Statistical contingency has a different impact on preparation judgements than on causal judgements

Previous studies on causal learning showed that judgements about the causal effect of a cue on an outcome depend on the statistical contingency between the presence of the cue and the outcome. We demonstrate that statistical contingency has a different impact on preparation judgements (i.e., judgements about the usefulness of responses that allow one to prepare for the outcome). Our results suggest that preparation judgements primarily reflect information about the outcome in prior situations that are identical to the test situation. These findings also add to previous evidence showing that people can use contingency information in a flexible manner depending on the type of test question.     

Predictions and causal estimations are not supported by the same associative structure

Studies performed by different researchers have shown that judgements about cue-outcome relationships are systematically influenced by the type of question used to request those judgements. It is now recognized that judgements about the strength of the causal link between a cue and an outcome are mostly determined by the cue-outcome contingency, whereas predictions of the outcome are more influenced by the probability of the outcome given the cue. Although these results make clear that those different types of judgement are mediated by some knowledge of the normative differences between causal estimations and outcome predictions, they do not speak to the underlying processes of these effects. The experiment presented here reveals an interaction between the type of question and the order of trials that challenges standard models of causal and predictive learning that are framed exclusively in associative terms or exclusively in higher order reasoning terms. However, this evidence could be easily explained by assuming the combined intervention of both types of process.     

Judgement of act-outcome contingency: The role of selective attribution

In the first experiment subjects were presented with a number of sets of trials on each of which they could perform a particular action and observe the occurrence of an outcome in the context of a video game. The contingency between the action and outcome was varied across the different sets of trials. When required to judge the effectiveness of the action in controlling the outcome during a set of trials, subjects assigned positive ratings for a positive contingency and negative ratings for a negative contingency. Furthermore, the magnitude of the ratings was related systematically to the strength of the actual contingency. With a fixed probability of an outcome given the action, judgements of positive contingencies decreased as the likelihood that the outcome would occur without the action was raised. Correspondingly, the absolute value of ratings of negative contingencies was increased both by an increment in the probability of the outcome in the absence of the action and by a decrement in the probability of the outcome following the action. A systematic bias was observed, however, in that positive judgements were given under a non-contingent relationship when the outcome frequency was relatively high. However, this bias could be reduced by giving extended exposure to the non-contingent schedule (Experiment 2).

This pattern of contingency judgements can be explained if it is assumed that a process of selective attribution operates, whereby people are less likely to attribute an outcome to some potential target cause if another effective cause is present. Experiments 2 and 3 demonstrated the operation of this process by showing that initially establishing another agent as an effective cause of the outcome subsequently reduced or blocked the extent to which the subjects attributed the outcome to the action.

Finally, we argue that the pattern and bias in contingency judgements based upon interactions with a causal process can be explained in terms of contemporary conditioning models of associative learning.     

Re-examination of the role of within-compound associations in the retrospective revaluation of causal judgements

We investigated blocking and retrospective revaluation of causal judgements using a scenario in which food cues acted as potential causes of an allergic reaction as the outcome. In the blocking contingency,the treatment cues were either paired or unpaired with the outcome prior to a second stage in which sequential compounds of treatment and target cues were paired with the outcome. The order of this compound and treatment training was reversed in retrospective revaluation contingencies. When the interstimulus interval between the treatment and target cues was unfilled on compound trials (Experiments 1 and 3), both blocking and retrospective revaluation were observed in that the target cue trained in compound with the paired treatment cue attracted lower causal ratings than the target cue trained in compound with the unpaired treatment cue. By contrast, performing a mental arithmetic task using numerals presented during the interstimulus interval had no effect on the magnitude of blocking but rendered retrospective revaluation unreliable (Experiments 2 and 3). These results provide further support for accounts of revaluation based upon within-compound associations.     

Instrumental judgment and performance under variations in action-outcome contingency and contiguity

The intentional theory of instrumental performance proposes that performance of an action is determined in part by a belief about its causal effectiveness in producing a desired outcome. At variance with this notion, previous implicit learning experiments appear to have yielded dissociations between subjects' performance and beliefs. In two experiments, subjects were given an opportunity to perform an action--pressing a key on a computer keyboard--which was associated with an outcome on the computer screen according to a free-operant contingency. The subjects in one group were asked to judge the effectiveness of the action in causing the outcome, while those in a second group were asked to maximize their points score under a payoff schedule. In the first study, the effect of varying the contingency between the action and outcome was examined by keeping the probability of an outcome contiguous with an action constant and varying the probability of an outcome in the absence of an action. Performance and judgments showed a comparable sensitivity to variations of the instrumental contingency. In the second study, the delay between the action and the resultant outcome was varied. Increasing the action-outcome delay from 0 sec up to 4 sec produced a systematic decline in both causal judgments and performance relative to noncontingent, control conditions. These results are in accord with the intentional theory of performance, but they present difficulties for the notion of implicit learning.     

