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Biomedical subjects

P M Smeets

Publications and source records attributed to P M Smeets.

At least 19 recordsLinked to original sources
PubMed1991

Establishing mirror-image discriminations with progressively delayed extra-stimulus prompts.

Progressively delayed extra-stimulus prompts were used to help normal preschool children discriminate left-right mirror-image stimuli. Two issues were addressed, the attention guiding properties of the prompts and the necessity for their gradual elimination. The study consisted of four experiments in which one or multiple prompt conditions were used. Each condition involved three prompts: a reference prompt for indicating the S+ and two superimposed prompts, one on the S+, and one on the S-. The prompts required subjects to respond to the orientation of the S+ (Orientation condition) or to the location of the reference prompt (Location condition); or allowed them to respond to the discriminative shapes of the superimposed prompts (Shape condition). The results showed the following. First, most subjects rapidly learned to respond to the Orientation prompts. Second, delayed orientation prompting was always successful regardless of how the prompts were eliminated. Delay training was never successful in either of the other two conditions. Third, the Orientation condition did not reliably produce learning unless the delayed prompting procedure was used.

Attention↗
PubMed1991

Emergent simple discrimination in children: transfer of stimulus control under non-reinforced conditions.

Previous research on humans suggests that simple discriminations may emerge if both stimuli, B1 and B2, are compounded with the stimuli of a previously trained discrimination, A1 (S+) and A2 (S-), and responding to the compounds, B1A1 and B2A2, is reinforced. Two questions were addressed. First, do simple discriminations also emerge if (a) only one stimulus, B1, is compounded with a training stimulus, A1 (S+) or A2 (S-); or with both training stimuli, A1 (S+) and A2 (S-); and (b) neither B1 nor B2 is compounded with the training stimuli? Second, do simple discriminations emerge if reinforcement in the presence of the AB compounds is withheld? Normal preschool children served as subjects. The study consisted of six experiments. Transfer occurred in all experiments regardless of whether both test stimuli, one test stimulus, or none of the test stimuli were compounded with the training stimuli under non-reinforced conditions. The results can be described by the following rules: Respond to any stimulus that includes a component of a "correct" stimulus of a previous discrimination. Otherwise, respond away from the stimulus that incorporates a component from an "incorrect" stimulus of a previous discrimination. The implications of data for sensory pre-conditioning and language-based accounts are discussed.

Attention↗
PubMed1990

Discrimination training of mirror-image stimuli with a delayed-prompt technique: some critical dimensions of extra-stimulus prompts.

Research on fading and delay procedures has shown that extra-stimulus prompts frequently fail to help children learn difficult discriminations. The present study analyzed two delay conditions for an extra-stimulus prompt to help preschoolers discriminate mirror-image stimuli as a function of the configurations and locations of the prompts. All subjects were selected on their ability to discriminate the task stimuli in the presence of a third stimulus, a replica of the S+ and an arrow pointing to that stimulus; and on their inability to do so without these stimuli. Experiments 1 and 2 compared these prompt configurations (S+ replica, arrow) when presented equidistant from the task stimuli. Experiment 3 analyzed the contribution of the replica configuration in terms of its location, in between stimuli or immediately above the S+. Experiment 4 investigated the extent to which the results of the previous experiments could be influenced by the methodology for the assessment of prompt control. The results consistently demonstrated that most subjects did not learn the task unless the extra-stimulus prompt had the same configuration as the S+ and was located equidistant from both task stimuli.

Attention↗
PubMed1990

Time-delay discrimination training: replication with different stimuli and different populations.

Two time-delay conditions for teaching complex visual discriminations to normal preschoolers and children with mild and moderate intellectual handicaps were compared. One condition involved spatially separating the distinctive components from the redundant parts of both stimuli (multiple dynamic distinctive-feature prompts). The other condition involved adding a colored field to the correct stimulus (single static nondistinctive-feature prompt). The effect of the latter condition was assessed with unlearned and learned tasks. The study consisted of four experiments. In one experiment, children were also required to use the prompts for self-monitoring responses given before prompting had occurred. The results indicated that for all populations and stimuli (a) time delay of multiple dynamic distinctive-feature prompts consistently produced learning, and (b) time delay of the single static nondistinctive-feature prompt almost never produced learning and frequently led to a complete loss of discriminative performance on previously learned tasks. The resistance to disruption was a function of the training history (i.e., with or without time delay) and IQ level. Self-monitoring increased the efficacy of time delay when multiple dynamic distinctive-feature prompts were used but not when the single static nondistinctive-feature prompt was used.

Adolescent↗
PubMed1989

Teaching moderately mentally retarded children basic reading skills.

The present study assessed the efficacy of a program for teaching moderately mentally retarded children basic reading skills. Central to the program were the use of a phonemic alphabet as well as the application of pictorial cueing and stimulus manipulation techniques. The program consisted of six phases. It started with the training of graphemes for vowels (Phase 1) and ended with the training of two-syllable words (Phase 6). Four moderately mentally retarded students participated. Given time constraints, not all subjects completed all phases of the program. The training ended with the reading of one-syllable three letter words for one subject, one-syllable four letter words for two subjects, and two-syllable words for one subject. Subsequent generalization tests revealed that all subjects were capable of reading untrained words of the same complexity as those previously trained; and to read and, to a lesser extent, understand simple sentences. The execution of the program required an average training time of 35 hours per subject. Aspects pertaining to the validity of the program, the efficacy of the procedures, and the relevance of the learned skills are discussed.

Adolescent↗
PubMed1989

Establishing sound blending in moderately mentally retarded children: implications of verbal instruction and pictorial prompting.

The present study evaluated a program for establishing blending of consonants (C) and vowel-consonant (VC) syllables in moderately mentally retarded children. The study consisted of two experiments. Experiment 1 assessed whether the subjects' failure to blend was due to the task requirements per se, or to the inadequacy of the instructional terminology ("Say together"). Experiment 2 evaluated the implications of using pictorial prompts in the acquisition and generalization of C-VC blending. The data revealed that (a) adequate verbal instruction had a modest but significant effect on the subjects' blending performance (Experiment 1), and (b) training without pictorial prompts resulted in better blending of trained and untrained C-VC items than training with pictorial prompts (Experiment 2).

Adolescent↗
PubMed1989

A classical conditioning procedure for the hearing assessment of multiply handicapped persons.

The present study evaluated the viability of a classical conditioning procedure with an air puff as unconditioned stimulus for the hearing assessment of multiply handicapped children and adolescents. All subjects were also exposed to operant conditioning, which consisted of a modified visual reinforcement audiometry (VRA) procedure or involved edible reinforcement contingent on a reaching response (for blind subjects). The findings indicate that the classical conditioning procedure was successful with 21 of the 23 subjects, whereas operant conditioning succeeded with 15 of the subjects. Thresholds obtained with classical conditioning were mostly equal to or within 10 dB of those obtained with operant conditioning and also matched previously available hearing estimates. These findings seem to suggest that the classical procedure can be a useful behavioral alternative for audiological assessment.

Adolescent↗
PubMed1988

Time-delay discrimination training with impulsive children: self-monitoring nonwait responses and the dimensions of prompts.

This study investigated whether in time-delay discrimination training, the performance of impulsive children can be improved by requiring self-monitoring of the correctness of nonwait responses, and to what extent these improvements are a function of the dimensions of the prompts. Four experiments, in each of which multiple prompts were used, one for each stimulus (S+, S-), were done. Comparisons between time delay of distinctive- and nondistinctive-feature prompts, with and without self-monitoring, were made across and within subjects. Time delay of distinctive-feature prompts without self-monitoring did not produce learning. The added requirement of self-monitoring nonwait responses led to a dramatic improvement in performance, but only when distinctive-feature cues were used for prompting and self-monitoring.

Behavior Therapy↗
PubMed1987

Stimulus manipulation versus delayed feedback for teaching missing minuend problems to difficult-to-teach students.

The present study evaluated two procedures, Stimulus Manipulation and Delay Feedback Only, for teaching difficult-to-teach students to solve missing minuend problems (i.e., missing number problems starting with a minus sign). The Stimulus Manipulation procedure was directed at establishing the target skill with a minimum of errors. The training consisted of three phases of several steps each. The first phase was designed to establish a nonnumerical response to a prompt, the shape of which was gradually transformed into the final discriminative stimulus. The second phase was designed to extend the control of this stimulus to the numerical operations and to eliminate all supplementary stimuli. The third phase gradually eliminated the originally trained nonnumerical responses. The Delayed Feedback Only procedure included no stimulus manipulation and consisted of the experimenter giving only delayed right.wrong feedback on the solutions. The data indicate that both procedures resulted in all (N = 4) subjects (a) learning to solve the target problems, (b) generalizing this skill to similar, more advanced problems, and (c) maintaining it over multiple intervals of several consecutive weeks. However, systematic differences in error rate and long-term retention across training methods were observed, favoring the Stimulus Manipulation procedure.

