Handwriting changes under the effect of alcohol

Area of Science:

• Forensic Science
• Psychology

Background:

• Document examiners face challenges assessing handwriting under alcohol influence.
• Previous studies lacked statistical rigor, relying on subjective observations of alcohol's effects on handwriting.

Purpose of the Study:

• To statistically validate reported effects of alcohol on handwriting.
• To determine the predictability of specific handwriting alterations due to alcohol consumption.
• To investigate the correlation between alcohol levels and handwriting changes.

Main Methods:

• Collected handwriting samples from 73 participants before and after alcohol consumption.
• Utilized a stereo microscope and video spectral comparator (VSC 2000) for detailed analysis.
• Employed statistical methods including repeated measures ANOVA and Pearson correlation.

Main Results:

• Alcohol significantly increased handwriting parameters: word length, letter height, spacing, angularity, tremor, and tapered ends.
• A significant correlation was found between alcohol levels and alterations in letter height, angularity, and tapered ends.
• Handwriting changes were observed at all alcohol levels, contradicting previous claims that alcohol levels are poor indicators.

Conclusions:

• Document examiners can identify alcohol-induced handwriting differences, but must exercise caution due to high variability.
• The presence of combined handwriting alterations strongly suggests alcohol influence.
• While alcohol alone doesn't cause all alterations, specific changes are reliable indicators of intoxication.