Discounting and conditionalization

When people are asked to judge the strengths of two potential causes of an effect, they often demonstrate discounting--devaluing the strength of a target cause when it is judged in the presence of a strong (relative to a weak) alternative cause. Devaluing the target cause sometimes results from conditionalization--holding alternative causes constant while evaluating the target cause. Yet discounting not attributable to conditionalization also occurs. We sought to dissociate conditionalization and discounting (beyond that accounted for by conditionalization) by having subjects perform either a spatial or a verbal working memory task while learning a causal relation. Conditionalization was disrupted by the verbal task but not the spatial task; however, discounting was disrupted by the spatial task but not the verbal task. Conditionalization and discounting are therefore cognitively dissociable processes in human causal inference.     

Judgement of two causal candidates from contingency information: II. Effects of information about one cause on judgements of the other cause

When judgements are being made about two causes there are eight possible kinds of contingency information: occurrences and nonoccurrences of the outcome when both causes are present, when Cause 1 alone is present, when Cause 2 alone is present, and when neither cause is present. It is proposed that contingency information is used to some extent to judge proportionate strength, which is the proportion of occurrences of the outcome that each cause can account for. This leads to a prediction that judgements of one cause will be influenced by information about occurrences, but not nonoccurrences, of the outcome when only the other cause is present. In six experiments consistent support was found for this prediction when the cause being judged had a positive relation with the outcome, but no consistent tendency was found when the cause being judged had a negative relation with the outcome. The effects found for causes with positive contingency cannot be explained by the Rescorla-Wagner model of causal judgement nor by the hypothesis that causal judgements are based on conditional contingencies.     

Inattentional blindness for negative relationships in human causal learning

The present study focuses on the effect of selective attention on causal learning. Three effects of the level of attention to predictive symptoms in positive and negative contingency learning tasks are reported. First, participants accurately detected a positive relationship between an incidental cue and a contingent outcome, although judgements were slightly lower than those for the attended cue. Second, participants were unable to detect negative relationships between incidental cues and outcomes, which suggests a major role of selective attention in this type of learning. Third, participants retrieved the frequency of each trial type more accurately in the attended conditions than in the incidental conditions. These findings show how attention guides and constrains human causal learning and reveal an inattentional blindness effect for negative contingency learning.     

Inattentional blindness for negative relationships in human causal learning

The present study focuses on the effect of selective attention on causal learning. Three effects of the level of attention to predictive symptoms in positive and negative contingency learning tasks are reported. First, participants accurately detected a positive relationship between an incidental cue and a contingent outcome, although judgements were slightly lower than those for the attended cue. Second, participants were unable to detect negative relationships between incidental cues and outcomes, which suggests a major role of selective attention in this type of learning. Third, participants retrieved the frequency of each trial type more accurately in the attended conditions than in the incidental conditions. These findings show how attention guides and constrains human causal learning and reveal an inattentional blindness effect for negative contingency learning.     

Spatial separation of target and competitor cues enhances blocking of human causality judgements

Three experiments were carried out. Each required subjects to make judgements about the causal status of cues following a two-stage blocking procedure. In Stage 1 a competitor cue was consistently paired with an outcome, and in Stage 2 the competitor continued to be paired with the outcome but was accompanied by a target cue. It was predicted that causal judgements for the target would be reduced by the presence of the competitor. In Experiments 1 and 2 the blocking procedure was implemented as a computer simulation of a card game during which subjects had to learn which cards produced the best payouts. The cues that subjects used to make their judgement were colours and symbols that appeared on the backs of the cards. When the target and competitor cues appeared on the same card blocking effects did not emerge, but when they appeared as part of different cards blocking effects were found. Thus, spatial separation of target and competitor cues appeared to facilitate blocking. Experiment 3 replicated the blocking result using spatially separated target and competitor cues.     

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.     

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.     

Causal judgements about two causal candidates: Accounting for occurrences,estimating strength,and the importance of interaction judgements

When two possible causes of an outcome are under consideration, contingency information concerns each possible combination of presence and absence of the two causes with occurrences and nonoccurrences of the outcome. White (2008) proposed that such judgements could be predicted by a weighted averaging model integrating these kinds of contingency information. The weights in the model are derived from the hypothesis that causal judgements seek to meet two main aims, accounting for occurrences of the outcome and estimating the strengths of the causes. Here it is shown that the model can explain many but not all relevant published findings. The remainder can be explained by reasoning about interactions between the two causes, by scenario-specific effects, and by variations in cell weight depending on quantity of available information. An experiment is reported that supports this argument. The review and experimental results support the case for a cognitive model of causal judgement in which different kinds of contingency information are utilised to satisfy particular aims of the judgement process.     

