Free-operant forgetting: Delayed stimulus control of multiple-schedule performance

Pigeons' responses were reinforced in two components of several multiple variable-interval variable-interval schedules of food reinforcement. In one component, the key was illuminated green for 15 seconds and white for 45 seconds. In the other component, the key was illuminated red for 15 seconds and white for 45 seconds. Values for the exponent of the power functions relating response ratios to reinforcement ratios were higher in the presence of the discriminative stimuli (green or red) than in the presence of white. Sensitivity of response ratios to changes in reinforcement ratios provided an index of the extent to which responding was under delayed stimulus control by prior discriminative stimuli.     

Local contrast in behavior allocation during multiple-schedule components

Allocation of responses between two keys was studied during two alternating multiple-schedule components. Responses were recorded in successive quarters of each component. Variable-interval reinforcer schedules on the two keys were constant throughout the experiment for one (constant) component and were varied over conditions on one key for the other, producing changes in reinforcer ratios for the varied component. Behavior allocation for the first quarter of the constant component was inversely related to varied-component reinforcer ratios, a form of local contrast, but this relationship was not observed later in the component. During the first quarter of the varied component, slopes of matching lines were high and decreased later in the component. It is argued that this form of local contrast cannot be explained in terms of reallocation of extraneous reinforcers between components, and that the matching law for concurrent operants does not capture some sources of control over behavior allocation. A simple extension of the matching law is offered that adequately describes behavior changes during both components. A version of this formulation can predict contrast effects in absolute response rates.     

The effectiveness of and preschoolers' preferences for variations of multiple-schedule arrangements

Multiple schedules of reinforcement have been used to teach children to recruit attention only when it is available, thereby minimizing disruptive requesting during instructional activities. This procedure involves alternating periods of continuous reinforcement (CRF) with periods of extinction and correlating each period with a distinct and continuous discriminative stimulus. The present study evaluated the effectiveness of and children's preferences for multiple schedules in which (a) two different stimuli, one correlated with reinforcement (S+) and another correlated with extinction (S-), were presented; (b) only an S+ was presented (i.e., no stimulus was correlated with extinction), and (c) neither an S+ nor an S- was presented (i.e., a mixed schedule). S+/S- and S+ arrangements were similarly effective for 7 children, but 3 preferred the S+/S- condition and 4 preferred the S+ condition. Correlational analyses suggested that children who responded more effectively given the S- (discrimination indexes were relatively high) preferred the S+/S- condition, whereas children who responded less effectively given the S- preferred the S+ condition. The implications of these findings for arranging multiple schedules for social responses are discussed.     

Additional evidence from a paradigm for inferring discriminative processes in children and adults

A previously developed paradigm which incorporates a correlational methodology into an experimental context was used in the present study to specify more definitely the attribute(s) underlying verbal discrimination learning under normal conditions. In the case of fifth- and sixth-grade children, it was found that frequency theory is sufficient to account for performance on the task. However, older subjects were less homogeneously reliant on the frequency attribute. While many older subjects appeared to utilize frequency cues, others adopted strategies that resulted in the utilization of attributes other than frequency.     

Additional considerations when measuring adaptive control in conflict tasks

A recent review article by Braem et al. (2019, Trends in Cognitive Sciences) summarises some of the major challenges associated with investigating the dynamics of cognitive control in conflict tasks and recommends steps that researchers can take to minimise these challenges. This commentary highlights two further considerations for researchers studying the dynamics of cognitive control. First, researchers should consider analysing effects stemming from trial n - 2 to identify (a) how the congruency sequence effect emerges over a longer series of trials and (b) whether residual feature-integration effects remain in confound-minimised designs. Second, data from hand-tracking studies indicates that the dynamics observed in button-press measures of response time reflect the functioning of dissociable processes. Consequently, researchers should consider how the various manipulations used to investigate the dynamics of cognitive control might impact different processes underlying performance.     

Stimulus control of free-operant avoidance: The contribution of response rate and incentive relations between multiple-schedule components

The associations formed in the components of a multiple schedule can be classified as (1) stimulus-response (S-R) associations and (2) stimulus-reinforcer (S-S^R) associations. The present experiments sought to determine the individual contribution of these S-R and S-S^R associations to stimulus control by manipulating them independently. Responses postponed shocks by 25 sec in the presence of a tone alone and a light alone in all experiments. The contingencies programmed in the absence of both tone and light established a reference for the S-R and S-S^R associations in tone and in light. All four possible combinations of signalling response increase or decrease together with incentive increase or decrease were studied. Although the influence of the contingencies operating in the absence of tone and light was difficult to detect from response rates in tone or light, presenting tone and light together revealed clear effects. Response rates in tone and light together relative to those in either alone depended upon the contingency operating in the absence of tone and light. Stimulus-response and stimulus-reinforcer associations appeared to counteract each other when in opposition and combine together to enhance each other when in agreement. This suggested that the associations of a stimulus to response and to incentive combine algebraically in determining stimulus control. An algebraic analysis in terms of the S-R and S-S^R associations conditioned to the stimulus elements comprising the training and test stimuli accounted for the observed patterns of data.     

