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1.
Exp Aging Res ; 50(3): 376-399, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37009776

RESUMO

We investigated whether individuals who are good at recognizing previously presented items are also good at recognizing the context in which items were presented. We focused specifically on whether the relation between item recognition and context recognition abilities differs in younger and older adults. It has been hypothesized that context memory declines more rapidly in older adults due to an age-related deficit in associative binding or recollection. To test this hypothesis, younger and older adults were asked to remember lists of names and objects, as well as the context (i.e. their size, location, and color) that accompanied those items. Following presentation of each list, recognition tests for items and context were administered. Confirmatory factor analysis (CFA) models analyzing both item and context scores together provided no evidence of separate factors for item and context memory. Instead, the best-fitting model separated performance by item-type, regardless of context, and no differences were found in the structure of these abilities in younger and older adults. These findings are consistent with the limited previous latent variable research on context memory in aging suggesting that there is no context recognition memory ability separable from item memory in younger nor older adults. Instead, individual differences in recognition memory abilities may be specific to the domain of the studied stimulus.


Assuntos
Envelhecimento , Reconhecimento Psicológico , Humanos , Idoso , Rememoração Mental
2.
J Neurosci ; 42(3): 435-442, 2022 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-34815317

RESUMO

In everyday conversation, we usually process the talker's face as well as the sound of the talker's voice. Access to visual speech information is particularly useful when the auditory signal is degraded. Here, we used fMRI to monitor brain activity while adult humans (n = 60) were presented with visual-only, auditory-only, and audiovisual words. The audiovisual words were presented in quiet and in several signal-to-noise ratios. As expected, audiovisual speech perception recruited both auditory and visual cortex, with some evidence for increased recruitment of premotor cortex in some conditions (including in substantial background noise). We then investigated neural connectivity using psychophysiological interaction analysis with seed regions in both primary auditory cortex and primary visual cortex. Connectivity between auditory and visual cortices was stronger in audiovisual conditions than in unimodal conditions, including a wide network of regions in posterior temporal cortex and prefrontal cortex. In addition to whole-brain analyses, we also conducted a region-of-interest analysis on the left posterior superior temporal sulcus (pSTS), implicated in many previous studies of audiovisual speech perception. We found evidence for both activity and effective connectivity in pSTS for visual-only and audiovisual speech, although these were not significant in whole-brain analyses. Together, our results suggest a prominent role for cross-region synchronization in understanding both visual-only and audiovisual speech that complements activity in integrative brain regions like pSTS.SIGNIFICANCE STATEMENT In everyday conversation, we usually process the talker's face as well as the sound of the talker's voice. Access to visual speech information is particularly useful when the auditory signal is hard to understand (e.g., background noise). Prior work has suggested that specialized regions of the brain may play a critical role in integrating information from visual and auditory speech. Here, we show a complementary mechanism relying on synchronized brain activity among sensory and motor regions may also play a critical role. These findings encourage reconceptualizing audiovisual integration in the context of coordinated network activity.


Assuntos
Córtex Auditivo/fisiologia , Idioma , Leitura Labial , Rede Nervosa/fisiologia , Percepção da Fala/fisiologia , Córtex Visual/fisiologia , Percepção Visual/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Córtex Auditivo/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Córtex Visual/diagnóstico por imagem , Adulto Jovem
3.
J Cogn Neurosci ; : 1-19, 2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34232999

RESUMO

If the tendency to discount rewards reflects individuals' general level of impulsiveness, then the discounting of delayed and probabilistic rewards should be negatively correlated: The less a person is able to wait for delayed rewards, the more they should take chances on receiving probabilistic rewards. It has been suggested that damage to the ventromedial prefrontal cortex (vMPFC) increases individuals' impulsiveness, but both intertemporal choice and risky choice have only recently been assayed in the same patients with vMPFC damage. Here, we assess both delay and probability discounting in individuals with vMPFC damage (n = 8) or with medial temporal lobe (MTL) damage (n = 10), and in age- and education-matched controls (n = 30). On average, MTL-lesioned individuals discounted delayed rewards at normal rates but discounted probabilistic rewards more shallowly than controls. In contrast, vMPFC-lesioned individuals discounted delayed rewards more steeply but probabilistic rewards more shallowly than controls. These results suggest that vMPFC lesions affect the weighting of reward amount relative to delay and certainty in opposite ways. Moreover, whereas MTL-lesioned individuals and controls showed typical, nonsignificant correlations between the discounting of delayed and probabilistic rewards, vMPFC-lesioned individuals showed a significant negative correlation, as would be expected if vMPFC damage increases impulsiveness more in some patients than in others. Although these results are consistent with the hypothesis that vMPFC plays a role in impulsiveness, it is unclear how they could be explained by a single mechanism governing valuation of both delayed and probabilistic rewards.

