Minimizing sleep deprivation effects in healthy adults by differential outcomes

DigiDOP: A framework for applying digital technology to the Differential Outcomes Procedure (DOP) for cognitive interventions in persons with neurocognitive disorders

We present a framework -Digi-DOP- that includes a series of evidence-based recommendations to design and apply cognitive interventions for people with Neurocognitive Disorders (NCDs) using a relatively new approach, the Differential Outcomes Procedure (DOP). To do so, we critically review the substantial experimental research conducted with relevant clinical and non-clinical populations, and the theoretical underpinnings of this procedure. We further discuss how existing digital technologies that have been used for cognitive interventions could be applied to overcome some of the limitations of DOP-based interventions and further enhance DOP benefits. Specifically, we present three digital DOP developments that are currently being designed, investigated and/or tested. Finally, we discuss constraints, ethical and legal considerations that need to be taken into account to ensure that the use of technology in DOP-based interventions proposed here does not widen disparities and inequalities. We hope that this framework will inform and guide digital health leaders and developers, researchers and healthcare professionals to design and apply DOP-based interventions for people with NCDs.

Discriminative learning and associative memory under the differential outcomes procedure is modulated by cognitive load

Working memory (WM) has been thought to be the cause of associative memory deficits in older adults. Previous research has demonstrated the benefits of a discriminative learning procedure, the differential outcomes procedure (DOP), to ameliorate such associative-memory maintenance deficits in situations that simulate adherence to medical prescriptions in both healthy and pathological ageing. Specifically, the DOP involves rewarding each correct response to each stimulus-stimulus association with a distinct and unique outcome (reinforcer). The aim of the present study was to explore the limits of this procedure by testing the amount of cognitive load at which the DOP improves discriminative learning and associative memory in a task that simulates adherence to medical treatment in undergraduate students. During the training phase, participants were asked to learn three pill/name (low-load condition) or four pill/name associations (high-load conditions) under the DOP in comparison with a control condition (the non-differential outcomes condition, NOP). Long-term retention of such learned associations was tested 1h and 1week after completion of the training phase. Participants showed a better accuracy and long-term retention of the learned associations when the DOP was used, but just in the high-load condition. These results suggest that when WM is overtaxed, the DOP plays a fundamental role in the long-term maintenance of the learned stimulus-stimulus associations, rendering such learning procedure as a useful technique to enhance people's discriminative learning and associative memory.

Learning and Recall of Medical Treatment-Related Information in Older Adults Using the Differential Outcomes Procedure

It has recently been reported that the differential outcomes procedure (DOP) might be one of the therapeutical techniques focused at promoting autonomy in the elderly to deal with their medical issues. Molina et al. (2015) found that a group of healthy young adults improved their learning and long-term retention of six disorder/pill associations when each relationship to be learned was associated with a particular reinforcer (the differential outcomes condition) compared to when they were randomly administered (the non-differential outcomes condition). In the present study, we extend these findings to older adults who usually show difficulties to remember to take their medications as prescribed. Participants were asked to learn the association between three pills and the specific time at the day when they had to take each medication. Two memory tests were also performed 1 h and 1 week after completing the training phase. Results showed a faster learning of the task and long-term retention of the previously learned associations (pill/time of day) when differential outcomes were used. Furthermore, the older adults’ performance in the learning and memory phases did not differ from that of the younger adults in the DOP condition. These findings demonstrate that this procedure can help elderly people to ameliorate not only their learning, but also their long-term memory difficulties, suggesting the potential for the DOP to promote adherence to treatment in this population.

The Differential Outcomes Effect Using Sensory Outcomes in a Many-to-One Matching-to-Sample Task

Abstract The present study was designed to evaluate the use of sensory outcomes (visual vs. auditory) using a differential outcomes procedure to facilitate learning in a many-to-one matching-to-sample task. For one group of participants (differential outcomes) each correct stimulus-choice sequence was always followed by a different outcome; whereas for the rest of participants (non-differential outcomes) each correct sequence was followed by the same outcome. Participants trained with differential outcomes showed a faster acquisition and higher overall accuracy than participants trained with non-differential outcomes. The results provide a new extension the differential outcomes effect by using sensory outcomes and many-to-one matching to-sample task; applications of the differential outcomes procedure are discussed.

