Seeing is believing: The effect of brain images
on judgments of scientific reasoningq,qq
David P. McCabea,*, Alan D. Castelb
aDepartment of Psychology, Colorado State University, Campus Box 1876,
Fort Collins, CO 80523-1876, USA
bDepartment of Psychology, University of California, 1285 Franz Hall, Box 951563,
CA 90095-1563, Los Angeles, USA
Received 19 December 2006; revised 25 July 2007; accepted 25 July 2007
Brain images are believed to have a particularly persuasive influence on the public percep-
tion of research on cognition. Three experiments are reported showing that presenting brain
images with articles summarizing cognitive neuroscience research resulted in higher ratings
of scientific reasoning for arguments made in those articles, as compared to articles accompa-
nied by bar graphs, a topographical map of brain activation, or no image. These data lend
support to the notion that part of the fascination, and the credibility, of brain imaging
research lies in the persuasive power of the actual brain images themselves. We argue that
brain images are influential because they provide a physical basis for abstract cognitive pro-
cesses, appealing to people’s affinity for reductionistic explanations of cognitive phenomena.
? 2007 Elsevier B.V. All rights reserved.
Keywords: Scientific communication; fMRI; Brain imaging; Persuasion; Cognitive neuroscience
0010-0277/$ - see front matter ? 2007 Elsevier B.V. All rights reserved.
qThis manuscript was accepted under the editorship of Jacques Mehler.
qqWe would like to thank Chelsea Beman for assistance in running the participants in this study.
*Corresponding author. Tel.: +1 970 491 3018; fax: +1 970 491 1032.
E-mail addresses: email@example.com (D.P. McCabe), firstname.lastname@example.org (A.D. Castel).
Available online at www.sciencedirect.com
Cognition 107 (2008) 343–352
Understanding scientific data is often a complex process for both scientists and the
lay public alike. Scientific communication is facilitated by presenting summaries of
mation about the quality or importance of the scientific data. For example, physical
social sciences, such as sociology and economics, which use tables to a greater degree
(Smith, Best, Stubbs, Archibald, & Roberson-Nay, 2002). Thus, to the extent that
physical sciences are perceived as more credible than social sciences, visual displays
are associated with a greater degree of scientific credibility (Smith et al., 2002).
other methods of presentation are often used. For example, in cognitive neuroscience,
brain activity measured using fMRI (functional magnetic resonance imaging) or PET
(positron emission tomography) is sometimes presented in tables or graphs, but is
often represented using images of the brain with activated areas highlighted in color.
These brain images have been portrayed in the media as localizing brain areas associ-
being in love, and believing in God, among other things (Nicholson, 2006). Further-
more, both scientists and the media have suggested that using brain images to repre-
sent brain activity confers a great deal of scientific credibility to studies of
cognition, and that these images are one of the primary reasons for public interest
in fMRI research (Carey, 2006; Dobbs, 2005; Racine, Bar-Ilan, & Illes, 2005).
The excitement about brain imaging research has not been without controversy.
Many scientists, particularly cognitive neuroscientists and ethicists, are concerned
about how the data from fMRI studies are being interpreted, particularly by the
lay media and the general public, both of whom have shown a tendency to oversim-
plify and misrepresent conclusions from brain imaging studies. Racine et al. (2005)
have argued that popular press coverage of brain imaging research has led to a type
of neuro-realism, such that the phenomena under study become, ‘‘uncritically real,
objective or effective in the eyes of the public’’ (p. 160). Similarly, Dumit (2004)
has argued that brain images naturally communicate that different ‘‘kinds of people’’
(e.g., normal or depressed) are represented by different patterns of brain activation,
and that these images are intuitively interpreted as being credible representations of
cognitive activity. This tendency to interpret brain images as credible may be related
to people’s natural affinity for reductionistic explanations of cognitive phenomena
(cf., Weisberg, Keil, Goodstein, Rawson, & Gray, in press), such that physical rep-
resentations of cognitive processes, like brain images, are more satisfying, or more
credible, than more abstract representations, like tables or bar graphs.
The primary purpose of the present study was to examine whether brain images
actually do have a particularly powerful persuasive influence on the perceived cred-
ibility of cognitive neuroscience data. In order to achieve this goal, ratings of the
quality of articles summarizing cognitive neuroscience data were examined for arti-
cles that were accompanied by brain images, and those that were accompanied by
other representations of data, or no representation at all.
D.P. McCabe, A.D. Castel / Cognition 107 (2008) 343–352
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