Unconscious Decision Making? 1
To be published in Behavioral and Brain Sciences (in press)
© Cambridge University Press 2012
Below is the copyedited final draft of a BBS target article that has been accepted for
publication. This updated preprint has been prepared for formally invited commentators.
Please DO NOT write a commentary unless you have been formally invited.
Unconscious influences on decision making: A critical
review
Ben R. Newell
School of Psychology, University of New South Wales, Sydney 2052, Australia.
ben.newell@unsw.edu.au
http://www2.psy.unsw.edu.au/Users/BNewell/Index.html
David R. Shanks
Division of Psychology and Language Sciences, University College London, 26
Bedford Way, London WC1H 0AP, England
d.shanks@ucl.ac.uk
http://www.ucl.ac.uk/psychlangsci/research/CPB/people/cpb-staff/d_shanks
Abstract: To what extent do we know our own minds when making decisions?
Variants of this question have preoccupied researchers in a wide range of domains,
from mainstream experimental psychology (cognition, perception, social behavior) to
cognitive neuroscience and behavioral economics. A pervasive view places a heavy
explanatory burden on an intelligent cognitive unconscious, with many theories
assigning causally effective roles to unconscious influences. This article presents a
novel framework for evaluating these claims and reviews evidence from three major
bodies of research in which unconscious factors have been studied: multiple-cue
judgment, deliberation without attention, and decisions under uncertainty. Studies of
priming (subliminal and primes-to-behavior) and the role of awareness in movement
and perception (e.g., timing of willed actions, blindsight) are also given brief
consideration. The review highlights that inadequate procedures for assessing
awareness, failures to consider artifactual explanations of “landmark” results, and a
tendency to uncritically accept conclusions that fit with our intuitions have all
contributed to unconscious influences being ascribed inflated and erroneous
explanatory power in theories of decision making. The review concludes by
recommending that future research should focus on tasks in which participants’
attention is diverted away from the experimenter’s hypothesis, rather than the highly
reflective tasks that are currently often employed.
Keywords: awareness; conscious; decision making; deliberation; intuition; judgment;
perceptual-motor skills; unconscious
Unconscious Decision Making? 2
1. Introduction
Psychology is concerned with understanding how the mind controls and determines
behavior. Fundamental to this goal is whether unconscious influences play a
significant role in the generation of decisions and the causation of behavior generally.
Everyday notions such as “gut instinct” and “intuition” capture the idea that subtle
influences falling outside awareness can bias behavior. Claims that “People possess a
powerful, sophisticated, adaptive unconscious that is crucial for survival in the world”
(Wilson 2002, p. vii) and that we should think less rather than more about complex
decisions (Dijksterhuis et al. 2006) have a strong grip on both theoretical perspectives
and the public imagination (e.g., Gigerenzer 2007; Gladwell 2005; Lehrer 2009). This
article evaluates a wide range of research findings from the past 20 or so years that
have contributed to the development of this perspective.
The unconscious has of course played a major role in the history of psychology,
certainly predating Freud’s extensive development of the concept. But in the past few
years it has been the focus of extensive research in mainstream experimental
psychology, including cognition, perception, and social behavior, as well as in
cognitive neuroscience, behavioral economics, and other domains. Our focus is on the
core process of decision making, which relates to all of these areas.
In this article we take decision making to refer to the mental processing that leads to
the selection of one among several actions (choices). Construed this way, we exclude
examples such as neurons or brain networks making “decisions”. Thus the visual
system’s computation of low-level properties is not decision making on this
definition. We view consciousness as a property of individuals and hence do not
Unconscious Decision Making? 3
believe it serves any useful purpose to ask whether area V5’s computation of motion,
for instance, is or is not conscious. (It is, in contrast, perfectly reasonable to ask
whether an individual’s judgment of motion is conscious).
1
The outline of the article is as follows: We begin by describing a framework for
illustrating how unconscious processes could be causally effective in decision making
(as defined above). We then articulate some of the requirements for an adequate test
of awareness and discuss the legacy of Nisbett and Wilson’s (1977) highly influential
work. The body of the article reviews three major areas of research from the decision-
making tradition in which unconscious factors have been studied: multiple-cue
judgment, deliberation without attention, and decisions under uncertainty. A final
section considers research from the priming literature, both subliminal priming and
the so-called primes-to-behavior studies that are prevalent in social cognition (e.g.,
Bargh et al. 1996). Although few of these studies relate specifically to decision
making, they are provocative illustrations of possible unconscious influences on
behavior and thus warrant consideration in our review.
We do not, however, claim to offer a comprehensive literature review of all the
research domains relevant to our guiding question. In particular, we only give very
brief consideration (in section 6, Discussion) to the literature investigating awareness
of decisions about movements (e.g., Libet 1985), illusory conscious will (e.g., Wegner
2004, and neuroscience phenomena such as blindsight (e.g., Weiskrantz 1986).
Restricting our focus of course leaves us open to the criticism that we are “looking in
the wrong place” for the evidence. Our response is twofold: First, pragmatic
considerations make it impossible to consider all the evidence in a single article, but
we contend that the areas we have selected have been highly influential in bolstering
claims for unconscious decision making. Second, the areas we focus on in the core of
Unconscious Decision Making? 4
the review are those that are most readily identified as involving decisions in the sense
defined above. In the motor-movement and neuroscience domains, the nature of the
decision being made and the information relied upon to make that decision are,
arguably, less well defined in the first place, thus making discussions of peoples’
awareness of them that much more difficult. We expand on these issues further in
Section 6, the general discussion.
Our critical analysis points to a surprising conclusion, that there is little convincing
evidence of unconscious influences on decision making in the areas we review, and
that, as a consequence, such influences should not be assigned a prominent role in
theories of decision making and related behaviors. This conclusion is consistent with
the view that conscious thoughts are by far the primary driver of behavior
(Baumeister et al. 2011) and that unconscious influences – if they exist at all – have
limited and narrow effects.
1.1 A framework for the components of decision making
Our first step in examining the role of the unconscious in theories of decision making
is to propose a framework for thinking about how decisions could be influenced by
unconscious processes. The framework is based on the lens model (Brunswik 1952),
popularized in the judgment and decision making field by Hammond, Stewart, and
many others (for overviews, see Hammond & Stewart 2001; Karelaia & Hogarth
2008).
The basic premise of the lens model is that a decision maker views the world through
a “lens of cues” that mediates between a stimulus in the environment and the internal
perceptions of the decision maker, as shown in Figure 1. The double convex lens in
the center of the diagram shows a constellation of cues that diverge from a criterion or
event in the environment (left side of figure). The decision maker uses these cues to
Unconscious Decision Making? 5
achieve (e.g., correctly estimate) the criterion, and so these cues are shown as
converging (right side of figure) on a point of response or judgment in the mind of the
decision maker. The lens model conceptualizes decision making as being guided by
judgment (see note 1). An application of the lens model in the domain of medical
diagnosis (e.g., Harries et al. 2000) would construe the physician as attempting to
decide on the best treatment (the judgment) for a patient by determining the likelihood
of a disease (the criterion) given the symptoms (cues) relied upon in making the
judgment.
