HASSET ET A EVAL

Question 1

What are the 3 main strengths of the study?

Answer 1

High level of control
Highly Reliable
Highly valid
Objective measures/data

Question 2

What are the 3 main weaknesses of the study?

Answer 2

Ecological validity
Generalisability
Ethics/consent

(Subjectivity/correlations)

Question 3

High level of control

Answer 3

Example: Ppts were not allowed to drink alcohol for caffeine before the experiment.
Explanation: Caffeine is a well known stimulant that can interfere with ability to fall asleep and may disrupt sleep cycle. Alcohol, a well known sedative similarly disrupts the normal sleep cycle.
Conclusion: By controlling for these extraneous variables researchers can attribute changes in the iv with the dv establishing internal validity and thus infer a causal relationship.

Question 4

Objective measures and data where implemented (objectivity)

Answer 4

Evidence: Quantitative data such as brain waves, eye movement patterns and REM sleep was collected using EEG and EOG. The electrodes were placed consistently ensuring the EEG would provide consistent info.
Explanation: EOG/EEGs are objective biological measures that allow precise measurements to be taken uninfluenced by any research bias. The data collected from these measures would also be easy to collect, analyse statistically.
Conclusion: This ensures the results are scientifically credible and reliable motivating the limitations of subjective self reports.

Question 5

Highly valid

Answer 5

Evidence: Ppts found it too hard to estimate dream length so a fixed option of 15/5 mins was introduced.
Explanations. This helps to explore the link in a controlled, reliable way but also reduced participant variables such as differences in ability to make estimations/expressiveness.
Conclusions: These changes mitigate effects of ppt variables and increase the reliability and validity of the study

Question 6

Low Ecological validity

Answer 6

Evidence: Ppts were not in their usual sleep setting, under observations and connected to different machines and may have been used to drinking coffee and alcohol.
Explanations: these differences may result in different behaviour that the ppts wouldn’t normally exhibit. For instance they may feel nervous/ uncomfortable.
Conclusions: this situation is unusual and unlike to happen in real life reducing mundane realism and thus does not provide accurate or valid behaviour. Researchers cannot be sure if differences in the dv is due to manipulation or a reaction to unusual setting.

Question 7

Generalisability

Answer 7

Evidence: Small sample that is limited in size, and is not representative with only 9 ppl being studied.
Explanation: The results cannot be accurately generalised to the broader population due to its size. The volunteer sampling could also have resulted in an unusual sample ( chose to participate as they dreamed more frequently/vividly).
Conclusion: It is possible that sleep patterns vary from person to person and their study would have benefited from a large diverse sample.

Question 8

Subjectivity/ low validity

Answer 8

Evidence: Ppts reports of their dream content is subjective and dependent on individual differences such as expressiveness. Also, self reported experiences of dreaming can be prone to recall bias or inaccuracies.
Explanation: Thus there are some confounding variables such as individual differences that are not accounted for that lowers the internal validity of the study and causal relationships cannot be inferred.

Question 9

What are some other weaknesses of the study?

Answer 9

Correlations- only a relationship was found but the nature of it is unclear

Ethics- informed consent not gained because ppts not told about EEG/whether they were in rem/ eye patterns. Disruption of natural sleep cycles-reside concerns about wellbeing. Sleep is vital for health and cognitive functioning and ppts may have not bent aware of consequences of sleep interruption.