Developing stimulus control of the high-rate social-approach responses of an adult with mental retardation: a multiple-schedule evaluation

We evaluated a multiple schedule in which the extinction (S-) components were signaled overtly by a black lanyard and the reinforcement (S+) components were not correlated with any programmed stimuli in developing stimulus control over the high-rate social-approach responses of an adult with mental retardation. Responding was consistently low in the presence of the S- and consistently high when the lanyard was absent (i.e., the S+ condition). Component durations were thinned successfully to a level that was manageable for caregivers.     

Information producing responses in normal and retarded children.

Normal and retarded children were given trials on several discriminations which varied in difficulty. On standard discrimination trials the retarded subjects did not differ from the MA control subjects in the number of errors made but both groups made more errors than the CA control group. On other trials if subjects were not sure which stimulus was correct they were allowed to press an information key which made the discrimination easier. The retarded subjects made significantly more informational key responses than either of the control groups. These results confirmed the findings of prior investigations dealing with outerdirectedness in an experimental situation which did not allow distractibility to be a significant factor.     

Anticipatory postural control in children

Postural responses, triggered by sensory feedback, are present very early in a child's development. The purpose of the present study was to investigate the ability of children to anticipate postural disturbances caused by self-initiated movements and their ability to coordinate anticipatory postural adjustments with movement execution. Children (N = 32) aged 4 to 14 years were asked to stand quietly on a stable force plate and to raise their right arm forward (or backward) to the horizontal position after a visual stimulus. Changes in the center of pressure beneath the feet were recorded before and during the arm raise. The anticipatory (feedforward) postural patterns seen before the arm movement, and noted in a previous study of adults, were present in the youngest of the children (4 years, 2 months). Longer reaction times and inconsistent postural responses (in the anteroposterior direction) suggest that children are less capable than adults of coordinating the anticipated postural adjustment with the forthcoming limb movement, however. In the lateral plane, anticipatory postural responses were initiated more consistently.     

Visual perception and gaze control in judging versus producing phase relations

We studied visual perception and gaze control in nine participants while they judged the relative phase between two oscillating stimuli (Experiment 1), and while they moved their hand--and therewith a concurrent feedback signal--in-phase or in antiphase with an oscillating stimulus (Experiment 2). As in previous studies, the mean relative phase judgements in Experiment 1 corresponded to the presented phase relations (0 degree, 45 degrees, 90 degrees, 135 degrees, and 180 degrees), whereas their standard deviations followed an inverted U-function of relative phase. The relative phase judgements were hardly affected by the degree of visibility (fully visible, inner parts occluded, outer parts occluded) and the amplitude (5 degrees, 10 degrees, and 20 degrees) of the stimuli. Stimulus-gaze coupling decreased as relative phase increased, and its variability correlated with that of the relative phase judgements. Taken together, task performance and gaze behaviour suggested that the judgement of relative phase might be flexibly based on different variables, rather than a single variable like relative direction of motion. In Experiment 2, the production of the antiphase relation was less stable than that of the in-phase relation. Performance deteriorated when the outer parts of the signals were occluded and when their amplitudes were reduced. Stimulus-gaze coupling was stronger during in-phase than during antiphase tracking and weaker when the signals were partially occluded and when their amplitudes were reduced. Stimulus-gaze coupling at 0 degrees and 180 degrees was stronger in Experiment 2 than in Experiment 1, suggesting that the visual perception of relative phase may benefit from its active production. Overall, the results clearly indicated that visual perception of relative phase and the corresponding gaze control are strongly task-dependent.     

The effects of component duration on multiple-schedule performance in closed and open economies.

Pigeons responded on multiple variable-interval variable-interval schedules of reinforcement in an open and a closed economy. Equal duration components were increased in duration while the component rates of reinforcement were held constant, the component schedules were reversed, and component duration was decreased. In the open economy, daily sessions were limited to 1 hr, and subjects were maintained at 80% of their free-feeding weights through supplemental feeding when necessary in their home cages. In the closed economy, subjects were housed in their experimental chambers and no deprivation regimen was enforced. Relative response rate decreased as components were lengthened in the open economy, whereas in the closed economy relative rate increased as components were lengthened. Response proportions overmatched reinforcer proportions to a greater extent at long component durations in the closed economy, but there was no systematic effect of component duration on responding in the open economy.     

