Hoff, E. (2003). The specificity of environmental influence: Socioeconomic status affects early vocabulary development via maternal speech. Theory Ample data has demonstrated a correlation between SES and children’s language development This study tested the hypothesis that SES-related differences in the development of children’s productive vocabulary can be explained by SES- related differences in their language-learning experiences (i.e., they are trying to show cause)Methods 33 high-SES and 30 mid-SES monolingual English mom-child dyad; children matched for vocabularies at time 1 Pre-measures of maternal speech Pre-and post-measures of children’s vocabularyTheory Ample data has demonstrated a correlation between SES and children’s language development This study tested the hypothesis that SES-related differences in the development of children’s productive vocabulary can be explained by SES- related differences in their language-learning experiences (i.e., they are trying to show cause)Methods 33 high-SES and 30 mid-SES monolingual English mom-child dyad; children matched for vocabularies at time 1 Pre-measures of maternal speech Pre-and post-measures of children’s vocabulary Key insight Strengths Explains relationship between SES and children’s language development Controlled for birth orderWeaknesses Only looked at high- and mid-SES families; other factors may be at work in low-SES families Only 1 observation to assess maternal speech & only 2 observations to assess children’s vocabs Possible age confound; children were matched on vocab skills, not age, which ranged from mosStrengths Explains relationship between SES and children’s language development Controlled for birth orderWeaknesses Only looked at high- and mid-SES families; other factors may be at work in low-SES families Only 1 observation to assess maternal speech & only 2 observations to assess children’s vocabs Possible age confound; children were matched on vocab skills, not age, which ranged from mosFindings SES significantly related to children’s vocab growth SES significantly related to maternal speech (# word tokens, # word types, mean length utterances) SES-related maternal speech properties significantly related to children’s vocabulary growth After variance attributable to birth order and child vocab at Time 1 was removed, properties of maternal speech accounted for 22% of variance in child outcome, leaving only a nonsignificant 1% of variance in child vocab growth attributable to SES Thus, maternal speech properties mediate relationship between SES and children’s vocab developmentFindings SES significantly related to children’s vocab growth SES significantly related to maternal speech (# word tokens, # word types, mean length utterances) SES-related maternal speech properties significantly related to children’s vocabulary growth After variance attributable to birth order and child vocab at Time 1 was removed, properties of maternal speech accounted for 22% of variance in child outcome, leaving only a nonsignificant 1% of variance in child vocab growth attributable to SES Thus, maternal speech properties mediate relationship between SES and children’s vocab development SES Vocabulary growth SES-related properties of maternal speech