The capacity to predict future events permits a creature to detect, model, and manipulate the causal structure of its interactions with its environment. Behavioral experiments suggest that learning is driven by changes in the expectations about future salient events such as rewards and punishments. Physiological work has recently complemented these studies by identifying dopaminergic neurons in the primate whose fluctuating output apparently signals changes or errors in the predictions of future salient and rewarding events. Taken together, these findings can be understood through quantitative theories of adaptive optimizing control.

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A Neural Substrate of Prediction and Reward

Well-being : the foundations of hedonic psychology

This article considers the role of the hippocampus in memory function. A central thesis is that work with rats, monkeys, and humans--which has sometimes seemed to proceed independently in 3 separate literatures--is now largely in agreement about the function of the hippocampus and related structures. A biological perspective is presented, which proposes multiple memory systems with different functions and distinct anatomical organizations. The hippocampus (together with anatomically related structures) is essential for a specific kind of memory, here termed declarative memory (similar terms include explicit and relational). Declarative memory is contrasted with a heterogeneous collection of nondeclarative (implicit) memory abilities that do not require the hippocampus (skills and habits, simple conditioning, and the phenomenon of priming). The hippocampus is needed temporarily to bind together distributed sites in neocortex that together represent a whole memory.

Memory and the hippocampus: A synthesis from findings with rats, monkeys, and humans.

the total number of papers may exceed 10,000. Nevertheless, cost consideration forced us to consider mostly published papers and technical reports in English. 4 Formula 4 in Seifert (1991) is in error—a multiplier of n, of cell size, is missing in the numerator. 5 Unfortunately, the technique of meta-analysis cannot be applied, at present time, to such effects because the distribution of dis based on a sampling of people, whereas the statistics of techniques such as ARIMA are based on the distribution of a sampling of observations in the time domain regardless of the size of the people sample involved (i.e., there is no way to compare a sample of 100 points in time with a sample of 100 people). That is, a sample of 100 points in time has the same degrees of freedom if it were based on an observation of 1 person or of 1,000 people. 258 KLUGER AND DENISI From the papers we reviewed, only 131 (5%) met the criteria for inclusion. We were concerned that, given the small percentage of usable papers, our conclusions might not fairly represent the larger body of relevant literature. Therefore, we analyzed all the major reasons to reject a paper from the meta-analysis, even though the decision to exclude a paper came at the first identification of a missing inclusion criterion. This analysis showed the presence of review articles, interventions of natural feedback removal, and papers that merely discuss feedback, which in turn suggests that the included studies represent 1015% of the empirical FI literature. However, this analysis also showed that approximately 37% of the papers we considered manipulated feedback without a control group and that 16% reported confounded treatments, that is, roughly two thirds of the empirical FI literature cannot shed light on the question of FI effects on performance—a fact that requires attention from future FI researchers. Of the usable 131 papers (see references with asterisks), 607 effect sizes were extracted. These effects were based on 12,652 participants and 23,663 observations (reflecting multiple observations per participant). The average sample size per effect was 39 participants. The distribution of the effect sizes is presented in Figure 1. The weighted mean (weighted by sample size) of this distribution is 0.41, suggesting that, on average, FI has a moderate positive effect on performance. However, over 38% of the effects were negative (see Figure 1). The weighted variance of this distribution is 0.97, whereas the estimate of the sampling error variance is only 0.09. A potential problem in meta-analyses is a violation of the assumption of independence. Such a violation occurs either when multiple observations are taken from the same study (Rosenthal, 1984) or when several papers are authored by the same person (Wolf, 1986). In the present investigation, there were 91 effects derived from the laboratory experiments reported by Mikulincer (e.g., 1988a, 1988b). This raises the possibility that the average effect size is biased, because his studies manipulated extreme negative FIs and used similar tasks. In fact, the weighted average d in Mikulincer's studies was —0.39; whereas in the remainder of the

The effects of feedback interventions on performance: A historical review, a meta-analysis, and a preliminary feedback intervention theory.

