The Drawbacks of Laboratory Experiments

There are many different research designs that a researcher can choose from when planning their experiment. One of the most commonly used research design is the laboratory experiment. This week I am going to be exploring this type of experiment and underlining why I believe the weaknesses of laboratory experiments outweigh the strengths.

A laboratory experiment is conducted under highly controlled conditions. Participants are brought to a lab setting to be tested. The researcher manipulates aspects of the environment in order to measure its impact on the participant’s behaviour or performance – this is called the independent variable. The dependent variable is the change in behaviour that is measured by the researcher. The dependent variable is believed to be under the control of the independent variable. All other variables are controlled as far as possible. This way, conclusions of cause and effect can be made since only the independent variable is controlled so it is assumed that this is what causes the behaviour change.

One clear example of a laboratory study was conducted by Liebert and Baron (1972)*, who were investigating aggression in children. The participants in this study consisted of 5 – 9 year old children. The children were split into two groups; the first group watched a violent video clip that contained fighting, shooting and stabbing, whereas the second group watched a nonviolent, exciting video clip. Making the independent variable the type of program watched. The children were then taken to another room, in which there was two buttons. The children were told that another child in the next room was completing a handle-turning game, and that if they pressed the ‘HELP’ button, the handle would become easier to turn for the other child, but if they pressed the ‘HURT’ button the handle would become very hot and hurt the child. The amount of times each button was pressed was measured by the researcher as aggression – this was the dependent variable in the study. It was found that both boys and girls were more likely to press the ‘HURT’ button if they had watched the violent video.

Although laboratory experiments are thought to have high levels of control, it is very difficult to control every single different variable that may be having an effect on the results. Confounding variables are factors (other than the independent variable) that could cause changes in participants’ performance on the dependent variable if not properly controlled by the experimenter. For example, in the study conducted by Liebert and Baron, the children who watched the violent video clip and pressed the ‘HURT’ button more frequently may have been naturally more aggressive than the other participants. So, the children’s pre-existing levels of aggression may have been acting as a confounding variable, and the independent variable may have had no effect. Although people can argue that laboratory experiments can display cause and effect due to their high levels of control, it is next to impossible to completely control every variable. There may be other variables having an impact that the researcher is unaware of, which is why I believe that the results from laboratory experiments cannot always be fully trusted.

This high level of control leads to experiment settings that are very unnatural, and participants are often asked to complete very strange and bizarre tasks. Therefore, individuals are more than likely going to behave very differently in laboratory experiment situations than they would in real and natural settings. Consequently, laboratory experiments lack ecological validity and mundane realism, as they are not true to real life. For example, in the study conducted by Loftus and Palmer (1974)** into the eyewitness testimony, participants watched a video clip of a car crash and then asked to estimate the speed of the travelling car. This study was obviously conducted in an artificial setting. Watching a video of a car crash would not create the same emotional impact as seeing a car crash in real life. This lack of ecological validity that surrounds laboratory experiments also makes it very difficult to generalise finding from experiments to real life situations.

Although it is believed that laboratory studies should have high internal validity, this can be greatly reduced by demand characteristics. Demand characteristics are cues that may allow participants to guess the aim of the experiment. If a participant is aware of certain aspects of the experiments they may try to behave in a way that they think they are expected to behave. For example, whilst on their way to participate in Bandura’s bobo doll study, a four-year-old whispered to her mother: ‘Look mummy, there’s the doll we have to hit’ (Noble, 1975)*** (hitting the doll was one of the dependent variables being measured in this study). This is a clear example of a participant displaying demand characteristics. So, again, the realism of laboratory studies is reduced by demand characteristics.

One further problem of laboratory experiments concerns ethics. There must always be some form of deception involved in such experiments. If the participants knew every aspect of the study, then it would be pointless to carry it out. In order to produce valid results, participants must be deceived to some extent. However, there are guidelines that must be followed regarding ethics, making it difficult for researchers to produce ethical research.

