Psychol Bull July 2011 PMID 21534650

The bystander-effect: a meta-analytic review on bystander intervention in dangerous and non-dangerous emergencies.

Peter Fischer, Joachim I Krueger, Tobias Greitemeyer, Claudia Vogrincic, Andreas Kastenmüller, Dieter Frey, Moritz Heene, Magdalena Wicher, Martina Kainbacher

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Mentions

133
Peak: 25 in Jun 2020
across 4 sources since Jun 2019

Extended reach

631,437
potential audience

Total likes

386

Video views

3,455

Mentions per month

Jun 2019 – Dec 2025

Where it's discussed

  • News70 articles
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AI synopsis

What people are saying

The collective discussions reflect a nuanced view, with some posts emphasizing the robustness of the meta-analysis from multiple studies, while others debate its applicability in dangerous emergencies, using terms like 'robust effect' and 'outdated view.' Words such as 'complex', 'challenging', and 'debate' demonstrate high engagement and interest, while references to research design changes and implications illustrate the moderate impact of the findings.

AgreementModerate agreement

Most discussions recognize that the meta-analysis confirms the existence of the bystander effect, although some challenge its universality in dangerous situations.

InterestHigh interest

The discussions delve into details about research methods, the nuance of the findings, and implications, indicating high interest.

EngagementModerate engagement

Participants reference multiple studies, statistical summaries, and debates around the effect’s validity, showing active engagement.

ImpactModerate impact

The discourse indicates that the research influences understanding by challenging previous assumptions, thereby slightly changing the perception of the effect.

Abstract in brief

  • The review updates previous research on the bystander effect, showing that the presence of others generally decreases helping behavior, but this effect varies depending on factors like danger level and physical costs.
  • It finds that in dangerous emergencies, people tend to help more because they're more aroused and recognize the seriousness faster, aligning with the arousal-cost-reward model.
  • Interestingly, in some situations, bystanders can actually support and encourage intervention, especially when they are familiar, male, or in virtual presence, which can reduce the usual bystander effect.]

Top posts

Most liked on X and Bluesky
Rutger Bregman
@rcbregman · X

A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and bystanders can communicate with each other 'additional bystanders even lead to more, rather than less, helping.' https://t.co/8319gZ31sH

Jun 9, 2020 · 243 likes · 27 shares · 355,359 followers View post →
Ramón Nogueras
@RamonNogueras · X

y si alguien sabe lo que hay que hacer, lo cual a menudo sucede. Esto no falsea los resultados de Latané y Darley pero sí pasa una cosa: que cuando se revisa la evidencia de este efecto, pues no es tan claro como parece. https://t.co/90gdIcc0Nm

Jan 19, 2022 · 97 likes · 3 shares · 41,902 followers View post →
H.Asada
@AsadaHirofumi88 · X

@teritamadozo こんなんどうでしょう?エビデンス重視の人には刺さるかも。 人数が多いと責任が拡散し、誰も行動しなくなる「傍観者効果」が発生する。10人いれば誰かが、ではなく、10人いるから誰も気づかない。 https://t.co/CynsKLD0YB

Apr 18, 2025 · 9 likes · 4 shares · 109 followers View post →
Giovanni Fanfoni
@GiovanniFanfoni · X

@ChiaraSegalina @cliobix @alesaura L'effetto spettatore https://t.co/KZFMZaF0JS è stato dimostrato in più occasioni https://t.co/0tGeOvFYOE e tende ad attenuarsi quanto più gli spettatori si conoscono, è identificabile il colpevole della situazione di emergenza, è chiara l'emergenza

Aug 2, 2020 · 5 likes · 3 shares · 4,628 followers View post →
Hackingsocialfr
@hackingsocialfr · X

@Enroweb il y a au contraire un petit effet qui est démontré par cette meta-analyse (fischer et al 2011), https://t.co/V1jqr89CeV , l'abstract montre que l'analyse est plus complexe que ce que postulait Darley, ça dépend beaucoup des situations et des variables.

Oct 5, 2022 · 2 likes · 14,737 followers View post →
Jarryd Bartle
@JarrydBartle · X

A meta-analysis in 2011 of bystander-effect research found that taking into account different research designs, an effect could only be seen in non-dangerous situations (where there was a low risk of actual harm). https://t.co/H2ouYQFam3 /8

Jun 29, 2020 · 2 likes · 3,149 followers View post →

All mentions

morgan
@vicodinszz · X

@thisisnanaadjoa up until 2011, the last systematic review of bystander research had been published in 1981 and was not a quantitative meta-analysis in the modern sense. there’s so much more nuance to it than what people make it to be. https://t.co/RHqC0ofGX3 https://t.co/LQloaaonwd https://t.co/NANvwaWuLK

Sep 16, 2025 · 2 likes · 1,678 followers View post →
てりたま|公認会計士の新しい生き方を見つける
@teritamadozo · X

RT @AsadaHirofumi88: @teritamadozo こんなんどうでしょう?エビデンス重視の人には刺さるかも。 人数が多いと責任が拡散し、誰も行動しなくなる「傍観者効果」が発生する。10人いれば誰かが、ではなく、10人いるから誰も気づかない。 https://…