In this article we propose mechanisms that govern the processing of emotional information, particularly those involved in fear reduction. Emotions are viewed as represented by information structures in memory, and anxiety is thought to occur when an information structure that serves as program to escape or avoid danger is activated. Emotional processing is denned as the modification of memory structures that underlie emotions. It is argued that some form of exposure to feared situations is common to many psychotherapies for anxiety, and that confrontation with feared objects or situations is an effective treatment. Physiological activation and habituation within and across exposure sessions are cited as indicators of emotional processing, and variables that influence activation and habituation of fear responses are examined. These variables and the indicators are analyzed to yield an account of what information must be integrated for emotional processing of a fear structure. The elements of such a structure are viewed as cognitive representations of the stimulus characteristic of the fear situation, the individual's responses in it, and aspects of its meaning for the individual. Treatment failures are interpreted with respect to the interference of cognitive defenses, autonomic arousal, mood state, and erroneous ideation with reformation of targeted fear structures. Applications of the concepts advanced here to therapeutic practice and to the broader study of psychopathology are discussed.

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Emotional processing of fear : exposure to corrective information

A concise introduction to scalar timing theory.

Ten rats were trained to press a right lever following two successive sounds and to press a left lever following four successive sounds. Three sound sequences were used in initial discrimination training, such that reliable classification could not be based on the duration of each sound, the interval between sounds, or the total duration of the sound sequence. Classification of seven novel sound sequences suggested that the animals were either using number or the sum of sound durations in a sequence as the relevant cue. When this total sound duration was put in conflict with number, rats classified by number. The conclusion was that rats can discriminate number, even when temporal cues are controlled.

/pdf/discrimination-of-the-number-of-sequential-events-by-rats-3rlgrilvko.pdf

Discrimination of the number of sequential events by rats

Two experiments assessed the effects of nutrients on timing behavior by rats. The nutrients were laced with saccharin and given to rats as a snack before training on a 20-s peak-interval procedure. The primary component of the snacks for four groups of 10 rats was lecithin (phosphatidylchcline), protein (casein), carbohydrate (sucrose), or a nonnutrient (saccharin). The primary measure of behavior was the time of the rat's highest response rate during a trial (peak time), which represented the interval during which the rat maximally expected food. With a lecithin snack, peak time was gradually shifted over sessions to a shorter time, remained shifted to the left of the normal function with additional testing, and then remained at the shorter time on two sessions after the snack was discontinued; with the protein snack, peak time was abruptly shifted to a shorter time, returned to normal with additional testing, and then rebounded to a longer time when the snack was discontinued; with a carbohydrate, snack peak time was abruptly shifted to a longer time, returned to normal with additional testing, and then rebounded to a shorter time when the snack was discontinued. The behavioral patterns produced by the nutrients were interpreted in terms of precursor effects on central neurotransmitter synthesis and release, psychological stages of an information-processing model, and mathematical parameters of a scalar timing theory. Nutrients are substances contained in food that are important for supplying either the energy or the molecular building blocks that the body requires for normal functioning. Drugs are typically considered to be substances that are given for their effect on a specific organ or type of cell and are not generally considered to be essential components of normal body function. All healthy members of a particular species require essentially the same nutrients, but a drug ordinarily would be only administered to control a particular disease or create an abnormal condition. In this article, we describe three nutrients that when administered in relatively pure form as a snack before a test session can act like drugs in modifying psychological processes involved in temporal discrimination. Some nutrients can give rise to important changes in the chemical composition of structures in the brain (e.g., Wurtman, 1982; Zeisel, 1982). It should be possible to relate these biochemical changes to changes in timing behavior that can be explained by a psychological process model. At present the observed effects of nutrients on behavior have included changes in activity, attention and performance, food selection, and mood; as yet, no quantitative models have been developed to describe the effects of nutrients on behavior. Current

Nutrients That Modify the Speed of Internal Clock and Memory Storage Processes

The effective use of secondary data.

Arginine vasopressin innoculates against age-related increases in sodium-dependent high affinity choline uptake and discrepancies in the content of temporal memory

Russell M. Church

Papers

A concise introduction to scalar timing theory.

Discrimination of the number of sequential events by rats

Nutrients That Modify the Speed of Internal Clock and Memory Storage Processes

The effective use of secondary data.

Arginine vasopressin innoculates against age-related increases in sodium-dependent high affinity choline uptake and discrepancies in the content of temporal memory