Evolutionary Psychology Study - Curtis et al (2004)

Define evolutionary psychology

A change over time in the inheritance of behaviors/traits that are believed to be advantageous

What is the aim of the study

To investigate that the trait of disgust has evolved to protect us from disease and pathogens

What is the research method

questionnaire

What was the sample

40,000 individuals from 165 countries

Outline the method of the study

The sample completed a web-based survey using 20 photo stimuli.

They were shown a variety of different images, and the images were organised in pairs. One image of each pair was of infectious/potentially harmful stimuli whereas the other was of non-infectious stimuli

For example, one pair contained an image of a plate of bodily fluids and an image of a plate of blue viscous liquid

Participants had to rank each image from 1-5 (1 being the most disgusting and 5 being the least disgusting)

What were the results of this study

Images of infectious/potentially-harmful stimuli were ranked as significantly more disgusting than similar images with little or no disease relevance

This pattern of response was found across all regions of the world

What are strengths of this study

High generalisability - large sample size

High cross-cultural validity - samples taken from 165 countries

High repeatability - easy to replicate the survey

High reliability - the pattern of results remained constant across all countries of the world

What are weaknesses of this study

Low internal validity - subjective ranking system

Low construct validity - social desirability through ranking process

Suggest a linking paragraph for this study

Curtis et al demonstrates how disgust has evolved to help humans protect themselves from disease

For example, the pictorial infectious/pathogenic stimuli was ranked as significantly more disgusting than similar images which depicted non-infectious items

This is important because it shows how humans feel more disgusted by items which could cause them disease and this disgust causes them to avoid such items. It is also important to note that this pattern of results was common across all regions of the world, therefore this defence mechanism is common across all humanity

Therefore, evolutionary behaviours can be inherited.