2007 the Impact of Perceived Experience on Likelihood Judgments For

The impact of perceived experience on likelihood judgments forself and others: An experimental approach

PETER HARRIS*

University of Shefeld, Shefeld, UK

Abstract

This study examines the effect of an experimental manipulation of perceived experience on self and

others likelihood ratings for a set of relatively commonplace misfortunes. Participants were randomly

assigned to a condition in which they were asked whether they had ever experienced the events

(designed to induce higher perceived experience) or whether they had done so frequently, typically, etc.

(designed to induce lower perceived experience). The manipulation led to increases in ratings of both

perceived self-likelihood and others likelihood, in ease of imagining the outcome and recall of a past

occurrence, and to decreases in perceived control over the events in the higher perceived experience

condition. The increases in ease of imagining mediated the impact of manipulated experience on

comparative likelihood whereas the decreases in perceived control did not. There was little evidence

that event controllability moderated the impact of experience on comparative likelihood for these

events. Copyright # 2006 John Wiley & Sons, Ltd.

People are typically comparatively optimistic about the future, tending to judge their risk of future

negative life events to be lower than that of their peers. This has been shown for a wide range of events,

from colon cancer through divorce to catching a cold or getting a parking ticket (Shepperd, Helweg-

Larsen, & Ortega, 2003). The term optimistic bias has been coined for the robust nding that the

comparative likelihood judgments of samples of participants are typically skewed in an optimistic

direction.1 Comparative optimism is widespread, hard to undermine (Weinstein & Klein, 1995) and has

been proposed to be core to normal psychological functioning (Taylor & Brown, 1988). The current

study addresses the impact of perceived experience on the component judgments of comparative

optimism, self and others likelihood.

Theoretical and empirical research on comparative optimism has focussed on a small number of

potential moderators of the phenomenon, such as perceived outcome severity (e.g. Weinstein, 1987),

preventability (e.g. Harris, 1996) and the focus of the current study, personal experience (e.g. Burger &

Palmer, 1992). Understanding more about the moderators of optimism is a step towards understanding

why people are comparatively optimistic (Helweg-Larsen & Shepperd, 2001).

European Journal of Social Psychology

Eur. J. Soc. Psychol. 37, 141151 (2007)

Published online 18 August 2006 in Wiley InterScience

(www.interscience.wiley.com). DOI: 10.1002/ejsp.339

*Correspondence to: P. Harris, Department of Psychology, University of Shefeld, Western Bank, Shefeld S10 2TP, UK.E-mail: [email protected] Armor and Taylor (1998) for other denitions of optimism.

Copyright # 2006 John Wiley & Sons, Ltd.Received 29 June 2005

Accepted 29 December 2005

EXPERIENCE AND COMPARATIVE LIKELIHOOD

Most studies of personal experience and comparative optimism have employed the direct method of

assessing comparative likelihood. In the direct method participants are explicitly asked how their risk

compares with others and use a single scale to provide their answer (anchored, e.g., at much less likely

and much more likely). Using this method, studies have generally found that personal experience is

associated with less optimism (e.g. Weinstein, 1980, 1987), although not necessarily its absence (e.g.

McKenna & Albery, 2001; Weinstein, Lyon, Rothman, & Cuite, 2000) and occasional studies nd no

evidence of reductions in optimism at all (e.g. Welkenhuysen, Evers-Kiebooms, Decruyenaere, & van

den Berghe, 1996).

Why might experience eliminate or at least reduce comparative optimism? In a review, Helweg-

Larsen and Shepperd (2001) suggest two main mechanisms. First, experience might reduce perceived

personal control, leading people to believe that they have no more control over events than others.

Second, experience makes it easier for people to imagine themselves as victims. The current study tests

these two hypothesised mediators of self and others likelihood.

One implication of the rst mechanism is that experience should primarily affect events perceived to

be controllable (i.e. that event controllability should moderate the relationship between experience and

comparative optimism). In contrast, imagination should affect risk perceptions regardless of event

controllability. Indeed, this is the mechanism by which Weinstein, in his seminal 1980 paper

introducing optimistic bias, posited that experience might moderate it: personal experience should

make it easier to recall past occurrences of the event and to imagine situations in which the event could

occur, leading to greater perceived probability through the mechanism of availability (p. 807). There is

good research evidence that imagination increases risk perception (Anderson, 1983; Kahneman &

Tversky, 1982) and some evidence that experience increases imagination (Greening, 1997). However,

less is known about the impact of imagination on comparative likelihood (Sparks, Harris, & Raats,

2003).

