Cerebrum Article

Video Games Affect the Brain—for Better and Worse

We hear conflicting reports about how video games affect our brains. One study will suggest that video games help us learn; another might imply that they make young people more aggressive. Douglas A. Gentile argues that how games influence our brains is not an either-or proposition; games can have both positive and negative consequences, and which of these researchers find depends on what they are testing. Gentile proposes that researchers focus their investigations on five attributes of video game design to tease out these disparate effects.

Published: July 23, 2009
child plays driving game on tablet

Video gamers, parents, politicians and the press often lionize or attack video games, which opens the door to spin that obfuscates our understanding of how these games affect people. For example, the European Parliament has been debating whether to limit children’s access to video games. In a press statement about the report that resulted from its deliberations, the parliament concluded that games could have “harmful effects on the minds of children.” Reporting on this statement, however, the headline in the Guardian read, “Video games are good for children.”

Psychologists and neuroscientists conducting well-designed studies are beginning to shed light on the actual effects of video games. These studies show a clear trend: Games have many consequences in the brain, and most are not obvious—they happen at a level that overt behaviors do not immediately reflect. Because the effects are subtle, many people think video games are simply benign entertainment.

Research projects of variable strength have substantiated claims of both beneficial and harmful effects. Too often the discussion ends there in a “good” versus “evil” battle, reminiscent of the plots of the violent video games themselves.

Games May Teach Skills—or Desensitize Us to Violence

Well-designed video games are natural teachers.1 They provide immediate feedback on the player’s success by distributing reinforcements and punishments, assist in learning at different rates, and offer opportunities to practice to the point of mastery and then to automaticity. Video games also can adapt themselves to individual learners and train players in a way that helps them transfer knowledge or skills to the real world. Gamers repeat actions as they play, and repetition is one precondition for long-term potentiation—the strengthening of brain-cell connections (synapses) through repeated use that is thought to underlie memory storage and learning. To cite a mnemonic that Canadian psychologist Donald Hebb coined in 1940, “Neurons that fire together wire together.”

Several lines of research suggest that playing video games can lead to different types of benefits. For example, a 2002 U.S. Department of Education report presented evidence on the effectiveness of educational games.2 One neuroscience study, published in Nature, showed that playing action video games can improve visual attention to the periphery of a computer screen.3 Another study, which appeared in Nature Neuroscience, demonstrated that action games can improve adults’ abilities to make fine discriminations among different shades of gray (called contrast sensitivity), which is important for activities such as driving at night.4 Other research suggests that games requiring teamwork help people develop collaboration skills.5

Several types of studies provide evidence that video games that include “pro-social” content—situations in which characters help each other in nonviolent ways—increase such conduct outside of game play, too. In one study, 161 college students were randomly assigned to play one of several violent games, neutral games, or pro-social games (in which helpful behavior was required). After playing, the students completed a task in which they could either help or hurt another student. Those who had played the violent games were more hurtful to other students, whereas those who had played the pro-social games were more helpful.6

Games may be beneficial for doctors, too. A study involving 33 laparoscopic surgeons—doctors who conduct minimally invasive surgery by using a video camera to project the surgical target area onto a screen as they work—linked video game play to improved surgical skill, as measured in a standardized advanced-skill training program. In fact, the surgeons’ amount of game time was a better predictor of advanced surgical skill in the training drills than their number of years in practice or number of real-life surgeries performed.7

While some reports have linked video games to negative consequences such as obesity, attention problems, poor school performance and video game “addiction,” most research has focused on the effects of violent games. Dozens of psychological studies indicate that playing violent games increases aggressive thoughts, feelings and behaviors, in both the short term8 and the long term.9 This makes sense from psychological and cognitive neuroscience perspectives: Humans learn what they practice. But what really happens in our brains when we play violent video games?

