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P M Smeets

Publications and source records attributed to P M Smeets.

At least 19 recordsLinked to original sources
PubMed2001

Derived stimulus--response and stimulus--stimulus relations in children and adults: assessing training order effects.

Preschool children and adults received training on three sets of successive discriminations: (1) A1-R1,A2-R2, (2) B1-R1,B2-R2, and (3) A1-R3,A2-R4. Then they received tests assessing derived stimulus-response relations (B1-R3, B2-R4) and stimulus-stimulus relations (e.g., A1-B1, A2-B2). Four training protocols were used. The protocols differed with regard to the order in which the sets were trained: Many-To-One (1-2-3), One-To-Many-1 (1-3-2), One-To-Many-2 (3-1-2), and One-To-One (3-2-1 or 2-3-1). The adults displayed class-consistent B-R and A-B performances over all conditions. The children displayed class consistent B-R performances more often in Many-To-One and One-To-Many than in One-To-One. Their A-B performances were highly consistent with the trained A-R and tested B-R performances. Present findings are consistent with the stimulus equivalence account rather than with the mediated response account.

Child Development↗
PubMed2001

A precursor to the relational evaluation procedure: searching for the contextual cues that control equivalence responding.

The precursor to the relational evaluation procedure (pREP) is a go/no-go successive discrimination procedure for examining stimulus equivalence. Previous research has shown that it does not readily produce equivalence responding unless some matching-to-sample (MTS) procedures are incorporated into the experimental sequence. Two experiments attempted to identify contextual cues that would generate equivalence responding on the pREP. Experiment 1 examined the effects of using abstract symbols or various verbal labels as response options on the pREP. Only the words same and different, when used as response options, reliably produced equivalence responding across 4 subjects. Experiment 2 examined different pretraining preparations designed to attach the functions of the words same and different to abstract symbols that could then be used as response options on the pREP. The most effective pretraining procedure involved multiple-exemplar training during which subjects were trained to respond to abstract symbols in the presence of pairs of stimuli that were either formally the same or different. The abstract symbols were subsequently used as response options with the pREP, and all subjects reliably demonstrated equivalence responding. The findings suggest that the relations of same and different may be fundamental to equivalence responding. These findings are discussed in terms of what they suggest about the nature of the equivalence phenomenon specifically and derived relational responding more generally.

Adult↗
PubMed2000

Assessing the necessity of hospital stay by means of the appropriateness evaluation protocol: how strong is the evidence to proceed?

OBJECTIVE: To review the Appropriateness Evaluation Protocol (AEP) with respect to assessing the necessity of hospital stay at the University Hospital of Maastricht. DESIGN: Literature search in Medline focusing on the validity, reliability and possibilities for intervention plus a description and the first results of pilot studies with a Dutch version of the Adult-Medical AEP (days of stay). SETTING: The University Hospital of Maastricht, a 700-bed university and regional hospital in the south of The Netherlands. MAIN OUTCOME MEASURES: Face, content, and convergent validity, and reliability in terms of overall or specific agreement and by kappa, of the Adult-Medical AEP when used by physicians and nurses. RESULTS: In comparison with other instruments, a comparatively good performance by the AEP has been reported in the literature. Literature review revealed limitations in the AEP as a general and truly valid and reliable instrument for assessing the necessity of hospital stay. In applying a Dutch version (azM-AEP) similar difficulties were encountered. CONCLUSION: Based on the literature review and our own findings, we conclude that the validity and reliability of the different versions of the AEP are not yet up to standard. Regarding the results of the interventions thus far, we do not encourage further use until additional improvements to both the instrument and the review conditions have been made. Perhaps a more disease-specific modulation and assessments based on computerized medical records could improve its applicability in clinical practice in general.

Adult↗
PubMed2000

Derived relational responding as generalized operant behavior.

