there is a relationship between 2D:4D ratio and aggression.

What is 2D:4D ratio?

Finger length ratio- it differs between men and women, so is sexually dimorphic.

What does a smaller 2D:4D ratio indicate?

Higher aggression levels

What are smaller digit ratios thought to be due to?

Higher prenatal testosterone levels/greater sensitivity to androgens

What are androgens?

Male hormones

What did Bailey and Hurd (2005) find?

The smaller the 2D:4D ratio the higher the level of aggression, more so in males than females.

Operationalised one-tailed hypothesis

There will be a negative correlation between 2D:4D ratio (cm) and anger scores (out of 165).

Describe the procedure of your biological practical

• 18 psychology students aged 16-17 from the same Sixth Form- opportunity sample

• Each participant measured their index and ring finger with a ruler and divided the 2D by the 4D to find the ratio

• They were given a questionnaire with 34 questions by Buss and Warren (2000) in which they had to score each question from 1-5

• The scores were added up (except question 19 which was reverse scored) and a Spearman’s Rho was conducted to find the correlation

Evaluate the generalisability of your biological practical

Strengths

/

Weaknesses

• Small sample- 18 participants

• Shared characteristics- aged 16-17, psychology students, all from same Sixth Form

Evaluate the reliability of your biological practical

Strengths

• Standardised- every participant was given the same questionnaire and used the same method to find the 2D:4D ratio

Weaknesses

• OTOH- each participant measured their own finger length, this is subjective

Evaluate the applicability of your biological practical

Strengths

• Can be used to explain aggression- due to higher levels of testosterone in the womb

Weaknesses

• Socially sensitive- may upset people with shorter digit ratios as it assumes they’re more aggressive

Evaluate the validity of your biological practical

Strengths

/

Weaknesses

• Low ecological validity- lab experiment

• Low mundane realism- questionnaire about aggression

• Demand characteristics- psychology students can more easily guess the aim

• Social desirability- participants may change their scores

Evaluate the ethics of your biological practical

Strengths

• Informed consent

• Right to Withdraw

• Confidentiality

• No deception

Weaknesses

• Protection from harm- may be distressing to find out you’re a very aggressive person

• Consent- participants were under 18 and so may not have the capacity to consent

• No debrief