A decade ago, in an imaging study using positron emission tomography (PET), eight men undertook a goal-directed motor task for a monetary reward: They played a video game in which they moved a tank through a battlefield to destroy enemy tanks. Researchers found that a neurotransmitter called dopamine, which is involved in learning and feelings of reward, was released in the brain’s striatum as the men played.10 This and other studies suggest that the release of dopamine and stress hormones may be related not only to ideas of violence and harm, but also to motivation and winning.

Other studies have focused on how specific brain regions of players of violent games respond under varying circumstances. For instance, René Weber and his colleagues asked 13 experienced gamers to play a violent game while undergoing functional magnetic resonance imaging (fMRI) brain scans.11 The violence in the game was not continuous, so researchers coded the game play frame by frame. At various points the player’s character was fighting and killing, in imminent danger but not firing a weapon, safe with no threats, or dead.

By imaging players’ brain activity before, during and after each violent encounter, the investigators found that immediately before firing a weapon, players displayed greater activity in the dorsal anterior cingulate cortex. This area involves cognitive control and planning, among other functions. While firing a weapon and shortly afterward, players showed less activity in the rostral anterior cingulate cortex (rACC) and amygdala. Because interaction between these brain areas is associated with resolving emotional conflict, their decreased functioning could indicate a suppression of the emotional response to witnessing the results of taking violent action.

bar chart
When playing a high-violence video game, players accustomed to such games showed lower activity (measured via signals from magnetic resonance imaging) in the rostral anterior cingulate cortex (rACC), whereas players used to low-violence games displayed higher activity. This difference suggests that gamers who often play violent games may be desensitized to aggression and violence. (Courtesy of K. Thomas and D. A. Gentile)

Does this evidence prove that repeated play of violent games desensitizes players to aggression and violence? In a study we are still conducting, 13 late-adolescent male gamers played a game while undergoing fMRI scans. The game ( Unreal Tournament ) can be set either to include or not to include violent actions. The most interesting preliminary findings appear in the contrast between gamers who habitually play violent, first-person shooter games and those who play less violent games. The latter show increases in rACC activity (suggesting emotional responses) during violent episodes, as expected. We interpret this to mean that while people who are not used to seeing violent images show a strong emotional reaction when confronted with them, those who regularly play violent games do not simply lack an emotional reaction—they actively suppress it, as reflected in their rACC activity (see the figure). These players may have become desensitized to violence in video games. Another study has found a correlation between repeated exposure to violent games and desensitization, as well as increased aggressive behavior in the real world.12

Researchers are continuing to investigate whether repeated exposure to violent games over time truly does desensitize players and increase their aggressive feelings and thoughts. Beyond that, we must find out whether such responses and behaviors become automatic.

Aspects of Video Games Illuminate Their Effects

If video games can be both beneficial and harmful to players, how can we predict their effects on individuals and populations? And how can scientists stay out of the polarizing debate while still reporting the results of their studies? The answer to the second question is that scientists must be precise. I see five aspects of video games that can affect players: amount, content, structure, mechanics and context. Together, these aspects can explain different research results.


We would expect that as people spend more time playing video games, their risk of performing poorly in school, becoming overweight or obese, and developing specific negative physical health outcomes (such as carpal tunnel syndrome and other repetitive stress injuries) would increase. We may also correlate more time spent playing with a higher number of video-induced seizures in people with epilepsy or photosensitivity disorder.

These correlations might begin with gamers’ existing characteristics. For example, low-performing students are more likely to spend more time playing, which may give them a sense of mastery that eludes them at school. Nonetheless, every hour that a child spends on video games is not spent doing homework, reading, creating, or participating in other activities that might have more educational benefit. Longitudinal studies support the idea that children’s school performance worsens as their gaming time increases.

Furthermore, excessive video game play often reduces time for physical activity, which could account for the link between the amount of gaming and obesity. Movement games (such as Dance Dance Revolution and some Nintendo Wii games) may have the opposite effect, however. Finally, repetition of a game’s features may magnify the consequences of the four other aspects I cite.


