Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
A bias caused by inappropriate averaging in experiments with randomized stimuli
Stockholm University, Faculty of Social Sciences, Department of Psychology.
Stockholm University, Faculty of Social Sciences, Department of Psychology.
2006 (English)In: Journal of Parapsychology, ISSN 0022-3387, Vol. 70, no 2, 233-254 p.Article in journal (Refereed) Published
Abstract [en]

Using simulations, a bias caused by inappropriate averaging in experiments with randomized stimuli is described. As an illustrating example, experiments aimed at demonstrating "presentiment" by showing arousal to be higher prior to arousing stimuli than prior to calm stimuli are considered. It is shown that such results could be obtained if (a) the participant believes that the likelihood of an activating stimulus being presented on the next trial increases after a calm stimulus has been presented (the gamblerĀ“s fallacy) and (b) overall arousal means are calculated across individual arousal means or for a pooled sample of all possible stimulus sequences. The effect becomes very small when participants are pooled before averaging, provided that the number of trials per participant and/or the number of participants is sufficiently large. The bias decreases as the length of the stimulus sequence increases, and becomes zero in an infinitely long sequence. Basically, the bias can be explained by the fact that the expected mean arousal level before calm stimuli increases as a function of sequence length. Various possible strategies for reducing or eliminating the bias are discussed, but none of them is judged to be fully satisfactory. A generalized version of the bias is outlined and discussed. It is argued that, in some form, the bias may occur in various types of experiments, both within and outside parapsychology. It is also argued that numerous previous experiments need to be checked for occurrence of the bias.

Place, publisher, year, edition, pages
2006. Vol. 70, no 2, 233-254 p.
Keyword [en]
prejudices, parapsychology, gamblers' fallacy
National Category
Psychology
Identifiers
URN: urn:nbn:se:su:diva-16634OAI: oai:DiVA.org:su-16634DiVA: diva2:183154
Available from: 2008-12-19 Created: 2008-12-19 Last updated: 2011-01-11Bibliographically approved

Open Access in DiVA

No full text

Other links

http://search.ebscohost.com/login.aspx?direct=true&db=aph&AN=31232800&site=ehost-live

Search in DiVA

By author/editor
Dalkvist, JanWesterlund, Joakim
By organisation
Department of Psychology
Psychology

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 54 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf