Equivalence relations, contextual control, and naming

This paper reports two experiments that investigated the role of verbal behavior in the emergence and generalization of contextually controlled equivalence classes. During both experiments, participants were trained with two different combinations of the same easily nameable, yet formally unrelated, pictorial stimuli. Match-to-sample baselines for eight four-member classes were established under the contextual control of two colors. In the presence of one color, conditional relations were established between stimuli whose normative names rhymed. In the presence of the other color, conditional relations were established between stimuli whose normative names did not rhyme. Although, during Experiment 1, all participants demonstrated equivalence classes involving rhyming stimuli, none demonstrated the formation of nonrhyme equivalence classes. To investigate this finding, Experiment 2 evaluated whether participants would demonstrate both rhyme and nonrhyme equivalence classes given more extensive exposure to the experimental contingencies. All participants demonstrated contextually controlled rhyme and nonrhyme equivalence classes, although rhyme classes were demonstrated with greater facility than nonrhyme classes. Results indicate that visual stimuli are named, that verbal bases for stimulus classification can affect the emergence of contextually controlled equivalence classes, and that untrained contextually controlled conditional discriminations involving novel stimuli can emerge on the basis of participants' verbal behavior.     

Cumulative semantic inhibition in picture naming: experimental and computational studies

We report an experiment in which subjects named 120 pictures, consisting of series of five pictures drawn from each of 24 semantic categories (and intermixed with 45 fillers). The number of intervening trials (lag) between successive presentations of members of the same category varied from two to eight. Subjects' naming latencies were slowed by 30 ms for each preceding member of the category. This effect was both cumulative and linear, and unrelated to the lag elapsing since the previous presentation of a category member. These results definitively demonstrate the occurrence of cumulative interference for word retrieval by prior retrieval of other exemplars of the same semantic category-cumulative semantic inhibition. We claim that this inhibition effect could only occur if the spoken word production system possesses three specific properties (competition, priming, and sharing of semantic activation). We provide computational-modelling evidence in support of this claim. We show that no current theory of spoken word production has all of these properties. In their current form, all these theories are falsified by these results. We briefly discuss the obstacles that may be encountered by current models were they modified to account for our findings.     

Variable solutions to the same problem: aberrant practice effects in object naming by three aphasic patients

Although deficits in confrontation naming are a common consequence of damage to the language areas of the left cerebral hemisphere, some patients with aphasia show relatively good naming ability. We measured effects of repeated practice on naming latencies for a set of pictured objects by three aphasic patients with near-normal naming ability and by neurologically intact young and older adults. While the non-injured participants showed a systematic reduction in overall mean latencies and reduced trial-to-trial latency variability, the aphasic patients did not. Examination of the latency distributions suggests that successful naming by aphasic patients may come about by different underlying operations.     

Is action naming better preserved (than object naming) in Alzheimer's disease and why should we ask?

The present study compared object and action naming in patients with Alzheimer's dementia. We tested the hypothesis put forward in (some) previous studies that in Alzheimer's dementia the production of verbs, that is required in action naming, is better preserved than the production of nouns, that is required in object naming. The possible reason for the dissociation is that verbs are supported predominantly by frontal brain structures that may remain relatively better preserved in early Alzheimer's disease. Objects, on the other hand, are supported by temporal lobe structures that are affected early in the disease. An alternative hypothesis, which is supported by other studies, is that action naming is more impaired than object naming due to verbs being semantically more complex than nouns. In order to test these contrasting hypotheses, the present study used more stringent methodology than previous studies. We used a larger set of stimuli with carefully matched object and action items and we collected not only accuracy data but also naming latencies, a measure that is sensitive to even mild lexical retrieval problems. We compared the performance of 19 patients with mild to moderate Alzheimer's disease with that of 19 healthy age matched participants. We found that both the patients and the comparison group responded faster and made fewer errors on the object pictures than the action pictures. A qualitative analysis of the naming errors indicated that object and action naming pose different demands for the language system. The results overall suggest that the patients' performance is an exaggeration of the pattern present in the comparison participants.     

Contributions of response set and semantic relatedness to cross-modal Stroop-like picture-word interference in children and adults

Resistance to interference from irrelevant auditory stimuli undergoes development throughout childhood. To test whether semantic processes account for age-related changes in a Stroop-like picture-word interference effect, children (3- to 12-year-olds) and adults named pictures while listening to words varying in terms of semantic relatedness to the pictures and response set membership. In Experiments 1 and 2, with animal and clothing pictures, the interference effect observed in children, but not in adults, depended on the distractors' status as members of the response set. In Experiment 3, with unrelated pictures, adults, but not children, showed greater interference for trials with distractors in the response set. These results indicate developmental changes in picture-word interference involving the establishment of a response set in working memory.     

Differential vocalization in budgerigars: towards an experimental analysis of naming.

