Valuing the future: a MADA example involving nuclear waste storage

Intertemporal decision making involves decisions that have consequences that span several periods of time and often extend far into the future. The purpose of this paper is to discuss and highlight the differences associated with different evaluation methods designed to cope with the long-term impacts of a decision including discounting. The concepts and ideas are illustrated in the context of a decision about a nuclear waste facility. We show how applying different discounting methodologies can greatly affect the decision made, especially over long time periods. © 1998 John Wiley & Sons, Ltd.     

Time and Its Relationship to Development in the Life Course: Some Reflections from a Study of HIV-Positive Adults

Although adult development is commonly understood as change over time, the relationship between time and development is rarely highlighted in research in the field. This paper first reviews 3 dimensions of time that interact in the study of developmental processes in the life course. The 3 dimensions are historical time; chronological age or life time; and social time, the culturally-specific, systematic ordering of life events. Second, the paper utilizes data from a follow-up study of HIV-positive men and women to illustrate the importance of time in development. In the original study, an HIV-positive diagnosis was viewed as a death sentence and had the effect of suspending the normal developmental patterns of adult life. Two years later, with the advent of protease inhibitors—an event in historical time—participants had reengaged with life time, once again making social time a relevant factor in their development. These data demonstrate how a better understanding of adult development can be achieved when historical time, life time, and social time are moved center stage in the study of developmental processes.     

How U.S. Children and Adolescents Spend Time: What It Does (and Doesn't) Tell Us About Their Development

Young people develop as "the sum of past experiences," and data on their time use are one means of quantifying those experiences. U.S. children and adolescents spend dramatically less time than in the agrarian past in household and income-generating labor. Because such labor is usually repetitive and unchallenging, this reduction has probably not deprived youths of crucial developmental experience. The schoolwork replacing this time has a clearer relationship to developmental outcomes. American teens, however, spend less time on schoolwork than teens in other industrialized countries. American teenagers have more discretionary time, much spent watching television or interacting with friends; spending large amounts of time in these activities is related to negative developmental outcomes. Increasing amounts of young people's discretionary time, however, appear to be spent in structured voluntary activities, like arts, sports, and organizations, which may foster initiative, identity, and other positive developmental outcomes.     

Actions and outcomes: two aspects of agency

Agency can be construed as both the manner in which autonomous individuals embark on particular courses of action (or inaction), and the relationship between such agents and the outcomes of the courses of action on which they embark. A promising strategy for understanding both senses of agency consists in the combination of a modal logic of agency and branching time semantics. Such is the strategy behind stit theory, the theory of agentive action developed by Nuel Belnap and others. However, stit theoretic evaluations of the agentive relationship between agents and outcomes that are uncertain—due to either the presence of indeterminism, or the possible intervention of other agents—yield counterintuitive results. This paper develops a pair of alternative operators (the “act” operators) for modeling agency with respect to uncertain outcomes. Unlike the stit-theoretic model, the act-theoretic model of agency with respect to a particular state of affairs does not require that the state of affairs be realized in every possible history. If the state of affairs in fact obtains in the actual history, and its obtaining was dependent on the agent’s pursuing a particular course of action, then the agent is deemed agentive under act theory.     

SPACE AND TIME FROM A NEO‐WHITEHEADIAN PERSPECTIVE

Russell Stannard distinguishes between objective time as measured in theoretical physics and subjective time, or time as experienced by human beings in normal consciousness. Because objective time, or four‐dimensional space‐time for the physicist, does not change but exists all at once, Stannard argues that this is presumably how God views time from eternity which is beyond time. We human beings are limited to experiencing the moments of time successively and thus cannot know the future as already existing in the same way that God does. I argue that Stannard is basically correct in his theological assumptions about God's understanding of time but that his explanation would be more persuasive within the context of a neo‐Whiteheadian metaphysics. The key points in that metaphysics are (1) that creation is contained within the structured field of activity proper to the three divine persons of the Christian doctrine of the Trinity and (2) that the spontaneous decisions of creatures are continually ordered and reordered into an ever‐expanding totality already known in its fullness by the divine persons.     