Therapeutic techniques for the treatment of certain infantile personality disorders in ego disturbed children

This paper has discussed certain ego disturbed children of preschool and school age with infantile personality disorders. Although these children do not form a sharp diagnostic category, it is of clinical importance to differentiate them both from the neuroses and from other more serious ego disorders. These predominantly infantile children suffer chronic ego arrest and deviations as well as some degree of internal conflicts. Reality adaptation is characteristically distorted, ego defenses imbalanced, and social relations aberrant. Unlike some other borderline types, however, these children have no significant potential for psychosis. They are not prone to panicky anxiety attacks, or to psychoticlike ego regressions or withdrawal. Ego disturbed children with infantile personality disorders pose certain typical problems of therapeutic technique. They do not possess the ego strength for classical analysis, nor are they suitable candidates for a purely supportive or nurturing treatment. I have argued that the particular psychopathology of these children requires a form of corrective developmental treatment in which the therapist plays a flexible role and uses a combination of techniques corresponding to the child's progressive ego development. Early in treatment primarily supportive and nurturing techniques are used to promote a corrective identification and strengthen the defenses. As treatment proceeds, however, selected interpretations are introduced to modify the internal conflicts that block personality integration and development. Especially important are the mobilization and interpretation of hostile aggression. In the later treatment phases the therapist becomes increasingly more frustrating to the child's infantile wishes, encouraging reality adaptation and social maturation. The various shifts in therapeutic technique create resistances whose interpretation and working through are integral to the treatment process and cure.     

Effortful control,positive emotional expression,and behavior problems in children born preterm

The present study focused on the role of high effortful control in the expression of positive emotion and development of behavior problems in children born preterm (mean gestational age = 31.4 weeks). Using data from a prospective longitudinal study, the present study assessed effortful control and behavior problems at 24 and 36 months and positive emotional expression at 24 months in a sample of 173 children born preterm. Less positive emotional expression was associated with higher effortful control for boys but not girls. Higher effortful control was associated with fewer total behavior problems, but this relation was attenuated when socioeconomic assets were included in the model. More socioeconomic assets were associated with fewer behavior problems for both boys and girls and higher effortful control for girls. Socioeconomic assets appear to be an important factor in the development of effortful control and behavior problems in children born preterm regardless of gender, whereas positive emotional expression was important for boys. Future intervention research should examine fostering adaptive levels of effortful control in high-risk populations as a means to facilitate resilience processes.     

Scope of attention, control of attention, and intelligence in children and adults

Recent experimentation has shown that cognitive aptitude measures are predicted by tests of the scope of an individual's attention or capacity in simple working memory tasks and also by the ability to control attention. However, these experiments do not indicate how separate or related the scope and control of attention are. An experiment with 52 children (10 to 11 years old) and 52 college students included measures of the scope and control of attention, as well as verbal and nonverbal aptitude measures. The children showed little evidence of using sophisticated attentional control, but the scope of attention predicted intelligence in that group. In adults, both the scope and control of attention varied among individuals and accounted for considerable individual variance in intelligence. About one third that variance was shared between scope an d control, and the rest was unique to one or the other.Scope and control of attention appear to be related but distinct contributors to intelligence.     

Stimulus modality and working memory performance in Greek children with reading disabilities: Additional evidence for the pictorial superiority hypothesis

This study investigated the effects of stimulus presentation modality on working memory performance in children with reading disabilities (RD) and in typically developing children (TDC), all native speakers of Greek. It was hypothesized that the visual presentation of common objects would result in improved learning and recall performance as compared to the auditory presentation of stimuli. Twenty children, ages 10–12, diagnosed with RD were matched to 20 TDC age peers. The experimental tasks implemented a multitrial verbal learning paradigm incorporating three modalities: auditory, visual, and auditory plus visual. Significant group differences were noted on language, verbal and nonverbal memory, and measures of executive abilities. A mixed-model MANOVA indicated that children with RD had a slower learning curve and recalled fewer words than TDC across experimental modalities. Both groups of participants benefited from the visual presentation of objects; however, children with RD showed the greatest gains during this condition. In conclusion, working memory for common verbal items is impaired in children with RD; however, performance can be facilitated, and learning efficiency maximized, when information is presented visually. The results provide further evidence for the pictorial superiority hypothesis and the theory that pictorial presentation of verbal stimuli is adequate for dual coding.