On the locus of the stimulus suffix effect

Two experiments contrasted short-term memory and sensory memory (precategorical acoustic storage) explanations of the stimulus suffix effect. Experiment 1 attempted to interfere with recency recall by forcing subjects to encode nonverbal acoustic suffixes into a verbal, articulatory code. Subjects in this condition showed recall that was comparable to that of subjects who were told to ignore the suffixes. However, Experiment 2 showed that silently mouthed articulation of a suffix can produce interference on recall of recency items, although not as much as that produced by vocal articulation. The results are discussed in terms of current models of the stimulus suffix effect.     

The effects of stimulus familiarization on patterns of visual selection

Patterns of visual selection were recorded as Ss viewed pairs of stimulus drawings in which the two members were either both incongruous or both banal. Prior to presenting the paired stimuli, S was preexposed to either one member of the stimulus pair or to the incongruous or banal counterpart of one member of the stimulus pair. The results indicate that: (1) preexposure to a stimulus reduced its potential to elicit looking responses, and the magnitude of that reduction was greater for incongruous stimuli than for banal stimuli; (2) preexposure to an incongruous stimulus affected the potential of its banal counterpart to elicit looking responses, but preexposure to a banal stimulus did not affect the potential of its incongruous counterpart to elicit similar responses; and (3) the reduced potential of the preexposed member of a stimulus pair to elicit looking responses waned after 10 sec. These results were discussed in light of an “information-conflict resolution” model of visual selection.     

The impact of familiarization strategies on the missing-letter effect

When reading a text and searching for a target letter, readers make more omissions of the target letter if it is embedded in frequent function words than if it is in rare content words. While word frequency effects are consistently found, few studies have examined the impacts of passage familiarity on the missing-letter effect and studies that have present conflicting evidence. The present study examines the effects of passage familiarity, as well as the impacts of passage familiarization strategy promoting surface or deep encoding, on the missing-letter effect. Participants were familiarized with a passage by retyping a text, replacing all common nouns with synonyms, or generating a text on the same topic as that of the original text, and then completed a letter search task on the familiar passage as well as an unfamiliar passage. In Experiment 1, when both familiar and unfamiliar passages use the same words, results revealed fewer omissions for the retyping and synonyms conditions. However, in Experiment 2, when different words are used in both types of texts, no effect of familiarization strategy was observed. Furthermore, the missing-letter effect is maintained in all conditions, adding support to the robustness of the effect regardless of familiarity with the text.     

Establishing stimulus control of vocal stereotypy displayed by young children with Autism

We examined the vocal stereotypy of three boys who were diagnosed with an Autism Spectrum Disorder (ASD). Results of functional analyses indicated that each participant's vocal stereotypy was maintained by non‐social consequences. For two participants, verbal reprimands were provided contingent on vocal stereotypy in the presence of a red card (RC). For the third participant, after verbal reprimands alone did not decrease vocal stereotypy, toys were withdrawn contingent on vocal stereotypy in the presence of the RC. For all three participants, vocal stereotypy was permitted without programmed consequences the presence of a green card (GC). The results showed that vocal stereotypy decreased in the presence of the RC for all three participants; however, vocal stereotypy came under inhibitory control of the RC for only one of the three participants. The potential utility of using punishment to develop stimulus control of automatically reinforced problem behavior in academic settings is briefly discussed. Copyright © 2009 John Wiley & Sons, Ltd.     

The effect of training procedures on the overlearning reversal effect in young children

The performance of 80 preschool children on a reversal problem was studied as a function of amount of training and type of training procedure used during acquisition and reversal. In the extinction phase of reversal learning, subjects given a correction procedure during the reversal problem made fewer perseverative errors than subjects given noncorrection. In the reversal midplateau phase of reversal learning, overtraining facilitated reversal learning for subjects receiving noncorrection during the acquistion problem, but not for subjects receiving correction. A shift in training procedure between acquisition and reversal increased the number of subjects who reached criterion immediately after perseveration. Since these results are difficult to explain in terms of traditional learning theories, an alternative response-switching strategy explanation was proposed.     