For experience to moderate comparative optimism, it has to reduce or eliminate the relative

difference between perceived self-risk and perceived others risk by, for example, increasing self-risk

more than others risk. Unfortunately, the direct method of measuring comparative likelihood does not

tell us what changes occur in self and others risk following experience, as neither component of the

comparative judgment is measured independently.2 However, in the indirectmethod participants make

separate judgments for themselves and others and comparative likelihood is given by the difference

between the ratings. Using this method, therefore, researchers can assess the impact of experience on

the separate components of the comparative judgment.

To date relatively few studies on comparative optimism have examined this question using the

indirect method. From these there appears to be support for the claim that experience typically serves to

increase self-risk (Burger & Palmer, 1992; Greening, 1997; Stapel & Velthuijsen, 1996; van der Velde,

van der Pligt, & Hooykaas, 1994), but less clear evidence about its effect on others risk: Some studies

do not report judgments for this target (e.g. Greening, 1997; Shepperd, et al., 2003; Stapel &

Velthuijsen, 1996) others report no change (e.g. Absetz, Aro, Rehnberg, & Sutton, 2000; Weinstein

et al., 2000) yet others nd others risk also increases with experience (e.g. Higgins, St. Amand, &

Poole, 1997).

The nding that experience can increase the perception of others risk is consistent with the rst of

Weinsteins tentative propositions from his 1989 review of the impact of personal experience:

2Moreover, several researchers have argued that the direct method, despite its high face validity, primarily assesses self-risk (e.g.Chambers, Windschitl, & Suls, 2003; Covey & Davies, 2004; Price, Pentecost, & Voth, 2002). It may therefore be a less adequatemeasure of comparative likelihood than once thought (see also Weinstein & Klein, 1996).

Copyright # 2006 John Wiley & Sons, Ltd. Eur. J. Soc. Psychol. 37, 141151 (2007)

142 Peter Harris

personal experience generally leads people to see hazards as more frequent and to view themselves as

potential future victims (p. 46); seeing something as more frequent is formally equivalent to seeing

average likelihood as higher. In support of this, Weinstein (1989) cites 12 studies, in 10 of which

experience was associated with increases in perceived likelihood for people in general (Table 5, p. 42).

Moreover, although Helweg-Larsen and Shepperd (2001) conclude that the (very limited) evidence

available from research on comparative likelihood suggests experience affects self rather than others

risk judgments, they accept that it may also affect others risk (p. 87). Clearly, there is uncertainty

concerning the impact of experience on judgments of others likelihood.

Therefore, the current study attempts to manipulate perceived experience and to examine the impact

of this manipulation on judgments of self and others likelihood, event controllability and ease of

imagination of future events. It is one of the few studies to address the potential mechanisms by which

experience is hypothesised to affect comparative optimism and the only one to date to do so

experimentally.

MANIPULATING PERCEIVED EXPERIENCE

It is, of course, both practically difcult and ethically unacceptable to manipulate whether someonewill

experience misfortune. Consequently, an attempt is made here to manipulate peoples perceptions of

their experience, in this case by using a series of relatively commonplace misfortunes of the sort that we

typically try to avoid but experience from time to time.

Researchers interested in comparative risk (especially optimistic bias) have traditionally tended to

focus on major life events, such as attempted suicide, cancers and HIV. However, such major life events

represent only a subset, albeit an important one, of the negative life events that typically confront us.

Moreover, participants typically have little personal experience of these more traditional events and it

would be hard to persuade them that they had experienced such things when they have not.

More recently, researchers have turned their attention also to more commonplace events and shown

that comparative risk judgments for such events have features in common with the more traditional

negative events (e.g. Chambers et al., 2003; Shepperd et al., 2003). For example, Shepperd et al. (2003)

have shown that both types of event elicit comparative optimism and show similar levels of consistency

over time. Nevertheless, clearly there are differences between commonplace and traditional events and

caution will be needed in extrapolating from the current study to the broader literature on optimistic

bias.