4.
Ear Hear ; 42(6): 1656-1667, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34320527

RESUMO

OBJECTIVE: Spoken communication is better when one can see as well as hear the talker. Although age-related deficits in speech perception were observed, Tye-Murray and colleagues found that even when age-related deficits in audiovisual (AV) speech perception were observed, AV performance could be accurately predicted from auditory-only (A-only) and visual-only (V-only) performance, and that knowing individuals' ages did not increase the accuracy of prediction. This finding contradicts conventional wisdom, according to which age-related differences in AV speech perception are due to deficits in the integration of auditory and visual information, and our primary goal was to determine whether Tye-Murray et al.'s finding with a closed-set test generalizes to situations more like those in everyday life. A second goal was to test a new predictive model that has important implications for audiological assessment. DESIGN: Participants (N = 109; ages 22-93 years), previously studied by Tye-Murray et al., were administered our new, open-set Lex-List test to assess their auditory, visual, and audiovisual perception of individual words. All testing was conducted in six-talker babble (three males and three females) presented at approximately 62 dB SPL. The level of the audio for the Lex-List items, when presented, was approximately 59 dB SPL because pilot testing suggested that this signal-to-noise ratio would avoid ceiling performance under the AV condition. RESULTS: Multiple linear regression analyses revealed that A-only and V-only performance accounted for 87.9% of the variance in AV speech perception, and that the contribution of age failed to reach significance. Our new parabolic model accounted for even more (92.8%) of the variance in AV performance, and again, the contribution of age was not significant. Bayesian analyses revealed that for both linear and parabolic models, the present data were almost 10 times as likely to occur with a reduced model (without age) than with a full model (with age as a predictor). Furthermore, comparison of the two reduced models revealed that the data were more than 100 times as likely to occur with the parabolic model than with the linear regression model. CONCLUSIONS: The present results strongly support Tye-Murray et al.'s hypothesis that AV performance can be accurately predicted from unimodal performance and that knowing individuals' ages does not increase the accuracy of that prediction. Our results represent an important initial step in extending Tye-Murray et al.'s findings to situations more like those encountered in everyday communication. The accuracy with which speech perception was predicted in this study foreshadows a form of precision audiology in which determining individual strengths and weaknesses in unimodal and multimodal speech perception facilitates identification of targets for rehabilitative efforts aimed at recovering and maintaining speech perception abilities critical to the quality of an older adult's life.


Assuntos
Audiologia , Percepção da Fala , Adulto , Idoso , Idoso de 80 Anos ou mais , Teorema de Bayes , Feminino , Audição , Humanos , Masculino , Pessoa de Meia-Idade , Ruído , Percepção Visual , Adulto Jovem
5.
Exp Aging Res ; 47(3): 203-219, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33615996

RESUMO

Background: This study addresses two issues: Whether age-related differences in working memory (WM) can be studied in online samples, and whether such differences reflect an inhibitory deficit. Currently, the evidence is mixed, but the playing field was not level because traditional statistics cannot provide evidence for the null hypothesis.Experiment 1: MTurk workers (ages 19-74) performed simple and complex visuospatial WM tasks to determine whether a secondary task affected the rate of age-related decline. Performance on both tasks replicated previous laboratory studies, establishing that age-related differences in WM can be studied online. Bayesian analyses revealed it is ten times as likely that there is no inhibitory deficit on visuospatial WM tasks as that there is.Experiment 2: The effects of irrelevant location information on visuospatial WM were examined in older (Mage = 64.0) and younger (Mage = 25.0) MTurk workers. Irrelevant locations produced interference, but both groups were equally affected. Bayesian analyses provided support for the null hypothesis of no age difference.Conclusions: The results of both experiments on working memory not only revealed equivalent visuospatial inhibitory function in older and younger adults, they also demonstrated that age-related differences in visuospatial WM can be effectively studied online as well as in the laboratory.


