Hi there! I just had a question regarding reliability and validity in the research methods section. I'm not too sure on how these can be applied in a question or research scenario, let alone what they even are! If anyone can explain this to be that would be amazing.
Also, in terms of long-term potentiation, how are we supposed to answer in a question on the role of glutamate? Is it just that it is excitatory and therefore helps strengthen the connection? Thanks!
Validity: is whether the variables in a research actually/acurately represent the variables that they are said to measure.
for example: measuring cortisol levels in the blood stream is a valid measure of stress, however measuring IQ results to represent memory would be invalid.
in psych, everything we study is a psychological construct (it can't be directly measures), so we need valid measures of the effects of this construct.
to go into more detail validity can be categorized as internal or external validity.
Internal valditity is whether there is a causal relationship between the IV and DV, that is whether the iV actually caused the change in the DV. So if you want to discuss validity in research scenario always discuss the effects of exraneous/confounding variables, as they cast doubt on whether the IV caused the change in the DV and thus whether the research is internally valid. internal validity also impacts whether you can draw a conclusion (for e.g/ a valid conclusion cannot be drawn due to the presence of X confounding variable)
external validity is whether the results can be generalised to an external setting or wider population. For this you'll have to discuss whether the sample is representitive and whether the opperationalisation of the variables is valid. For example, an experiment that takes place in a sleep lab is not externally valid, because of the dissonance between natrual settings and those in the experiment. Moreover, If i'm measuring memory through IQ scores, I can't generalise my findings to suggest that my IV can be used to improve students memories in the classroom.
reliability is the liklihood that replicating the experiment will provide simillar/same results. If something is reliable the findings can be generalised to the wider population due to their consistency. In the exam, you can discuss reliability if you are given a standard deviation, if the s.dev is high the experiment is likely unreliable due to the variability between participants. There is an overlap between reliability and external validity. Moreover if something is more objective its more likely to be reliable than a subjective measure.
It is possible to have an experiment that is invalid but reliable, but not vice versa.
Also,
Glutamate plays an important role in synaptic plasticity:
synaptic plasticity is the ability of connections between neurons to change in strength. Synaptic plasticity plays a fundamental role in learning and memory because this feature of the nervous system enables the learning of new memories. Two key processes that occur as a result of synaptic plasticity are LTP and LTD. They take place throughout the brain, but to a greater extent in the cerebral cortext and the hippocampus, at glutamageric synapses. Glutamageric synapses are synaptic connections whereby glutamate is released and glutamate receptors uptake this neurotransmitter. Therefore glutamate plays a role in LTP and LTD by modulating the excitability properties of neurons. LTP is when the same group of neurons fire together simultaneously, glutamate is released, and its excitatory effect enables information to travel along these neural pathways, as a result neurons along such pathways become more sensitive to glutamate, due to the increased sensitivity and number of glutamate receptors. Thus glutamate makes neurons along this pathway more excitable, and thus enhances their efficiency in transmitting info. (obviously LTD is the opposite)
hope this helped