In the current study, participants were assigned randomly to one of two conditions. In the higher

perceived experience condition, they were asked whether they had ever experienced the event in

question. In the lower perceived experience condition, they were asked whether they had done so

frequently, typically and so on. The wording of this question was the only difference between

conditions. The rationale was that most participants should be able to bring to mind an instance of most

of the events, but the threshold for a yes response is lower when the adverb is ever. For example, most

of those asked if they had ever missed a train or plane would be able to bring to mind an example and

answer yes; more of those asked whether they did so quite often would recall insufcient examples to

meet their threshold for the adverb and answer no. Consequently, participants in the higher perceived

experience condition should tend to answer the experience questions afrmatively whereas those in the

lower perceived experience condition should do so less often. Salancik (1974) and Salancik and

Conway (1975) have used a similar manipulation in their research on attitudes (see also Weinstein &

Klein, 1995, Study 2, for a conceptually similar manipulation).


Experience and comparative likelihood 143

The predictions are that, compared with participants in the lower perceived experience condition,

those in the higher perceived experience condition will have higher ratings of self-likelihood and ease

of imagination and lower ratings of control over the events. Less clear is whether perceived experience

will affect others likelihood and whether it will moderate comparative optimism. As described earlier,

perceived event controllability can be considered as a potentialmoderator of the effect of experience on

comparative likelihood and a potential mediator of these effects. (For more on this distinction and

testing combined mediation and moderation, see Baron & Kenny, 1986.) Consequently, both

possibilities were tested as was the hypothesis that increases in ease of imagination mediated the effect

of experience on likelihood judgments.

METHOD

Participants

The sample comprised 99 students of various disciplines at the University of Shefeld, of whom 50

were female and 46 were male (3 did not disclose their sex). The mean age of the sample was 20.6 years

(SD 2.0 years).

Materials and Procedure

A separate sample of 30 second year undergraduate psychology students rated a pool of 24 everyday

events for perceived controllability using a 7-point scale anchored at no control at all and total control,

with intermediate points labelled hardly any control, a little control, moderate control, high control and

almost total control. From these ratings, ve lower (M 2.81), ve moderate (M 3.51) and vehigher control events (M 4.08) were selected for use in this study (Table 1). Events variedsignicantly in rated controllability, F(2, 56) 44.9, p< 0.001.

Table 1. The events

Higher controlTypically turning up to the wrong place to meet peopleTypically turning up late to meet peopleQuite often oversleeping when it is important not toRarely being sufciently conscientious or reliableOften being unkind or rude to family members

Moderate controlQuite often missing or nearly missing trains and planesOften forgetting anniversaries or birthdaysTypically not keeping in touch with friendsFrequently misplacing or losing keysGenerally not keeping resolutions

Lower controlTypically failing to impress special peopleGenerally nding it hard to reverse into tight parking spacesTypically choosing the wrong queue at the supermarketTypically getting lost in unfamiliar placesOften not sticking to plans


144 Peter Harris

In the experimental study, participants were instructed to answer the questions honestly and

accurately, working through them in order. Immediately following the instructions came the

manipulation. In the lower perceived experience condition the participants were asked, Have you

experienced any of these events in the past? followed by the 15 events, in random order, with an adverb

for each event (i.e. worded exactly as in Table 1). In the higher perceived experience condition the

participants were asked, Have you EVER experienced any of these events in the past? again followed

by the 15 events, but without any other adverb (e.g. misplacing or losing a set of keys, getting lost in an

unfamiliar place). Responses were given by ticking yes or no.

This was the only difference between the conditions: the remainder of the questionnaire was

identical in both conditions.

Immediately following the experience question was a mood rating: Before you continue, could you

please rate your CURRENTMOOD. That is, your mood RIGHT NOW. Responses were given on a 7-

point scale (very bad/down, moderately bad/down, slightly bad/down, neither good nor bad, slightly

good, moderately good, very good). At the top of the next page came the recall question: How easy is it

for you to RECALL a past occasion on which you, followed by the events (e.g. misplaced or lost a set

of keys, got lost in an unfamiliar place). Next came the imagine question: How easy is it for you to

IMAGINE a FUTURE occasion in which you might, followed by the events (e.g. misplace or lose a set

of keys, get lost in an unfamiliar place). Responses were given on a 6-point scale (not at all easy,

slightly easy, quite easy, moderately easy, very easy, extremely easy). For the recall question the

response option have never experienced was also provided.

Next came the likelihood questions, on two separate pages, with the events described using the

wording in Table 1. First were the self-likelihood ratings: Please use the following rating scale to

indicate how likely it is that you will experience each of the following events sometime in the future.

The following page contained the likelihood ratings for the average other: Please use the following

rating scale to indicate how likely it is that the average University of Shefeld student of your age and

sex will experience each of the following events sometime in the future. Ratings were given on an 11-

point scale anchored at impossible (0) and extremely likely (10).