Assuntos
Envelhecimento , Percepção Espacial , Idoso , Teorema de Bayes , Humanos , Memória de Curto Prazo , Testes Neuropsicológicos
6.
Ear Hear ; 41(3): 549-560, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31453875

RESUMO

OBJECTIVES: This study was designed to examine how speaking rate affects auditory-only, visual-only, and auditory-visual speech perception across the adult lifespan. In addition, the study examined the extent to which unimodal (auditory-only and visual-only) performance predicts auditory-visual performance across a range of speaking rates. The authors hypothesized significant Age × Rate interactions in all three modalities and that unimodal performance would account for a majority of the variance in auditory-visual speech perception for speaking rates that are both slower and faster than normal. DESIGN: Participants (N = 145), ranging in age from 22 to 92, were tested in conditions with auditory-only, visual-only, and auditory-visual presentations using a closed-set speech perception test. Five different speaking rates were presented in each modality: an unmodified (normal rate), two rates that were slower than normal, and two rates that were faster than normal. Signal to noise ratios were set individually to produce approximately 30% correct identification in the auditory-only condition and this signal to noise ratio was used in the auditory-only and auditory-visual conditions. RESULTS: Age × Rate interactions were observed for the fastest speaking rates in both the visual-only and auditory-visual conditions. Unimodal performance accounted for at least 60% of the variance in auditory-visual performance for all five speaking rates. CONCLUSIONS: The findings demonstrate that the disproportionate difficulty that older adults have with rapid speech for auditory-only presentations can also be observed with visual-only and auditory-visual presentations. Taken together, the present analyses of age and individual differences indicate a generalized age-related decline in the ability to understand speech produced at fast speaking rates. The finding that auditory-visual speech performance was almost entirely predicted by unimodal performance across all five speaking rates has important clinical implications for auditory-visual speech perception and the ability of older adults to use visual speech information to compensate for age-related hearing loss.


Assuntos
Percepção da Fala , Estimulação Acústica , Idoso , Percepção Auditiva , Humanos , Fala , Percepção Visual
7.
Psychol Rec ; 69(3): 415-424, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32095026

RESUMO

Discounting refers to decreases in the subjective value of an outcome with increases in some attribute of that outcome. The attributes most commonly studied are delay and probability, with far less research on effort and social discounting. Although these attributes all represent costs that reduce subjective value, it is as yet unclear how the extent to which they do so is related at the individual level. Accordingly, the present study examined the degree to which individual participants discounted hypothetical monetary rewards on each of four discounting tasks in which the delay, probability, effort, and number of people with whom the money was to be shared were manipulated. At the group level, larger amounts were discounted less steeply than smaller amounts when delay and effort were varied, whereas larger amounts were discounted more steeply when probability and number of people were varied. At the individual level, the correlational pattern was examined using exploratory factor analysis. A six-factor structure (with separate factors for delay and effort, and two factors each for social and probability discounting) described the relations among indifference points. At a more molar level, a two-factor structure, which corresponded to the direction of the observed magnitude effects, described the relations among area-under-the-curve measures of discounting in the eight conditions resulting from crossing two monetary amounts with the four cost factors. We conclude that despite sharing some similarities, individual and group differences in discounting involving the different types of costs reflect mostly separate processes and traits.

