Gilchrist and Nesburg

• Study design


  Laboratory experiment
• Method

  1. Participants randomly allocated to be deprived of food for 20 hours or not

  2. Participants told they would complete an image matching activity

  3. Participants shown images of food for 15 seconds

  4. Participants shown the image again with its brightness reduced

  5. Participants asked to readjust the image to be the same as originally
• Evaluation

  • This theory has practical applications, especially in the field of marketing products
  • Sellers of food, drink and other products can focus on using appealing imagery in marketing knowing customers will be drawn to their product
• Due to the study requiring the participants not to eat for 20 hours


  This may have set up an obvious demand characteristic with participants feeling they were expected to respond to pictures of food
• Participants feeling they were expected to respond to pictures of food


  They may have exaggerated their response to images to food to help the researcher
• Due to the independent groups design of the experiment


  There may have been individual differences that caused the result
• Participants in the experimental group


  May have had by chance a different perception of brightness
• The study showed that motivation can affect our perception
• The study had ecological validity because the participants really were hungry
• The study was carefully controlled, with matched timing and exactly the same conditions for both groups, apart from hunger
• This means it would be easy for other researchers to replicate the study
• Limitations of the study


  • There were not very many participants and they were all students of a similar age, so it is difficult to apply these results to other types of people
  • The participants were volunteers so their behaviour might not have been representative, as they were keen to take part in the study
  • They might also have guessed what the study was about, which could have also affected their behaviour
• Aim: To investigate how motivation affects perception.

  Results: The participants who had been food deprived adjusted the image to be brighter than the participants who had not been food deprived.

  Conclusions: This suggests that motivation, in this case motivation to eat, influences perceptual set with people seeing food as brighter.