The major aim of the present study was to demonstrate that derived relational responding may be viewed as a form of generalized operant behavior. In Experiment 1, 4 subjects were divided into two conditions (2 in each condition). Using a two-comparison matching-to-sample procedure, all subjects were trained and tested for the formation of two combinatorially entailed relations. Subjects were trained and tested across multiple stimulus sets. Each set was composed of novel stimuli. Both Conditions 1 and 2 involved explicit performance-contingent feedback presented at the end of each block of test trials (i.e., delayed feedback). In Condition 1, feedback was accurate (consistent with the experimenter-designated relations) following exposure to the initial stimulus sets. When subjects' responding reached a predefined mastery criterion, the feedback then switched to inaccurate (not consistent with the experimenter-designated relations) until responding once again reached a predefined criterion. Condition 2 was similar to Condition 1, except that exposure to the initial stimulus sets was followed by inaccurate feedback and once the criterion was reached feedback switched to accurate. Once relational responding emerged and stabilized, response patterns on novel stimulus sets were controlled by the feedback delivered for previous stimulus sets. Experiment 2 replicated Experiment 1, except that during Conditions 3 and 4 four comparison stimuli were employed during training and testing. Experiment 3 was similar to Condition 1 of Experiment 1, except that after the mastery criterion was reached for class-consistent responding, feedback alternated from accurate to inaccurate across each successive stimulus set. Experiment 4 involved two types of feedback, one type following tests for mutual entailment and the other type following tests for combinatorial entailment. Results from this experiment demonstrated that mutual and combinatorial entailment may be controlled independently by accurate and inaccurate feedback. Overall, the data support the suggestion, made by relational frame theory, that derived relational responding is a form of generalized operant behavior.

Adolescent↗
PubMed1999

Prospective study of home morphine infusion in 62 terminally ill patients.

The project "Infusion Therapy at Home" studied the practice of parenteral infusion therapy at home. Among the treatment modalities was the administration of morphine infusions to terminally ill patients. With infusion of morphine, patients were pain-free on 73% of the treatment days. Quality of care, quality of life, and costs were acceptable.

Adolescent↗
PubMed1997

Emergent conditional discriminations in children and adults: stimulus equivalence derived from simple discriminations.

This study examines whether trained and derived simple discriminations lead to conditional relations between discriminative stimuli of the same and opposite (S+, S-) functions. After being trained on an arbitrary X-Y task (X1-Y1, X2-Y2) and on two simple discrimination tasks (A1+/A2- and B1+/B2-), children (Experiment 1) and adults (Experiment 2) were tested on the formation of novel simple discriminations (A3+/A2- and B3+/B2-) and conditional stimulus relations between all directly and indirectly paired A stimuli and between all directly and indirectly paired B stimuli (A1-A2-A3, B1-B2-B3). Subjects who formed these sets also received A2-X1 and B1-X2 training followed by a series of probes to assess the formation of two five-member stimulus equivalence classes (A1-A2-A3-X1-Y1, B1-B2-B3-X2-Y2). A modest majority of the children matched the directly paired stimuli (A2-A1, B2-B1 and A1-A2, B1-B2; A2-A3, B2-B3 and A3-A2, B3-B2) with one another while only a few of them also matched the indirectly paired stimuli with one another (A1-A3, B1-B3 and A3-A1, B3-B1). Those who did also related all the A and B stimuli with the designated X and Y stimuli. By contrast, all normal adults matched all paired and conditionally linked stimuli with one another. Present findings and those of related studies on stimulus equivalence are discussed from a stimulus contiguity perspective.

Age Factors↗
PubMed1997

Functional equivalence in children: derived stimulus-response and stimulus-stimulus relations.

The present study investigated the simultaneous occurrence of emergent stimulus-response relations (functional equivalence) and stimulus-stimulus relations (stimulus equivalence). After being pretrained and tested on two symbolic match-to-sample tasks (X1-Y1, X2-Y2), 20 4- and 5-year-old children were trained to emit specified responses to pairs of stimuli (A1-R1, B1-R1, A2-R2, B2-R2) in one setting (original training) and to emit other responses to one member of each pair (A1-R3, A2-R4) in another setting (reassignment training). Of the 18 children who responded correctly on all trained tasks, 15 emitted the novel responses also in the presence of the nonreassigned stimuli (B1-R3, B2-R4). Eleven of these children also matched same-class stimuli with one another (A1-B1, A2-B2, and vice versa). Additional tests with four of these children documented the formation of conditional response-stimulus relations (R3-B1, R4-B2) in all four children, and of conditional response-response relations (R1-R3, R2-R4, and vice versa) in two of them. Children who did not show stimulus control transfer also failed to match same-class stimuli with one another. Present findings, together with those obtained in animal research, suggest that functional equivalence can imply but does not require stimulus equivalence.

Child, Preschool↗
PubMed1996

Emergent simple discriminations and conditional relations in children, intellectually impaired adults, and normal adults.