8.
Psychol Med ; 48(16): 2702-2709, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-29463327

RESUMO

BACKGROUND: Exposure to traumatic events is surprisingly common, yet little is known about its effect on decision making beyond the fact that those with post-traumatic stress disorder are more likely to have substance-abuse problems. We examined the effects of exposure to severe trauma on decision making in low-income, urban African Americans, a group especially likely to have had such traumatic experiences. METHOD: Participants completed three decision-making tasks that assessed the subjective value of delayed monetary rewards and payments and of probabilistic rewards. Trauma-exposed cases and controls were propensity-matched on demographic measures, treatment for psychological problems, and substance dependence. RESULTS: Trauma-exposed cases discounted the value of delayed rewards and delayed payments, but not probabilistic rewards, more steeply than controls. Surprisingly, given previous findings that suggested women are more affected by trauma when female and male participants' data were analyzed separately, only the male cases showed steeper delay discounting. Compared with nonalcoholic males who were not exposed to trauma, both severe trauma and alcohol-dependence produced significantly steeper discounting of delayed rewards. CONCLUSIONS: The current study shows that exposure to severe trauma selectively affects fundamental decision-making processes. Only males were affected, and effects were observed only on discounting delayed outcomes (i.e. intertemporal choice) and not on discounting probabilistic outcomes (i.e. risky choice). These findings are the first to show significant differences in the effects of trauma on men's and women's decision making, and the selectivity of these effects has potentially important implications for treatment and also provides clues as to underlying mechanisms.


Assuntos
Negro ou Afro-Americano , Desvalorização pelo Atraso/fisiologia , Pobreza , Trauma Psicológico/fisiopatologia , População Urbana , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Assunção de Riscos , Fatores Sexuais
9.
Memory ; 26(8): 1042-1052, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29667476

RESUMO

People can rehearse to-be-remembered locations either overtly, using eye movements, or covertly, using only shifts of spatial attention. The present study examined whether the effectiveness of these two strategies depends on environmental support for rehearsal. In Experiment 1, when environmental support (i.e., the array of possible locations) was present and participants could engage in overt rehearsal during retention intervals, longer intervals resulted in larger spans, whereas in Experiment 2, when support was present but participants could only engage in covert rehearsal, longer intervals resulted in smaller spans. When environmental support was absent, however, longer retention intervals resulted in smaller memory spans regardless of which rehearsal strategies were available. In Experiment 3, analyses of participants' eye movements revealed that the presence of support increased participants' fixations of to-be-remembered target locations more than fixations of non-targets, and that this was associated with better memory performance. Further, although the total time fixating targets increased, individual target fixations were actually briefer. Taken together, the present findings suggest that in the presence of environmental support, overt rehearsal is more effective than covert rehearsal at maintaining to-be-remembered locations in working memory, and that having more time for overt rehearsal can actually increase visuospatial memory spans.


Assuntos
Meio Ambiente , Fixação Ocular/fisiologia , Memória de Curto Prazo/fisiologia , Aprendizagem Espacial/fisiologia , Navegação Espacial/fisiologia , Adolescente , Adulto , Atenção/fisiologia , Sinais (Psicologia) , Feminino , Humanos , Masculino , Rememoração Mental/fisiologia , Retenção Psicológica/fisiologia , Software , Adulto Jovem
10.
Hippocampus ; 25(4): 432-43, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25676022

RESUMO

How does the ability to imagine detailed future experiences (i.e., episodic prospection) contribute to choices between immediate and delayed rewards? Individuals with amnesia do not show abnormally steep discounting in intertemporal choice, suggesting that neither medial temporal lobe (MTL) integrity nor episodic prospection is required for the valuation of future rewards (Kwan et al. (), Hippocampus, 22:1215-1219; Kwan et al. (2013), J Exp Psychol, 142:1355-1369 2013). However, hippocampally mediated episodic prospection in healthy adults reduces the discounting of future rewards (Peters and Büchel (2010), Neuron, 66:138-148; Benoit et al. (2011), J Neurosci, 31:6771-6779), raising the possibility that MTL damage causes more subtle impairments to this form of decision-making than noted in previous patient studies. Intertemporal choice appears normal in amnesic populations, yet they may be unable to use episodic prospection to adaptively modulate the value assigned to future rewards. To investigate how the extended hippocampal system, including the hippocampus and related MTL structures, contributes to the valuation of future rewards, we compared the performance of six amnesic cases with impaired episodic prospection to that of 20 control participants on two versions of an intertemporal choice task: a standard discounting task, and a cued version in which cues prompted them to imagine specific personal future events temporally contiguous with the receipt of delayed rewards. Amnesic individuals' intertemporal choices in the standard condition were indistinguishable from those of controls, replicating previous findings. Surprisingly, performance of the amnesic cases in the cued condition indicates that amnesia does not preclude flexible modulation of choices in response to future event cues, even in the absence of episodic prospection. Cueing the personal future to modulate decisions appears to constitute a less demanding or a qualitatively different (e.g., personal semantic) form of prospection that is not as sensitive to MTL damage as prospective narrative generation.


