Starting time, depending on power and car size.

<p>Error bars represent standard errors.</p

Correlation between front surface size and mean speed estimations.

<p>Correlation between front surface size and mean speed estimations.</p

Vehicles used in virtual reality.

<p>Vehicles used in virtual reality.</p

Results of Study 1 (Adoption-Task).

<p><i>I</i>_1<i>t</i> and <i>I</i>_2<i>t</i> are Indicator or Dummy variables indicating the stimulus category (<i>I</i>_1<i>t</i>: 1 = African infants, 0 = Caucasian infants; <i>I</i>_2<i>t</i>: 1 = dog puppies, 0 = Caucasian infants). <i>S</i>_<i>t</i> represents participants’ sex (0 = male, 1 = female). <i>A</i> indicates participants’ age (0 = mean age of the sample).</p><p>Robust estimators were used for statistical inference with respect to fixed effects and variance components to account for possible violations of model assumptions, such as normality of Level-2 residuals. Degrees of freedom were computed based on the Satterthwaite’s Approximation to account for the moderate sample size at Level 2 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121554#pone.0121554.ref046" target="_blank">46</a>]. Therefore, the degrees of freedom were not necessarily integers and could vary across tests independent of the number of parameters.</p><p>Results of Study 1 (Adoption-Task).</p

Descriptive statistics of Study 1: Adoption-Task.

<p>Relative frequencies are presented for cute and less cute faces being chosen for each stimulus category and separately for male and female participants.</p

Mean cuteness scores of the stimuli used in Study 1.

<p>Mean cuteness scores of the stimuli used in Study 1.</p

Results of Study 1 (Toy-Task).

<p><i>I</i>_1<i>t</i> and <i>I</i>_2<i>t</i> are Indicator or Dummy variables indicating the stimulus category (<i>I</i>_1<i>t</i>: 1 = African infants, 0 = Caucasian infants; <i>I</i>_2<i>t</i>: 1 = dog puppies, 0 = Caucasian infants). <i>S</i>_<i>t</i> represents participants’ sex (0 = male, 1 = female). <i>A</i> indicates participants’ age (0 = mean age of the sample).</p><p>Robust estimators were used for statistical inference with respect to fixed effects and variance components to account for possible violations of model assumptions, such as normality of Level-2 residuals. Degrees of freedom were computed based on the Satterthwaite’s Approximation to account for the moderate sample size at Level 2 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121554#pone.0121554.ref046" target="_blank">46</a>]. Therefore, the degrees of freedom were not necessarily integers and could vary across tests independent of the number of parameters.</p><p>Results of Study 1 (Toy-Task).</p

Results of Study 2.

<p><i>I</i>_1<i>it</i> and <i>I</i>_2<i>it</i> are Indicator or Dummy variables indicating the stimulus category (<i>I</i>_1<i>it</i>: 1 = African infants, 0 = Caucasian infants; <i>I</i>_1<i>it</i>: 1 = dog puppies, 0 = Caucasian infants). <i>H</i>_<i>it</i> reflects the health state (0 = mean assessment of perceived health across all stimuli and participants, a positive value indicates perceived above-average illness frequency). <i>S</i>_<i>t</i> represents participants’ sex (0 = male, 1 = female). <i>A</i>_<i>t</i> indicates participants’ age (0 = mean age of the sample). For interpreting the coefficients all other predictor variables have to be held constant.</p><p>An unstructured covariance structure was used for the random part at Level 2. Hence, the variances and covariances of Level 2 residuals were estimated without any constraints. Robust estimators were used for statistical inference with respect to fixed effects and variance components to account for possible violations of model assumptions, such as normality of Level-2 residuals. Degrees of freedom were computed based on the Satterthwaite’s Approximation to account for the moderate sample size at Level 2 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121554#pone.0121554.ref046" target="_blank">46</a>]. Therefore, the degrees of freedom were not necessarily integers and could vary across tests independent of the number of parameters.</p><p>Results of Study 2.</p

Descriptive statistics of Study 1: Toy-Task.

<p>Relative frequencies are presented for cute and less cute faces being chosen for each stimulus category and separately for male and female participants.</p

Results of the pre-study (Model 2).

<p><i>I</i>_1<i>it</i> and <i>I</i>_2<i>it</i> are Indicator or Dummy variables indicating the stimulus category (<i>I</i>_1<i>it</i>: 1 = African infants, 0 = Caucasian infants; <i>I</i>_2<i>it</i>: 1 = dog puppies, 0 = Caucasian infants). <i>C</i> represents cuteness category (<i>C</i>_<i>it</i>: 0 = less cute, 1 = cute). Robust estimators were used for statistical inference with respect to fixed effects and variance components to account for possible violations of model assumptions, such as normality of Level-2 residuals. Degrees of freedom were computed based on the Satterthwaite’s Approximation to account for the moderate sample size at Level 2 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0121554#pone.0121554.ref046" target="_blank">46</a>]. Therefore, the degrees of freedom were not necessarily integers and could vary across tests independent of the number of parameters.</p><p>Results of the pre-study (Model 2).</p