Finally came the control question: Please indicate how much control you think you have over

whether you are likely to experience each of the following events sometime in the future. Tick the point

on the scale that best reects your control as you see it. Ratings to the events (misplacing or losing

keys, getting lost in an unfamiliar place, etc.) were given on the same 7-point scale of controllability

described earlier.

Participants were approached in a coffee bar of the students union at the University. Questionnaires

were completed in situ.

RESULTS

An alpha level of 0.05 was used for all analyses. For post hoc comparisons (paired t tests with

Bonferroni-correction, Howell, 2002) individual comparisons used an alpha of 0.017, giving a family

wise error rate of 0.05.

The mean ratings of experience and recall were calculated for each participant over all 15 events

(Table 2). One-way analysis of variance for unrelated samples, with condition (higher or lower

perceived experience) as the independent variable conrmed that participants in the higher perceived

experience condition answered yes more often to the experience question, F(1, 97) 70.5, p< 0.001.Thus the manipulation was successful. Participants in the higher perceived experience condition also



reported nding it easier to recall a past occurrence of the events, F(1, 97) 7.0, p 0.009. Conditiondid not affect mood, F(1, 97)< 1, p 0.56.

The data for imagination, self-likelihood, average other likelihood and perceived control are in

Table 3. Likelihood ratings were analysed using 4-way analysis of variance for mixed designs.

Between-participants IVs were condition and sex, and within-participants IVs were target (self or

other) and event controllability (lower, moderate, or higher). Event controllability was included to

assess whether control moderates the experience/likelihood relationship (which would be shown by

signicant condition controllability interactions) and also whether it is a potential mediator of thisrelationship (which would be shown by a signicant main effect of controllability or interaction with

target, Baron & Kenny, 1986, p. 1179).

There were signicant main effects of condition, F(1, 79) 11.7, p 0.001, target, F(1,158) 34.7, p< 0.001 and event controllability, F(2, 158) 24.7, p< 0.001: likelihood ratings werehigher for higher (M 5.7) than lower perceived experience (M 4.8) and for other (M 5.3) than forself (M 4.4). Post hoc tests revealed signicant differences between higher (M 4.9) and moderate(M 5.7) control events but not between these and lower control events (M 5.3). The main effects ofcondition and event controllability indicate that further analysis of the possible mediating role of

perceived control on the experience/likelihood relationship is appropriate (Baron & Kenny, 1986).3

The condition target interaction was not signicant, F(1, 158)< 1, p 0.50, indicating thatcondition did not moderate optimistic bias.4 However, the event controllability target interaction wassignicant, F(2, 158) 10.0, p< 0.001; Thus, event controllability moderated optimistic bias. Post hoc

Table 2. Mean ratings by experience condition

Lower (n 49) Higher (n 50)Experience 0.43 (0.2) 0.77 (0.2)Recall 2.70 (0.9) 3.20 (1.0)Mood 5.30 (1.4) 5.50 (1.2)

Note: Standard deviations in brackets. Recall scored 0 to 6, mood 1 to 7.

Table 3. Principal-dependent variables by condition and event controllability

Eventcontrollability

Lower (n 49a) Higher (n 50a)

Lower Moderate Higher Lower Moderate Higher

Likelihood Self 4.53a (2.08) 5.05a (2.10) 3.53b (2.04) 5.24a,b (2.01) 5.72a (2.27) 4.90b (2.30)Other 5.31a (1.63) 5.48a (1.60) 4.89b (1.59) 6.03a (1.94) 6.43a (1.91) 6.08a (2.05)

Imagination 2.07a (1.06) 2.36a (1.20) 1.74b (1.14) 2.76a,b (1.12) 3.00a (1.20) 2.49b (1.23)Control 3.38a (0.92) 3.87b (0.90) 4.13c (0.87) 2.89a (0.96) 3.53b (1.22) 3.69c (1.22)

Note: Standard deviations in brackets. Means with different subscripts in each condition within rows differ signicantly on posthoc tests. Likelihood scored 0 to 10, imagination 0 to 5, control 0 to 6.aMaximum ns.

3The main effects of condition and target were both qualied by two-way interactions with sex. Males (M 4.3) had lowerlikelihood ratings overall than females (M 5.3) in the lower perceived experience condition, but not in the higher (M 6.0,M 5.6 respectively). Likewise, males (M 4.4) had lower self-likelihood ratings than females (M 5.2), but there were no sexdifferences in others ratings (M 5.8, M 5.7 respectively).4The event controllability condition target sex interaction approached signicance, F(2, 158) 2.6, p 0.076, potentiallyindicating some qualication to this position. However, it was not close enough to signicance to warrant further analysis.


