Overview

This report summarizes results from the S8 pilot examining how product category (Cosmetics, Drugs, Food) shapes perceived risk and perceived efficacy. All analyses are within-subjects. The final analytic sample size, after excluding participants who did not complete debrief or failed the attention check, is N = 138.

Scale Reliability

Cronbach’s alpha for each 3-item risk scale:

Cronbach’s Alpha for Risk Scales
Category Raw_Alpha Std_Alpha
Cosmetics 0.877 0.878
Drugs 0.825 0.831
Food 0.838 0.839

All three scales show good-to-excellent internal consistency (α > .80).

Descriptive Statistics

Risk Means by Category

Descriptive Statistics: Risk by Category
Mean_R_C SD_R_C Mean_R_D SD_R_D Mean_R_F SD_R_F N
-0.572 1.344 0.855 1.273 -1 1.331 138

Efficacy Means by Category

Descriptive Statistics: Efficacy by Category
Mean_E_C SD_E_C Mean_E_D SD_E_D Mean_E_F SD_E_F N
1.261 1.129 1.431 1.143 1.92 1.019 138

Risk Perception Across Categories

Omnibus Test

## 
## Error: factor(subjID)
##            Df Sum Sq Mean Sq F value Pr(>F)
## Residuals 137  449.3   3.279               
## 
## Error: factor(subjID):Category
##            Df Sum Sq Mean Sq F value Pr(>F)    
## Category    2  260.4  130.22   135.7 <2e-16 ***
## Residuals 274  263.0    0.96                   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Pairwise Comparisons (Bonferroni-corrected)

Risk: Pairwise Comparisons
Comparison Mean_Diff t_value df p_value p_bonferroni Significant
Cosmetics vs Drugs -1.4275 -11.6202 137 0e+00 0e+00 Yes
Cosmetics vs Food 0.4275 3.9795 137 1e-04 3e-04 Yes
Drugs vs Food 1.8551 15.1005 137 0e+00 0e+00 Yes

Risk Plots

Efficacy Perception Across Categories

Omnibus Test

## 
## Error: factor(subjID)
##            Df Sum Sq Mean Sq F value Pr(>F)
## Residuals 137  263.7   1.925               
## 
## Error: factor(subjID):Category
##            Df Sum Sq Mean Sq F value   Pr(>F)    
## Category    2  32.34  16.171   19.09 1.74e-08 ***
## Residuals 274 232.16   0.847                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Pairwise Comparisons (Bonferroni-corrected)

Efficacy: Pairwise Comparisons
Comparison Mean_Diff t_value df p_value p_bonferroni Significant
Cosmetics vs Drugs -0.1703 -1.4816 137 0.1407 0.4222 No
Cosmetics vs Food -0.6594 -6.3483 137 0.0000 0.0000 Yes
Drugs vs Food -0.4891 -4.3168 137 0.0000 0.0001 Yes

Efficacy Plots

3 (Category) × 2 (Measure) Interaction

This is the key test of whether category shapes risk and efficacy differently — i.e., the asymmetry between risk and efficacy perceptions.

Omnibus ANOVA

## 
## Error: subjID
##            Df Sum Sq Mean Sq F value Pr(>F)
## Residuals 137  240.1   1.752               
## 
## Error: subjID:Category
##            Df Sum Sq Mean Sq F value Pr(>F)    
## Category    2  102.9   51.44   98.19 <2e-16 ***
## Residuals 274  143.5    0.52                   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Error: subjID:Measure
##            Df Sum Sq Mean Sq F value Pr(>F)    
## Measure     1  653.3   653.3   189.3 <2e-16 ***
## Residuals 137  472.9     3.5                   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Error: subjID:Category:Measure
##                   Df Sum Sq Mean Sq F value Pr(>F)    
## Category:Measure   2  189.9   94.96      74 <2e-16 ***
## Residuals        274  351.6    1.28                   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Interaction Plot

Risk vs. Efficacy Within Each Category

Risk vs Efficacy: Paired Comparisons Within Category
Category Mean_Diff t_value df p_value p_bonferroni Significant
Cosmetics -1.8333 -10.7396 137 0.000 0.0000 Yes
Drugs -0.5761 -3.3558 137 0.001 0.0031 Yes
Food -2.9203 -17.2668 137 0.000 0.0000 Yes

Summary

  • Category significantly affects both risk and efficacy perceptions on their own.
  • The Category × Measure interaction is significant, indicating category shapes risk and efficacy differently — the core evidence for asymmetric schema borrowing.
  • Risk perception shows a sharp, selective elevation for Drugs relative to Cosmetics and Food.
  • Efficacy perception increases more gradually across categories and does not show the same drug-specific spike.
  • The risk-efficacy gap is significant within every category, but is notably smaller for Drugs than for Cosmetics or Food — consistent with the drug schema pulling risk up disproportionately relative to efficacy.