The human mind has been the subject of study and a source of fascination for centuries. The conscious and subconscious phenomenon that occur in the mind determine a person’s behavior. Studies of these effects have contributed to the advancement of treatment of psychological problems. They have also furthered various other fields such as marketing. Here are some such psychological effects that you might find interesting to read.

1 The “Tetris effect” occurs when people spend so much time and attention on an activity that their thoughts, dreams, and mental images become full of it. 

The effect was named after the video game Tetris in which the gamer has to manipulate falling tetrominoes to create horizontal lines without gaps. People who played it for long periods of time often find themselves thinking of fitting together buildings, boxes, and any other geometrical objects, hallucinating or dreaming about falling tetrominoes, or seeing them in the corner of their eyes.

The Tetris effect is also known to occur in people who participate in speedcubing, a competition that involves solving a variety of puzzles, especially the Rubik’s cube, and experience involuntary visualization of various moves to solve the cube. Mathematicians such as Srinivasa Ramanujan and Friedrich Engels have reported dreaming of numbers or equations, the latter remarking “last week in a dream I gave a chap my shirt-buttons to differentiate, and he ran off with them.” A variation of the Tetris effect is the condition of “sea legs,” an illusion that the floor is rising and falling that people who’ve been on a boat feel after getting back onto land. (source)

2 The “Pygmalion effect” is a psychological phenomenon in which a person’s performance depends on what others expect of them. The higher the expectations, the more they try to perform better.

Robert Rosenthal, Distinguished Professor of Psychology at the University of California, and Lenore Jacobson, an ex-principal of an elementary school in South San Francisco, conducted a study to test the hypothesis that a person’s reality can be influenced positively or negatively by other people’s expectations of that person. They gave students an IQ test the results of which were not disclosed to the teachers. Instead, the teachers were given names of 20% of the students who were randomly chosen, and told that they could be “intellectual bloomers.”

The students were given another IQ test at the end of the study. Though all six grades showed a mean increase in test results in both control and experimental groups, the first and second grade showed a significant increase among the students whose names were given to the teachers. This led to the conclusion that teachers’ expectations have an impact on the students’ performance, especially at a younger age. According to Rosenthal, elementary school teachers might subconsciously behave in ways that influence the students. The effect was named after Pygmalion, a sculptor in Greek mythology, who fell in love with a statue he made.

There is a corollary to Pygmalion effect called the “Golem effect,” which is the decrease in performance due to low expectations. Several educational psychologists criticized the study pointing that average IQ scores are an unreliable measure of the class’s intellect, while others argued that the teachers could have behaved as they did because they knew what the study was for. (source)

3 The “sleeper effect” is the delayed change in attitude seen when someone becomes persuaded by a message or advertisement over time even though they were against it at first because of a suspicious cue.

People watch an engaging or persuasive advertisement on television and become persuaded by it, but gradually their attitudes shift back to those they originally held before watching it, almost as if they have never watched it at all. On the other hand, when people watch a persuasive message that is followed by something that makes it untrustworthy, like a disclaimer or reference to an untrustworthy source., the viewers who at first discount the message tend to become more persuaded with exposure to it over time.

This effect was first observed among WWII soldiers, a group of whom were shown the Frank Capra’s propaganda film Why We Fight in an attempt to change opinions and morals by psychologist Carl Iver Hovland and his colleagues. The soldiers’ opinions were measured five days and nine weeks after watching the movie. They found that the difference in opinions between the group who watched the movie and those who didn’t was greater after nine weeks than after five days. (source)

4 The “false consensus effect” occurs when people overestimate how many others share their opinions, beliefs, and habits. It is a cognitive bias that leads people to think they are “normal” according to a consensus that doesn’t exist. 

Also known as “false consensus bias,” the effect is a result of a desire to conform and be liked by others. It is often seen in groups as the members are more likely to think their collective opinion is also expressed by the larger population. They reach a consensus, and since it is rarely disputed owing to the limited contact with those who hold different views, the group believes everyone thinks as they do. (source)

5 The “hostile media effect” is the tendency for people with strong opinions to perceive neutral media coverage as biased against them and in favor of their opponents. 

This effect was first proposed by Robert Vallone, Lee Ross, and Mark Lepper who also conducted experiments to study it. In 1982, pro-Palestinian and pro-Israeli students at Stanford University were shown news clips related to the Sabra and Shatila massacre. When measured objectively, the pro-Israeli students found them to have more anti-Israeli references and the pro-Palestinian students found more anti-Palestinian references. Both also said that if a neutral person watched the clips they’d find their side to be more negative.

