Age and Sex Differences in Spatial and Mechanical Tilt in Adolescence: Evidence for the Mediating Effects of Processing Speed and <i>g</i>

Tilt refers to an ability profile and is based on within subject differences in two abilities, yielding strength in one ability (e.g., academic) and weakness in another ability (e.g., mechanical). The current study examined sex differences in the development of mechanical and spatial tilt. Tilt was based on mechanical and spatial abilities contrasted with academic abilities (math or verbal), yielding mechanical tilt (mechanical &gt; academic), spatial tilt (spatial &gt; academic), and academic tilt (academic &gt; mechanical/spatial). Participants were 13- to 17-year-olds from the National Longitudinal Survey of Youth (N = 6969), and tilt scores were based on the Armed Services Vocational Aptitude Battery. While sex differences in mechanical tilt (favoring males) increased with age, sex differences in spatial tilt did not, suggesting that sex differences are more sensitive to mechanical abilities. For males and females, academic tilt (math tilt or verbal tilt) increased with age, while mechanical and spatial tilt decreased with age. Finally, cascade models of mechanical tilt (which showed the largest sex differences) indicated that age-related increases in processing speed boosted g, which in turn influenced tilt. The results support vocational preference and investment theories. Such theories assume that, compared to females, males are more likely to invest in mechanical abilities and activities involving things (vs. people), boosting mechanical tilt. Future research might examine factors that influence sex differences in the development tilt such as developmental period (childhood vs. adulthood), ability level (intellectually disabled vs. gifted), and motivational variables (e.g., grit and self-efficacy).