What a video game is about—its content—may determine what players take with them from the game to real life. Studies indicate not only that games that include educational content can improve related education skills,2 but also that games designed to help children manage chronic health problems (such as asthma or diabetes) are more effective than doctors’ pamphlets in training children to recognize symptoms and to take their medications.13 Similarly, studies reporting that games with violent content increase aggressive thoughts, feelings and behaviors suggest that these violent tendencies can extend into real-life situations.6

Learning that results from video games may last only for the duration of the game, for a few minutes after play ceases or for the long term. Many content-focused studies, such as those in which children learn information about their health, also show that in-game learning can transfer to the real world in the long term.

Studies of games with violent content also tend to demonstrate transfer of learning to real-world situations. Studies in several countries, including one consisting of 1,595 children in Japan and the United States, suggest that children who play violent games become more aggressive in their daily lives (as reported by their peers or teachers, for example).9

The research question has shifted from whether game content transfers to nongame situations to how it does so. New studies are focusing on the cognitive and behavioral processes by which learning and transfer occur. Learning may transfer to other tasks as a result of fluid intelligence. This term refers to the ability to reason and to solve new problems independently of previously acquired knowledge. In one study, researchers had participants complete a gamelike computer training task. They found that training designed to improve working memory (the temporary storage and use of information) leads to a transfer to fluid intelligence. Moreover, the extent of the gain was related to the amount of training.14


A video game’s on-screen structure contributes to its effects. For example, some games require a player to scan the screen constantly for small changes, such as signals announcing the sudden appearance of an “enemy,” and to respond quickly to these changes. Effective scanning allows the player to shift attention swiftly and automatically from the center of the screen to the periphery.3 Such visual attention is analogous to the type of skill that an air-traffic controller needs: the ability to scan all screen areas, to detect minute changes and to respond quickly.

Some games require players to navigate three-dimensional virtual worlds on a two-dimensional screen. To navigate successfully, players must use multiple depth cues (such as interposition, in which closer objects obscure more distant ones, and motion parallax, in which objects move across the visual field faster if they are closer to the viewer). These games should improve a gamer’s ability to get 3-D information from 2-D depth cues and use it in other contexts. Because navigating a virtual world requires players to maintain awareness of orientation and landmarks, these games also could improve way-finding skills and mental rotation skills. Such transfer could explain the findings of the laparoscopic surgeon study, because the surgeons need to gather detailed 3-D information from a 2-D screen while maintaining awareness of both the screen’s periphery and objects that are not on the screen. The biological basis of how a game’s structure affects players requires further research.


We should anticipate that the mechanics of game play require gamers to hone particular motor skills, which may also transfer to related real-life situations. A game’s mechanics relate to its structure. Movements of the controller change what a player sees on the screen, which in turn affects how the player uses the controller. This feedback loop is consistent with hand-eye coordination.

We would expect to see improvements when gamers practice isolated movements or coordinate them between dominant and nondominant hands, in terms of both fine motor skills (such as making tiny adjustments with the thumb on a game pad) and gross motor abilities (such as practicing a baseball swing on the Nintendo Wii). This expectation also applies to the use of the devices required to play a game. For example, playing driving games with a wheel and pedals is likely to transfer to real-world driving more effectively than playing the same game with a keyboard and mouse.


Finally, we should suppose that the social context of a game influences its effects on the brain and learning. Some games require cooperation and teamwork for success. For example, in some quests of the multiplayer online game World of Warcraft, players with different skills must work together to solve puzzles and to overcome barriers. Other games, such as the battle simulator Call of Duty, require real-time coordinated action. Games that involve teamwork may improve players’ skills in cooperation and coordination, but scientists have conducted almost no research in this area.

A game’s social context may change other outcomes as well. For example, playing violent games with a group of friends who provide social support for aggressive actions might yield greater increases in aggressive behaviors in other contexts than playing the same games by oneself. Conversely, providing players with pro-social motives to help their friends might mitigate increases in aggressive behaviors. Because social context is more difficult to study than the consequences of game content or amount of play, researchers will need to design new experimental methods.

