Notes on discounting

In general, if a variable can be expressed as a function of its own maximum value, that function may be called a discount function. Delay discounting and probability discounting are commonly studied in psychology, but memory, matching, and economic utility also may be viewed as discounting processes. When they are so viewed, the discount function obtained is hyperbolic in form. In some cases the effective discounting variable is proportional to the physical variable on which it is based. For example, in delay discounting, the physical variable, delay (D), may enter into the hyperbolic equation as kD. In many cases, however, the discounting data are not well described with a single-parameter discount function. A much better fit is obtained when the effective variable is a power function of the physical variable (kDS in the case of delay discounting). This power-function form fits the data of delay, probability, and memory discounting as well as other two-parameter discount functions and is consistent with both the generalized matching law and maximization of a constant-elasticity-of-substitution utility     

Rate, Probability and Matching: Comments on ��The Identities Hidden in the Matching Laws, and Their Uses�� by David Thorne

David Thorne's (2010) article, “The Identities Hidden In The Matching Laws, And Their Uses” performs a valuable service in pointing out alternative expressions of matching. However, some identities tend to obscure rather than illuminate empirical relationships. Three such problematic instances are discussed: interresponse time as a function of interval and ratio schedule parameters; probability equality as implying rate matching; the apparent simplicity of probabilistic functions, as opposed to response rate functions, of reinforcement rate.     

当前阅读研究中眼动指标述评

文章重点介绍了阅读研究中常用的眼动指标,它们包括注视时间、眼跳、回视和瞳孔直径等,从字和区域这两个方面探讨了这些眼动指标所反映的认知加工过程,以及选择这些指标时应该注意的问题。最后对眼动指标的选择和使用等问题提出了几点看法。     

Imprecise Epistemic Values and Imprecise Credences

A number of recent arguments purport to show that imprecise credences are incompatible with accuracy-first epistemology. If correct, this conclusion suggests a conflict between evidential and alethic epistemic norms. In the first part of the paper, I claim that these arguments fail if we understand imprecise credences as indeterminate credences. In the second part, I explore why agents with entirely alethic epistemic values can end up in an indeterminate credal state. Following William James, I argue that there are many distinct alethic values that a rational agent can have. Furthermore, such an agent is rationally permitted not to have settled on one fully precise value function. This indeterminacy in value will sometimes result in indeterminacy in epistemic behaviour—that is, because the agent’s values aren’t settled, what she believes might not be.     

Coding Counsellor Behaviour in Motivational Interviewing Sessions: Inter‐Rater Reliability for the Swedish Motivational Interviewing Treatment Integrity Code (MITI)

The aim of this study was to evaluate inter‐rater reliability when using the Swedish version of the Motivational Interviewing Treatment Code (MITI) as an adjunct to MI training, clinical practice and research. Coders were trained to use the MITI for scoring taped sessions. The 4‐month basic training had a duration of 39 hours. Following training, 60 audio‐taped live interviews were randomly assigned for MITI coding. Mean intra‐class correlation (ICC) coefficients were calculated for 7 coders across all pairs of coders. Cronbach's alpha was calculated to estimate the covariance between each pair across their common interviews. Six months later, a second inter‐rater reliability test was performed, when 5 coders coded the same 15 randomly selected tapes. At the second reliability testing the mean ICC was 0.81 and the mean Cronbach's alpha was 0.96. However, the ICC varied for different sub‐variables of the MITI, ranging from 0.42 empathy to 0.79 for number of Closed questions. In conclusion, MITI shows promising potential to be a reliable tool to confirm and enhance MI training as well as practice in clinical settings and in evaluating MI integrity in clinical MI research. However, coder assessment of empathy and MI‐spirit, “global” variables, requires further refinement.     

Can membership-functions capture the directionality of verbal probabilities?

Verbal probabilities are a common mean for communicating risk and uncertainties in many decision-making settings (e.g., finance, medicine, military). They are considered directional because they elicit a focus on either the outcome occurrence (e.g., there is a chance) or on its non-occurrence (e.g., it is unlikely). According to a quantitative perspective, directionality is dependent on the vague probabilistic meaning conveyed by verbal probabilities—e.g., p(outcome) > .50 = > focus on outcome occurrence. In contrast a more qualitative perspective suggests that directionality depends on contextual factors. The present study tested whether the directionality of verbal probabilities was determined by their vague probabilistic meaning, by contextually manipulated variables (i.e., representativeness and base rate), or by a combination of both. Participants provided their own expressions to describe the guilt of a suspect and then assessed the vague probabilistic meaning and directionality associated with those expressions. Results showed that directionality was mainly determined by the vague probabilistic meaning but also by the base rate of guilt. Although attention focus on the occurrence or the non-occurrence of the target outcome is dependent on vague probabilistic meaning, it cannot be fully accounted for by it.     

Humble persons are more helpful than less humble persons: Evidence from three studies

Connections between humility and other prosocial qualities led us to develop a humility–helpfulness hypothesis. In three studies, humble persons were more helpful than less humble persons. In Study 1, participants (n?=?117) completed self-report measures of humility, the Big Five, and helpfulness. In Study 2, participants (n?=?90) completed an implicit measure of humility and were presented with an unexpected opportunity to help someone in need. In Study 3, participants (n?=?103) completed self-report and implicit measures of humility and were presented a similar helping opportunity. Humility and helpfulness correlated positively when personality and impression management were controlled. Humble participants helped more than did less humble participants even when agreeableness and desirable responding were statistically controlled. Further, implicit humility uniquely predicted helping behavior in an altruistic motivation condition.     

The effectiveness of feedback in multiple-cue probability learning

How effective are different types of feedback in helping us to learn multiple contingencies? This article attempts to resolve a paradox whereby, in comparison to simple outcome feedback, additional feedback either fails to enhance or is actually detrimental to performance in nonmetric multiple-cue probability learning (MCPL), while in contrast the majority of studies of metric MCPL reveal improvements at least with some forms of feedback. In three experiments we demonstrate that if feedback assists participants to infer cue polarity then it can in fact be effective in nonmetric MCPL. Participants appeared to use cue polarity information to adopt a linear judgement strategy, even though the environment was nonlinear. The results reconcile the paradoxical contrast between metric and nonmetric MCPL and support previous findings of people's tendency to assume linearity and additivity in probabilistic cue learning.     

Estimating the effect of word predictability on eye movements in Chinese reading using latent semantic analysis and transitional probability

Latent semantic analysis (LSA) and transitional probability (TP), two computational methods used to reflect lexical semantic representation from large text corpora, were employed to examine the effects of word predictability on Chinese reading. Participants' eye movements were monitored, and the influence of word complexity (number of strokes), word frequency, and word predictability on different eye movement measures (first-fixation duration, gaze duration, and total time) were examined. We found influences of TP on first-fixation duration and gaze duration and of LSA on total time. The results suggest that TP reflects an early stage of lexical processing while LSA reflects a later stage.