Vicente J. Pérez Fernández

Efecto de la edad y el tipo de reforzador en la equivalencia-equivalencia mediante un procedimiento de partición

Equivalence – Equivalence responding (Barnes et al., 1997), based on derived or non-explicitly trained relational responding, supports a behaviour-analytic model of analogical reasoning. Conditional discriminations are the most common procedure used to train its prerequisites. In this exploratory work we test Vaughan’s (1988) simple discrimination procedure instead to derive Eq-Eq responses in children. Two factors were assessed: type of reinforcer used (primary or secondary) and age of participants (9-10 or 12-13 years). The procedure successfully leaded to the derivation of equivalence – equivalence responses, and both factors influenced the results: selecting older children and applying primary reinforcement leaded to faster learning and better results in the equivalence – equivalence test. No interaction between factors was found. This training procedure can provide a new way to investigate the behavioural prerequisites of this important ability

Failure to find symmetry in pigeons after multiple exemplar training

BACKGROUND An experiment with pigeons was conducted for 46 months in order to test the multiple-exemplar training (MET) hypothesis of symmetry derivation. According to this hypothesis, symmetry is progressively derived after an extensive training of multiple examples of direct and inverse relations among arbitrary stimuli. METHOD Four pigeons were given extensive training in direct (e.g., A1-B1; A2-B2) and inverse (e.g., B1-A1; B2-A2) arbitrary conditional discriminations. Once pigeons learned a complete reversal (e.g., AB and BA), a new reversal with different stimuli was trained (e.g., CD and DC, etc.). Subjects were assigned to two different stimulus sets, and sample-comparison order was counterbalanced. RESULTS Pigeons learned between 4 and 24 conditional discriminations, but none showed evidence of symmetry. Discriminability of samples and comparisons was identified as an important factor because it affected direct and inverse discriminations differently. CONCLUSIONS Despite the negative results reported, this study provides some insights that might help to improve current research on MET and symmetry: We describe some lessons learned about the design of long-term experiments involving a high number of stimuli and finally, we discuss some control strategies for stimulus discriminability that might also contribute to facilitate symmetry derivation in pigeons.