Assuntos
Amnésia/patologia , Comportamento de Escolha/fisiologia , Sinais (Psicologia) , Desvalorização pelo Atraso , Hipocampo/patologia , Amnésia/etiologia , Amnésia/fisiopatologia , Humanos , Processamento de Imagem Assistida por Computador , Imaginação , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Recompensa , Fatores de Tempo , Percepção do Tempo
11.
Mem Cognit ; 43(3): 357-66, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25921723

RESUMO

Although individuals with high and low working memory (WM) span appear to differ in the extent to which irrelevant information interferes with their performance on WM tasks, the locus of this interference is not clear. The present study investigated whether, when performing a WM task, high- and low-span individuals differ in the activation of formerly relevant, but now irrelevant items, and/or in their ability to correctly identify such irrelevant items. This was done in two experiments, both of which used modified complex WM span tasks. In Experiment 1, the span task included an embedded lexical decision task designed to obtain an implicit measure of the activation of both currently and formerly relevant items. In Experiment 2, the span task included an embedded recognition judgment task designed to obtain an explicit measure of both item and source recognition ability. The results of these experiments indicate that low-span individuals do not hold irrelevant information in a more active state in memory than high-span individuals, but rather that low-span individuals are significantly poorer at identifying such information as irrelevant at the time of retrieval. These results suggest that differences in the ability to monitor the source of information, rather than differences in the activation of irrelevant information, are the more important determinant of performance on WM tasks.


Assuntos
Atenção/fisiologia , Memória de Curto Prazo/fisiologia , Reconhecimento Psicológico/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
12.
Hippocampus ; 24(11): 1375-80, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24976273

RESUMO

The capacity to anticipate future experiences of regret has been hypothesized to explain otherwise irrational aspects of human decision-making, including the certainty effect (Kahneman and Tversky (1979) Econometrica 47:263-291) and the common ratio effect (Allais (1953) Econometrica 21:503-546). The anticipated regret hypothesis predicts that individuals incapable of episodically imagining their personal futures, as has been reported for people with extensive damage to medial temporal lobe structures and resulting deficits in episodic thought, should be immune to these effects. We report that K.C., who has extensive bilateral damage to his hippocampus and adjacent medial temporal lobe structures and nearly complete deficits in his ability to episodically imagine his personal future, nonetheless displays both the certainty and the common ratio effects. These results suggest that the episodic anticipation of future regret does not explain the general human tendency to display the certainty and common ratio effects.


Assuntos
Comportamento de Escolha/fisiologia , Emoções/fisiologia , Hipocampo/fisiopatologia , Imaginação/fisiologia , Pensamento/fisiologia , Idoso , Amnésia/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Lobo Temporal/fisiopatologia
13.
Mem Cognit ; 42(7): 1118-29, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24874509

RESUMO

In the present experiments, we examined the effects of environmental support on participants' ability to rehearse locations and the role of such support in the effects of secondary tasks on memory span. In Experiment 1, the duration of interitem intervals and the presence of environmental support for visuospatial rehearsal (i.e., the array of possible memory locations) during the interitem intervals were both manipulated across four tasks. When support was provided, memory spans increased as the interitem interval durations increased, consistent with the hypothesis that environmental support facilitates rehearsal. In contrast, when environmental support was not provided, spans decreased as the duration of the interitem intervals increased, consistent with the hypothesis that visuospatial memory representations decay when rehearsal is impeded. In Experiment 2, the ratio of interitem interval duration to intertrial interval duration was kept the same on all four tasks, in order to hold temporal distinctiveness constant, yet forgetting was still observed in the absence of environmental support, consistent with the decay hypothesis. In Experiment 3, the effects of impeding rehearsal were compared to the effects of verbal and visuospatial secondary processing tasks. Forgetting of locations was greater when presentation of to-be-remembered locations alternated with the performance of a secondary task than when rehearsal was impeded by the absence of environmental support. The greatest forgetting occurred when a secondary task required the processing visuospatial information, suggesting that in addition to decay, both domain-specific and domain-general effects contribute to forgetting on visuospatial working memory tasks.


