Distant Causation in <Emphasis Type="Italic">C</Emphasis>+

The action language C+ of Giunchiglia, Lee, Lifschitz, McCain and Turner is a high-level, logical formalism for the representation of domains involving action and change. However, one cannot directly express relationships which hold between states more than one time-step distant, or even say that one action determines another at the next time. We present C+_timed, a generalization of C+ which removes these limitations. As for C+, translations to the language of causal theories are given. We also define a new kind of transition system called a ‘run system’ to provide a graphical semantics. Finally, we show how domains involving prohibition and permission can be modelled, by incorporating the ideas of another extension of C+.     

Representation and Reasoning about Evolutions of the World in the Context of Reasoning about Actions

The first step in reasoning about actions and change involves reasoning about how the world would evolve if a certain action is executed in a certain state. Most research on this assumes the evolution to be only a single step and focus on formulating the transition function that defines changes between states due to actions. In this paper we consider cases where the evolution is more than just a single change between one state and another. This is manifested when the execution of an action may trigger execution of other actions, or when multiple agents act on the environment following certain strategies.     

IQ stability: the relation between child and young adult intelligence test scores in low-birthweight samples

The stability of IQ from childhood to adulthood in low-birthweight subjects was measured in two independent samples with follow-up intervals of approximately 14 and 9.5 years. In both samples, intelligence was assessed with the WISC at a mean age of 9.5. Twenty-six subjects were retested with the WAIS at a mean age of 23.5, and 78 subjects with the BPP (the Danish Military Draft Board Intelligence Test) at the age of 19.1. Both samples obtained childhood and adult test scores below the expected means. For the Wechsler Verbal, Performance and Full-Scale IQs, the stability quotients were 0.86, 0.86, and 0.89 in the WAIS sample, and the retest correlations for the three IQs with the BPP score were 0.66, 0.65, and 0.74. Thus, the majority of children showed stable patterns of intellectual development from middle childhood to young adulthood.     

任务难度对基于位置返回抑制时间进程的影响

在返回抑制的实验范式下,采用线索一靶子模式进行了视觉字母觉察实验、实验发现,返回抑制在线索与靶子之间的时间间隔（ＳＯＡ）为７００ｍｓ时出现,且在９００ｍｓ时消退。这与先前许多实验发现的返回抑制在ＳＯＡ为３００ｍｓ左右时出现的结果不一致。作者认为,实验任务的难度是影响返回抑制时间进程的一个重要因素。     

时点,时距和时序信息加工之间相关性研究

本研究分为两个实验,分别采用预期式和回溯式范型,探讨时距、时序和时点三者之间信息加工的相关性,结果发现：同一时间经历,时距估计与时序判断随注意参与程度的增加,由负相关趋势向正相关变化;时距估计与时点离散度可能呈正相关趋势;时序判断与时点离散度随注意参与程度的增加,由负相关趋势向正相关变化。     

A Gabbay-Rule Free Axiomatization of T×W Validity

The semantical structures called T×W frames were introduced in (Thomason, 1984) for the Ockhamist temporal-modal language, _O, which consists of the usual propositional language augmented with the Priorean operators P and F and with a possibility operator . However, these structures are also suitable for interpreting an extended language, _SO, containing a further possibility operator ^s which expresses synchronism among possibly incompatible histories and which can thus be thought of as a cross-history simultaneity operator. In the present paper we provide an infinite set of axioms in _SO, which is shown to be strongly complete forT ×W-validity. Von Kutschera (1997) contains a finite axiomatization of T×W-validity which however makes use of the Gabbay Irreflexivity Rule (Gabbay, 1981). In order to avoid using this rule, the proof presented here develops a new technique to deal with reflexive maximal consistent sets in Henkin-style constructions.     

Developmental changes in associations between auditory-visual events

The goal of the present study was twofold: to examine the influence of two amodal properties, co-location and temporal synchrony, on infants' associating a sight with a sound, and to determine if the relative influence of these properties on crossmodal learning changes with age. During familiarization 2-, 4-, 6- and 8-month-olds were presented two toys and a sound, with sights and sounds varying with respect to co-location and temporal synchrony. Following each familiarization phase infants were given a paired preference test to assess their learning of sight-sound associations. Measures of preferential looking revealed age-related changes in the influence of co-location and temporal synchrony on infants' learning sight-sound associations. At all ages, infants could use temporal synchrony and co-location as a basis for associating an auditory with a visual event and, in the absence of temporal synchrony, co-location was sufficient to support crossmodal learning. However, when these cues conflicted there were developmental changes in the influence of these cues on infants' learning auditory-visual associations. At 2 and 4 months infants associated the sounds with the toy that moved in synchrony with the sound's rhythm despite extreme violation of co-location of this sight and sound. In contrast, 6- and 8-month-olds did not associate a specific toy with the sound when co-location and synchrony information conflicted. The findings highlight the unique and interactive effects of distinct amodal properties on infants' learning arbitrary crossmodal relations. Possible explanations for the age shift in performance are discussed.     

Ratio versus difference comparators in choice.

Several theories in the learning literature describe decision rules for performance utilizing ratios and differences. The present paper analyzes rules for choice based on either delays to food, immediacies (the inverse of delays), or rates of food, combined factorially with a ratio or difference comparator. An experiment using the time-left procedure (Gibbon & Church, 1981) is reported with motivational differentials induced by unequal reinforcement durations. The preference results were compatible with a ratio-comparator decision rule, but not with decision rules based on differences. Differential reinforcement amounts were functionally equivalent to changes in delays to food. Under biased reinforcement, overall food rate was increased, but variance in preference was increased or decreased depending on which alternative was favored. This is a Weber law finding that is compatible with multiplicative, scalar sources of variance but incompatible with pacemaker rate changes proportional to food presentation rate.