We identify naming as the basic unit of verbal behavior, describe the conditions under which it is learned, and outline its crucial role in the development of stimulus classes and, hence, of symbolic behavior. Drawing upon B. F. Skinner's functional analysis and the theoretical work of G. H. Mead and L. S. Vygotsky, we chart how a child, through learning listener behavior and then echoic responding, learns bidirectional relations between classes of objects or events and his or her own speaker-listener behavior, thus acquiring naming-a higher order behavioral relation. Once established, the bidirectionality incorporated in naming extends across behavior classes such as those identified by Skinner as the mand, tact, and intraverbal so that each becomes a variant of the name relation. We indicate how our account informs the specification of rule-governed behavior and provides the basis for an experimental analysis of symbolic behavior. Furthermore, because naming is both evoked by, and itself evokes, classes of events it brings about new or emergent behavior such as that reported in studies of stimulus equivalence. This account is supported by data from a wide range of match-to-sample studies that also provide evidence that stimulus equivalence in humans is not a unitary phenomenon but the outcome of a number of different types of naming behavior.Key words: naming, verbal behavior, language, symbolic behavior, stimulus equivalence, listener behavior, rule governance, speech for self, consciousness, match to sample, children Within behavior analysis in recent years there has been an upsurge of interest in the study of human behavior in general and, more particularly, in those complex behavioral phenomena that many previously considered to be the exclusive concern of cognitive psychology. Language, or verbal behavior, and its interactions with other behavior are now at the center of a great deal of research, and it is increasingly evident that behavior analysts wish to reclaim the high ground of behavioral complexity and deal with issues such as word meaning, semantic relations, and symbolic behavior (e.g

Objective: To measure children's consumption of, and liking for, fruit and vegetables and how these are altered by a peer modelling and rewards-based intervention. Design: In this initial evaluation of the programme, children's consumption of fruit and vegetables were compared within and across baseline and intervention phases. Setting: Three primary schools in England and Wales. Subjects: In total, 402 children, aged from 4 to 11 y. Intervention: Over 16 days, children watched six video adventures featuring heroic peers (the Food Dudes) who enjoy eating fruit and vegetables, and received small rewards for eating these foods themselves. Main outcome measures: Fruit and vegetable consumption was measured (i) in school at lunchtime and snacktime using a fivepoint observation scale, with inter-rated reliability and weighed validation tests; and (ii) at home using parental recall. A questionnaire measured children's liking for fruit and vegetables before and after the intervention. Results: Consumption during the intervention was significantly higher than during baseline at lunchtime and at snacktime (Po0.001 in all instances). Consumption outside school was significantly higher during the intervention on weekdays (Po0.05) but not weekend days. Following the intervention, children's liking for fruit and vegetables also showed a significant increase (Po0.001). Conclusions:The peer modelling and rewards-based intervention was shown to be effective in bringing about substantial increases in children's consumption of, and expressed liking for, fruit and vegetables.

Objective: To evaluate a peer-modelling and rewards-based intervention designed to increase children's fruit and vegetable consumption. Design: Over a 5-month period, children in an experimental and a control school were presented with fruit and vegetables at lunchtime. Children aged 5-7 y also received fruit at snacktime (mid-morning). The intervention was implemented in the experimental school and levels of fruit and vegetable consumption were measured at baseline, intervention and at 4-month follow-up. Setting: Two inner-city London primary schools. Subjects: In total, 749 children aged 5-11 y. Intervention: Over 16 days children watched video adventures featuring heroic peers (the Food Dudes) who enjoy eating fruit and vegetables, and received small rewards for eating these foods themselves. After 16 days there were no videos and the rewards became more intermittent. Main outcome measures: Consumption was measured (i) at lunchtime using a five-point observation scale; (ii) at snacktime using a weighed measure; (iii) at home using parental recall. Results: Compared to the control school, lunchtime consumption in the experimental school was substantially higher at intervention and follow-up than baseline (Po0.001), while snacktime consumption was higher at intervention than baseline (Po0.001). The lunchtime data showed particularly large increases among those who initially ate very little. There were also significant increases in fruit and vegetable consumption at home (Po0.05). Conclusions: The intervention was effective in bringing about substantial increases in children's consumption of fruit and vegetables.

In three experiments, 2- to 4-year-old children, following pretraining with everyday objects, were presented with arbitrary stimuli of differing shapes. In Experiment 1A, 9 subjects were trained one common tact response, "zag," to three of these and a second tact, "vek," to another three. In category match-to-sample Test 1, 4 subjects sorted accurately when required only to look at the sample before selecting from five comparisons. The remaining 5 subjects succeeded in Test 2, in which they were required to tact the sample before selecting comparisons. Experiment 1B showed, for 2 of these subjects, that tact training with 12 arbitrary stimuli established two six-member classes that were still intact 6 weeks later. In Experiment 2, 3 new subjects participated in a common tact training procedure that ensured that none of the exemplars from the same class were presented together prior to the test for three-member classes. Two subjects passed category Test 1 and the third passed Test 2. Tests showed subjects' listener behavior in response to hearing /zog/ and /vek/ to be in place. These experiments indicate that common naming is effective in establishing arbitrary stimulus classes and that category match-to-sample testing provides a robust measure of categorization.

Following pretraining with everyday objects, 1- to 4-year-old children received listener training with three pairs of arbitrary stimuli of differing shapes. For each pair, 9 children were trained to select one stimulus in response to the spoken word /zog/ and the other to the spoken word /vek/. Next, in the look-at-sample category match-to-sample test, none categorized the six stimuli correctly when asked to look at the sample before selecting from five comparisons. Seven of these children failed a subsequent test of corresponding speaker behavior (tact test); following tact training, 5 of them passed either a repeat of the look-at-sample category test (2 subjects) or an alternative category test (3 subjects) in which they were required to tact the sample before selecting comparisons. The remaining 2 failed both category tests. Of the 2 who passed the tact test, 1 passed the tact-sample category test; the other failed to complete category testing. Two children were next given a second stimulus set. One passed the look-at-sample category test and the tact test; the other failed both tests but passed the tact-sample category test after tact training. The results show that 1- to 4-year-old children may learn listener behavior without corresponding speaker behavior. The results also show that common listener behavior is not sufficient to establish arbitrary stimulus classes, and they are consistent with the proposition that naming may be necessary for categorization of such stimuli.