Apr 18, 2025 · 4 shares · 8,385 followers View post →
khak
@k_h_a_k · X

RT @AsadaHirofumi88: @teritamadozo こんなんどうでしょう?エビデンス重視の人には刺さるかも。 人数が多いと責任が拡散し、誰も行動しなくなる「傍観者効果」が発生する。10人いれば誰かが、ではなく、10人いるから誰も気づかない。 https://…

Apr 18, 2025 · 4 shares · 472 followers View post →
kazu
@kazu27511059 · X

RT @AsadaHirofumi88: @teritamadozo こんなんどうでしょう?エビデンス重視の人には刺さるかも。 人数が多いと責任が拡散し、誰も行動しなくなる「傍観者効果」が発生する。10人いれば誰かが、ではなく、10人いるから誰も気づかない。 https://…

Apr 18, 2025 · 4 shares · 1,274 followers View post →
H.Asada
@AsadaHirofumi88 · X

@teritamadozo こんなんどうでしょう?エビデンス重視の人には刺さるかも。 人数が多いと責任が拡散し、誰も行動しなくなる「傍観者効果」が発生する。10人いれば誰かが、ではなく、10人いるから誰も気づかない。 https://t.co/CynsKLD0YB

Apr 18, 2025 · 9 likes · 4 shares · 109 followers View post →
Dennis Lee
@DennisL73061433 · X

The bystander-effect: a meta-analytic review on bystander intervention in dangerous and non-dangerous emergencies. https://t.co/ZtWzX3OliF

Jan 6, 2024 · 26 followers View post →
Richard Bentall #FBPE @richardbentall.bsky.social
@RichardBentall · X

@JustBeingDandy @PaulEmbery Interesting, but that study does not prove the by-stander effect is a myth (the headline is misleading). These 105 studies prove that it is real: https://t.co/s3sNSVJaRG

Nov 7, 2023 · 31,920 followers View post →
Richard Bentall #FBPE @richardbentall.bsky.social
@RichardBentall · X

@squarelywaiter @PaulEmbery https://t.co/s3sNSVJaRG

Nov 7, 2023 · 31,920 followers View post →
Richard Bentall #FBPE @richardbentall.bsky.social
@RichardBentall · X

@JustBeingDandy @PaulEmbery Here's a meta-analysis (statistical integration) of 105 studies of the bystander effect conducted between the 1960s and the 2000s. It's a robust effect. https://t.co/s3sNSVJaRG

Nov 7, 2023 · 31,920 followers View post →
Richard Bentall #FBPE @richardbentall.bsky.social
@RichardBentall · X

@Swiss____Tony @JustBeingDandy @PaulEmbery Hi troll. Here is a statistical summary of 105 studies of the by-stander effect conducted between the 1960s and the present day. https://t.co/3VpyF1FsfX

Nov 7, 2023 · 31,920 followers View post →
Richard Bentall #FBPE @richardbentall.bsky.social
@RichardBentall · X

@MPscabsOUT @PaulEmbery Here's a meta-analysis of 105 studies of the by-stander phenomenon, conducted between the 1960s and the present day. It's a robust, much-repeated effect - the more people watching, the less likely people are to intervene. https://t.co/3VpyF1FsfX

Nov 7, 2023 · 1 like · 31,920 followers View post →
Maryam Esfandiari
@Esfandiari_mary · X

برای مطالعه بیشتر : https://t.co/AIBrySALxM

May 4, 2023 · 62 followers View post →
Hackingsocialfr
@hackingsocialfr · X

@Enroweb il y a au contraire un petit effet qui est démontré par cette meta-analyse (fischer et al 2011), https://t.co/V1jqr89CeV , l'abstract montre que l'analyse est plus complexe que ce que postulait Darley, ça dépend beaucoup des situations et des variables.

Oct 5, 2022 · 2 likes · 14,737 followers View post →
J Farrow
@Blaster8645 · X

@strawberreli @KartGarfunkel @femboyanc0m @RndmStreetMedic [Remainder of citation from previous comment.] Psychological Bulletin, 137(4), 517–537. https://t.co/6oCvPtz22D

May 16, 2022 · 767 followers View post →
J Farrow
@Blaster8645 · X

@strawberreli @KartGarfunkel @femboyanc0m @RndmStreetMedic Fischer, P., Krueger, J. I., Greitemeyer, T., Vogrincic, C., Kastenmüller, A., Frey, D., Heene, M., Wicher, M., & Kainbacher, M. (2011). The bystander-effect: A meta-analytic review on bystander intervention in dangerous and non-dangerous emergencies. [citation too long]

May 16, 2022 · 767 followers View post →
Clarita
@ClaraJaraGar · X

RT @RamonNogueras: y si alguien sabe lo que hay que hacer, lo cual a menudo sucede. Esto no falsea los resultados de Latané y Darley pero s…

Jan 20, 2022 · 3 shares · 325 followers View post →
Aimar Vega Fernández
@AimarVegaFernnd · X

