is a general intelligence factor that, according to Spearman and others, underlies specific mental abilities and is therefore measured by every task on an intelligence test.

'g' is the general intelligence factor.

Explanation:

g factor is key factor for for all mental ability test.g factor is responsible for performance  of cognitive ability measure.according to spearman all task of intelligence test which are included verbal and mathematical  test.that are influenced by g factor.

g factor helps in phychometric investigation cognitive abilities and human intelligence.