The Time Course of Attention: It Is Better Than We Thought

ABSTRACT— What is the time course of attention? Research using rapid-stimulus streams has suggested that it is rather slow: Attention takes half a second to recover from processing one thing before it can process the next. This period is referred to as the attentional blink , and it is thought to reflect a fundamental bottleneck in conscious processing. If this period does exist, such a limitation would have severe consequences in real-life situations in which multiple events may rapidly succeed each other (e.g., in traffic). However, findings that support the attentional blink are at odds with other findings indicating that attention is not reduced, but enhanced, following potentially important occurrences. The article reviews evidence that these opposite effects are actually closely related. The attentional blink is a consequence of selection mechanisms that are not severely limited, but have an adaptive function: They enhance perception in response to relevant information but suppress perception in response to irrelevant information. It means that humans are better geared for real life than was previously thought.     

Differential Effects of Two Spelling Procedures on Acquisition,Maintenance and Adaption to Reading

An alternating treatments design was used to assess the effects of a constant time delay (CTD) procedure and a cover-copy-compare (CCC) procedure on three students’ acquisition, subsequent maintenance, and adaptation (i.e., application) of acquired spelling words to reading passages. Students were randomly presented two trials of word lists from their respective curriculum under each condition once daily. Results suggest that both procedures were effective for helping students efficiently acquire spelling words, but the CCC condition resulted in more words learned for all participants, although less pronounced when instructional time was considered. However, the CTD procedure resulted in substantially higher levels of maintenance for Jeremy and Leon, with no significant difference between the two procedures for the Anthony. Adaptation of acquired spelling words to reading was about equal under both conditions for Anthony and Leon, while Jeremy showed higher levels of performance in the CTD procedure. Discussion focuses on discrepant results, matching instructional procedures to specific learning concerns, and directions for future research.     

Trauma,causality and time: Some reflections: EPISTEMOLOGY STUDY GROUP,PORTO ALEGRE PSYCHOANALYTICAL SOCIETY1

Based on the studies and discussions of the Epistemology Study Group of the Porto Alegre Psychoanalytical Society, the authors aim to connect the notions of psychical determinism with the concept of trauma and temporality, from a perspective of the mind as a complex system. Following consideration of the concept of psychical determinism, they attempt to expand the discussion on causality. They propose that trauma be situated in the body of contemporary psychoanalysis, where emotional experience is favoured over factual events, leading to the need to rethink the concept of trauma and its usefulness. In the same way, in the light of recent developments, the authors revisit the Freudian etiologic equation, with a proposal that an i, for imaginary factor, be included, corresponding to an element of complexity. The question of temporality, connected with trauma and the therapeutic action of psychoanalysis, is approached within a vision of irreversible time, characteristic of complex systems, far‐from‐equilibrium‐which is how the authors understand psychical functioning.     

A method for describing preschoolers' activity preferences

We designed a series of analyses to develop a measurement system capable of simultaneously recording the free-play patterns of 20 children in a preschool classroom. Study 1 determined the intermittency with which the location and engagement of each child could be momentarily observed before the accuracy of the measurement was compromised. Results showed that intervals up to 120 s introduced less than 10% measurement error. Study 2 determined the extent of agreement between two observers who simultaneously collected data for 20 children using 30-, 60-, 90-, and 120-s momentary time sampling (MTS) intervals. The three larger intervals resulted in high levels of interobserver agreement (above 90%), whereas the 30-s interval resulted in unacceptably low levels of agreement (less than 80%). By allowing observers to select from among the different MTS intervals via a datasheet array and then collect data with the chosen system, Study 3 determined observers' preferences for the remaining MTS intervals. Both data collectors preferred the 90-s MTS procedure. The sensitivity of the 90-s MTS procedure, which was shown to be accurate, reliable, and preferred, was then demonstrated by its use to describe activity preferences of a classroom of children in Study 4. This system identified high- and low-preference activities for individual children and revealed interesting patterns of response allocation by the group.     

Time to completion of web-based physics problems with tutoring

We studied students performing a complex learning task, that of solving multipart physics problems with interactive tutoring on the web. We extracted the rate of completion and fraction completed as a function of time on task by retrospectively analyzing the log of student-tutor interactions. There was a spontaneous division of students into three groups, the central (and largest) group (about 65% of the students) being those who solved the problem in real time after multiple interactions with the tutorial program (primarily receiving feedback to submitted wrong answers and requesting hints). This group displayed a sigmoidal fraction-completed curve as a function of logarithmic time. The sigmoidal shape is qualitatively flatter for problems that do not include hints and wrong-answer responses. We argue that the group of students who respond quickly (about 10% of the students) is obtaining the answer from some outside source. The third group (about 25% of the students) represents those who interrupt their solution, presumably to work offline or to obtain outside help.