RT @RamonNogueras: y si alguien sabe lo que hay que hacer, lo cual a menudo sucede. Esto no falsea los resultados de Latané y Darley pero s…

Jan 19, 2022 · 3 shares · 214 followers View post →
Beatriz
@yo_meiga · X

RT @RamonNogueras: y si alguien sabe lo que hay que hacer, lo cual a menudo sucede. Esto no falsea los resultados de Latané y Darley pero s…

Jan 19, 2022 · 3 shares · 144 followers View post →
Ramón Nogueras
@RamonNogueras · X

y si alguien sabe lo que hay que hacer, lo cual a menudo sucede. Esto no falsea los resultados de Latané y Darley pero sí pasa una cosa: que cuando se revisa la evidencia de este efecto, pues no es tan claro como parece. https://t.co/90gdIcc0Nm

Jan 19, 2022 · 97 likes · 3 shares · 41,902 followers View post →
ℒ.
@LadyDeeks · X

RT @GiovanniFanfoni: @ChiaraSegalina @cliobix @alesaura L'effetto spettatore https://t.co/KZFMZaF0JS è stato dimostrato in più occasioni ht…

Aug 2, 2020 · 3 shares · 484 followers View post →
Paola B.
@Paolaaa81 · X

RT @GiovanniFanfoni: @ChiaraSegalina @cliobix @alesaura L'effetto spettatore https://t.co/KZFMZaF0JS è stato dimostrato in più occasioni ht…

Aug 2, 2020 · 3 shares · 571 followers View post →
Emanuela
@cliobix · X

RT @GiovanniFanfoni: @ChiaraSegalina @cliobix @alesaura L'effetto spettatore https://t.co/KZFMZaF0JS è stato dimostrato in più occasioni ht…

Aug 2, 2020 · 3 shares · 783 followers View post →
Giovanni Fanfoni
@GiovanniFanfoni · X

@ChiaraSegalina @cliobix @alesaura L'effetto spettatore https://t.co/KZFMZaF0JS è stato dimostrato in più occasioni https://t.co/0tGeOvFYOE e tende ad attenuarsi quanto più gli spettatori si conoscono, è identificabile il colpevole della situazione di emergenza, è chiara l'emergenza

Aug 2, 2020 · 5 likes · 3 shares · 4,628 followers View post →
Jarryd Bartle
@JarrydBartle · X

A meta-analysis in 2011 of bystander-effect research found that taking into account different research designs, an effect could only be seen in non-dangerous situations (where there was a low risk of actual harm). https://t.co/H2ouYQFam3 /8

Jun 29, 2020 · 2 likes · 3,149 followers View post →
YangDailyPodcast
@YangDailyCast · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 11, 2020 · 27 shares · 2,448 followers View post →
upton o. goode
@uptonogoode1 · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 10, 2020 · 27 shares · 3 followers View post →
Jay
@double1yellow · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 3 followers View post →
Bakor Al-tayar
@Bakor24 · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 294 followers View post →
(((AnneLane Witt)))
@VaPriestess · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 2,797 followers View post →
fra
@fraiefaire · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 677 followers View post →
Lord Barham The Wake
@Ezquid · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 1,569 followers View post →
allverschlingerForFuture
@allverschlinger · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 7 followers View post →
Magnus Lie Hetland
@mlhetland · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 866 followers View post →
Budy Hartono has housing insecurities
@Hartonope · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 757 followers View post →
Janette McLeod
@truffle57 · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 209 followers View post →
alex//❤️‍
@alex_ryanne · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 240 followers View post →
J.B. Negrón
@negronjb · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 1,448 followers View post →
Rachel (@rachelmack@bsky.social)
@rachelmack · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 1,450 followers View post →
Red Dead Sebdemption
@dflukey · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 963 followers View post →
Why So Gullible?
@TestWithScience · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 140 followers View post →
David Richter
@drichter77 · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 258 followers View post →
2021 time
@TheDefinitiveK · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 89 followers View post →
Syahmi Rafsanjani
@SyahmiRafsan · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 7,650 followers View post →
Gin McNarnia
@Jimmcnary · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 376 followers View post →
William P.
@Wep1985 · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 2,214 followers View post →
Genevieve
@genevieveisgg · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 3,813 followers View post →
Johanna Berg
@johannaberg · X

RT @rcbregman: A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and byst…

Jun 9, 2020 · 27 shares · 2,391 followers View post →
Rutger Bregman
@rcbregman · X

A 2011 meta-analysis even found that there's a 'reverse bystander effect'. When the situation is life-threatening and bystanders can communicate with each other 'additional bystanders even lead to more, rather than less, helping.' https://t.co/8319gZ31sH

Jun 9, 2020 · 243 likes · 27 shares · 355,359 followers View post →
Lasse S. Liebst
@LSLiebst · X

@ScotlandYardCSI This presents an outdated view of the bystander effect. First, the effect does not generalize to dangerous emergencies: https://t.co/cq8lBC1TIn. Second, in most public emergencies someone will intervene to help: https://t.co/y0yrYfCgxn

Jun 23, 2019 · 509 followers View post →