Modelling Dyadic Interaction with Hawkes Processes

We apply the Hawkes process to the analysis of dyadic interaction. The Hawkes process is applicable to excitatory interactions, wherein the actions of each individual increase the probability of further actions in the near future. We consider the representation of the Hawkes process both as a conditional intensity function and as a cluster Poisson process. The former treats the probability of an action in continuous time via non-stationary distributions with arbitrarily long historical dependency, while the latter is conducive to maximum likelihood estimation using the EM algorithm. We first outline the interpretation of the Hawkes process in the dyadic context, and then illustrate its application with an example concerning email transactions in the work place.     

Talking about parts of a past experience: The impact of discussion style and event structure on memory for discussed and nondiscussed information

This experiment examined the impact of selective postevent discussion of high- and low-elaborative styles on 5- and 6-year-olds' (N = 47) memory for discussed and nondiscussed aspects of a staged event ("Visiting the Pirate"). The event contained both logically and arbitrarily connected scenes. Discussion was spaced over 3 days, and memory was assessed 1 day later. Compared with a no-discussion condition, memory for discussed information was enhanced after high- but not low-elaborative discussion for both logically and arbitrarily connected scenes. For arbitrarily connected scenes, memory for nondiscussed aspects was impaired relative to the no-discussion condition, with the degree of impairment being equal after high- and low-elaborative discussion. In contrast, for logically connected scenes, memory for nondiscussed information was not impaired after discussion of either style.     

Bringing order to the arbitrary: one- to two-year-olds’ recall of event sequences

Recall by children ages 16–32 months was tested on event sequences that were either arbitrarily ordered or were constrained by enabling relations. Even the youngest children reliably recalled the enabling sequences. It was not until 20 months and older that the children performed at above-chance levels on the arbitrarily ordered events.     

Pseudorandom numbers for mini- and microcomputers : A generalized feedback shift register algorithm

The advantages of the generalized feedback shift register pseudorandom number algorithm over all other pseudorandom number generators are described. These advantages are: (1) It produces multidimensional pseudorandom numbers; (2) it has arbitrarily long period, independent of word size of the computer on which it is implemented; (3) it is faster than other pseudorandom number generators; (4) the “same” floating-point pseudorandom number sequence is obtained on any machine; that is, the high-order mantissa bits of each pseudorandom number agree on all machines: examples are given for IBM 360, SPERRY-RAND-UNIVAC 1108, CONTROL DATA 6000, and HEWLETT-PACKARD 2100 series computers; and (5) it can be coded in compiler languages (is portable). This pseudorandom number generator is ideal for mini- and microcomputers, since only two additions and an exclusive-or are needed for its execution.     

Acoustic confusion of digits in memory and recognition

It has been shown that, contrary to current opinion, digits do not confuse arbitrarily and that similar patterns of confusion are observed in memory and auditory recognition tasks. Two alternative measures of stimulus similarity are compared.     

The semantic specificity of gestures when verbal communication is not possible: The case of emergency evacuation

The aim of the present study was to examine the comprehension of gesture in a situation in which the communicator cannot (or can only with difficulty) use verbal communication. Based on theoretical considerations, we expected to obtain higher semantic comprehension for emblems (gestures with a direct verbal definition or translation that is well known by all members of a group, or culture) compared to illustrators (gestures regarded as spontaneous and idiosyncratic and that do not have a conventional definition). Based on the extant literature, we predicted higher semantic specificity associated with arbitrarily coded and iconically coded emblems compared to intrinsically coded illustrators. Using a scenario of emergency evacuation, we tested the difference in semantic specificity between different categories of gestures. 138 participants saw 10 videos each illustrating a gesture performed by a firefighter. They were requested to imagine themselves in a dangerous situation and to report the meaning associated with each gesture. The results showed that intrinsically coded illustrators were more successfully understood than arbitrarily coded emblems, probably because the meaning of intrinsically coded illustrators is immediately comprehensible without recourse to symbolic interpretation. Furthermore, there was no significant difference between the comprehension of iconically coded emblems and that of both arbitrarily coded emblems and intrinsically coded illustrators. It seems that the difference between the latter two types of gestures was supported by their difference in semantic specificity, although in a direction opposite to that predicted. These results are in line with those of Hadar and Pinchas‐Zamir (2004), which showed that iconic gestures have higher semantic specificity than conventional gestures.     

