hello there and welcome back to the mr sin channel last time we talked about different research methods in psychology and today we're going to be expanding our conversation with topic 1.3 defining psychological science the experimental method now don't forget if you're finding value in these topic review videos make sure to subscribe and drop a like on the video this lets me know that you want me to make more psychology videos now experiments allow researchers to understand if one variable causes another variable this is known as a causal relationship when looking at causal relationship we're looking at the relationship between an independent variable which is the cause and a dependent variable which is the effect remember independent is the cause and dependent is the effect that's going to be important for you to remember for example let's say i was conducting an experiment to better understand how using a phone before you go to sleep impacts your sleep the iv or independent variable would be the phone being used before you go to bed and the dv the dependent variable would be the quality of sleep or the amount of sleep that you get now in order to see if there's truly a relationship between our two variables we need to have an experimental control this means we need to make sure that everything besides our independent variable is being held at a constant by having control in an experiment we are able to understand if the independent variable and the dependent variable are truly connected we can also reduce the chance of a placebo effect impacting our study the placebo effect is when a person acts differently because they expect a certain outcome in order for us to truly understand if our variables are connected we need to have a controlled experiment and we also need to only give the independent variable to a select group of the participants the rest of the people in the experiment will be given a placebo a placebo is something that is as close as possible to the independent variable but it's missing a key component of the iv this way the placebo does not impact the participant but also does not let the participant know that they are not receiving the iv for example let's say my hypothesis is if someone takes ibuprofen it would significantly reduce their headache the independent variable is the ibuprofen and the dependent variable is the strength and length of the headache if i gave everyone in the study ibuprofen i would not know if the ibuprofen truly reduced the headaches or if people were having their headaches go away because of the placebo effect participants might have expected the headaches to go away because they expected the drug would remove them to truly understand the cause and effect between the iv and the dv i can give some participants in this experiment ibuprofen and the rest of the participants would get a sugar pill aka a placebo these two different groups are known as an experimental group and in a control group the experimental group is the group that gets the independent variable which for this experiment is the ibuprofen and the control group is also sometimes referenced as the placebo group and that's because they're the ones that get the placebo which for this experiment is the sugar pill that looks like ibuprofen speaking of the control group we have to be aware that sometimes we might have confounding variables and they could impact participants in the experiment confounding variables or variables other than the iv that could impact the dv these are variables that the researcher was not able to remove from the experiment group or the control group for example if we go back to our experiment with ibuprofen it could be that some of our participants had a large lunge and some of them didn't have any lunch at all which could impact the results of the experiment the more control there is in an experiment the less confounding variables there will be however in the real world this is not always possible and the more you try to control an experiment the more you risk creating an inauthentic environment which could create new confounding variables as participants might change their behavior another thing researchers must consider when conducting an experiment is bias when conducting an experiment it is important that researchers keep their bias out of the experiment after all the goal is to have accurate data to do this researchers can conduct a single blind or a double-blind study a single blind study is when participants in an experiment are unaware if they're in the control group or the experimental group where a double-blind study is when participants and the researcher conducting the study are both unaware of what grouped the participants in double-blind studies can help reduce unintentional bias that the researcher may have during an experiment researchers should also randomly assign participants into either the control group or the experimental group to make sure that they have a quality experiment with accurate results this is known as random assignment and it's different from random selection a concept from our last video random selection remember is when participants are randomly selected to be part of a study and random assignment is when participants are randomly assigned to be part of the control group or experimental group now sometimes it's not ethical or possible to have random assignments in an experiment for example if i want to conduct a study on depression i can't just randomly assign participants to the controlled or experimental group i can't decide who's depressed and who is not so instead of running an experiment i would have to run a quasi-experiment this is an experiment that does not include random assignment of participants one thing to note here is that this type of experiment cannot determine cause and effect this is because differences between groups are not controlled by random assignments one last type of study i want to mention here is a correlational study and we talked briefly about these studies in our last video just like quasi experiments correlational studies do not show cause and effect the only experiment that does show cause and effect is a controlled experiment correlational studies collect data through surveys naturalistic observations interviews or by looking at past studies researchers are seeking information on the relationship between two different variables the data is collected and is plotted with the first variable often on the x-axis and the second variable on the y-axis of a scatter plot typically these scatter plots will have a negative correlation we'll go more in depth into negative correlations and positive correlations in our unit one topic five video all right we've gone over a variety of different aspects of a quality experiment now comes the time to practice read the scenario on the screen and answer the following questions when you are done check the comment section below for the answers also while you're down there don't forget to hit that subscribe button and the like button it helps support the channel and it's free it also lets me know that you want more ap psychology videos and of course if you need some more help with ap psychology check out the discord server there's a link in the description below as always i'm mr sin and until next time i'll see you online you