Effects of delayed constructed-response identity matching on spelling of dictated words

We studied the effects of delayed constructed-response identity matching on spelling with 6 first graders with histories of school failure. After training, the children learned to spell words to dictation and their cursive writing improved. These results replicate studies showing that delayed constructed-response matching establishes spelling. For 2 children, spelling of generalization words--words formed by recombining the syllables of training words--also improved. These results extend studies that have shown recombinative generalization in reading and spelling.     

Naming and categorization in young children: II. Listener behavior training

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.     

Morphological processing: a comparison between free and bound stem facilitation

Linguists distinguish between words formed from free stems (e.g., actor: act) and those formed from bound stems (e.g., spectator: spect). In a forward masked priming task, we observed significant morphological facilitation for prime-target pairs that shared either a free (e.g., deform-CONFORM) or a bound (e.g., revive-SURVIVE) stem. Relative to an unrelated baseline, magnitudes of facilitation for free (e.g., form) and bound (e.g., vive) stems were significant and comparable, but relative to an orthographic baseline free stem facilitation was greater than bound stem facilitation. In addition, the magnitude of bound (but not free) stem morphological facilitation correlated with the number of morphological relatives.     

Identity matching-to-sample with olfactory stimuli in rats

Identity matching-to-sample has been difficult to demonstrate in rats, but most studies have used visual stimuli. There is evidence that rats can acquire complex forms of olfactory stimulus control, and the present study explored the possibility that identity matching might be facilitated in rats if olfactory stimuli were used. Four rats were trained on an identity match-to-sample procedure with odorants mixed in cups of sand as stimuli. Digging in the sample cup produced two comparison cups, and digging in the comparison cup that contained the same scent as the sample was reinforced. When criterion accuracy levels were reached, novel stimuli were added to the baseline training regimen. All 4 rats reached terminal performance of above 90% correct matching with more than 20 different baseline stimuli and matched novel stimulus combinations with above-chance accuracy; 3 of the 4 rats matched novel stimuli at levels significantly above chance. Accurate matching performance was demonstrated both with 2- and 3-comparison procedures. These results suggest that generalized matching-to-sample can be observed in rats when olfactory stimuli are used and, furthermore, that multiple-exemplar training may be important for its emergence.     

The emergence of symmetry in a conditional discrimination task using different responses as propioceptive samples in pigeons

In Experiment 1, 10 pigeons were exposed to a successive symbolic matching-to-sample procedure in which the sample was generated by the pigeons' own behavior. Each trial began with both response keys illuminated white, one being the "correct" key and the other the "incorrect" key. The pigeons had no way of discriminating which key was correct and which incorrect, since these roles were assigned on a random basis with the same probability of 0.5 for each key. A fixed ratio of five responses was required on the correct key. However, each time the pigeon pecked the incorrect key, the correct key response counter reset. Five consecutive pecks on the correct key was the only way to end this component, and switch off both key lights. Two seconds later, these same keys were illuminated again, one green and the other red (comparison stimuli). Now, if the correct white key had been on the left, a peck at one color produced food, and if the correct white key had been on the right, a peck at the other color produced food. When the pigeons had learned this discrimination, they were exposed to several symmetry tests (simultaneous presentations of both keys illuminated the same color-i.e., both red or both green), in order to interchange the sample with the comparison stimuli. In Experiment 2, the importance of requiring discrimination between the samples and between the comparisons was analyzed. In Experiment 3, we compared the results of Experiment 1 with a slightly different experiment, which resulted in discrimination of key position, an exteroceptive stimulus. The results showed that symmetry emerged only when different responses were used as samples.     

Testing response-stimulus equivalence relations using differential responses as a sample

This study tested the notion that an equivalence relation may include a response when differential responses are paired with stimuli presented during training. Eight normal adults learned three kinds of computer mouse movements as differential response topographies (R1, R2, and R3). Next, in matching-to-sample training, one of the response topographies was used to select a comparison stimulus B (B1, B2, or B3) conditionally upon presentation of sample stimulus A (A1, A2, or A3), and to select stimulus D (D1, D2, or D3) conditionally upon presentation of stimulus C (C1, C2, or C3). After two sample-comparison-response relations (ABR and CDR) were established, 18 sample-comparison relations were tested (BA, DC, RA, RB, RC, RD, AC, CA, AD, DA, BC, CB, BD, DB, AA, BB, CC, and DD). In the RA, RB, RC, and RD tests, the differential responses (R1, R2, and R3) were used as sample stimuli. All subjects made class-consistent comparison selections in the tests. This study provides evidence that responses may become members of an equivalence class.     

