Lorraine G. Allan

The perception of time

The present paper organizes and evaluates selected portions of the time perception literature. Emphasis is on data and theory concerned primarily with judgments of brief temporal intervals. Research concerning the psychophysical law for time, Weber’s law, the time-order error, and the role of nontemporal information is evaluated. This is followed by a consideration of current, quantitatively oriented, theoretical formulations for time perception.

Human bisection at the geometric mean

Abstract Theoretical developments have proceeded relatively independently in the human and animal timing literatures, even though many of the issues addressed have been similar. In the animal timing literature, an influential model is Scalar Timing. There have been few direct applications of Scalar Timing to human timing. The main purpose of the present paper is to present human timing data from experiments designed specifically to evaluate Scalar Timing. A human analog of the animal bisection discrimination procedure was used. The human bisection data were consonant with Scalar Timing: bisection was at the GM of the two referent durations and psychometric functions superposed when normalized by the bisection point.

A note on measurement of contingency between two binary variables in judgment tasks

Varied measures of contingency have appeared in the psychological judgment literature concerned with binary variables. These measures are examined, and the inappropriateness of some are noted. As well, it is argued that accurate judgments about related variables should not be used to infer that the judgments are based on the appropriate information.

Human contingency judgments: Rule based or associative?

The study of the mechanism that detects the contingency between events, in both humans and nonhuman animals, is a matter of considerable research activity. Two broad categories of explanations of the acquisition of contingency information have received extensive evaluation: rule-based models and associative models. This article assess the two categories of models for human contingency judgments. The data reveal systematic departures in contingency judgments from the predictions of rule-based models. Recent studies indicate that a contiguity model of Pavlovian conditioning is a useful heuristic for conceptualizing human contingency judgments.

The effect of a prior presentation on temporal judgments in a perceptual identification task

Subjects read aloud words presented once at the rate of one per second. A perceptual identification task, involving 30- or 50-msec presentations, followed. Some of the words presented for identification had been read previously; others were new. After each presentation, in addition to identifying the word, the subjects judged its duration. The data indicate that a single presentation of a word affects its later perception, as revealed by enhanced perceptual identification, longer duration judgments, and better temporal discrimination. A second experiment showed that a single presentation influenced duration judgments even when identification was not required. The final experiment addressed the issue of what is preserved in memory from a prior presentation. The results from the three experiments indicate that duration judgments provide a valuable dependent measure of memory in the perceptual identification task and support the misattribution hypothesis: A prior presentation enhances perceptual identification, and this increase in relative perceptual fluency is incorrectly attributed to a longer presentation duration.

The effect of representations of binary variables on judgment of influence

Abstract Studies concerned with judgments of contingency between binary variables have often ignored what the variables stand for. The two values of a binary variable can be represented as a prevailing state (nonevent) or as an active state (event). Judgments under the four conditions resulting from the combination of a binary input variable that can be represented as event-nonevent or event-event with an outcome variable that can be represented in the same way were obtained. It is shown in Experiment 1, that judgments of data sets which exhibit the same degree of covariation depend upon how the input and output variables are represented. In Experiment 2 the case where both the input and output variables are represented as event-nonevent is examined. Judgments were higher when the pairing of the input event was with the output event and the input nonevent with the output nonevent that when the pairing was of event with nonevent, suggesting a causal compatibility of event-event pairings and a causal incompatibility of event-nonevent pairings. Experiment 3 demonstrates that judgments of the strength of the relation between binary input and output variables is not based on the appropriate statistical measure, the difference between two conditional probabilities. The overall pattern of judgments in the three experiments is mainly explicable on the basis of two principles: (1) judgments tend to be based on the difference between confirming and disconfirming cases and (2) causal compatibility in the representation of the input and output variables plays a critical role.

Psychophysical theories of duration discrimination

There are few quantitative theories of duration discrimination and few established empirical phenomena to guide theorizing. This paper discusses three such theories and several empirical findings. The theories assume that the discrimination is based only upon information extracted from the temporal extent of the stimulus pattern, and experimental evidence is presented that clearly supports this assumption for many stimulus patterns. Recent findings which indicate that duration information is analyzed in certain ways that are fundamentally different from other stimulus dimensions are reviewed, the duration discrimination psychometric function is examined, and the time-order error is discussed. The three theories are compared in terms of their ability to incorporate the empirical data.

The widespread influence of the Rescorla-Wagner model

The theory of Pavlovian conditioning presented by Robert Rescorla and Allan Wagner in 1972 (the Rescorla-Wagner model) has been enormously important in animal learning research. It also has been applied in a variety of areas other than animal learning. We summarize the contribution of the Rescorla-Wagner model to research in verbal learning, social psychology, human category learning, human judgments of correlational relationships, transitive inference, color aftereffects, and physiological regulation. We conclude that there have been few models in experimental psychology as influential as the Rescorla-Wagner model.

Duration discrimination of brief light flashes.

The data from four experiments indicate that when Os discriminate between light flashes of different durations, for durations for which Bloch’s law has been shown to hold, their discriminations are frequently made on the temporal information available in the flashes rather than on their apparent brightness. A model for duration discrimination which specifies that discriminability depends only on the difference in duration between the two brief flashes, and is independent of their durations, is presented and applied to the data.

A Signal Detection Theory Analysis of the Placebo Effect

Some instances of the placebo effect may be understood as a particular type of error made by the patient—a false positive error. False positive errors are common (indeed, frequently encouraged) in medical decision making, both by diagnosticians and by patients, and are the inevitable consequence of concluding that an ambiguous signal (e.g., attenuation of pain, relief of depression) did, or did not, occur. Signal detection theory (SDT) was developed to model errors in the detection of ambiguous signals. The authors use SDT to understand the false positive errors that might be made by patients administered a placebo and termed a placebo effect.