Being watched doesn't make you nicer:
no effect of visible and invisible eye
primes on prosocial behavior in a
masked priming study
Jacob Jolij * and Tineke de Haan
Department of Experimental Psychology, Faculty of Behavioural and Social Sciences, University of
Groningen
*
To whom correspondence should be addressed:
Jacob Jolij
Experimental Psychology
Grote Kruisstraat 2/1
9712 TS Groningen
The Netherlands
+31 50 363 6348
j.jolij@rug.nl
Abstract
‘Priming’ refers to a psychological manipulation were the presentation of a stimulus (the ‘prime’)
alters subsequent behavior of an observer. Priming has been well studied in both cognitive and social
psychology, but the effect has recently been met with a large body of criticism, primarily because of
failures to replicate specific effects. Here, we studied the effects of priming with a pair of eyes on
prosocial behavior. Recent studies have reported an increase of prosocial behavior after participants
were primed with eyes, possibly because of the induced feeling of being watched. Here we sought to
replicate and extend these results with both masked (invisible) and unmasked (visible) primes. We
failed to obtain any effect of eye primes on prosocial behavior with both masked and unmasked
primes, but instead found substantial evidence for the null hypothesis that eye primes do not
influence prosocial behavior. These findings cast further doubt on the idea that complex human
behavior, such as prosocial behavior, is easily modulated by 'social primes'. We discuss our findings in
the light of neuroscientific and social psychological literature on unconscious processing and social
priming, and suggest an alternative explanation for our results, including suggestions for new
experiments to further investigate moderating variables in social priming.
Introduction
Humans have a vast behavioral repertoire, and selecting the 'right thing to do' in a given situation is
therefore hardly trivial. Not surprisingly, we rely to a large extent on external cues and information
to guide our behavior, quite often without us realizing this. A recent example is provided by Keizer et
al.: in a real-world study in the city of Groningen, people were more likely to litter (which is
prohibited in the city's by-laws) when there are clear cues of rule-breaking behavior in the
environment, such as graffiti sprayed on a wall with a clear 'graffiti not allowed'-sign [1].
The idea that our behavior is largely guided by external cues is of course far from new, but the
concept of 'social’ or ‘behavioral’ priming (we refer to the phenomenon as social priming in the
remainder of this manuscript) has received overwhelming interest in the literature. Famous
examples include Bargh et al.'s demonstration that being primed with words related to the elderly
make people walk slower, and the finding that being primed with the word 'professor' makes people
perform better at cognitive tests by Dijksterhuis and Van Knippenberg [2, 3]. Despite the fact that
many of such fascinating examples lack a firm theoretical underpinning, the phenomenon of 'social
priming' has led many researchers and even popular media to claim that our decisions are primarily
guided by external factors, and often bypass our conscious awareness [4, 5].
However, social priming is met with increasing criticism. The lack of a firm theoretical background,
problems with statistical power, potentially flawed methodology [6, 7], the exposure of several highprofile studies as fraudulent [8, 9], but most importantly, repeated failures to directly replicate
several effects [10-13] has led to strong skepticism towards the notion of social priming. The
sentiment towards social priming amongst many scientists in related areas of psychology, such as
experimental psychology or methodology, is nicely reflected in a satirical blog bost by Erasmus
University (Rotterdam, NL) professor of cognitive psychology Rolf Zwaan, in which he provides a
'recipe' for social priming studies, including tips such as "to come up with an experimental
manipulation [...] all you need to do is take an expression literally", and "...the dependent measure of
choice in social priming research is candy. [...] You can't go wrong with candy!" [14]. On a more
serious note, Daniel Kahneman sent an open letter to several labs studying social priming, published
in Nature, in which he stated he "...see[s] a trainwreck coming for the field" [15].
A reason for the observed skepticism amongst cognitive psychologists and neuroscientists may be
that in cognitive psychology and neuroscience, priming is a widely studied and fairly well-understood
phenomenon. However, the behavioral effects in 'cognitive' priming are not nearly as spectacular as
that in 'social' priming: priming effects in cognitive psychology are quite often limited to changes in
reaction times, changes in recall rates of studied items, or biasing the interpretation of ambiguous
sensory input [eg., 16-18], and these findings are well-replicated [12]. Priming is often interpreted as
a "stimulus paving the way for a subsequent stimulus" [19] or providing 'priors' for the analysis of
subsequent sensory input [18], processes that may even be initiated by primes that are presented
outside awareness [16, but see 20]. In other words, there is good reason to believe that 'primes', in a
general sense of the word, do work, even when participants are unaware of being primed, but most
cognitive psychologists and neuroscientists would find the high-level priming effects described in the
field of 'social priming' highly implausible.
However, given that priming in a more general sense does seem to produce effects, there is a distinct
possibility that social priming, despite all the criticism, is a real phenomenon and that we are in fact
continuously 'primed' by all kinds of cues from our environment. To further investigate this
possibility, in this study we have focused on a biologically plausible form of social priming. Several
recent studies have shown that cues of being watched (in particular the presence of eyes) promote
prosocial behavior. In a laboratory study, Haley and Fessler found that the presence of a pair of
stylized eyes (blended in as part of a logo) on the background of a computer screen made
participants make more generous offers in an ultimatum game than when participants were
presented with a neutral background [21]. A conceptual replication of this study by Bateson, Nettle,
and Roberts, which was carried out in a real-life setting, showed that the amount of money paid into
the authors' university department pantry's honesty box1 was significantly larger when the authors
put up pictures of a pair of eyes in the pantry than when they put up pictures of flowers, even when
controlled for overall consumption [22].
Contrary to the apparently implausible social priming effects described earlier, both from a social
psychological as from a cognitive neuroscience perspective these results seem highly plausible. First,
in social psychology it is widely accepted that humans conform to group norms - classic (and widely
replicated) studies by Asch and coworkers and Sherif and coworkers have clearly demonstrated this
[23, 24]. In particular, when one's behavior can be observed by others, one is likely to conform to
social norms [23]. Being cued with eyes provides a context of being watched, which may result in the
observed prosocial behavior in the studies mentioned before [21, 22]. Moreover, eyes constitute a
powerful biological signal. Direction of gaze, for example, is processed nearly automatically [25] and
recent neuroimaging studies confirm that the brain is sensitive to eyes even these are not
consciously perceived [26]. Together, this makes the idea that presence of a pair of eyes results in
changes in prosocial behavior rather plausible.
Here we sought to further investigate of conscious and unconscious processing in guiding behavior
by means of priming prosocial behavior using eyes. In earlier work, we have observed that the role of
unconsciously processed information in guiding behavior is rather limited, and that the brain's
executive systems often prefer consciously processed information over unconsciously processed
information in perceptual decision making [27, 28]. We have proposed that this 'repression of
unconscious information' may in part be a strategy to avoid unwanted 'social' priming effects: if we
are so easily guided by our environment as some social priming studies lead us to believe, our
representation of that environment ought to be as accurate as possible in order to avoid
inappropriate behavioral priming [27-30]. Based on this idea, we hypothesized that unmasked, and
thus consciously processed primes would produce a priming effect, whereas masked, unconsciously
processed primes would not produce a priming effect.
However, we failed to confirm our hypotheses. Although we did not find a priming effect for masked
eyes, as we expected, we also failed to find any evidence for priming of prosocial behavior in an
dictator game with unmasked, consciously processed eyes. Rather, a Bayes factor analysis of our data
1
An honesty box is common in British university pantries, where staff and students can make tea and coffee. The users are
asked to pay for their consumption by depositing money in a box called the 'honesty box'. Such payments can be made per
consumption, but sometimes also in advance for a month, or a semester. Payment is typically compulsory, but given that
most of these pantries are unsupervised there is no sanction for not paying one's tea or coffee, other than an annual note
from the Head of School to all staff and students insisting that all pay for their consumptions, “or else...”
revealed substantial support for the null hypothesis of no effect of primes on behavior. These results
cast further doubt on the idea that complex decisions and behaviors are easily influenced by external
cues.
Methods
Ethics statement
This study was approved by the local Ethics Committee ("Ethische Commissie Psychologie van het
Heymans Instituut voor Psychologisch Onderzoek") and carried out according to the Declaration of
Helsinki.
Participants
118 first-year students (92 women, mean age 21.6 years, SD 3.9 years) gave their written informed
consent to participate in this study. Participants were rewarded with study credit for their
participation; experiment participation is a required part of the psychology curriculum in Groningen.
Stimuli and procedure
Participants were tested in a computer laboratory with 8 cubicles, i.e. 8 participants per session.
After receiving general instructions from the experimenter, participants were shown on the
computer screen that they were paired with a participant from another session in a dictator game,
and that they could earn up to 5 additional study credits for their participation. These five additional
credits would be distributed between the two participants by one of them (the 'dealer'), and this
distribution would be final (i.e., the 'dealer' is in full control). After these instructions, participants
got to see whether they would be the recipient or the dealer. Obviously, all participants were
assigned the role of 'dealer'.
After receiving their role instructions, participants were given 20 seconds to think about their choice.
Critically, during these 20 seconds a countdown timer appeared. Centrally, time to decision (in s) was
presented, flanked by the prime images, which could be masked or unmasked. Masking was done
using a metacontrast mask. Based on [21] and [22] we have chosen eyes as prosocial primes, and
flowers as a neutral control prime. In the masked conditions, the primes were presented for 10 ms,
directly followed by a mask for 150 ms, preceded by a blank interval for 840 ms during which only
the counter was presented. The unmasked stimuli were shown for 110 ms, followed by the mask for
150 ms, preceded by a blank interval with only the counter of 740 ms. Masking parameters were
chosen on basis of a small pilot experiment (N=6). In this pilot, none of participants reported
awareness of the masked stimuli, but yet they reported to have seen all unmasked stimuli. See figure
1 for a schematic overview of a single trial, and an example of the stimuli used. After the countdown
interval, participants had to indicate how many credits they wanted to give to the recipient player,
ranging from 0 to 5 credits, in whole credits. Finally, an exit questionnaire was administered, asking
whether participants had seen the primes, and whether they had seen through the manipulation.
Please note that participants only participated in one single condition (see table 1 for the distribution
of participants over the conditions).
Analyses
Data were analyzed in SPSS version 20 (IBM, Natick, USA). To assess effect of our manipulations, we
used a 2x2 univariate anova with the number of credits given to the recipient as dependent measure,
and prime (flowers or eyes) and level of masking (masked or unmasked) as factors. The number of
research participation credits students still needed to fulfill the requirements of their was taken into
account as covariate. We expect participants to give more credits to the 'recipient' when primed with
unmasked eyes than in the other three conditions, and expected a moderating effect of the number
of credits still required (with more credits still required resulting in smaller offers to the recipient).
To assess evidence in favor of the null hypothesis that eye primes do not increase generosity
compared to flower primes, we computed Bayes factors for the conscious and unconscious
conditions, using Zoltan Dienes’ web applet
(http://www.lifesci.sussex.ac.uk/home/Zoltan_Dienes/inference/bayes_factor.swf). Since we had no
explicit expectation about the size of an eventual effect, we used a flat distribution ranging from 0 to
5 as a prior.
Results
The results of the exit questionnaire show that our manipulation was successful: in the masked
conditions, only 3 participants indicated to have seen the primes. These participants have been
removed from the analysis. See table 1 for the exact numbers of participants entered into the
analysis per condition. None of the participants had seen through the manipulation, although most
participants indicated they believed to be participating in a variant of Prisoner's Dilemma.
On average, 2.1 credits (of 5) were given to the 'recipient', pooled over all four conditions. However,
this number was not influenced by prime (F(1, 103) = .654, η2 = .006, p = .654, 95% CI [-.235 .765]),
masking (F(1,103) = .917, η2 = .009, p = .340, 95% CI [-.622 .378]), nor was there an interaction
between prime and level of masking (F(1,103) = .503, η2 = .005, p =.480). Finally, no effects of
required course credit were observed (F(1,103)= .595, η2 = .006, p = .442). See figure 2. In sum, the
frequentist analyses we used uncovered no evidence that presence of a pair of eyes increases
generosity. To control for the contribution of participants who did share any credits [see 21], we
performed a χ2-test in which we tested whether the distribution of participants not sharing any credit
differed between the conditions. This was not the case (χ2(15) = 14.818, p = .465).
The Bayes factors analysis revealed substantial support for the null hypothesis of no effect of eye
primes over flower primes: collapsed over masked and unmasked targets, the Bayes factor is 5.26 in
favor of the null; for unmasked stimuli the Bayes factor is 3.57 in favor of the null; finally, for masked
stimuli the Bayes factor is 7.69 in favor of the null. All these Bayes factors are over the criterion of B =
3 for substantial evidence for the null.
Discussion
We have tried to replicate and extend the finding that priming participants with a cue of being
watched, in this case a pair of eyes, makes them behave more prosocially, and whether this priming
effect is contingent on awareness of the primes. However, in this study we have failed to find any
evidence of priming at all – rather, we find substantial evidence for the null hypothesis. How can we
explain these results?
Of course, there are some notable differences between our study and earlier studies on priming
prosocial behavior using eye primes [21, 22]. Bateson, Nettle and Roberts [22] present a quasiexperimental design in which they report increased deposits in a department honesty box in weeks
in which they put up a picture of eyes compared to weeks in which they put up a picture of flowers.
Although there is no reason at all to doubt the validity of this dataset, the quasi-experimental design
of authors makes it virtually impossible to evaluate the size and magnitude of the priming effect. We
do not know how many 'participants' there were, nor do we know the characteristics of these
participants. Moreover, although Bateson, Nettle and Roberts have quite cleverly controlled for
consumption by looking at overall milk consumption (tea is typically consumed with milk in the UK),
there may have been many factors uncontrolled for that may have contributed to the observed
effects, such as participants seeing through the manipulation, participants paying for a full semester
in one week or even participants not taking milk with their consumption. We therefore acknowledge
the work by Bateson, Nettle, and Roberts as an interesting real-life demonstration of the eyepriming-effect, but given the many caveats we will not consider it further here.
Our study shares more features with the laboratory study of Haley and Fessler [21], who compared
the effect of several prime types (cues of being watched versus neutral primes in auditory and visual
modalities) on offers made in a dictator game. Since we modelled our experiments after this study,
we tried to keep most features in line with those of Haley and Fessler - sample size (N ~ 30 per
group), paradigm (dictator game) and decision time (20 s) were comparable. Notable deviations,
though, were 'currency' (real money in [21], study credits in our study), setting (in a large computer
testing room in [21], in cubicles in our study), and, most importantly, prime presentation (on the
background of the computer desktop in [21], centrally flashed during countdown in our study).
First, we would like to note that our sample size is equivalent to that of Haley and Fessler [21], which
does not comply with Simonsohn's advice to use a sample size of 2.5 times that of the original study
in direct replications [31]. As a result, our failure to find an effect cannot be interpreted as evidence
that the effect we sought to replicate does not exist. However, it should be noted that our study is
not a direct replication attempt, but rather a conceptual replication. Moreover, if the lack of an
effect in our study could have been attributed to lack of power, our Bayes factor analysis would have
revealed ‘inconclusive’ evidence for the null, rather than the substantial evidence for the null
hypothesis we find in our dataset. What we may conclude, therefore, is that the effect of eye primes
on prosocial behavior does not generalize from the settings used by Haley and Fessler [21] and
Bateson, Nettles, and Roberts [22]. Our failure to find an effect is informative about the actual
overall effect size, and the conditions in which it occurs [32].
One explanation for the observed null result is that in our experiment there was a moderating
variable, eradicating the effect specifically in the present study. Could any of the factors in which our
study deviated from Haley and Fessler’s [21] have caused the lack of an effect we observe? First,
there is little reason to assume that the deviation in 'currency' might have resulted in a total lack of
effect: even with completely virtual 'currencies' (that is, tokens that hold no real-world value) strong
effects have been reported with social interaction paradigms as we used here [33]. Our 'currency',
despite having no direct economic value, did have real world value to the participants, and indeed
we observed that participants choose to keep most credits to themselves, rather than offering an
equal split.
Second, the presentation of the primes differed. In our unmasked condition, primes were presented
centrally and were clearly visible to the participants. In the original study by Haley and Fessler [21],
the primes were part of a logo and 'hidden' (but easily visible) on the computer screen. In both
studies, participants have seen the primes, but is seems quite obvious that in our study the primes
have drawn more attention than the primes used by Haley and Fessler, even though none of our
participants was explicitly aware of the function of the eye primes. Can attention have such a
moderating effect? In social psychology the elaboration likelihood model accounts for the effects of
'peripheral' versus 'central' processing of information in attitude and behavior change. When people
are willing and able to process information centrally, the cognitive elaboration will result in favorable
or unfavorable thoughts resulting in a change in attitude. However, if, for some reason, someone is
not willing or able to engage in effortful processing of information, peripheral cues (such as an
illustration next to a newspaper article) may influence one's opinion without explicit awareness [34].
Although we would allow ourselves considerable freedom of interpretation, we may hypothesize
that a similar process can explain the discrepancy between our null findings and the findings of Haley
and Fessler [21]. Suppose that indeed eye primes automatically trigger a proneness to behave more
prosocially. According to the elaboration likelihood model, peripheral processing of eye primes will
then automatically result in a more prosocial attitude. Central processing of the primes, however,
may have more unpredictable results, as an observer's own present attitude will play a role in an
eventual attitude change. As stated above, we may assume that the main difference in prime
presentation between the two studies is the amount of attention allocated to the primes. In our
study, this may have led to central processing of the primes, allowing for conscious deliberation and
the observed null result, whereas in [21] the lack of attention for primes resulted in peripheral
processing, and a shift in attitude toward prosocial behavior.
We emphasize that this explanation is highly speculative, though. It does not explain why the masked
primes in our study did not produce a priming effect - given that eyes are powerful social cues that
are processed even in absence of awareness [26], according to our proposed explanation we would
expect a priming effect for masked primes, which we do not find, nor predicted based on our
hypotheses about the respective roles of conscious and unconscious visual processing in guiding
behavior [27-29]. The only way we can ‘save’ this explanation is by introducing attention as an
additional moderating factor: social priming effects are only produced by consciously perceived, yet
unattended stimuli. Fortunately, this highly specific hypothesis can easily be tested. There are
numerous paradigms to manipulate attention for stimuli, ranging from cueing [35] to the attentional
blink [36], and many ways to measure the amount of attention stimuli receive, for example using
brain evoked potentials [37].
To summarize, we have primed participants with masked and unmasked images of eyes and flowers
and studied the effects of these primes on prosocial behavior. Based on the literature, we expected
eye primes to make participants behave more prosocially, here measured by means of offers made in
an dictator game, but we failed to find any evidence of a priming effect. Given the nature of our
study, we cannot conclude that the eye priming effect does not exist in general, but rather that if the
effect exists, that its nature is elusive, it does not generalize, and that moderating effects play a role
in obtaining the effect. We speculate that attention may be one such moderating variable and
propose ways to test this hypothesis. Although we believe our study does not allow for falsification
or confirmation of 'eye priming', or social priming in general, there is one point we do wish to
emphasize: priming of complex social behavior is not straightforward. In that light, our null result
further confirms that priming does not work unconditionally. Although it would be the dream of
many idealists to make people nicer or smarter (or, alternatively, the dream of a less idealistic
individual to influence voting or consumer behavior) using such an easy manipulation of just showing
an image, 'social priming' simply does not work that way. We are only just beginning to uncover the
exact underpinnings of the effect. Given the large potential impact of social priming, we feel that all
information, including null results, is important in establishing how and if social priming works.