Previous research has shown that when, under non-reinforced conditions, stimuli are added to S+ and S- stimuli in simultaneous discrimination tasks, transfer between paired stimuli is likely to occur. The present study examined whether this procedure also leads to the formation of conditional relations between paired stimuli. In Experiments 1, 2, and 3, normal pre-school children were trained on a simultaneous discrimination task with A1 reinforced and A2 not reinforced (A1+/A2-). Then they received two tests (no programmed consequences): one with B stimuli superimposed on the A stimuli (A1B1/ A2B2), and one with B stimuli only (B1/B2). Subjects who selected A1B1 and B1 also received conditional discrimination tests: one with B1 or B2 as samples and A1 and A2 as comparisons (B-A), and one in which the functions of these stimuli were reversed (A-B). Intellectually impaired adults and normal adults served in Experiments 4 and 5, respectively. These experiments were basically the same except that the subjects were also given the opportunity to demonstrate transfer from B to C via BC (B1C1/B2C2 and C1/C2 tests). Most children (75%) and intellectually impaired adults (75%) treated the conditional discrimination probe tasks as simple discriminations and typically selected the trained and derived S+ stimuli. The remaining children, intellectually impaired adults, and all normal adults related all directly and indirectly linked stimuli of the same functions conditionally to one another (A-B, B-C, A-C, and vice versa). The present findings suggest that, as humans develop, conditional stimulus relations may emerge from tasks and stimulus configurations that are increasingly remote from traditional conditional discrimination tasks.

Adult↗
PubMed1994

Stability of emergent simple discriminations in young children.

This study compared two procedures for establishing and reversing stimulus control transfer across simple discriminations in children. One procedure, stimulus contiguity, started with training of a color discrimination task, red omega (S+) vs yellow omega (S-). This task was followed by two nonreinforced tests, one with colored forms, red lambda and yellow pi; and one with black forms, lambda and pi. Children who selected the lambda on both tests received a reversal task. Two types of reversals were used: one in which the contingencies for red and yellow were reversed (Reversal 1) and one in which the forms were presented with opposite colors, yellow lambda and red pi (Reversal 2). The second procedure, match-to-sample training, was the same except that the colors and forms were conditionally related to one another. The results showed that (a) both procedures were more effective in establishing than in reversing stimulus control transfer, (b) Stimulus Contiguity was more effective than match-to-sample training, and (c) both procedures were more effective in changing the form discrimination with Reversal 1 than with Reversal 2.

Child↗
PubMed1994

A revised blocked-trial procedure for establishing arbitrary matching in children.

The present study evaluated a modified blocked-trial procedure in the learning of arbitrary matching tasks (A1-B1, A2-B2) by children. The procedure consisted of five steps. In Step 1, the comparisons (B1 and B2) were presented simultaneously with the samples (A1 and A2). The comparisons were presented at fixed locations (B1 left and B2 right), and the samples, A1 and A2, were randomly presented in successive trials. Subjects were reinforced for placing A1 on B1 and A2 on B2. Step 2 was the same except that the locations of B1 and B2 were reversed. Step 3 was the same as Steps 1 and 2 but with reversed B1-B2 locations after every fourth trial. Step 4 was the same as Step 3 except that the B1-B2 locations randomly changed over trials. Step 5 was the same as Step 4 except that subjects were required to point to the B stimuli. The procedure was highly effective--far more so than the traditional blocked-trial procedure.

Child↗
PubMed1993

Emergent simple discrimination in children: preference for non-preferred stimuli.

Previous research (Smeets, 1991) suggested that when given a new discrimination, children respond on the basis of physical similarity with previously discriminated stimuli. They respond to a stimulus similar to another preferred stimulus (S+ transfer) and respond away from a stimulus similar to another nonpreferred stimulus (S- transfer). When both types of transfer apply to the same stimulus (S+ transfer prevails, S+ Priority Transfer (S+PT). The present study demonstrated that S+PT also occurs when the criterion task consists of two nonpreferred stimuli. When given a choice between two previously nonpreferred stimuli, one similar and one dissimilar to other preferred stimuli, children select the first one. They do not so, however, when a nonpreferred stimulus resembling another preferred stimulus is presented with a new nonpreferred stimulus. These findings suggest that the children's preferences were not based on the physical resemblance with other (non)preferred stimuli but on the functions (S+, S-, S0) of individual stimulus components. A theoretical model is presented that accounts for all experimental data reported in the previous and present study. The model implies that discriminative responding not only results from but also determines the functional properties of individual stimulus elements.

Child↗
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↗