According to Horne and Lowe (1996) naming is an intra-individual relation
between listening, echoing, and tacting. This thesis investigates how each of
the latter protoverbal behaviours is learned and how they combine to form the
first verbal relation, that is, naming.
Exposure to the relation between the auditory listener stimulus and
corresponding object was not sufficient for learning the first set of experimental listener relations. Listener behaviour training was therefore conducted in 18 infants in a 2-stimulus or 3-stimulus simultaneous conditional auditory-visual discrimination procedure. Following many trials of reinforcement of correct listener responding, six infants in the 3-stimulus condition (M = 150 trials), and nine infants in the 2-stimulus condition (M = 120 trials), learned the listener relations. Four of the infants were next trained on further pairs of listener relations in the 2-stimulus procedure; a total of 22 further listener relations were learned with considerable learning economies in 16 of these.
In 36 infants, production of speech-like vocalisations was increased through
operant conditioning of all vocal responding. However, learning to echo did
not emerge without reinforcement of correct responses in echoic trials. Nine
infants learned a total of 23 echoic relations after many reinforced trials (M =
720 trials [3-stimulus], 92 trials [2-stimulusl). Once a minimal echoic
repertoire was established, four infants were able to rapidly learn a further 22
echoic relations.
Nine infants learned a total of 44 name (that is, corresponding listener, echoic,
and tact) relations. Learning tacting behaviours in respect of the first set of
stimuli was slow. Contrary to the predictions of Sidman's stimulus equivalence account, tacting did not emerge following learning of the corresponding listener relations, or even when the corresponding listener and echoic relations were learned. As predicted by the naming account of Horne and Lowe ( 1996), reinforcement for echoing the object's name while looking at the object was necessary and sufficient to establish tacting of a total of 22 stimuli by nine infants (M = 745 trials [3-stimulusJ, 26 trials [2-stimulus]). Four infants were next trained on further novel stimulus pairs; a total of 22 new name relations were learned. Established minimal echoic repertoires facilitated rapid learning of these subsequent sets of name relations, when unprompted echoic responses were produced as the infants oriented to the corresponding object during listener training trials. This acceleration of learning accords with higher order naming as defined by Horne and Lowe (1996).
It is argued that the results of this investigation of the determinants of naming,
including the rapidly learned higher order naming of older infants, accord with
Horne and Lowe's account and contradict the predictions of both Sidman's
(1994) Equivalence and Hayes' (1991; Hayes & Hayes, 1992) Relational Framing accounts of the ontogenesis of naming in human infants.