Several further studies conducted on issues such as the problems in Bosnia, US presidential elections, the South Korean National Security Act, and others have also shown a hostile media effect. Explanations for the effect include selective recall, selective perception, and reasoning motivated by their side’s plight. (source)

6 The “Macbeth effect”, or “Lady Macbeth effect,” occurs when someone feels the desire to clean oneself or has thoughts of cleaning oneself after experiencing or remembering a feeling of shame. 

The effect was named after Lady Macbeth from Shakespeare’s play Macbeth who goads her husband into killing the king and develops a compulsive desire to wash her hands on which she imagines there are bloodstains. The effect is an example of priming, a psychological technique in which one stimulus subconsciously influences another stimulus.

During one experiment, a group of participants was asked to recall something good they have done and another group something bad. Then they were asked to fill missing letters in the words “W_ _H,” “SH_ _ER,” and “S_ _P,” The ones who recalled a bad deed were 60% more likely to fill the words as “wash,” “shower,” and “soap” instead of words like “wish,” “shaker,” and “stop.”

In another experiment in which the participants were asked to perform self-cleaning, those who lied orally preferred to use an oral cleaning product while those who wrote down the lie preferred a hand-cleaning product showing that the effect is also localized to the body part performing the bad deed. (source)

7 The “Diderot effect” occurs when someone buys something new and feels compelled to upgrade or replace their existing possessions that are related to or nearby the new one. 

This effect was first described by18th-century French philosopher Denis Diderot in his essay “Regrets on Parting with My Old Dressing Gown“ In the essay, he tells how an elegant dressing gown he received as a gift forced him to find himself not living up to its style and end up in debt as he replaced his old pieces of furniture with new costly ones. The effect was named after Diderot in 1988 by anthropologist and scholar of consumption patterns Grant McCracken. It is a point often discussed in topics such as green consumerism and sustainable consumption. (source)

8 The “spotlight effect” is a cognitive bias in which people believe that their embarrassing behaviors are noticed more than they actually are. 

The spotlight effect first appeared in the journal Current Directions in Psychological Science in 1999 and was coined by Thomas Gilovich and Kenneth Savitsky though the phenomenon was studied several times before. The reasoning behind the effect is that people tend to forget that though they are the center of their own world they are not the center of everyone’s world hence making an inaccurate judgement on how noticeable they or their flaws are.

There are other effects that are an extension of the spotlight effect. One of them is the “Hawthorne effect,” or “observer effect,” in which a person tends to modify his behavior when someone is observing them. This often leads to incorrect results during studies if the researchers do not realize the effect their observation has on the subjects. Another is the “audience effect,” or “social facilitation,” in which the person tends to perform better on a simple task and worse on a complex task when being observed compared to when alone. (source)

9 The “pratfall effect” is the tendency for someone who is generally perceived to be competent or incompetent to become more attractive or less attractive respectively after making a mistake. 

The pratfall effect, also known as the “blemishing effect,” was originally described by American psychologist Elliot Aronson in 1966. Aronson had students listening to a tape in which an actor pretending to participate in the radio quiz show College Bowl would answer 92% of the questions correctly and another answers only 30% correctly. The first one would reveal that they had come from an exceptional high school with exception academic scores, while the second would admit to be from an ordinary school with mediocre scores.

Towards the end, they actors would commit a blunder in the experimental tape and no blunder in the control tape. When asked to rate the attractiveness of the quiz participants, Aronson found that the blunderer portrayed to be intelligent was rated more attractive and the mediocre blunderer was perceived to be less attractive.

There are, however, believed to be several contributing factors such as the tendency for the observer to compare themselves with the individual. If the observer has similar competency to the individual, the former is less likely to find the latter attractive after a blunder as that would threaten the concept of self and self-esteem of the observer. (source)

10 “Semantic satiation” is a phenomenon in which a word or a phrase loses its meaning temporarily when you listen to, say, read, or write it repeatedly. 

The term “semantic satiation” dates back to 1962 and was coined by Leon Jakobovits James in his doctoral dissertation at McGill University, Canada. Also known as “semantic saturation” or “verbal satiation,” the effect is believed to occur because the repetition triggers repeated neural pattern associated with the meaning of the word causing a decrease in the intensity of the neural activity. According to James, the concept can be used to treat phobias through systematic desensitization. One developed application is the treatment of speech anxiety experienced by stutterers by semantic satiation thus decreasing the intensity of negative emotions while speaking. (source)