Modeling the effect of reward amount on probability discounting

The present study with college students examined the effect of amount on the discounting of probabilistic monetary rewards. A hyperboloid function accurately described the discounting of hypothetical rewards ranging in amount from $20 to $10,000,000. The degree of discounting increased continuously with amount of probabilistic reward. This effect of amount was not due to changes in the rate parameter of the discounting function, but rather was due to increases in the exponent. These results stand in contrast to those observed with the discounting of delayed monetary rewards, in which the degree of discounting decreases with reward amount due to amount-dependent decreases in the rate parameter. Taken together, this pattern of results suggests that delay and probability discounting reflect different underlying mechanisms. That is, the fact that the exponent in the delay discounting function is independent of amount is consistent with a psychophysical scaling interpretation, whereas the finding that the exponent of the probability-discounting function is amount-dependent is inconsistent with such an interpretation. Instead, the present results are consistent with the idea that the probability-discounting function is itself the product of a value function and a weighting function. This idea was first suggested by Kahneman and Tversky (1979), although their prospect theory does not predict amount effects like those observed. The effect of amount on probability discounting was parsimoniously incorporated into our hyperboloid discounting function by assuming that the exponent was proportional to the amount raised to a power. The amount-dependent exponent of the probability-discounting function may be viewed as reflecting the effect of amount on the weighting of the probability with which the reward will be received.     

Auditory-phonetic projection and lexical structure in the recognition of sine-wave words

Speech remains intelligible despite the elimination of canonical acoustic correlates of phonemes from the spectrum. A portion of this perceptual flexibility can be attributed to modulation sensitivity in the auditory-to-phonetic projection, although signal-independent properties of lexical neighborhoods also affect intelligibility in utterances composed of words. Three tests were conducted to estimate the effects of exposure to natural and sine-wave samples of speech in this kind of perceptual versatility. First, sine-wave versions of the easy and hard word sets were created, modeled on the speech samples of a single talker. The performance difference in recognition of easy and hard words was used to index the perceptual reliance on signal-independent properties of lexical contrasts. Second, several kinds of exposure produced familiarity with an aspect of sine-wave speech: (a) sine-wave sentences modeled on the same talker; (b) sine-wave sentences modeled on a different talker, to create familiarity with a sine-wave carrier; and (c) natural sentences spoken by the same talker, to create familiarity with the idiolect expressed in the sine-wave words. Recognition performance with both easy and hard sine-wave words improved after exposure only to sine-wave sentences modeled on the same talker. Third, a control test showed that signal-independent uncertainty is a plausible cause of differences in recognition of easy and hard sine-wave words. The conditions of beneficial exposure reveal the specificity of attention underlying versatility in speech perception.     

The Patient–Doctor Relationship Questionnaire (PDRQ-9) in Primary Care: A Validity Study

This study assessed the validity of the Patient–Doctor Relationship Questionnaire-9 (PDRQ-9) in a primary care sample (N = 180). Convergent validity was assessed through a correlation between the patient-rated PDRQ-9 and the physician-rated Difficult Doctor Patient Relationship Questionnaire-10 (DDPRQ-10). Discriminant validity was assessed through correlations between the PDRQ-9 and patient age, patient- and physician-reported health and psychological distress. To determine if the PDRQ-9 could discriminate between groups, patient PDRQ-9 ratings were compared between patients who were treated by faculty physicians versus those who were treated by residents. An exploratory factor analysis confirmed that the PDRQ-9 was made up of a single factor. The PDRQ-9 scale was internally consistent (α = .96) and significantly and negatively correlated with the DDPRQ-10 (r = ?.22, p = .003) and was not significantly correlated with patient age, health, or psychological distress. PDRQ-9 ratings were statistically greater in patients who were treated by faculty physicians than those who were treated by residents (p = .01). This study provides additional support for the reliability and validity of the PDRQ-9 as a measure of the doctor–patient relationship in a primary care sample.     

Spirituality in Occupational Therapy: Do We Practice What We Teach?

This mixed-method study examined the responses of 97 occupational therapists on the subject of spirituality in occupational therapy practice. The inclusion of spirituality into the Occupational Therapy Practice Framework (2008) implies that clinicians address spirituality as a component of client-centered practice. This research revealed a gap between education, theory, and practice as evidenced in the quantitative and qualitative data. Although occupational therapy is intended to be holistic, therapists require a more complete understanding of what spirituality is and what the role of the occupational therapist is when addressing spirituality in evaluation or treatment. The discussion of this research provides information for future occupational therapy educators and educational programs as they seek to incorporate the construct of spirituality into curricula.     

Differential components of reactivity and attentional control predicting externalizing behavior

The present study examined the contribution of early reactivity and regulation on externalizing behavior in preadolescence. Moreover, subcomponents of attentional control (i.e., attention shifting and attention focusing) and negative reactivity (i.e., sadness and anger) were examined individually to test whether a specific combination of factors uniquely contributed to the outcome. A subset of data were utilized from the ongoing, longitudinal RIGHT Track project (N = 404), in which parents reported on individual factors at age 4 and teachers reported on externalizing behavior at age 10. A hierarchical linear regression analysis revealed a significant interaction between anger reactivity and attention shifting when controlling for early externalizing behavior, where children with high levels of anger and low levels of attention shifting experienced the greatest increase in externalizing behavior over time. An increased focus on specificity is needed in research on the interplay between reactivity and regulation in the prediction of externalizing behavior.     

Autonomy Support and Structure Enhance Children's Memory and Motivation to Reminisce: A Parental Training Study

Thirty parents observed their preschoolers (M _age = 4;2) experience a standardized laboratory event and discussed the event with their child later that day. Children's memory for this event was subsequently tested at two delay intervals. Prior to the laboratory event, parents were randomly assigned to receive either autonomy-support training (Condition A) or elaborative-structure training (Condition B); training followed the event. Autonomy support-trained parents became more autonomy-supportive following the training; structure-trained parents became more structurally elaborative. Short-term experimenter–child memory interviews took place 2 weeks after the laboratory event; children of autonomy support-trained parents appeared more engaged in this memory interview, while children of structure-trained parents provided more recall and more thematically coherent memory narratives. Long-term experimenter–child interviews took place 8 months after the laboratory event; children of autonomy support-trained parents provided more information in the directed phase of this interview and appeared more engaged in the interview. The effects of high parental autonomy support and high elaborative structure for children's memory and motivation to reminisce are discussed.     

Frontotemporal neural systems supporting semantic processing in Alzheimer’s disease

We hypothesized that semantic memory for object concepts involves both representations of visual feature knowledge in modality-specific association cortex and heteromodal regions that are important for integrating and organizing this semantic knowledge so that it can be used in a flexible, contextually appropriate manner. We examined this hypothesis in an fMRI study of mild Alzheimer’s disease (AD). Participants were presented with pairs of printed words and asked whether the words matched on a given visual–perceptual feature (e.g., guitar, violin: SHAPE). The stimuli probed natural kinds and manufactured objects, and the judgments involved shape or color. We found activation of bilateral ventral temporal cortex and left dorsolateral prefrontal cortex during semantic judgments, with AD patients showing less activation of these regions than healthy seniors. Moreover, AD patients showed less ventral temporal activation than did healthy seniors for manufactured objects, but not for natural kinds. We also used diffusion-weighted MRI of white matter to examine fractional anisotropy (FA). Patients with AD showed significantly reduced FA in the superior longitudinal fasciculus and inferior frontal-occipital fasciculus, which carry projections linking temporal and frontal regions of this semantic network. Our results are consistent with the hypothesis that semantic memory is supported in part by a large-scale neural network involving modality-specific association cortex, heteromodal association cortex, and projections between these regions. The semantic deficit in AD thus arises from gray matter disease that affects the representation of feature knowledge and processing its content, as well as white matter disease that interrupts the integrated functioning of this large-scale network.