Download ecological-validity-sp-2012

MANN AND VRIJJ:
Ecological validity refers to the extent to which the findings of a result can be generalized to real life
situations. The aim of the Mann, Vrij and Bull study was to look for any systematic behavioural
indicators to distinguish between liars and those who are telling the truth.
The study is high in ecological validity as the participants in the study are unaware of a study taking
place. There is no risk of demand characteristics because participants are being observed through their
video clips and so there is no way they can change their behaviour by becoming aware of the aim of the
study. Their behaviour is also more representative of real life situations as there are no experimenter
effects where the experimenter’s expectations about a study can affect the participant’s behaviour.
Unlike previous studies, these participants are high stake liars that face real consequences such as life
imprisonment due to crimes ranging from murder, arson and rape. This means that they will be
experiencing cognitive load as they want to prevent themselves from getting caught. They will also try to
control their behaviour (attempted behavioural control) to make sure the interrogators don’t catch
them lying. Since this is a quasi experiment making use of high stake liars, facing real consequences, the
ecological validity of the study is high.
However, ecological validity is low because all the videotapes are taken from one police station and may
not be representative of lying in real life situations. The sample consisted of 16 participants only, all
from a similar background, ethnicity and area (mostly Caucasian). This means the results cannot be
generalised to a wider population as the sample is unrepresentative.
Apart from low population validity, the lack of controls also reduces ecological validity. Each clip for liars
is of different lengths and some have more than one interviewer, an attorney or an adult present. This
reduces the validity of the study as it may not be possible to control extraneous variables. Low validity,
in turn, reduces the ecological validity as it is less generalizable to real life settings.
LOFTUS AND PICKRELL:
Ecological validity refers to the extent to which the findings of a result can be generalized to real life
situations. The Loftus and Pickrell study aimed to find out whether it was possible to implant false
memories.
The study by Loftus and Pickrell is high in ecological validity because it implants a memory that is
realistic such as getting lost in the mall. The experimenters ensured that the true and false memories
chosen were not family folklore but rather real incidents that had happened to the participant and this
increased the ecological validity of the study.
Also, all participants filled the booklet at their homes so there was no chance for experimenter effects
that could have influenced participant’s responses as they would have responded to the experimenter’s
expectations. Moreover, the participants are deceived about the aim of the study and told that it is a
study “about the kind of things you may be able to remember from your childhood.” This meant that
there was low risk of demand characteristics that could have reduced the validity of the study as the
participant’s would have altered their behaviour if they understood the true aims of the study. High
validity leads to high ecological validity as the results can be generalized to real life situations.
However, the study is also low in ecological validity since it may be much harder to implant memories in
real life. Getting lost in a mall was too simplistic a memory and therefore it did not prove if it was
possible to implant an entirely new memory in participants. It must be noted, however, there were
studies conducted later such as throwing punch on the parents of the bride (an unusual memory) and
the experimenter’s were able to implant these false memories as 25 % recalled the memory by the third
interview.
Moreover, the study also lacks reliability. All participants are unable to give their interviews within a
week so it is difficult to compare their results for recall of the false memory. Similarly, while some
interviews were conducted on the telephone, others were conducted face to face. This also meant that
results were not comparable. This lack of reliability, in turn, reduces the validity of the study and
therefore it makes it is less generalizable to real life settings.
TAJFEL:
Ecological validity refers to the extent to which the results of a study can be generalized to real life
settings. Tajfel’s study aimed to investigate discrimination just by putting participants in groups.
The study was high in ecological validity as the boys were allotting real money. Each point they allotted
equaled one tenth of a penny. Moreover, the children were not informed about the aim of the study.
They were also told they had been grouped according to their visual judgments in study 1 (over
estimator and under estimator, high accuracy and low accuracy) whereas in Study 2 they were told they
had been grouped according to their artistic preferences. This helped ensured that no demand
characteristics came in to the study as the participants were unaware of the aim of the study and also
grouping them in this way would make them think their visual judgments and artistic preferences were
the aim of the study.
All subjects went through a 18 page booklet and went through the same slides when they were
grouped. They all filled the booklet in separate rooms. These controls ensured that the study’s validity
was high as they could control extraneous variables such as different presentation of booklets or some
participants being in the same room with other participants. This validity, in turn, makes the study
generalizable to real life settings.
However, the study is low in ecological validity as it is a lab experiment that uses a number of controls.
In real life, there are other factors that may influence discrimination. The tightly controlled situation
means participants don’t know who they are allotting money to. However, in real life, they did know
these children and this could have reduced their discrimination towards them. Similarly, everyone was
given a 18 page booklet with standardized matrices. In real life, discrimination takes other forms such as
aggression and verbal abuse and the lab experiment used an unrealistic way of studying discrimination.
Ecological validity is also low as participants may have guessed the aim when they were told to choose
points for different groups. Since the participants may have expected they had to act competitively, they
may have allotted the points accordingly. Moreover, the study may be low in population validity as the
students are all aged 15-16 years and are all from Bristol School. These students may be more
competitive as compared to other students in different cultures and this means the findings may not
necessarily apply to real life situations as it looks at a restricted sample.