in this first psychological research methods video I'm going to discuss the different types of experiments so lab field natural and quasi and discuss the strengths and weaknesses of each but if this is your first time coming to research methods you're going to hear lots of terminology that you don't know this can be a little intimidating but the more you hear these words and their definitions the more confident that you'll get with research methods I've made these videos short so you may want to watch them just once listening without taking any notes and then again paus into to write down the key ideas you can now follow along by making your notes in my psych boost workbook 150 full color work sheets covering all compulsory units it's on Amazon or you can get signed additions from our website and teachers can order packs for the whole class laboratory experiment the first type a laboratory or a lab experiment is probably familiar to you a lab experiment could literally be set in a laboratory but the important principle here is the experiment has full control over what happens in the experiment environmental factors like noise temperature and even the instructions given to the participants are all highly controlled and they don't vary between conditions we call these factors variables in a lab experiment the experimenter tries to make sure only one factor of the experiment called an independent variable changes between the conditions all other variables are kept the same this is so the experimenter can measure how changing this independent variable changes the variable measure measured known as the dependent variable for example we might want to investigate how changing the color of light in the room but nothing else influences a recall of numbers an advantage of using a lab experiment is by controlling for all of the variables you can be fairly confident in suggesting a cause and effect relationship because you kept everything else constant the variation you made to the independent variable caused the change measured in the dependent variable this High control over the experiment means we would argue that lab experiments have high internal blidy what they measured is true The observed effect is real and due to the change in the independent variable not some other uncontrolled Factor lab experiments are also highly replicable you can give the list of instructions to another researcher so a list of standardized procedures for the participants and variables to keep the same then if the researcher can conduct in the same way and get similar results your confidence in the validity of your findings increases however there are disadvantages lab experiments May lack external litery the laboratory is not like the real world and behaviors observed in lab conditions may not generalize to environments outside of the lab like the home school or work and this is known as lacking ecological validity also the tasks used in an experiment are often unusual not like the things we do in the real world so the behavior may not be the same as what we see in the real world and this is known as the tasks lacking mundane realism also being set in a lab participants are are well aware that they're in an experiment they know the experimenter wants to find something El and they're likely to change their behavior to match what they think is expected from them if this happens you would say your study suffers from demand characteristics field experiment field experiments attempt to fix some of the weaknesses of lab studies so instead of being set in a lab they're conducted in the real world for example in a natural setting of a shopping center places of work or schools places where people are used to behaving naturally and of course the strength of doing a field experiment is increased external validity people will be expected to show more naturalistic behavior in their natural environment so we can be confident in generalizing any behaviors measured to other situations meaning higher ecological abity also the task used are more likely to be real world tasks meaning increased mundane realism if the participants are unaware that they're taking part in a study which is easier in a field experiment demand characteristics are also not a problem the weaknesses of field experiments are due to the lack of control that we did have in the lab experiment the real world is chaotic and in a field experiment we're not able to control every possible variable that might change your measurement of the dependent variable these are known as extren variables and often in a field study researchers are not able to randomly assign participants to each condition this means that any effect observed may be due to a factor other than the change in the independent variable and this reduces the internal validity of the experiment natural experiment in the previous two types of experiment the researcher manipulates the independent variable themselves and then records the change in the dependent variable however in a natural experiment the levels of independent variable have already happened naturally the researcher just measures the change in the dependent variable so as an example let's imagine you wanted to study what would happen to Children's development if you stopped them from getting any love and affection early in life say you wanted to compare a group that had been deprived of love for less than six months months a group between 6 months and 2 years and a group that had had no emotional care for over 2 years and then you can put them with caring families well of course you can never actually conduct this as a lab experiment for ethical reasons but this did happen to children in Romania in the 1980s and a researcher called rter followed these children up as they grew and recorded the effect of this deprivation on their development watch my video on the Romanian orphan studies if you want to know what Ro found one strength of natural experiments is that it allows Research into areas that could never be done otherwise either due to ethical reasons like rter or cost also natural experiments are very high in external validity these changes have happened naturally in real life and would have happened with or without the researcher so any changes in Behavior can't be the result of demand characteristics however the researcher has no control over the experiment like randomizing participants to groups or controlling for exous variables there might be other factors that have influenced a dependent variable meaning we're not as sure of a cause and effect relationship between the IV and DV as we are in a lab study also because these situations occur naturally and are often rare these studies can't be replicated to see if we get the same results quasy experiment the final type of experiment is known as a quasy experiment it has an unusual name but actually it's quite simple in a true experiment you should be able to randomly assign participants to the different levels of the independent variable so blue light or green light on recall but there are lots of studies we like to conduct in which people can't be randomly assigned between conditions for example if we're studying gender or age or the difference between people with or without a mental health condition these groups already exist and if we can't as a researcher assign people to the different conditions or manipulate the levels of IV that is a quasi experiment a strength of this type of experiment is it's simply the only way to study these factors but a negative is there could be differences in these groups that goes beyond group membership say for example if we're conducting a study on males and females and biological ability to solve puzzles there may be differences in how males and females have been educated and socialized that actually explain these results these factors that changed systematically between the conditions and can't be controlled are known as confounding variables so that was types of experiments I have six tutorial videos covered the 2017 18 and 19 as and a level research method sections these videos have worked examples to every question question and a full of exam tips patrons at the neuron level and above can access these as well as many many more hours of exam tutorial videos as well as over 100 printable resources from across Thea level over on psych.com I do want to thank all the students and teachers who have supported Psy boost over on patreon drawing the development of the research methods unit it's their support that allows me to teach part-time so I can make psych boost on YouTube for everyone so thanks to them and I'll see you all in the next research methods video observations