References
1. Keizer K, Steg EM, Lindenberg S (2008). The spreading of disorder. Science: doi:
10.1126/science.1161405
2. Bargh JA, Chen M, Burrows, L (1996). Automaticity of social behavior: direct effects of trait
construct and stereotype-activation on action. J Pers Soc Psychol, 71: 230-244.
3. Dijksterhuis A, Van Knippenberg (1998). The relation between perception and behavior, or
how to win a game of trivial pursuit. J Pers Soc Psychol, 74: 865-877.
4. Dijksterhuis A (2006). Het Slimme Onbewuste [The Smart Unconscious, Dutch]. Amsterdam:
Bert Bakker.
5. Thaler RH, Sunstein, CR (2008). Nudge: Improving Decisions about Health, Wealth and
Happiness. New Haven: Yale University Press.
6. Simmons JP, Nelson LD, Simonsohn U. (2011). False-positive psychology: undisclosed
flexibility in data collection and analysis allows presenting anything as significant. Psychol Sci.
doi: 10.1177/0956797611417632.
7. Wicherts JM, Bakker, M. (2013). Broken windows, mediocre methods, and substandard
statistics. Group Processes Intergroup Relations. doi: 10.1177/1368430213502557.
8. Levelt Committee, Noort Committee, Drenth Committee (2012). Flawed science: The
fraudulent research practices of social psychologist Diederik Stapel. Retrieved from
https://www.commissielevelt.nl/wpcontent/uploads_per_blog/commissielevelt/2013/01/finalreportLevelt1.pdf.
9. Smeesters Follow-up Investigation Committee (2014). Report of the Smeesters Follow-up
Investigation Committee. Retrieved from
http://www.eur.nl/fileadmin/ASSETS/press/2014/maart/Report_Smeesters_followup_investigation_committee.final.pdf
10. Doyen S, Klein O, Pichon CL, Cleeremans A (2012). Behavioral priming: it's all in the mind, but
whose mind? PLoS One: doi: 10.1371/journal.pone.0029081.
11. Shanks DR, Newell BR, Lee EH, Balakrishnan D, Ekelund L, Cenac Z, Kavvadia F, Moore C
(2013). Priming intelligent behavior: an elusive phenomenon. PLoS One: doi:
10.1371/journal.pone.0056515.
12. Pashler H, Coburn N, Harris CR (2012) Priming of social distance? Failure to replicate effects
on social and food judgments. PLoS One: doi: 10.1371/journal.pone.0042510.
13. Klein RA et al. (2014). Investigating Variation in Replicability - a ‘‘Many Labs’’ Replication
Project. Social Psychology: doi: 10.1027/1864-9335/a000178.
14. Zwaan, R. (2013). How to cook up your own social priming article. Retrieved from
http://rolfzwaan.blogspot.nl/2013/09/how-to-cook-up-your-own-social-priming.html
15. Kahneman, D. (2013) A proposal to deal with questions about priming effects. Retrieved
from
http://www.nature.com/polopoly_fs/7.6716.1349271308!/suppinfoFile/Kahneman%20Lette
r.pdf
16. Eimer M, Schlaghecken F (1998). Effects of masked stimuli on motor activation: behavioral
and electrophysiological evidence. J Exp Psychol Hum Percept Perform, 24:1737-47.
17. Joordens S, Merikle PM. (1992). False recognition and perception without awareness. Mem
Cogni, 20:151-9.
18. Jolij J, Lamme VA (2010). Transcranial magnetic stimulation-induced 'visual echoes' are
generated in early visual cortex. Neurosci Lett: doi: 10.1016/j.neulet.2010.08.045
19. Lamme VA (2003). Why visual attention and awareness are different. Trends Cogn Sci, 7: 1218.
20. Pratte MS, Rouder JN (2009). A task-difficulty artifact in subliminal priming. Atten Percept
Psychophys: doi: 10.3758/APP.71.6.1276
21. Haley, K, Fessler, D. (2005). Nobody's watching? Subtle cues affect generosity in an
anonymous economic game. Evolution and Human Behavior, 26: 245-256.