El efecto de consecuencias diferenciales: un caso de investigación traslacional

La investigación traslacional representa un esfuerzo por integrar los hallazgos derivados de la investigación básica y aproximarlos al ámbito aplicado. El presente trabajo plantea al área de investigación relativa al Efecto de Consecuencias Diferenciales (ECD) como un caso de investigación traslacional caracterizada por su contribución en el aprendizaje de discriminaciones condicionales. Se realiza una revisión que parte de algunos de los trabajos germinales con animales de laboratorio y que continúa con los primeros estudios con humanos. Posteriormente, se revisan algunos estudios que destacan el potencial de aplicación de los Procedimientos con Consecuencias Diferenciales (PCD) como herramienta para el tratamiento de personas con diversos padecimientos asociados a deficiencias en el aprendizaje y la memoria, así como su empleo en el ámbito educativo en situaciones que implican el aprendizaje de discriminaciones condicionales.

Spatial working memory is enhanced in children by differential outcomes

Working memory (WM) is essential to academic achievement. Any enhancement of WM abilities may improve children’s school performance. We tested the usefulness of the differential outcomes procedure (DOP) to enhance typically developing children’s performance on a spatial WM task. The DOP involves a conditional discriminative learning task in which a correct choice response to a specific stimulus-stimulus association is reinforced with a particular reinforcer (outcome). We adapted a spatial memory task to be used with the DOP. Participants had to learn and retain in their WM four target locations of eight possible locations where a shape could be presented. Two groups of 5- and 7-year-old children performed the low-attentional version of the spatial task, and an additional group of 7-year-old children performed the high-attentional version. The results showed that compared with the standard non-differential outcomes procedure (NOP), the DOP produced better memory-based performance in 5-year-old children with the low-attentional task and in 7-year-old children with the high-attentional task. Additionally, delay intervals impaired performance in the NOP but not in the DOP. These findings suggest that the DOP may be a useful complement to other WM intervention programs targeted to improve children´s academic performance at school.

The Differential Outcomes Procedure Enhances Adherence to Treatment: A Simulated Study with Healthy Adults

Memory for medical recommendations is a prerequisite for good adherence to treatment, and therefore to ameliorate the negative effects of the disease, a problem that mainly affects people with memory deficits. We conducted a simulated study to test the utility of a procedure (the differential outcomes procedure, DOP) that may improve adherence to treatment by increasing the patient's learning and retention of medical recommendations regarding medication. The DOP requires the structure of a conditional discriminative learning task in which correct choice responses to specific stimulus-stimulus associations are reinforced with a particular reinforcer or outcome. In two experiments, participants had to learn and retain in their memory the pills that were associated with particular disorders. To assess whether the DOP improved long-term retention of the learned disorder/pill associations, participants were asked to perform two recognition memory tests, 1 h and 1 week after completing the learning phase. The results showed that compared with the standard non-differential outcomes procedure, the DOP produced better learning and long-term retention of the previously learned associations. These findings suggest that the DOP can be used as a useful complementary technique in intervention programs targeted at increasing adherence to clinical recommendations.

The differential outcomes procedure can overcome self-bias in perceptual matching

There are biases in perceptual matching between shapes and labels referring to familiar others, compared with when the labels refer to unfamiliar people. We assessed whether these biases could be affected by differential feedback (using the differential outcomes procedure [DOP]) compared with when feedback is provided using a nondifferential outcomes procedure (NOP). Participants formed associations between simple geometric shapes and labels referring to people the participant did or did not know (self, best friend, other). Subsequently, the task was to match a label to one of two shapes shown on a trial. When feedback for correct responses was given following the NOP condition, matches were faster to known people (self and friend) compared with those to an unknown person (stranger). However, this advantage for known personal relations was eliminated when participants were given feedback for correct responses following the DOP condition. The data are consistent with prior work showing that the DOP can facilitate the learning of taxing associations (for the stranger stimuli relative to the familiar self and friend stimuli). In addition, the results suggest that the facilitated perceptual matching for stimuli associated to individuals known personally may reflect better individuation of the association between the shape stimulus and the label, a process enhanced by using a DOP for associations with unfamiliar people.