In Experiment 1, 3 budgerigars (Melopsittacus undulatus) were trained with food reinforcement to make low- or high-frequency calls in response to different color stimuli, C1 and C2 (a color-naming task), using a gradual response-differentiation procedure and an automatic call-recognition system. Thus, a call within a certain frequency band was reinforced in the presence of C1 ("C1 call"), and a call within a different band was reinforced in the presence of C2 ("C2 call"). In Experiment 2, all 3 budgerigars were trained in a form-to-color matching-to-sample task, alternating trial by trial with either the color-naming task (2 birds) or an identity color matching-to-sample task (1 bird). Sample stimuli for the new matching-to-sample task were forms (F1 or F2) and comparisons were the same two colors (C1 and C2). Given Sample F1 or F2, birds had to make a call to produce Comparison Pair C1 and C2. With F1 as the sample, a peck on C1 was reinforced; with F2 as the sample, a peck on C2 was reinforced. Although no particular call was specified in the presence of F1 and F2, 2 birds made the C1 call in the presence of F1 and the C2 call in the presence of F2. In Experiment 3, the bird that failed to match form and color calls in Experiment 2 and another bird were first trained in a color-to-form matching-to-sample task: C1 to F3 and C2 to F4. In this task, to produce the comparison pair of forms, a high call (or low for the other bird) was required in the presence of C1, and a low call (or high) was required in the presence of C2. Both birds were then trained with an identity matching-to-sample task in which sample and comparison stimuli were the same two forms, F3 and F4. Trials on the identity task alternated with the color-to-form trials. Although no particular call was required in the presence of Samples F3 and F4, both birds came to make the C1 call in the presence of F3 and the C2 call in the presence of F4. Our technique promises to be useful for the study of emergent vocal relations in budgerigars and other animals.     

Color naming: A mapping in the IMCS of common color terms

This study can be considered a follow-up of the investigations of basic color terms by Berlin & Kay and others following their paradigm. It is complementary to these inasmuch as a different method was used for identifying focal areas and boundaries of common color categories, namely semantic differential scales and isosemantic mapping. Further, colors from the entire color space were studied. No comparisons were made between languages, this study being only concerned with the Swedish language. The purpose of this study was to provide a more thorough mapping of the "spread gradients" in various areas of the NCS color space of color categories as represented by the most common color terms.     

The development of functional and equivalence classes in high-functioning autistic children: the role of naming.

The development of functional and equivalence classes was studied in four high-functioning, preschool-aged autistic children. Initially, all subjects failed to demonstrate match-to-sample relations indicative of stimulus equivalence among two three-member classes of visual stimuli. Then, 2 subjects showed emergence of those relations after they were taught to assign the same name to all members in each class. Next, subjects were taught names for new stimuli outside the match-to-sample format. On subsequent match-to-sample tests, 2 subjects demonstrated untrained conditional relations among the stimuli given a common name. New, unnamed stimuli were then related via match-to-sample training to stimuli from sets of named stimuli. Tests for emergent conditional relations between the new unnamed stimuli and the named stimuli yielded positive results for 1 subject and somewhat mixed results for 3 subjects. Finally, without naming, 2 subjects developed stimulus equivalence among two new three-member classes of visual stimuli. These data suggest that naming may remediate failures to develop untrained conditional relations, some of which are indicative of stimulus equivalence.     

ALPHABET LETTERS AS TOKENS: TRAINING PRESCHOOL CHILDREN IN LETTER RECOGNITION AND LABELLING DURING A TOKEN EXCHANGE PERIOD1

In token economies, we typically consider the instructional opportunities available during the periods of token delivery, but may overlook educational opportunities available at the time of token exchange. The present studies examined the use of labelled tokens and routines in the token exchange period to teach alphabet letter recognition to economically disadvantaged preschool children. The children earned points for a variety of academic behaviors in an early morning classroom setting. At no time were alphabet letters introduced or taught during class. Later, during a midmorning token exchange period, operated according to a department store model, the children were given their points in the form of poker chips inscribed with upper-case alphabet letters. They were required to discriminate among these lettered chips before exchanging them for backup reinforcers sold in four or five stores. To assess alphabet letter knowledge, probe evaluations were periodically conducted in which questions requiring alphabet letter recognition and labelling were asked. The answers to these questions were not reinforced. Alphabet letter training during token exchange periods consisted of having a child display the lettered chips, whereupon a teacher asked a number of recognition-type questions. Wrong answers were corrected, and correct answers praised. The child was allowed to exchange the tokens when the number required for a purchase had been recognized correctly. The periodic probe evaluations revealed consistent increases in correct alphabet letter recognition and, as a byproduct, alphabet labelling was facilitated, even though not explicitly trained. Thus, once the letters were recognized, correct labelling shortly followed. The sequential training of new sets of letters was used to demonstrate experimental control within subjects for two children. A control for exposure to the letters was provided by using the labelled tokens, but requiring the counting of chips rather than letter discrimination in the exchange period for two other children. This procedure produced chance levels of letter recognition, which were subsequently improved when the discrimination procedure was added. Posttraining probes, conducted at one and three weeks after training when the labelled tokens and discrimination routines were no longer in use, revealed the same high levels of recognition and labelling performance found during training. Thus, it appears that labelled tokens may be used to teach discriminations during token exchange periods so long as responses are differentiated on the basis of relevant dimensions of the stimuli.     

PICTURE NAMING,MATCHING TO SAMPLE,AND HEAD INJURY: A STIMULUS CONTROL ANALYSIS

Computer-based procedures were used to examine oral naming and matching-to-sample performances in an adult with a head injury. Relatively few errors occurred when pictures were (a) named, (b) matched to dictated names presented simultaneously, (c) matched to dictation after a delay, and (d) matched to identical pictures presented simultaneously. More errors occurred on delayed than on simultaneous identity matching. On delayed matching trials, fewer errors occurred when instructions to name the samples were given.