When Even Arbitrary Order Becomes Important: Developments in Reliable Temporal Sequencing of Arbitrarily Ordered Events

By late in the first year of life, children show temporally ordered recall of event sequences, the orders of which are constrained by enabling relations; they do not reliably recall arbitrarily ordered events. Using elicited imitation, in two experiments, we examined age-and experience-related changes in young children's recall of events, the orders of which are arbitrary. The changes were found to have implications for the efficacy of verbal reminding and to be related to developments in language. Specifically, on the basis of a single experience, 16-month-olds did not accurately recall arbitrarily ordered event sequences either immediately or after a two-week delay (Experiment 1); 22-month-olds recalled the events immediately, but not after the delay; by 28 months, children recalled the events even after the delay (Experiment 2A). This development was accompanied by changes in the ability to benefit from verbal reminders: 28-month-olds' recall was facilitated by provision of verbal reminders, whereas that of the younger children was not. Moreover, age-related changes in accurate reproduction of lengthy arbitrarily ordered event sequences were found to be related to developments in language (Experiment 2B). Critically, the limitations on 1-year-olds' performance that are overcome with age are not absolute: After three experiences, 16-month-olds accurately recalled the events after a two-week delay; their recall was facilitated by verbal reminders (Experiment 1). The implications of these findings are discussed.     

Revising Republican Liberty: What is the Difference Between a Disinterested Gentle Giant and a Deterred Criminal?

This paper assesses the most well thought out contemporary conception of republican liberty put forward by Philip Pettit and Quentin Skinner. I demonstrate that it is incoherent: at least insofar as it seeks to pick out a form of unfreedom not captured by the negative conception of liberty. This incoherence arises because Pettit and Skinner cannot both hold that republican unfreedom is defined by one agent’s mere capacity to interfere arbitrarily with another agent and, at the same time, claim that republican freedom can be promoted by deterrence mechanisms. My contribution to contemporary republican theory is to suggest that a coherent republican conception can be achieved, however, through an important revision. This is to replace Pettit and Skinner’s antonym of republican liberty—the power to interfere arbitrarily—with a higher order power—the power to determine arbitrarily rules with respect to interference. This revised conception does pick out a genuinely distinct extension of unfreedom from the negative liberty conception. I believe it also reflects an important intuitive sense in which we may understand ourselves to be unfree, that is, to live under the rule of another.     

SEX DIFFERENCES IN VISUAL ENCODING SKILLS: READING SYMBOLS

Written language in all cultures is composed of symbols to which sounds have been attached somewhat arbitrarily. Meanings are also attached somewhat arbitrarily to letters and groups of letters. The transformation of symbols into sounds is generally seen to be part of the reading process, though it is not clear whether it is of equal importance at all stages of competence. It is possible that, at some stages, the skilled reader may have direct access to the meaning of a word or phrase from its visual representation. There is evidence from work of Coltheart, Hull and Slater (1975) that females tend to use phonological encoding to a greater extent than males when reading. Naish (1980) found that females encoded phonologically at a faster rate than males, and suggested that this might explain why the preferred mode of access to meaning appeared to be phonological for females but visual for males.     

Computer generation of textures

A method for displaying fixed or time-varying textured patterns under computer control is described. The luminance profiles of these patterns is fixed in one dimension (Y axis), but can be arbitrarily complex in the other dimension (X axis) since they are synthesized by software. An example of the use of the method in texture matching experiments is given.     

Conformity to experimenter-determined,payoff enforced criterion levels in the method of random staircases

Results obtained from Ss paid to meet arbitrary criteria are compared with ordinary determinations of limens for increments of white noise in a constant background of white noise. Multiple random, yes-no staircases are used. It is demonstrated that a S can reliably exhibit a variety of arbitrarily determined “thresholds” when appropriate pay-off contingencies are introduced.     

INFINITE REGRESS ARGUMENTS

Abstract

Gerald Cohen's critique of John Rawls's theory of justice is that it is concerned only with the justice of social institutions, and must thus arbitrarily draw a line between those inequalities excluded and those allowed by the basic structure. Cohen claims that a proper concern with the interests of the least advantaged would rule out ‘incentives’ for ‘talented’ individuals. I argue that Rawls's assumption that the subject of justice is the basic structure of society does not arbitrarily restrict the concerns of political justice, as Cohen claims. Further, I argue that it does not allow ‘deep’ inequalities within a just basic structure. When properly understood, Rawls's theory of justice is strongly egalitarian, taken as a theory of fairness in the way the burdens and benefits of social cooperation are distributed, even if it is not as egalitarian as Cohen wishes.     

