De Finetti's earliest works on the foundations of probability

Bruno de Finetti's earliest works on the foundations of probability are reviewed. These include the notion of exchangeability and the theory of random processes with independent increments. The latter theory relates to de Finetti's ideas for a probabilistic science more generally. Different aspects of his work are united by his foundational programme for a theory of subjective probabilities.This work would not have been possible in its present form without the generous help of Prof. Maria Carla Galavotti. For several years, she has unfailingly answered all my requests for papers difficult of access, and discussed the details of interpretation as well as the philosophy of probability in general. To her I express my gratitude for everything.     

Additivity and expected utility in risky multiattribute preferences

This experiment analyzed human preferences among even chance gambles for commodity bundles. The purpose of the experiment was to test several independence assumptions that distinguish between models for risky multiattribute preferences. In particular, the additivity and the expected utility part of the additive expected utility model were tested symmetrically. The degree and form of model violations were established, and the effects of instructions and of response modes were examined. All independence assumptions were violated by a bias to prefer a gamble or a commodity bundle that was previously matched against a standard. Systematic and strong violations that superseded this bias questioned the validity of the additive expected utility model. In violation of the additivity part of that model subjects consistently preferred the gamble with more balanced outcomes when comparing gambles with identical marginal probability distributions. This trend, called multiattribute risk aversion, was independent of subjects' single attribute risk attitude. Instructions and response modes had no noticeable impacts on these response patterns.     

Choice reaction time with a random foreperiod

Choice reaction latencies were measured at three different a priori probabilities for two stimulus alternatives. Unlike the results of some other studies, the mean latency of a given response was nearly the same whether the response was correct or incorrect. The discriminable stimuli were a 1000- or a 1700-Hz tone presented at 70 dB SPL. Latencies and standard deviations, based on about 17,000 observations, are reported for three observers. The data are compared with predictions of the optimum sequential model of Wald and Stone and two modifications of that random-walk model, one proposed by Link and Heath and the other proposed by Laming. Fast-guess analyses were also carried out. The three-parameter version of either the sequential or the modified random-walk models provided reasonably accurate predictions of the mean data for each observer. The parameters estimated by the fast-guess analysis were unrealistic. There are three obvious differences between this experiment and most previous choice reaction-time experiments. First is stimulus modality#x2014;we used an auditory signal, whereas most of the previous studies used a visual signal. Second, the observers practiced more in this experiment than in most previous experiments. Finally, there was a random foreperiod with a heavy penalty for anticipations. One or more of these factors is the probable reason for the discrepancy between our results and those of previous studies.     

Structuring of early reaching movements: a longitudinal study

Reaches, performed by 5 infants, recorded at 19 weeks of age and every third week thereafter until 31 weeks of age, were studied quantitatively. Earlier findings about action units were confirmed. At all ages studied, movements were structured into phases of acceleration and deceleration. Reaching trajectories were found to be relatively straight within these units and to change direction between them. It was also found that at all ages, there was generally one dominating transport unit in each reach. The structuring of reaching movements changed in four important ways during the period studied. First, the sequential structuring became more systematic with age, with the dominating transport unit beginning the movement. Second, the duration of the transport unit became longer and covered a larger proportion of the approach. Third, the number of action units decreased with age, approaching the two-phase structure of adult reaching. Finally, reaching trajectories became straighter with age.     

Recognizing images: The role of motivational significance,complexity, social content,age, and gender

Memory for affective events plays an important role in determining people’s behavior and well-being. Its determinants are far from being completely understood. We investigated how recognition memory for affective pictures depends on pictures’ motivational significance (valence and arousal), complexity (figure-ground compositions vs. scenes), and social content (pictures with people vs. without people) and on observers’ age and gender. Younger, middle-aged, and older adults viewed 84 pictures depicting real-life situations. After a break, the participants viewed 72 pictures, half of which had been viewed previously and half of which were novel, and were asked to endorse whether each picture was novel or had been presented previously. Hits, false alarms, and overall performance (discrimination accuracy) were our dependent variables. The main findings were that, across participants, recognition memory was better for unpleasant than pleasant pictures and for pictures depicting people than pictures without people. Low-arousal pictures were more accurately recognized than high-arousal pictures, and this effect was significantly larger among middle-aged and older adults than younger adults. Recognition memory worsened across adulthood, and this decline was steeper among men than women. Middle-aged and older women outperformed their male counterparts. This study suggests that how well we are able to successfully discriminate previously seen pictorial stimuli from novel stimuli depends on several pictures’ properties related to their motivational significance and content, and on observer’s age and gender.     

Developmental kinesics: How children acquire communicative and non-communicative nonverbal behavior

This article is a position paper concerning the major issues in the study of children's acquistion of nonverbal behavior. In linguistic theory non-verbal behavior may be considered irrelevant, it may be condsidered the precursor of verbal language, or it may be viewed as an integral part of human communication which is verbal and nonverbal. The author opts for the latter theory. Concerning the relationship between what is innate and what is learned, the paper discusses that nonverbal expression is innate, but culture determines its forms and its uses. The paper then presents a brief history of Developmental Kinesics, explaining its technical difficulties and its methodological complexities. It proceeds by documenting the function of maternal nonverbal behavior towards the neonate. Finally, the paper treats the levels of analysis. A distinction is drawn between communicative and non-communicative nonverbal behavior. Its affective, emotional function relates to ego state; its regulatory function governs face-to-face interaction; and its referential, informative function pertains to the message proper. The child also acquires the non-interactional aspects of body movements which distinguish different peoples. Expression and perception must be studied separately; and finally, nonverbal behavior has to be correlated with verbal behavior and particular attention has to be focused on the double bind.     

Ego development and the ethics of care and justice: the relations among them revisited

This study examined the links among ego development and the ethics of care and justice in 144 Norwegian men and women, 15 to 48 years old, taking into consideration age, sex, education, and verbal intelligence. As expected, the relationship between Loevinger's model of ego development and care-based moral reasoning as measured with Skoe's Ethic of Care Interview (ECI) was significantly stronger than the one between ego development and justice as measured with Rest's Defining Issues Test (DIT). Both ethics correlated significantly with verbal ability. Analyses showed that beyond its overlap with verbal intelligence, the variance shared between the ECI and ego development was substantial. By contrast, when verbal intelligence was controlled, the DIT was not significantly related to ego development or to the care ethic.