Examining these five aspects of video games has several benefits. It allows us to get beyond the dichotomous thinking of games as simply good or bad. It helps us understand why different types of studies have different outcomes. Finally, it tells us why these findings do not actually contradict each other but simply represent different levels of analysis.

With the exception of educational games, most video games’ effects on brain and behavior are unintentional on the part of both the designers and the players. Nonetheless, research suggests that the effects are real. Video games are neither good nor bad. Rather, they are a powerful form of entertainment that does what good entertainment is supposed to do—it influences us.


  1. D. A. Gentile and J. R. Gentile, “Violent Video Games as Exemplary Teachers: A Conceptual Analysis,” Journal of Youth and Adolescence 9 (2008): 127–141.
  2. R. F. Murphy, W. R. Penuel, B. Means, C. Korbak, A. Whaley, and J. E. Allen, A Review of Recent Evidence on the Effectiveness of Discrete Educational Software (Washington, DC: Planning and Evaluation Service, U.S. Department of Education, 2002).
  3. C. S. Green and D. Bavelier, “Action Video Game Modifies Visual Selective Attention,” Nature 423 (2003): 534–537.
  4. R. Li, U. Polat, W. Makous, and D. Bavelier, “Enhancing the Contrast Sensitivity Function through Action Video Game Training,” Nature Neuroscience 12 (2009): 549–555.
  5. R. Hämäläinen, T. Manninen, S. Järvela, and P. Häkkinen, “Learning to Collaborate: Designing Collaboration in a 3-D Game Environment,” Internet and Higher Education 9, no. 1 (2006): 47–61.
  6. D. A. Gentile, C. A. Anderson, S. Yukawa, M. Saleem, K. M. Lim, A. Shibuya, A. K. Liau, A. Khoo, B. J. Bushman, L. R. Huesmann, and A. Sakamoto, “The Effects of Prosocial Video Games on Prosocial Behaviors: International Evidence from Correlational, Longitudinal, and Experimental Studies,” Personality and Social Psychology Bulletin (2009).
  7. J. C. Rosser Jr., P. J. Lynch, L. Cuddihy, D. A. Gentile, J. Klonsky, and R. Merrell, “The Impact of Video Games on Training Surgeons in the 21st Century,” Archives of Surgery 142, no. 2 (2007): 181–186.
  8. C. A. Anderson, “An Update on the Effects of Playing Violent Video Games,” Journal of Adolescence 27 (2004): 113–122.
  9. C. A. Anderson, A. Sakamoto, D. A. Gentile, N. Ihori, A. Shibuya, S. Yukawa, M. Naito, and K. Kobayashi, “Longitudinal Effects of Violent Video Games on Aggression in Japan and the United States,” Pediatrics 122, no. 5 (2008): e1067–1072.
  10. M. J. Koepp, R. N. Gunn, A. D. Lawrence, V. J. Cunningham, A. Dagher, T. Jones, D. J. Brooks, C. J. Bench, and P. M. Grasby, “Evidence for Striatal Dopamine Release during a Video Game,” Nature 393 (1998): 266–268.
  11. R. Weber, U. Ritterfeld, and K. Mathiak, “Does Playing Violent Video Games Induce Aggression? Empirical Evidence of a Functional Magnetic Resonance Imaging Study,” Media Psychology 8, no. 1 (2006): 39–60.
  12. B. D. Bartholow, B. J. Bushman, and M. A. Sestir, “Chronic Violent Video Game Exposure and Desensitization to Violence: Behavioral and Event-Related Brain Potential Data,” Journal of Experimental Social Psychology 42, no. 4 (2006): 532–539.
  13. D. Lieberman, “Management of Chronic Pediatric Diseases with Interactive Health Games: Theory and Research Findings,” Journal of Ambulatory Care Management 24, no. 1 (2001): 26–38.
  14. S. M. Jaeggi, M. Buschkuel, J. Jonides, and W. J. Perrig, “Improving Fluid Intelligence with Training on Working Memory,” Proceedings of the National Academy of Sciences 105, no. 19 (2008): 6829–6833.