Experimental control of nodality via equal presentations of conditional discriminations in different equivalence protocols under speed and no-speed conditions

A within-participant comparison of simple-to-complex, complex-to-simple, and simultaneous protocols was conducted establishing different sets of three 7-member equivalence classes for 4 undergraduate students. The protocols were implemented under either accuracy-only or accuracy-plus-speed conditions while keeping number of presentations of training and testing trials equal. The results partially support previous reports of differential effects on acquisition, with participants completing more blocks in training under the simultaneous than the complex-to-simple and the simple-to-complex protocols. Across the protocols, however, the number of trials completed to criterion did not vary systematically. More important, response speed and accuracy did not decrease as a function of nodal number, with or without the speed contingency, or under any protocol. The latter results challenge the generality of previous reports of the nodality effect and the notion of "relatedness" of equivalence-class members, and support a reinforcement-contingency, instead of a structural, perspective on equivalence-class formation.     

Stimulus equivalence: testing Sidman's (2000) theory

Sidman's (2000) theory regarding the origin of equivalence relations predicts that a reinforcing stimulus common to distinct equivalence classes must drop out of the equivalence relations. This prediction was tested in the present study by arranging class-specific reinforcers, R1 and R2, following correct responding on the prerequisite conditional discriminations (Ax-Bx, Cx-Bx) for two stimulus classes, A1B1C1 and A2B2C2. A class-common reinforcer, R3, was presented following correct responding on the prerequisite conditional discriminations for a further two stimulus classes, A3B3C3 and A4B4C4. Sidman's theory predicts reinforcer inclusion within Classes 1 and 2 only, given this training arrangement. Experiment 1 tested for the emergence of four equivalence classes and of stimulus-reinforcer and reinforcer-stimulus relations in each class. Four of the 6 subjects demonstrated the reinforcer-based relations in all four equivalence classes, rather than in only those classes with a class-specific reinforcer, as Sidman's theory predicts. One of the remaining 2 subjects showed the reinforcer-based relations in three of the four classes. Experiment 2 extended these findings to document the emergence of interclass matching relations based on the common reinforcer R3, in 5 of 6 subjects, such that a Class 3 sample occasioned the selection of a Class 4 sample when the Class 3 comparison was absent, and similarly, a Class 4 sample occasioned the selection of a Class 3 comparison when the Class 4 comparison was absent. These interclass relations emerged despite the simultaneous maintenance of Class 3 and 4 baseline conditional discriminations, so that the Class 3 and 4 stimuli and reinforcer simultaneously were, and were not, part of a single larger equivalence class. These data are irreconcilable with Sidman's theory, and question the utility of the application of the equivalence relation in describing derived stimulus relations.     

Inhibitory priming effects in auditory word recognition: when the target's competitors conflict with the prime word

Several studies indicate that the number of similar sounding words that are activated during recognition is a powerful predictor of performance on auditory targets. Words with few competitors are processed more quickly and accurately than words with many competitors. In the present study, we examined the contribution of the competitor set size in determining the magnitude of the inhibitory priming effect. The data show that the priming effect is stronger when word targets have few competitors. This result supports the view of direct competition between lexical candidates.     

Rate-decreasing effects of the atypical neuroleptic risperidone attenuated by conditions of reinforcement in a woman with mental retardation

Effects of two doses of risperidone on the performance of a matching task under tangible reinforcement and nonreinforcement conditions were measured in a woman with mental retardation. In both conditions, time to complete the task increased and response rates decreased under two doses of risperidone. Accuracy was generally unchanged. These changes were much smaller in the tangible reinforcement condition; thus, reinforcement seemed to protect performance from the rate-decreasing effects of risperidone.