Strategic Polarization

In joint decision making, similarly minded people may take opposite positions. Consider the example of a marriage in which one spouse gives generously to charity while the other donates nothing. Such "polarization" may misrepresent what is, in actuality, a small discrepancy in preferences. It may be that the donating spouse would like to see 10% of their combined income go to charity each year, while the apparently frugal spouse would like to see 8% donated. A simple game-theoretic analysis suggests that the spouses will end up donating 10% and 0%, respectively. By generalizing this argument to a larger class of games, we provide strategic justification for polarization in many situations such as debates, shared living accommodations, and disciplining children. In some of these examples, an arbitrarily small disagreement in preferences leads to an arbitrarily large loss in utility for all participants. Such small disagreements may also destabilize what, from game-theoretic point of view, is a very stable equilibrium. Copyright 2001 Academic Press.     

Arbitrarily applicable spatial relational responding

Spatial reasoning, where novel spatial relationships are inferred based on trained relationships, can be conceptualized as arbitrarily applicable spatial relational responding. Here, we conducted two experiments to develop and validate, for the first time, a laboratory procedure to establish arbitrarily applicable spatial relational responding in adult humans. In Experiment 1, participants were trained on nonarbitrary spatial relational tasks designed to establish contextual cues for left of, right of, above, and below. Contextual cues were then used to train a series of arbitrary spatial relations involving four abstract shapes. Following training in a subset of arbitrary relations (A is left of B, B is above C, C is right of D), subsequent testing examined the emergence of untrained spatial relations (B is right of A, C is below B, D is left of C, D is below A and A is above D). When absent in initial tests, spatial relational responding was facilitated by a remedial training procedure incorporating nonarbitrary relational guidance. Participants showed patterns of spatial relational responding consistent with test relations. In Experiment 2, a variant reversal design yielded predictable, reversed spatial relational responses. Overall, the present procedures represent the first empirical demonstration of arbitrarily applicable spatial relational responding and thus, arguably, the first functional analytic model of spatial reasoning.     

Analysis and treatment of problem behavior evoked by music

The present study investigated the effects of differential negative reinforcement of other behavior (DNRO) on problem behavior evoked by music in a 7-year-old child with pervasive developmental disorder. Following an auditory stimulus assessment, DNRO was used to reduce problem behavior to near-zero levels. Results are discussed in terms of identifying establishing operations to govern treatment options and the use of negative reinforcement when arbitrarily imposed positive reinforcers do not compete with escape from auditory stimulation.     

Isolation and Non-Arbitrary Division: Frege's Two Criteria for Counting

In §54 of the Grundlagen, Frege advances an interesting proposal on how to distinguish among different sorts of concepts, only some of which he thinks can be associated with number. This paper is devoted to an analysis of the two criteria he offers, isolation and non-arbitrary division. Both criteria say something about the way in which a concept divides its extension; but they emphasize different aspects. Isolation ensures that a concept divides its extension into discrete units. I offer two construals of this: isolation as discreteness, i.e. absence of overlap, between the objects to be counted; and isolation as the drawing of conceptual boundaries. Non-arbitrary division concerns the internal structure of the units we count: it makes sure that we cannot go on dividing them arbitrarily and still find more units of the kind. Non-arbitrary division focuses not only on how long something can be divided into parts of the same kind; it also speaks to the way in which these divisions are made, arbitrarily or non-arbitrarily, as well as to the compositional structure of the objects divided.     

Complexity of visual icons studied via signal detection theory

Two investigations on how humans perceive information from visually rendered complex objects, such as military icons (glyphs) were conducted. A signal detection theory framework was employed to evaluate the sensitivity and specificity of human subject performance. The 6 adults tested showed that as complexity increased, their accuracy in performance decreased. Study 1 showed that complex dimensions (features) could not be assigned arbitrarily. Study 2 developed a rank ordering for features of an iconic object.     

Green's functions of magnetoelectroelastic solids with a half-plane boundary or bimaterial interface

Green's functions for magnetoelectroelastic medium with an arbitrarily oriented half-plane or bimaterial interface are presented in this paper. The derivation is based on an extended Stroh's formalism and coordinate-transform technique. In particular, a new coordinate variable is introduced to handle vertical or other boundary problems. These Green's functions satisfy related boundary or interface conditions. The Green's functions obtained can be used to establish boundary-element formulation and to analyse fracture behaviour involving half-plane boundaries or bimaterial interfaces.     

The narcissistic difficulties presented to the observer by the psychosomatic problem1

Dealing with psychosomatic realities often generates narcissistic neurotic resistances in the observer that form an obstacle to carrying out scientific work. The tendencies towards schematization and the enforced investigation of arbitrarily defined objects of study, such as they appear in some theoretical standpoints, are aspects of these resistances. The self-destruction evoked by the problem of the ‘death drives’ in its superficial dimension constitutes an obstacle of the same kind.