22. Bateson M, Nettle D, Roberts G. (2006). Cues of being watched enhance cooperation in a
real-world setting. Biology Letters, 2: 412-414.
23. Asch SE (1951). Effects of group pressure on the modification and distortion of judgments. In
H. Guetzkow (Ed.), Groups, leadership and men, pp. 177–190. Pittsburgh: Carnegie Press
24. Sherif M. (1935). A study of some social factors in perception. Archives of Psychology,
27(187): 1-60 .
25. Chen YC, Yeh SL (2012). Look into my eyes and I will see you: unconscious processing of
human gaze. Conscious Cogn.: doi: 10.1016/j.concog.2012.10.001
26. Whalen PJ, Kagan J, Cook RG, Davis FC, Kim H, Polis S, McLaren DG, Somerville LH, McLean
AA, Maxwell JS, Johnstone T. (2004) Human amygdala responsivity to masked fearful eye
whites. Sciencem 306: 2061,
27. Jolij J, Lamme, VA (2005). Repression of unconscious information by conscious processing:
evidence from affective blindsight induced by transcranial magnetic stimulation. Proc Natl
Acad Sci U S A, 102: 10747-10751.
28. Jolij J, Scholte HS, van Gaal S, Hodgson TL, Lamme VA (2011). Act quickly, decide later: longlatency visual processing underlies perceptual decisions but not reflexive behavior. J Cogn
Neurosci: doi: 10.1162/jocn_a_00034
29. Jolij J (2008). From affective blindsight to affective blindness: When cortical processing
suppresses subcortical information. In: Pichler, FL (Ed.). Neural Pathways Research, pp. 205220. New York: Nova Publishers.
30. Jolij J, Meurs M, Haitel E (2011). Why do we see what's not there? Commun Integr Biol, 4:
764-767.
31. Simonsohn U (2013). Small Telescopes: Detectability and the Evaluation of Replication
Results. Retrieved from http://dx.doi.org/10.2139/ssrn.2259879
32. van Assen MA, van Aert RC, Nuijten MB, Wicherts JM (2014). Why publishing everything is
more effective than selective publishing of statistically significant results. PLoS One: doi:
10.1371/journal.pone.0084896
33. Locey ML, Jones BA, Rachlin H (2011). Real and hypothetical rewards. Judgm Decis Mak, 6:
552-564.
34. Cacioppo JT, Petty RE (1984) . The Elaboration Likelihood Model of Persuasion. In: Kinnear TC
(Ed.). NA - Advances in Consumer Research Volume 11. Provo: Association for Consumer
Research, pp 673-675.
35. Posner MI, Snyder CR, Davidson BJ (1980). Attention and the detection of signals. J Exp
Psychol, 109: 160-174.
36. Raymond JE, Shapiro KL, Arnell KM (1992). Temporary suppression of visual processing in an
RSVP task: an attentional blink? J Exp Psychol Hum Percept Perform, 18: 849-860.
37. Vogel EK, Luck SJ, Shapiro KL (1998). Electrophysiological evidence for a postperceptual locus
of suppression during the attentional blink. J Exp Psychol Hum Percept Perform, 24: 16561674.
Figure captions
Figure 1. Overview of a typical trial. Trials started with a display of the counter, counting down from
20 s to 0 s indicating the time participants have to make their decision. At the end of every second, a
prime (flowers or eyes) was presented for 10 ms (masked primes) or 110 ms (unmasked primes),
followed by a metacontrast mask for the remainder of the full second. This cycle repeated until the
timer reached 0, after which participants had to make their decision about the split.
Figure 2. Results.
Table
Table 1. Distribution of participants over the experimental groups as entered into the
analyses.
Masked
Unmasked
Eyes
27
28
Flowers
27
29