Assuntos
Meio Ambiente , Memória de Curto Prazo/fisiologia , Percepção Espacial/fisiologia , Memória Espacial/fisiologia , Percepção Visual/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
14.
J Exp Anal Behav ; 122(1): 3-10, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38853291

RESUMO

The vast majority of studies on discounting have focused on simple delayed outcomes, but most everyday decisions are more complicated. The present experiment focused on one such scenario, an iconic self-control situation in which immediate gains are followed by delayed losses. The same participants were studied in all conditions to permit examination of individual differences in choice behavior using intercorrelations and factor analysis. Consistent with previous research, the hyperboloid model accurately described the form of the discounting function and discounting was not affected by the amount of the delayed loss when it was presented alone. However, replicating other studies, smaller delayed losses were discounted more steeply than larger ones when presented in combination with immediate gains. Exploratory factor analysis revealed two factors, one loading primarily on loss-only conditions and the other loading primarily on conditions involving outcomes that combined gains and losses. These results imply that there are individual differences in how one combines gains and losses and that this characteristic of individual decision making might be an important predictor of decisions in the many everyday choice situations that involve complex outcomes.


Assuntos
Desvalorização pelo Atraso , Individualidade , Humanos , Masculino , Feminino , Adulto Jovem , Recompensa , Modelos Psicológicos , Comportamento de Escolha , Análise Fatorial , Adulto , Autocontrole/psicologia
15.
Psychol Aging ; 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38647450

RESUMO

Although the authors of a recent meta-analysis concluded there were no age-related differences in the discounting of delayed rewards, they did not examine the effects of income (Seaman et al., 2022). Accordingly, the present study compared discounting by younger and older adults (Ages 35-50 and 65-80) differing in household income. Two procedures were used: the Monetary Choice Questionnaire and the Adjusting-Amount procedure. Whereas no age difference was observed between the higher income (> $80,000) age groups, a significant difference was observed between younger and older adults with lower incomes (< $50,000): The younger adults discounted more steeply than the older adults. These findings, which were observed with both discounting procedures, support our buffering hypothesis, which assumes that the scarcity associated with a lower income is a stressor that can lead to steeper discounting, but that age-related increases in emotional stability can buffer such stressors, leading to age-related differences between lower income age groups. In contrast, no age difference was observed in higher income adults who experience much less scarcity. Further support for the buffering hypothesis comes from the finding that there was no age-related difference in discounting by the lower income groups when distress was statistically controlled. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

16.
Learn Behav ; 41(2): 148-58, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22983791

RESUMO

Two experiments tested the effects of food deprivation on discounting in pigeons. An adjusting-amount procedure was used to estimate the subjective value of food at delays ranging from 1 to 24 s. Experiment 1 compared pigeons' discounting of delayed food reinforcers at 75 %-80 % and 90 %-95 % of free-feeding weight. Experiment 2 compared discounting under 1- and 23-h food deprivation. In both experiments at both deprivation levels, discounting was well described by the hyperboloid discounting function. No systematic effect of level of deprivation on degree of discounting was observed in either experiment. This finding is consistent with the view that pigeons' choices are controlled by the relative, rather than the absolute, value of reinforcers.


Assuntos
Comportamento de Escolha , Columbidae , Privação de Alimentos , Reforço Psicológico , Animais , Condicionamento Operante , Feminino , Esquema de Reforço , Fatores de Tempo
17.
Behav Processes ; 208: 104864, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37001683

RESUMO

The present study compared the two most prominent procedures for measuring delay discounting, the Adjusting-Amount procedure and the Monetary Choice Questionnaire (MCQ). Of interest was whether the two procedures measure the same construct. Results obtained from two online samples recruited using the Prolific (N = 150) and MTurk (N = 243) platforms revealed generally similar results for both procedures. Regardless of the procedure, the sample, the reward amount, and whether the discounting measure used was theoretically based (i.e., log k) or was atheoretical (i.e., area under the curve, proportion of choices of the delayed reward option), the degree of discounting on the Adjusting-Amount procedure was highly correlated with the degree of discounting on the MCQ, consistent with the hypothesis that both procedures assess the same construct.