All of these points lead me to believe that laboratory experiments are more trouble than they are worth. The only positive aspect is that they are highly controlled, therefore cause and effect can be established. However, it is next to impossible to control ever variable within an experiment, therefore confounding variable may be causing the behaviour change instead of the independent variable. Furthermore, this high control can lead to experiments lacking ecological validity, which leads to problems with generalising the results. Demand characteristics may cause participants to behave in an unusual way in order to please the experimenter, again causing a reduction in the validity of the results. Finally, ethical issues of deception may get in the way of researchers creating efficient experiments. Overall, I believe laboratory experiments to be very unnatural and they produce distorted views of how individuals behave in certain situations. Due to the many weaknesses surrounding laboratory experiments, I conclude that results from such experiments cannot be trusted.

* Liebert, R. M., & Baron, R. A. (1972). Some immediate effects of televised violence on children’s behaviour. Developmental Psychology, 6, 469 – 475.

** http://www.sciencedirect.com/science/article/pii/S0022537174800113

*** Noble, G. (1975). Children in front of the small screen. London: Constable.

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12 responses to “The Drawbacks of Laboratory Experiments

  1. Laboratory experiments are much more useful within research than you suggest in your blog. There are many advantages associated with using this particular research method compared to other experiments such as field and natural. Firstly, participants can be randomly allocated to the experimental conditions, which avoid the issue of participant variables. Secondly, participants can be compared against a control group in laboratory experiments therefore researchers can be more confident in establishing cause and effect.
    Thirdly, the laboratory method allows for researchers to gain a high level of control over extraneous variables. One of the main strengths of lab experiments is control. The more variables researchers have control over, the easier it becomes for them to draw conclusions about the effect the independent variable has on the dependent variable and this refers to high internal validity. A study demonstrating high levels of control comes from Bandura, Ross and Ross (1961)*, for example, the way in which the doll model produced exactly the same behaviour for each child and secondly the fact that each child was observed in the same room with the same toys.
    Furthermore and an important point to make when reviewing the features of science, laboratory experiments facilitate replication. Researchers can reproduce identical experimental conditions in order to assess the reliability of results gained from experimentation. This provides other researchers with the opportunity to falsify or verify the earlier result obtained. This is crucial within the research procedure to ensure that all scientific results are reliable. Clearly the use of laboratory experiments reflects scientific methodology ensuring accuracy, precision and reliability. However, both natural and field experiments cannot be replicated (Heiman, 1995)**.
    Whilst some critics argue that laboratory experiments lack mundane realism. Aronson (1992) has argued that experimental realism, in that, how involved participants become in the experiment is of more importance than mundane realism (how the experiment reflects real life). Laboratory experiments are high in experimental realism.

    Finally, laboratory experiments yield quantitative data which are then analysed through the use of inferential statistical tests. Such tests allow statements to be made concerning the likelihood the results occurred by chance.

    Each of these points demonstrates the usefulness of this research method within the scientific field and shows that despite being conducted in an artificial setting they are just as, if not more, useful than field and natural experiments and can in fact be trusted.

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  3. I don’t think laboratory experiments are bad per say in fact I think there is a lot more advantages than stated here (Henshel, 1980; Steinberg & Hunter, 1984).
    1. It is easy to replicate, as with the use of standardized procedures experimenters can ensure all participants follow the same routine, so we can be sure that differences that occur are not because certain participants did the task differently. Furthermore this also means researcher’s in the future can replicate the exact way the study was set out in order to see if they support or refute the previous experiments findings. Meaning if they provide support for the previous experiments findings the results increase in reliability.
    2. You can manipulate variables (to see if there is an effect for example with time of day the experimenter would be able to administer a reaction time task in the morning, afternoon and evening). Meaning the experimenter is more able to justify a cause and effect relation, this is further supported as laboratory experiments can control for extraneous and confounding variables, meaning the variable being tested is most likely the causing factor of the effect.
    Plus there are definite disadvantages to the use of natural experiments (Blundell & Dias, 2005).
    1. They sometimes are not replicable or very difficult to replicate, as researchers have a lack of control over the variables they are observing and therefore may not be able to accurately describe the procedure in order for people to replicate in the future.
    2. The lack of control over the extraneous variables mean it is harder to draw a cause and effect relationship. As the experimenter cannot be certain that the independent variable they are observing is what is actually causing the change in the dependent variable.
    3. There is also a sever limitation of how much you can manipulate variables within field investigations so the experimenter may not be able to asses the true effect.
    4. Samples are a lot harder to form and if you conduct a natural observation it may be that you collect your data from the person you have been observing only for them to request not to be in your experiment.
    So overall there is advantages and disadvantages to them both maybe the best way to provide the clearest and most reliable/valid data would be to asses theories via both methods (if possible). Use experimental methods to ensure data can be replicated so the theory is reliable and use natural experiments to ensure the data is valid (not subject to demand characteristics).

