Home > Uncategorized > All I need are my own expectations

All I need are my own expectations

You are an avid fan of experiments and the scientists behind those experiments. Your whole life is dedicated to researching, learning and understanding the results and what that means in the science world. It comes to your attention that the experiments you were deeply obsessed with are being criticized and questioned for lack of truth and transparency. Very curious as to why everything is being questioned, you start t look deeper into the scientists and the experiments and found out they were experiencing a phenomenon called Expectation bias which is also known as experimenters bias.

It’s not what I believe, so I don’t need it (Image 1)

Expectation bias happens when people tend to believe information or data that agree with their expectation of what may happen and disregard any information or data that goes against their expectation. This phenomenon is also known as Experimenter bias, in which the experimenter will believe data that agrees with his or her own expectation of what the outcome should be in the experiment and throw away conflicting ideas. We can relate this bias to automatic processing in cognition, which is our ability to gain and understand knowledge through our senses, thoughts and own experiences. When this bias happens we automatically attend to, or focus on what we expect and unconsciously oppose conflicting ideas, characteristics, and details. Another way we can relate expectation bias to cognitive processes is how it relates to false memories and retrieval of memories.

“Recent studies in the area of the Expectation/Experimenter Bias Effect, have raised questions regarding the validity of certain experimental findings in psychology (Brightman & Raymond, 277).” Given this statement a study was created to better understand what actually is effecting the experiments, whether it truly is just expectation bias or if there are other experimental factors that play into it. This study focused on the experimental task, task ambiguity and expectancy control groups. Experimenters were given previously scored children’s drawing test. In varying groups, an experimenter would grade based on a certain criteria, either with low, medium and high ambiguity; low, medium and high outcome expectancy, and the control group. Experimenters who received the high ambiguity grading instructions gave higher grades opposed to those who received low ambiguity instructions. As a result of this experiment, they found that EBE is not solely on a persons bias but also the ambiguity of experimental situations, and the structure and organization of each experiment. This also means experiments have to do a better job of make sure all aspects of their experiments are clear. If subjects of an experiment are not 100% sure of what they are supposed to do, it makes them assume and they may effect the results of the experiment. “It is suggested that the EBE may be minimized through the use of more carefully designed and executed studies in which ambiguity is eliminated (Brightman & Raymond, 287).” It is not just about the experimenter being biased its about the experiment itself that may subtly be biased with the wording of instructions and the way the experiment is laid out. There are a lot of factors that play into the role of expectation bias.

In a Draw-a-Man test experiment, several kindergarten and first grade students were asked to put together a 14 piece jigsaw puzzle of a man. Both groups had four sessions to practice putting the jigsaw together. The kindergartener’s were the control group and the first grades were the experimental group. They found that there was an increase in the experimental group and no change with the control group. However a group of researchers explored this study, and one of the researchers Medinnus felt like there were flaws in this experiment. Medinnus, Bobitt, and Hullet found that the experimenter had previously given the first graders (control group) more experience to learn the jigsaw puzzle. Medinnus thought there was a lack of validity and also importance of the relationship between the extra practice of the puzzles and the drawings. Not only did the DAM test have expectation bias by either the teachers and the experiment, there was also lack of knowledge from the experimenter about what control and experimental groups were. The analysis of the results found several flaw within the set up of the experiment, expectation bias being the biggest influence but also just general lack of knowledge and design.

Rosenthal believes that for expectation bias to happen its all in the “experimenter effects”, which in turn influences the actions and behaviors of the subjects. “In terms of Campbell and Stanley’s (1963) distinction, experimenter effects may be viewed as reducing the external validity of an experiment, while experimenter bias may reduce the internal validity of the experiment (Innes & Fraser, 299).” Rosenthal has come up with different scenarios that may be as to why expectation bias is so prevalent. Whether its the subjects personality or gender, whether it is the subtle and unintentional facial cues and contact that the experimenter has with its subjects. He believes that there is much more to expectation bias than it being the researchers are at fault. However with that being said expectation bias is a big deal and has caused a lack of confidence in experiments and studies, as people believe they are not fully accurate or truthful. In a few of Rosenthal’s experiments he gathered “experimenters” which were undergraduate and graduate students to expect various outcomes for several different subjects for the task being done. In photo-rating tasks and other experiments they found that data was collected to match the experimenters expectation of how things should happen. Many researchers have been trying to identify why expectation bias happens, and if there are any other influences or biases that also may occur during experiments and studies. They have questioned wether it is because of misinterpretation of the results, misinterpretation of the task at hand but, they assume that there is much more than expectation bias happening.

Expectation bias is important in cognitive psychology as it helps us better understand how experiments can be disrupted, altered and fixed with the simple idea of expectation bias. We learn to understand why so many experiments can have lots of biases, and how that has led to speculation and questioning of the validity of each study. The effects we see from expectation bias is in automatic processing. What we want to happen, what we want to see, and what we want to hear no matter the other information comes to the fore front of our brain without us really realizing that we are doing it. With our preconceived notions we have in experiments and in life, we automatically assume the information we want we agree, and the information that doesn’t match we throw away. However when we experiment and do studies, we need to look at all the information with open arms, so we can get rid of expectation bias and all other influencing factors. We need not to be biased. So expect nothing but the truth!


Hullett, J. W. (1975). POTENTIAL EXPERIMENTER BIAS IN THE EFFECTS OF TRAINING ON THE DRAW-A-MAN TEST (Book Review). Journal Of Educational Research, 69(2)

Innes, J. M., & Fraser, C. (1971). Experimenter bias and other possible biases in psychological research. European Journal Of Social Psychology, 1(3), 297-310.



Image 1 – http://www.forensicdentistryonline.org/kaiser-no-evidence-of-contextual-bias-in-bitemarks/

Image 2 – http://noahpinionblog.blogspot.com/2014/01/bad-event-studies.html

Image 3 – https://dsp.stackexchange.com/questions/10262/jigsaw-puzzle-isolating-the-pieces-separating-stuck-blobs

Image 4 – https://stpaulsbayprimary.com/kindergarten-meetings-with-parents/

Image 5  – https://study.com/academy/lesson/how-to-improve-validity-of-a-scientific-investigation.html

Image 6 – https://www.cartoonstock.com/directory/c/confirmation_bias.asp

Categories: Uncategorized Tags: , ,
  1. No comments yet.
You must be logged in to post a comment.