146 Peter Harris

tests revealed that optimistic bias (other minus self-likelihood) was signicantly greater for higher

(M 1.3) than for moderate (M 0.6) or lower (M 0.9) control events, but that moderate and lowercontrol events did not differ signicantly. The event controllability target condition interaction wasnot signicant, indicating that event controllability did not moderate the impact of experience on

comparative likelihood. However, the event controllability condition interaction approachedsignicance, F(2, 158) 2.9, p 0.058. This is potentially indicative of moderation of theexperience/overall likelihood relationship by event controllability. If subsequent analysis reveals a

signicant controllability condition interaction on ratings of perceived control, then further analysisof combined mediation and moderation would be warranted (Baron & Kenny, 1986).

Ratings of ease of imagination and perceived control were analysed using 3-way analysis of

variance for mixed designs, with IVs of condition, sex and event controllability. Therewas a signicant

main effect of condition on ease of imagination with, as predicted, greater ease reported in the higher

(M 2.8) than the lower (M 2.1) perceived experience condition, F(1, 90) 11.2, p 0.001. Ease ofimagination was also affected by event controllability, F(2, 180) 20.3, p< 0.001, (higher M 2.1,moderate M 2.7, lower M 2.4; all means differed signicantly on post hoc tests) and was higheramong females (M 2.6) than males (M 2.1), F(1, 90) 4.6, p 0.035. These main effects were notqualied by any signicant interactions. There was also a signicant main effect of condition on ratings

of perceived control with, as predicted, lower control ratings in the higher (M 3.4) than in the lower(M 3.8) perceived experience condition, F(1, 84) 5.0, p 0.028. There was also a signicant maineffect of event controllability on control ratings, F(2, 168) 49.1, p< 0.001, (higher M 3.9,moderate M 3.7, lower M 3.1; all means differed signicantly on post hoc tests).5 The eventcontrollability condition interaction was not signicant, F(2, 168)

R2 0.41, F(1, 94) 18.7, b0.41, p< 0.001. Finally, when comparative likelihood was regressedon experience and imagination simultaneously, R2 0.17, F(2, 93) 9.4, p< 0.001, experience was nolonger signicant, b0.07, p 0.61, but imagination was, b0.36, p 0.007. Thus imaginationmediated the effect of experience on comparative likelihood (Sobel z2.7, p 0.008).

When perceived control was regressed on experience, the effects were signicant, R2 0.18, F(1,94) 20.0, b0.42, p< 0.001. Control also predicted comparative likelihood, R2 0.06, F(1,94) 6.3, b 0.25, p 0.014. However, when comparative likelihood was regressed on experienceand perceived control simultaneously, R2 0.12, F(2, 93) 6.1, p 0.003, perceived control was notsignicant, b 0.14, p 0.19 while experience remained a signicant predictor, b0.26, p 0.019.Thus perceived control did not mediate the effect of experience on comparative likelihood (Sobel

z1.3, p 0.20).

DISCUSSION

The experimental manipulation was successful: participants in the higher perceived experience

condition responded afrmatively to the experience question more often than did those in the lower

perceived experience condition. They also reported nding it easier to recall a past occasion on which

they had experienced the event. The effects of the manipulation are not attributable to mood, as there

was no effect of condition on mood.

Following the manipulation, ratings of perceived control were signicantly lower among those in

the higher perceived experience condition. It has often been assumed that personal experience of an

event can reduce perceived control over that event and the current study has nally demonstrated this

effect experimentally. The manipulation also resulted in higher ratings of ease of imagining future

occasions on which the event might be experienced. Thus, the ndings support both elements of

Weinsteins (1980) original hypothesis that experience will affect likelihood by making it easier to

recall past occurrences and imagine situations in which the event could occur.

The manipulation also conrmed that perceived experience can increase both self and others

likelihood ratings. Previous research using the indirect method has produced inconsistent evidence

concerning the impact of experience on others risk. The current ndings are, however, consistent with

the ndings reviewed by Weinstein (1989) in which he showed that experience often results in

perceptions of increased likelihood for people in general. Theoretically, it is possible to posit both

cognitive and motivational mechanisms to account for the increases in others risk found here. For

example, the manipulation may have heightened the perceived frequency of the events and thus the

perception of increased vulnerability for both self and others. On the other hand, maintaining the sense

that others are more prone to negative events, even of the kind examined here, could serve a variety of

motivational goals, such as maintaining self-esteem or reducing anxiety, and thus be hard to shake.6

Future research should address the event and individual difference moderators of the impact of

experience on others risk, given the current ndings.