Adolescent↗
PubMed1987

Introducing EMR children to arithmetical operations: a program involving pictorial problems and distinctive-feature prompts.

This study assessed a program involving distinctive-feature prompts for teaching four EMR children to use the appropriate arithmetical operations (addition, subtraction, multiplication, and division) in the presence of multicomponent pictorial problems. The prompts highlighted critical features of the problems and cued the operations implied. The operations were computed by means of pocket calculators adapted to the response requirements. Training was carried out according to a modified multiple-probe design. Data indicate that the program was effective in establishing the use of operations with all subjects. This behavior was also displayed on problems portraying actions not included in training. The findings are discussed in terms of distinctive-feature prompting, orienting responses, and self-cueing. Attention is given to the generalization of responding across problems, and to educational implications of the program.

Child↗
PubMed1985

Hearing assessment in developmentally impaired infants: classical conditioning as a supplement to brainstem-evoked response audiometry (BERA).

The brainstem-evoked response audiometry (BERA) is probably the most common approach to hearing assessment in high-risk and developmentally handicapped infants. It is usually suggested, however, that BERA should not be the sole assessment method. In an attempt to determine an effective supplement to BERA, the present study evaluated a classical conditioning procedure with developmentally impaired babies. Within this procedure, different tones served as conditioned stimuli while an air-puff was used as the unconditioned stimulus. Results indicate that this procedure could be successfully applied with almost all of the babies.

Audiometry, Evoked Response↗
PubMed1985

Teaching mentally retarded children to use an experimental device for telling time and meeting appointments.

This study evaluated a program for teaching mentally retarded children to use an experimental clock-agenda combination (CAC). The CAC was designed to serve as a prosthetic device for children with minimal numerical skills and time concepts to (a) tell time to the nearest 5-minute interval, and (b) meet scheduled appointments. The target skills were trained in two phases, each of which consisted of two or more steps and substeps. A modified multiple-probe technique was used for each phase. Three mildly mentally retarded children and one moderately retarded child served as subjects. The data indicated that all subjects acquired both skills in 5 to 10 hours.

Child↗
PubMed1985

Shaping self-initiated toileting in infants.

We evaluated a method for training infants to cue their mothers on the need to eliminate. The program consisted of three phases: Phase I was directed at establishing a close temporal relationship between body signals (straining) and subsequent defecations on the potty; Phase II was designed to establish a relationship between prompted and unprompted potty reaching/grabbing responses and eliminations (defecations and urinations) on the potty; and Phase III served to establish unprompted potty reaching/grabbing responses as reliable precursors of eliminations. Four babies, between 3.1 and 6.6 months old, all completed the training before age 1 year, with no negative side effects.

Behavior Therapy↗
PubMed1979

Teaching toothbrushing behavior in severely retarded adults: systematic reduction of feedback and duration training.

Eight severely retarded adults were trained to brush their teeth. Component behaviours were trained in a predetermined sequence of 15 steps. Training included scheduled opportunities for independence performance, instruction, modelling and partial and total physical guidance. Four types of feedback were used, i.e., verbal praise plus explicit head nodding, explicit nodding, inconspicous nodding and no feedback. Stepwise reduction of feedback was made contingent on a subject's repeated performance of each individual step. Five of the eight subjects learned to perform all 15 steps for three consecutive sessions. A different procedure for fading out feedback was used for the other three subjects, two of which learned to perform 14 steps reliably. Acquisition training was followed by procedures to establish persistance of criterion performances for an interval of eight days. Training procedures were based on interval shaping. All seven subjects learned to demonstrate the 14 or 15 component behaviours after an interval of eight to 17 days in which no systematic training occured.

Adult↗
PubMed1976

Acquisition and cross modal generalization of receptive and expressive signing skills in a retarded deaf girl.

A transfer of stimulus control procedure was used to teach a retarded deaf girl manual signing skills. Eight manual signs were trained in the receptive modality; eight others in the expressive modality. Acquisition of receptive and expressive signing skills occurred for most signs after they had been trained in multiple baseline order. There was a marked difference in cross modal generalisation between each of the trained signing modalities. With some exception training of receptive sign discrimination had little effect on the expressive usage of these signs. In contrast, training in the expressive usage resulted in a near perfect acquisition of receptive sign discrimination.

Adolescent↗