Assuntos
Desvalorização pelo Atraso , Individualidade , Recompensa , Inquéritos e Questionários , Comportamento de Escolha
18.
Artigo em Inglês | MEDLINE | ID: mdl-36834239

RESUMO

Psychological distress reached historically high levels in 2020, but why, and why were there pronounced age differences? We address these questions using a relatively novel, multipronged approach, part narrative review and part new data analyses. We first updated previous analyses of national surveys that showed distress was increasing in the US and Australia through 2017 and then re-analyzed data from the UK, comparing periods with and without lockdowns. We also analyzed the effects of age and personality on distress in the US during the pandemic. Results showed distress levels and age differences in distress were still increasing through 2019 in the US, UK, and Australia. The effects of lockdowns in 2020 revealed the roles of social deprivation and fear of infection. Finally, age-related differences in emotional stability accounted for the observed age differences in distress. These findings reveal the limitations of analyses comparing pre-pandemic and pandemic periods without accounting for ongoing trends. They also suggest that differences in personality traits such as emotional stability modulate responses to stressors. This could explain age and individual differences in both increases and decreases in distress in response to changes in the level of stressors such as those occurring prior to and during the COVID-19 pandemic.


Assuntos
COVID-19 , Angústia Psicológica , Humanos , Pandemias , Controle de Doenças Transmissíveis , Emoções
19.
J Exp Anal Behav ; 119(1): 36-48, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36511664

RESUMO

Previous discounting research has focused on relatively simple situations (e.g., choosing between immediate and delayed gains, or between immediate and delayed losses) and the relations among amount, delay, and subjective value in such situations are now well established. Many everyday choice situations, however, are more complex, involving alternatives that combine gains and losses. In two experiments, participants discounted a monetary outcome that combined an immediate gain with a delayed loss. Consistent with the discounting framework, the value of the combination was approximately equal to the difference between the (undiscounted) value of the immediate gain and the (discounted) value of the delayed loss. More precise predictions of the relative subjective value of the delayed loss component of a combination were given by the same hyperboloid function that describes discounting in simple choice situations where outcomes only involve gains or losses, not both. As in previous studies, when the outcome was a simple one consisting of only a delayed loss, discounting was not affected by the amount of that loss. Surprisingly, however, when the loss was preceded by a gain, the degree to which the combination was discounted was affected by the amount of the loss. Notably, discounting of the delayed loss component of the combination decreased with the amount of the loss in a fashion similar to that observed with simple delayed gains, where smaller amounts are discounted more steeply than larger amounts. Choice situations involving immediate gains followed by delayed losses pose iconic self-control problems, and the present findings support the application of the discounting framework to these important everyday problems.


Assuntos
Desvalorização pelo Atraso , Recompensa , Humanos , Fatores de Tempo , Comportamento de Escolha
20.
PLoS One ; 18(10): e0292258, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37844072

RESUMO

The Monetary Choice Questionnaire (MCQ) is a widely used behavioral task that measures the rate of delay discounting (i.e., k), the degree to which a delayed reward loses its present value as a function of the time to its receipt. Both 21- and 27-item MCQs have been extensively validated and proven valuable in research. Different methods have been developed to streamline MCQ scoring. However, existing scoring methods have yet to tackle the issue of missing responses or provide clear guidance on imputing such data. Due to this lack of knowledge, the present study developed and compared three imputation approaches that leverage the MCQ's structure and prioritize ease of implementation. Additionally, their performance was compared with mode imputation. A Monte Carlo simulation was conducted to evaluate the performance of these approaches in handling various missing responses in each observation across two datasets from prior studies that employed the 21- and 27-item MCQs. One of the three approaches consistently outperformed mode imputation across all performance measures. This approach involves imputing missing values using congruent non-missing responses to the items corresponding to the same k value or introducing random responses when congruent answers are unavailable. This investigation unveils a straightforward method for imputing missing data in the MCQ while ensuring unbiased estimates. Along with the investigation, an R tool was developed for researchers to implement this strategy while streamlining the MCQ scoring process.


Assuntos
Projetos de Pesquisa , Recompensa , Interpretação Estatística de Dados , Inquéritos e Questionários , Simulação por Computador
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