POZZULO ET AL (LINE-UPS)
By: Maryam Faysal and Mashal Aamir
PSYCHOLOGY BEING INVESTIGATED
•Line-up
•False memory
•Eyewitness testimony
•False positive response
BACKGROUND
•Pozzulo studied child witnesses and recognized post event cognitive effects
•Research from, (Pozzulo and Lindsay 1997), showed that children were less likely
than adults to say ‘I don’t know’
•Through witness information, a line-up is formed
•False positive response
•Social factors may explain why children may make incorrect decisions in a line-up:
Have to choose a person rather than a choice to pick one
Child views the adult as the authority figure thus they tend to comply
Children are pressurized to choose as they fear they would get in trouble otherwise
AIM
The aim was to explore the effect of social versus cognitive factors on
children’s performance as eyewitnesses. Pozzolu did this by minimizing
any cognitive effects that could impair the children’s decision making.
The aims were to test four predictions.
METHOD
•Lab experiment
•3 independent variables:
 age: young children versus adults (IMD)
 line-up type: identification vs rejection (RMD)
 level of cognitive demand: cartoon vs human (RMD)
•Identification Test
•Dependent variable: whether the participant identified the correct face if
present or the empty silhouette if not
SAMPLE
•59 child participants
•Aged between 4 and 7 years
•Mean age of 4.98 years
•21 females and 38 males
•Recruited from kindergarten classes in 3
private schools in Eastern Ontario,
Canada
•53 adult participants
•Aged 17-30 years
•Mean age 20.54 years
•36 females and 17 males
•Recruited from introductory psychology
participant pool at Eastern Ontario
University
PROCEDURE
Human face targets
2 types of stimulus material:
•For the videos – 6 second clip, a female
brushing her hair and a male putting his coat.
Colored, no sound, 2-3 seconds of an
individual’s face.
•For the photo-arrays – different clothes than
video, 4 foil photographs with only the face,
neck and shoulders.
PROCEDURE
Cartoon face targets
2 types of stimulus material:
•For the videos- two 6 second clips; Dora the
Explorer talking to the audience and Go Diego
Go! putting on safety gloves. Colored, no sound,
no other cartoons and showed 2-3 seconds of
the target cartoons face.
•For the photo-arrays- still images of the
cartoons plus 4 'foils' found from the internet, 3
raters judged the similarity of approx. 10
cartoons and the 4 most similar in terms of
facial features, hair length and color were
chosen. They only showed the characters face.
PROCEDURE
•Target-present line-ups contained the target and 3 foils
•Target-absent line-ups contained 4 foils
•All line-ups contained a blank silhouette
•Line-up was shown to participants simultaneously
•Each target was randomly placed in the line-up except the 4th foil of the target-absent line-up
•All photographs were in black and white
•Each participant watched 4 videos in total
•Presented in a random order followed by a line-up
•The position of the target/foil was counterbalanced
•Videos and photo-arrays presented on 13-inch laptop screens
PROCEDURE
The following sequence was adopted for each participant:
•The 3 female experimenters were neatly dressed, wearing professional yet casual
clothing ( a sweater/blouse and dress pants).
•child and adult participants were tested separately, asked to pay attention and told
about being shown pictures and follow-up questions after.
•Participants were asked a free recall filler question (what did the cartoon character
look like?) Children were asked another question in case they did not respond to the
original question.
•The child P’s were asked to point to the target (if present) or the blank silhouette (if
not present) when shown the photo. Adult responses recorded on a matching sheet.
•Procedure repeated with all 4 videos. The DV was whether the participant identified
the correct face or empty silhouette.
RESULTS
2 key differences investigated:
1. Difference between children’s and
adult’s identification and rejection
accuracy
2. Difference between children’s
identification and rejection accuracy
between cartoon characters and
humans
The table shows that adults were
better than children at most tasks and
generally, responses to cartoons were
more accurate than human targets.
CONCLUSION
•As predicted, young children produced a significantly lower correct rejection rate than
adults for cartoon faces.
•As predicted, young children produced a significantly lower rejection rate than adults
for human faces.
•As predicted, young children and adults produced a comparable correct identification
rate for cartoon characters.
•As predicted, young children compared to adults produced a significantly lower rate
of correct identification for human faces.
STRENGTHS
•Lab experiment so high levels of
standardization
•Quantitative data was gathered
•High internal validity as demand
characteristics were controlled
WEAKNESSES
•Line-up was not real
•Low ecological validity
ETHICAL ISSUES
Ethical guidelines maintained:
•Informed consent was gained
•Right to withdraw granted
•Protection from psychological harm
THANK YOU!