Equivalence class formation in 11-month-old pre-linguistic infants

Abstract

Several studies have attempted to assess the role of naming in the emergence of equivalence relations, but results are inconsistent; on the one hand, there are reports of equivalence emerging without naming and on the other hand, some authors claim that naming is necessary for equivalence to emerge. The objective of the present study was to evaluate the emergence of equivalence relations in pre-linguistic infants. Five infants aged 11-to-12 months received training in four conditional discriminations (A1-B1, A2-B2, B1-C1, and B2-C2) in order to establish two three-member classes. The participants were tested in reflexivity, symmetry, transitivity and equivalence, and all scored higher than 75% on all tests. On the reflexivity tests, percentages were above 80%; on the symmetry tests, they varied from 75% to 100%; on the transitivity tests, they averaged 75%; while on the equivalence tests results ranged from 87.5% to 100% of correct responses. These results suggest that displaying some degree of expressive language is not necessary for the emergence of equivalence relations.