A timing-specific memory distortion effect in young children

It has been suggested that there are systematic distortions in children's memory for temporal durations, such that children's memory is not just less accurate than that of adults but qualitatively different. Experiment 1 replicated the memory distortion effect by demonstrating developmental change in the tendency to confuse a reference duration with one that is shorter rather than longer than it. When the long-term memory demands of the task were reduced by providing reminders of the reference duration on every trial, there were no such qualitative changes in error patterns (Experiment 2). Further evidence for developmental changes in memory distortion was found in the temporal generalization task of Experiment 3, in which stimuli were spaced logarithmically rather than linearly. In Experiment 4, a similar distortion pattern was absent in a task in which children made judgments about the pitch rather than the duration of stimuli, suggesting the effect may be specific to time estimation.     

Teaching young children to make accurate portion size estimations using a stimulus equivalence paradigm

The prevalence of obesity among children and adolescents has increased over the past four decades. Obesity can be conceptualized as a problem related to energy balance, where more energy is consumed than is expended through physical activity. One way that children may have a positive energy balance is through the overconsumption of foods (i.e., eating large portion sizes). Therefore, interventions that teach children to make accurate portion size estimations may be important to maintain overall health. In the current study, seven children between the ages of 4 and 7 years were taught to make accurate portion size estimations using a stimulus equivalence paradigm. Results suggested that the stimulus equivalence paradigm was effective in teaching five of seven participants to make more accurate portion size estimations during posttraining. Furthermore, five of seven participants estimated the target portion size of a novel food during extension sessions. These findings extend the current literature related to teaching children to make accurate portion size estimations. Although this was a translational study, results might help to inform existing nutrition education programs aimed at teaching children healthier eating habits.     

Assessment of attention to complex cues in young children: Manipulating prior reinforcement histories of stimulus components

Computer technology was employed to teach attentional skills to six young children. The procedure involved manipulating prior reinforcement histories of individual stimuli to examine whether this variable controlled the features of compound cues which young children attended to. Initially, three separate visual discriminations were conditioned. After criterion accuracy was achieved, stimuli were combined by keeping prior reinforcement contingencies unchanged for some elements and reversing them for remaining elements. Tests revealed when conflict-compound discriminations were acquired, children responded selectively to unchanged elements while not responding to reversed elements. Transfer effects were investigated by presenting compounds containing some or all novel cues. Variable test performance was observed following acquisition of compounds composed of novel cues. Consistent test performance occurred across children for compounds containing all pretrained cues. Separately training each stimulus component was the most reliable procedure for controlling the attention of young children.     

Two mechanisms in the stimulus suffix effect

The stimulus suffix is a redundant item presented immediately after a stimulus list. Its effect is the selective impairment of recall of the final items in a serially recalled, auditorily presented list of unconnected items. Two experiments indicate that there was no difference between the effects of suffixes .5 and 1.0 sec after the end of a digit list presented at a rate of one digit/sec. This suggests that the effect of the suffix, in this case the vowel sound "ah," is not a simple function of its time of arrival after the final digit, as has been thought. The possibility of more complex factors was supported in a further experiment which showed a slight reduction in the size of the suffix effect by repeating the suffix three times.     

Using stimulus equivalence‐based instruction to teach young children their caregivers' contact information

Stimulus equivalence‐based instruction (EBI) was used to teach young children of typical development three 4‐member equivalence classes containing contact information from three caregivers (e.g., mother, father, and grandmother). Each class comprised the caregiver's (a) photograph, (b) printed name, (c) printed phone number, and (d) printed name of employer. A pretest‐train‐posttest‐maintenance design with a nontreatment control group comparison was used. Pretests and posttests assessed the degree to which class‐consistent responding occurred across both visual–visual matching tasks and intraverbals. Intraverbal responding was also probed with a novel instructor. Overall, EBI participants scored significantly higher during the posttests than the control participants across both the derived relations and intraverbal tests. These differences maintained 2 weeks later. Thus, responding generalized to (a) a different topography (i.e., intraverbal), (b) auditory versions of the stimuli, and (c) in the presence of a novel instructor. How such procedures may benefit lost children are discussed.