Self-Deceived Individuals Are Better at Deceiving Others

<div><p>Self-deception is widespread in humans even though it can lead to disastrous consequences such as airplane crashes and financial meltdowns. Why is this potentially harmful trait so common? A controversial theory proposes that self-deception evolved to facilitate the deception of others. We test this hypothesis in the real world and find support for it: Overconfident individuals are overrated by observers and underconfident individuals are judged by observers to be worse than they actually are. Our findings suggest that people may not always reward the more accomplished individual but rather the more self-deceived. Moreover, if overconfident individuals are more likely to be risk-prone then by promoting them we may be creating institutions, including banks and armies, which are more vulnerable to risk. Our results reveal practical solutions for assessing individuals that circumvent the influence of self-deception and can be implemented in a range of organizations including educational institutions.</p></div

Self-deception and susceptibility to being deceived are positively associated.

<p>Scatterplots with best-fit lines for residuals of susceptibility to being deceived (median of the difference between a focal individual's estimate of peer performance and the actual performance of peers) plotted against residuals of self-deception (self-estimate of focal individual's performance – focal individual's actual performance) based on absolute grades (red circles and red bold lines) and relative ranks (blue squares and blue dotted lines) in (a) week one and (b) week six. The residuals were obtained via a partial correlation analysis that regressed (i) self-deception against actual grade and (ii) susceptibility to being deceived against actual grade.</p

Summary of demographic variables of study participants.

<p>*Participants' parent's professions were assigned to categories specified by the Office of National Statistics (ONS). Occupational data from the ONS were used as a reference and the gender-specific median annual full-time London earnings of the relevant category were assigned to each parent. The earnings of both parents were added together to obtain the family income. For the partial correlation analyses, the Hollingshead four factor index <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104562#pone.0104562-Hollingshead1" target="_blank">[20]</a> was derived from individual earnings (as above) for each parent and the index for the parent with the highest earnings was used as a measure of family income. The ONS table used to calculate family income was titled: PROV - Work Region Occupation SOC10 (2) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104562#pone-0104562-t003" target="_blank">Table 3</a>.7a Annual pay - Gross 2011.</p><p>Summary of demographic variables of study participants.</p

Self-deception and deception of others are positively associated.

<p>Scatterplots with best-fit lines for residuals of deception (median estimate of focal individual's performance by peers – focal individual's actual performance) plotted against residuals of self-deception (self-estimate of focal individual's performance – focal individual's actual performance) based on absolute grades (red circles and red bold lines) and relative ranks (blue squares and blue dotted lines) in (a) week one and (b) week six. The residuals were obtained via a partial correlation analysis that regressed (i) self-deception against actual grade and (ii) deception against actual grade. Mean ± s.d. of absolute level of self-deception was 1.93±1.54 grades and 2.11±1.70 ranks in week one and 1.72±1.42 grades and 2.04±1.99 ranks in week six. Mean ± s.d. of absolute level of deception was 1.90±1.48 grades and 1.80±1.30 ranks in week one, and 1.27±1.03 grades and 1.86±1.59 ranks in week six.</p

Sample sizes and sex ratios for the twelve tutorial groups included in this study.

1<p>UCL - University College London; QMUL - Queen Mary University of London.</p>2<p>Numbers in parentheses indicate the total number of students present during the tutorial since not all students chose to participate in this study.</p><p>29 students participated from UCL^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104562#nt102" target="_blank">1</a>} and 44 students from QMUL^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104562#nt102" target="_blank">1</a>} (total n = 73). The mean age ± s.d. of participants was 18.76±0.90 years and 85% were female.</p><p>Sample sizes and sex ratios for the twelve tutorial groups included in this study.</p

Boxplot of dictator donations (proportion of endowment given to receiver) according to gender for US players.

<p>Solid lines represent medians while the upper and lower boundaries of the box are the upper and lower quartiles of the data. The highest and lowest values in the data (excluding outliers) are indicated by the bars extending from the boxes.</p

Boxplot of dictator donations (proportion of endowment given to receiver) according to stake size for Indian players.

<p>Solid lines represent medians while the upper and lower boundaries of the box are the upper and lower quartiles of the data. The highest and lowest values in the data (excluding outliers) are indicated by the bars extending from the boxes. Circles represent outliers.</p

Boxplot of dictator donations (proportion of endowment given to receiver) according to year generated from raw data from Indian players.

<p>Solid lines represent medians while the upper and lower boundaries of the box are the upper and lower quartiles of the data. The highest and lowest values in the data (excluding outliers) are indicated by the bars extending from the boxes. Circles represent outliers.</p