That the manipulation thus maintained rather than eroded optimistic bias is consistent with some

previous ndings using the indirect method of assessing the bias but largely at odds with research that

has employed the direct method. One reason for this may lie in the nature of the direct method: Several

6Although the current study was not designed to tease apart possible explanations for an effect of experience on others risk, it waspossible to rule out one candidate explanation: there was no more evidence that people derived their others likelihood ratingsfrom their self-ratings than the reverse. That is, the inuence of the manipulation on others likelihood was rendered non-signicant when self-likelihood was included as a covariate. However, the same was also true with self-likelihood as thedependent variable and others likelihood as the covariate.


148 Peter Harris

recent theoretical accounts (e.g. Chambers et al., 2003) have suggested that likelihood judgments made

with the direct method are heavily determined by self-risk judgments. It may well be that studies using

the direct method, therefore, primarily assess the impact of experience on self-likelihood rather than

comparative likelihood. To avoid such ambiguity, studies should employ the indirect method whenever

possible when investigating the impact of experience on optimistic bias.

As well as testing for differences on the dependent variables, the study was designed to test two of

the principal mediating mechanisms that have been suggested for how experience might affect

comparative optimism: reductions in perceived control and increases in imagination. The evidence here

supports imagination but not control. This is an important nding, as there have been several attempts

to explain the apparent effect of experience on comparative likelihood by the impact of experience on

perceived control (e.g. Helweg-Larsen & Shepperd, 2001; Higgins et al., 1997). Researchers interested

in more major life events should test for changes in control perceptions following personal experience

and examine whether these mediate any effects of experience on comparative risk perceptions; the

current ndings suggest they may not. Indeed, the nding that imagination but not control mediated the

impact of experience is consistent with Greening (1997) who found the same for self-risk perception

following experience of an electrocution accident (see also Greening, Dollinger, & Pitz, 1996).

Weinstein (1989) also points out that the effects of experience on perceived control will vary with the

type of situation encountered.

Theoretically, the current ndings suggest future studies might also usefully examine the impact of

experience on the nature of the mental simulations people construct for themselves and others. In doing

so researchers could protably draw on Kahneman and Tverskys (1982) seminal analyses of the ways

in which simulated scenarios can change (also Kahneman & Miller, 1986).

Some other aspects of the ndings are also worthy of comment. For example, as with traditional

events (Harris, 1996), here event controllability moderated optimistic bias (the event controllabil-

ity target interaction was signicant). However, whereas signicantly more optimistic biaswas displayed for higher control events, moderate control events did not differ from lower control

ones. More signicantly, there was little evidence here that event controllability moderated the impact

of the manipulation on comparative likelihood (the condition event controllability targetinteraction was not signicant). Thus, the ndings of this experiment do not support either a

moderating or mediating role for perceived control after experience, at least for the sorts of events

investigated here.

Of course, the current ndings must not be overgeneralised, particularly in their implications for the

literature on optimistic bias. Research on optimistic bias has typically focussed on events such as

cancers, divorce and attempted suicide, and there are clear differences between such events and those

used here. Some of these differences might affect the way in which experience inuences self and

others risk perceptions. This may include the severity of the consequences and increased knowledge,

gained though victimisation, about risk factors, base rates and objective self-risk. Nevertheless, there

are important things in common as well as important differences between these commonplace events

and those used more typically in research on optimistic bias (Shepperd et al., 2003). Moreover, these

commonplace events represent a sizeable proportion of the future events that we judge and anticipate.

In conclusion, the current study is one of few to address the potential mechanisms by which

experience is hypothesised to affect comparative optimism and the only one to date to do so

experimentally. The experimental manipulation led to signicant increases in likelihood and

imagination and decreases in perceived control. The evidence suggests that the increase in imagination

is one of the mechanisms that lead to the changes in perceived likelihood for both self and others

produced by experience. Future studies should explore which variables determine when experience

also moderates others risk.



ACKNOWLEDGEMENTS

I thank Ellie Martin for her assistance in collecting the data and Dale Grifn and Bill Klein for their

helpful comments on previous drafts.

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