Practical Flashcards
Outline the rational and aim of your study:
The rational is 2D:4D digit ratio has been linked to pre-natal exposure to testosterone
Our aim was to see whether there was a correlation between 2D:4D digit ratio
(measured in cm) and self-reported aggression levels on a scale of 1-10.
Describe your sample and the sampling method you used for your study.
Our sample consisted of 13 (male = 1, female = 12) Caucasian participants aged 16-17,
all of whom lived in the same area (Bristol) in the UK and were privately educated at the
same school. The sampling method was opportunistic, as we asked the pupils in our
Psychology class to take part.
What was your research/alternative/ experimental hypotheses for the study you
conducted in Biological Psychology?
H1 There will be a significant relationship (correlation) between 2D:4D digit ratio
(measured in cm) and self-reported aggression on a scale out of ten, whereby O = no
aggression, 10 = high aggression.
What was your null hypotheses for the study you conducted in Biological Psychology?
Ho There will be NO significant relationship (correlation) between 2D:4D digit ratio
(measured in cm) and self-reported aggression on a scale out of ten, whereby O = no
aggression, 10 = high aggression. Any relationship will be due to chance.
What were your operationalised variables?
Levels of aggression as measured by a self-reported score out of 10, based on
the past month, whereby 10 = very high levels of aggression O = no
aggression.
2D:4D digit ratio as calculated by dividing the length (in cm) of the index
finger of the right hand by the length (in cm) of the ring finger of the right
hand. (A longer index finger will result in a ration higher than 1, while a
longer ring finger will result in a ration of less than 1.)
Outline TWO methodological strengths of your experiment.
We considered the ethical implications and gained informed consent. For example, we
informed all of our participants of the full aims of the study, which was investigating the
relationship between 2D:4D finger ratio and self-reported levels of physical aggression over
the past month. Therefore ensuring all participants were aware of what they were
consenting to take part in, so there was no deception.
We used a reliable method to gain 2D-4D finger ratio measurements as the instructions were
standardised. For example, all participants were asked to measure the lenath of their index
finger in cm from crease to tip and ring finger from crease to tip (excluding fingernail
length), before dividing the index finger length by the ring ginger length. Therefore, this
can be repeated and is reliable.
What inferential test did you use to analyse your data? Justify your decision.
We used Spearman’s Rho because (i) the test was of correlation, to see if one
covariable (2D:4D digit ratio) was related to the other (self-reported levels of
aggression on a scale of 10). (il) Our data was ordinal level and above as we used
ratios, based on measurements of each participant’s index and ring digit on their right
hand in cm and numerical measurements of rank 1-10 whereby 1 = low levels of
aggression, 10=high levels of aggression). (ill) The design was repeated measures as we
correlated pairs of data, with measurements of the two covariables taken from each
participant
Outline one weakness of your practical.
One weakness was our method to take measurements of finger length as each
participant took a measurement, using a rigid, 2-D ruler of their finger lengths. This
could have been inaccurate due to the awkward fit of the ruler and the 3D finger.
Also, they only took a single measurement, which could have been erroneous but was not
checked. As participants were aware of the aim of the study, and were measuring their
own finger length, these could have been subjective and again, were not checked. For
these reasons, the reliability and validity of the study can be criticised as the data
may not have been accurate.
Describe how you would overcome the weakness outlined above.
We could have taken scanned images of the participants’ right hands to enable a more
accurate measurement of finger length in cm, based on a 2D image. We could have
repeated the measurements three times and taken a mean average to work from. We
could have used a blind procedure, with 4 disinterested colleagues measuring the finger
lengths, to eliminate bias or subjectivity and to also give inter-rater reliability, as any
measurements disagreed upon could have been discarded from the study.