Inhibition of return, but not facilitation, disappears under vigilance decrease due to sleep deprivation

In this study, we assessed whether unspecific attention processes signaled by general reaction times (RTs), as well as specific facilitatory (validity or facilitation effect) and inhibitory (inhibition of return, IOR) effects involved in the attentional orienting network, are affected by low vigilance due to both circadian factors and sleep deprivation (SD). Eighteen male participants performed a cuing task in which peripheral cues were nonpredictive about the target location and the cue-target interval varied at three levels: 200 ms, 800 ms, and 1,100 ms. Facilitation with the shortest and IOR with the longest cue-target intervals were observed in the baseline session, thus replicating previous related studies. Under SD condition, RTs were generally slower, indicating a reduction in the participants' arousal level. The inclusion of a phasic alerting tone in several trials partially compensated for the reduction in tonic alertness, but not with the longest cue-target interval. With regard to orienting, whereas the facilitation effect due to reflexive shifts of attention was preserved with sleep loss, the IOR was not observed. These results suggest that the decrease of vigilance produced by SD affects both the compensatory effects of phasic alerting and the endogenous component involved in disengaging attention from the cued location, a requisite for the IOR effect being observed.

Visual recognition memory enhancement in children through differential outcomes

OBJECTIVE

The use of differential outcomes has been shown to enhance discriminative learning and face recognition in children and adults. In this study, we further investigated whether the differential outcome procedure (DOP) would also be effective in improving recognition memory for a wide range of stimuli with varying visual complexity (familiar objects, abstract stimuli, and complex scenes) in 5- and 7-year-old children.

METHOD

Participants viewed a sample stimulus and, after a short (5s) or a long (15s) delay, they had to identify the previously seen stimulus among four choice alternatives. In the differential outcomes condition, each sample stimulus was paired with a specific outcome; whereas in the non-differential conditions outcomes were administered randomly. In Experiment 2, we replicated Experiment 1 but in addition we asked participants to perform an articulatory suppression task to prevent verbal rehearsal.

RESULTS

Children showed a greater overall visual delayed recognition when differential outcomes were arranged in both experiments. The type of stimulus being used modulated this effect; a beneficial effect of the differential outcomes training was evident with abstract objects in Experiment 1 and with both, abstract objects and scenes in Experiment 2.

Differential outcomes training improves face recognition memory in children and in adults with Down syndrome

Previous studies have demonstrated that the differential outcomes procedure (DOP), which involves paring a unique reward with a specific stimulus, enhances discriminative learning and memory performance in several populations. The present study aimed to further investigate whether this procedure would improve face recognition memory in 5- and 7-year-old children (Experiment 1) and adults with Down syndrome (Experiment 2). In a delayed matching-to-sample task, participants had to select the previously shown face (sample stimulus) among six alternatives faces (comparison stimuli) in four different delays (1, 5, 10, or 15s). Participants were tested in two conditions: differential, where each sample stimulus was paired with a specific outcome; and non-differential outcomes, where reinforcers were administered randomly. The results showed a significantly better face recognition in the differential outcomes condition relative to the non-differential in both experiments. Implications for memory training programs and future research are discussed.

The effects of differential outcomes and different types of consequential stimuli on 7-year-old children's discriminative learning and memory

Researchers have demonstrated that discriminative learning is facilitated when a particular outcome is associated with each relation to be learned. Our primary purpose in the two experiments reported here was to assess whether the differential outcomes procedure (DOP) would enhance 7-year-old children's learning of symbolic discriminations using three different forms of consequences in which (1) reinforcers are given when correct choices are made ("+"), (2) reinforcers are withdrawn when errors are made ("-"), or (3) children receive a reinforcer following a correct choice and lose one following an incorrect choice ("+/-"), as well as different types of reinforcers (secondary and primary reinforcers, Experiment 1; primary reinforcers alone, Experiment 2). Participants learned the task faster and showed significantly better performance whenever differential outcomes were arranged independently of (1) the way of providing consequences (+, -, or +/-) and (2) the type of reinforcers being used. Interestingly, as in a previous study with 5-year-old children (Martínez, Estévez, Fuentes, & Overmier, The Quarterly Journal of Experimental Psychology 62(8):1617-1630, 2009), the use of the DOP also enhanced long-term persistence of learning.