Samuel D. Hannah

The sad truth about depressive realism

In one form of a contingency judgement task individuals must judge the relationship between an action and an outcome. There are reports that depressed individuals are more accurate than are nondepressed individuals in this task. In particular, nondepressed individuals are influenced by manipulations that affect the salience of the outcome, especially outcome probability. They overestimate a contingency if the probability of an outcome is high—the “outcome-density effect”. In contrast, depressed individuals display little or no outcome-density effect. This apparent knack for depressives not to be misled by outcome density in their contingency judgements has been termed “depressive realism”, and the absence of an outcome-density effect has led to the characterization of depressives as “sadder but wiser”. We present a critical summary of the depressive realism literature and provide a novel interpretation of the phenomenon. We suggest that depressive realism may be understood from a psychophysical analysis of contingency judgements.

Just tell me what to do: Bringing back experimenter control in active contingency tasks with the command-performance procedure, and finding cue density effects along the way

Active contingency tasks, such as those used to explore judgments of control, suffer from variability in the actual values of critical variables. The authors debut a new, easily implemented procedure that restores control over these variables to the experimenter simply by telling participants when to respond, and when to withhold responding. This command-performance procedure not only restores control over critical variables such as actual contingency, it also allows response frequency to be manipulated independently of contingency or outcome frequency. This yields the first demonstration, to our knowledge, of the equivalent of a cue density effect in an active contingency task. Judgments of control are biased by response frequency outcome frequency, just as they are also biased by outcome frequency.

An instance theory of associative learning

We present and test an instance model of associative learning. The model, Minerva-AL, treats associative learning as cued recall. Memory preserves the events of individual trials in separate traces. A probe presented to memory contacts all traces in parallel and retrieves a weighted sum of the traces, a structure called the echo. Learning of a cue–outcome relationship is measured by the cue’s ability to retrieve a target outcome. The theory predicts a number of associative learning phenomena, including acquisition, extinction, reacquisition, conditioned inhibition, external inhibition, latent inhibition, discrimination, generalization, blocking, overshadowing, overexpectation, superconditioning, recovery from blocking, recovery from overshadowing, recovery from overexpectation, backward blocking, backward conditioned inhibition, and second-order retrospective revaluation. We argue that associative learning is consistent with an instance-based approach to learning and memory.

Contingency judgements on the fly

The present research was conducted to establish the validity of a novel procedure for measuring human contingency judgements aimed at shortening the length of conventional procedures. Cues and outcomes were simple geometric shapes that were presented in a rapid streaming fashion, reducing the length of a block of trials from several minutes to a few seconds. We establish the reliability of the procedure by replicating two central findings in the contingency judgement literature, and we elaborate on the importance of this method for future research.

A Memory-Based Account of Retrospective Revaluation

We adapt an instance model of human memory, Minerva 2, to simulate retrospective revaluation. In the account, memory preserves the events of individual trials in separate traces. A probe presented to memory contacts all traces in parallel and causes each to become active. The information retrieved from memory is the sum of the activated traces. Learning is modelled as a process of cued-recall; encoding is modelled as a process of differential encoding of unexpected features in the probe (i.e., expectancy-encoding). The model captures three examples of retrospective revaluation: backward blocking, recovery from blocking, and backward conditioned inhibition. The work integrates an understanding of human memory and complex associative learning.

The consequences of surrendering a degree of freedom to the participant in a contingency assessment task.

Many studies of contingency judgments have used a task in which, on each trial, the participant is free either to respond or not to respond, and an outcome may, or may not, be presented. Typically, the experimenter specifies a nominal value for the contingency between responding and outcome, but the actual values of a variety of variables experienced by a particular participant depend on that participants frequency of responding. The results of computer simulations of various strategies for implementing the contingency manipulation, and the results of an experiment, indicate that the same nominal contingency value will lead to considerable variability in the actual contingency experienced by participants. Moreover, nominal contingency manipulations are confounded with the probability that the subject experiences an outcome. While researchers might be aware of these issues, not enough attention has been paid to their potential impact.

Producing biased diagnoses with unambiguous stimuli : The importance of feature instantiations

In this article, the authors demonstrate a laboratory analogue of medical diagnostic biasing (V. R. LeBlanc, G. R. Norman, & L. R. Brooks, 2001) in 2 experiments and explore the basis of this effect. Before categorizing novel exemplars, participants first evaluated the likelihood that the item was a member of the category suggested on that trial: either the correct category or a plausible alternative category. This was sufficient to produce a substantial bias toward the suggested category despite the use of unambiguous stimuli, explicit rules, and unhurried conditions--each of which would be likely to limit diagnostic bias. The authors argue that the production of this effect requires distinguishing between particular feature instantiations and more abstract representations of those features as well as allowing people to adopt a particular decision strategy mediating the use of instantiated features: a feature-recognition heuristic.

Neural temporal dynamics of contingency judgement.

The present study captures the dynamics of neural processing across positively contingent, negatively contingent, and noncontingent relations. In the setting of a hypothetical chat room conversation, participants rated the contingency of emotional response between two individuals. Event-related potentials (ERPs) were time-locked to the onset of each emotional event. Although each event alone was ambiguous regarding contingency, its neural response was characteristic of the overall contingent relation and the subsequent contingency rating. Very early displays of contingency modified the ERP anterior N1 (AN1) component amplitude. In contrast, the ERP selection negativity (SN) component amplitude seemed to be more sensitive to display properties than contingency. Our results point to the recruitment of early attentional processes for contingency judgement and highlight the efficiency of statistical information processing.

Featuring familiarity: how a familiar feature instantiation influences categorization.

We demonstrate that a familiar looking feature can influence categorization through 2 different routes, depending on whether a person is reliant on abstract feature representations or on concrete feature representations. In 2 experiments, trained participants categorized new category members in a 3-step procedure: Participants made an initial categorization, described the rule-consistent features indicated by the experimenter, and then recategorized the item. Critical was what happened on the second categorization after participants initially categorized an item based on a familiar, but misleading, feature. Participants who were reliant on abstract features most commonly reversed themselves after the rule-consistent features were pointed out, suggesting that the familiar feature had biased attention. Participants who were reliant on concrete feature representations, however, most commonly persisted with the initial response as if the familiar feature were more important than its rivals-the familiar feature biased decision making.

Age differences in contingency judgement linked to perceptual segregation

We demonstrate large differences in judging positive and null contingencies between younger and older adults with a task commonly used to explore cue competition in both contingency and causality judgements. The one-phase blocking task uses two cues, with separate contingencies with the same outcome. The age differences persisted even when participants knew in advance which of the two contingencies to judge. The age differences disappeared, however, when the stimulus display contained markers aiding perceptual segregation. We suggest that the age differences elicited in the one-phase blocking task are linked to decrements in perceptual segregation.