    Blundell, R., & Dias, C. D. (2005). Evaluation Methods for Non-Experimental Data. Fiscal Studies, 21, 427-468. DOI:10.1111/j.1475-5890.2000.tb00031.x

    Henshel, R. L. (1980). The purposes of laboratory experimentation and the virtues of deliberate artificiality. Journal of Experimental Social Psychology, 16, 466-478. DOI: 10.1016/0022-1031(80)90052-9

    Steinberg, D. M., & Hunter, W. G. (1984). Experimental Design: Review and comment. Technometrics, 26, 71-97. Retrieved from: http://www.jstor.org/stable/1268097

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  5. Although you are correct in that there are many drawbacks to laboratory experiments, there are also some pros to laboratory experiments that you have neglected here. One huge pro is the ability to greater control variables. Although you correctly state that sometimes it is impossible to control all variables, it is a lot easier in laboratory experiments compared to to others. There are also ways to improve this such as increased amounts of participants and counterbalancing. Another benefit is the ability to replicate laboratory experiments much more. So although there are negatives to laboratory experiments, there are also many positives also.

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  7. As everyone else said above there are a lot of positive things about carrying out laboratory experiments. I do not want to repeat everything that’s everyone else said. I personally think that the best advantage of them is that laboratory experiments are highly replicable, meaning they can be done all over again no matter how much time has passed and who the experimenter is. It kind of makes laboratory experiments immortal 🙂 And of course, the ability to manipulate different variables is great – means you can get rid of any confounding ones and find those that actually show an effect. However, I do agree with on some things – laboratory experiments can be a trouble, but then again any kind of experiment can be as well.

    P.S Good blog. Enjoyed reading it 🙂

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  9. When it comes to Lab experiments there are drawbacks but at the same time I’m afraid I’m going to have to be a bit of a sheep and agree with the others. Take for example your argument using Loftus and Palmer’s study. Elizabeth Loftus has quite literally redefined how eyewitness testimony is used in evidence, and how the police gather eyewitness testimonies (using Cognitive Interviews). My point is not to blab on about her research, but to say that yes, you are right in saying that the artificial design is not realistic. However, if you did witness a car accident, this would very likely induce trauma and we know that trauma can distort or erase our memory of an event (http://onlinelibrary.wiley.com/doi/10.1046/j.1440-1819.1998.0520s5S97.x/full). So if we can see that our memory can be altered under laboratory conditions, if you like a ‘baseline’, we know that there will always be some issue with (in our case) eyewitness testimony give or take other factors that may come in to play.

    By having lab experiments we can understand what variable exactly can have an effect, and when you combine that with other variables in the outside world, the effect can be dramatically increased but still include the origional effect. Kind of like maths: Origional tested and known effect + outside world = observed effect :).

  10. I can definitely see your point about the lack of authenticity associated with lab experiments, but I also see that as being part of their usefulness. I’m sure many fellow students are just the same as me and go through life ‘noticing’ things and thinking “that would make a good study”!! The problem is that life and all it entails is FULL of confounds…so what we think we are seeing may not be due to the reason we think it is. This said, the sensible thing would be to take the observed phenomenon into a highly controlled environment, to facilitate the removal of as many confounds as possible as see if there really is anything significant. So, to conclude, I agree that lab experiments can be very contrived, but if they are used as a tool to investigate real world phenomena, they could prove invaluable.

  11. Hello! Enjoyed reading your blog! I do, however, think that there are many advantages to Lab experiments. This article http://www.holah.karoo.net/experimental_method.htm explains nicely how experiments done in a lab can develop/test theories that are based on cause and effect – rather than, in the real world, being stuck with simply correltations between things. When we manipulate the variables in a study it is so that we can attempt to say that it is the thing that is causing the phenomenon. I agree with what you say about it not being a perfect solution, however, I do feel that there are huge advantages to lab studies.

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