Conditioned Inhibition in a Multiple Category Learning Task

Four experiments investigated inhibition that might arise in a task in which cues are associated with more than one outcome. In each experiment, human subjects played a game called 'Clues and Culprits' in which they were asked to judge the predictive strength of clues that had been associated with culprits in a series of hypothetical crimes. In a two-outcome version of the familiar conditioned inhibition paradigm (A+, AX- ), one clue was paired with one culprit on its own, but it was paired with a second culprit when it was combined with a second clue (A-1, AX-2). According to the delta rule, X should acquire inhibition for the first culprit; it should also acquire more inhibition than a differential cue merely associated with a second culprit (e.g. A-1, X-2). Inhibition was found with both procedures. However, the amount of inhibition did not differ between them, suggesting that mere association with a second outcome was sufficient to inhibit performance based on the first. Other data suggested the presence of cue competition. Also, when a cue associated with one culprit was paired with a second culprit on other trials, there was little evidence of unlearning of the first association.     

Causal powers and preventers: An explanatory account of cue interaction effects in human causal judgement

According to the causal powers theory, all causal relations are understood in terms of causal powers of one thing producing an effect by acting on liability of another thing. Powers can vary in strength, and their operation also depends on the presence of preventers. When an effect occurs, there is a need to account for the occurrence by assigning sufficient strength to produce it to its possible causes. Contingency information is used to estimate strengths of powers and preventers and the extent to which they account for occurrences and nonoccurrences of the outcome. People make causal judgements from contingency information by processes of inference that interpret evidence in terms of this fundamental understanding. From this account it is possible to derive a computational model based on a common set of principles that involve estimating strengths, using these estimates to interpret ambiguous information, and integrating the resultant evidence in a weighted averaging model. It is shown that the model predicts cue interaction effects in human causal judgement, including forward and backward blocking, second and third order backward blocking, forward and backward conditioned inhibition, recovery from overshadowing, superlearning, and backward superlearning.     

Temporal contiguity and the judgement of causality by human subjects

Three experiments examined the role of the degree of temporal contiguity between an action and an outcome in human causality judgement. In all the experiments subjects were required to perform an action—pressing a key on a computer keyboard—and to judge the extent to which the action caused an outcome on the computer screen to occur. The action and outcome occurred on a free-operant schedule. In the first experiment a 2-sec delay between the action and outcome reduced causality judgements relative to a situation in which there was no delay. In the second experiment judgements in conditions with delays of 0, 4, 8, and 16 sec were compared with judgements in conditions in which the same pattern of outcomes occurred non-contingently with respect to the subjects' responding. In both of these experiments the events were controlled by random ratio schedules, following the procedure of Wasserman, Chatlosh, and Neunaber (1983), in which each condition was divided into 1-sec intervals. In the third experiment judgements in conditions with delays of 0, 2, 4, or 8 sec were compared in a continuous procedure rather than one divided into 1-sec intervals. In all experiments the increasing delays led to progressively lower judgements of causality. The results are related to three accounts of the mechanism underlying human causality judgement and are also compared with results from analogous animal conditioning studies.     

Human judgements of control: The interaction of the current contingency and previous controllability

Two experiments were carried out to determine the effects of the learned helplessness treatment on judgement of control over a outcome. In the first experiment judgements were found to be sensitive to the actual level of response-outcome contingency. When the contingency level was high, this sensitivity was also influenced by pretreatment, in that a prior uncontrollable experience gave rise to lower judgements than both a controllable one and no experience at all. The latter pretreatments produced the most accurate judgements. In the second experiment the judgements after an uncontrollable task were found to be insensitive to a previous controllable or uncontrollable pretreatment. The results are discussed in terms of contingency-learning models.     

Perceiving a strong causal relation in a weak contingency: Further investigation of the evidential evaluation model of causal judgement

Contingency information is information about the occurrence or nonoccurrence of a certain effect in the presence or absence of a candidate cause. An objective measure of contingency is the δP rule, which involves subtracting the probability of occurrence of an effect when a causal candidate is absent from the probability of occurrence of the effect when the candidate is present. Causal judgements conform closely to δP but deviate from it under certain circumstances. Three experiments show that such deviations can be predicted by a model of causal judgement that has two components: a rule of evidence, that causal judgement is a function of the proportion of relevant instances that are judged to be confirmatory for the causal candidate, and a tendency for information about instances in which the candidate is present to have greater effect on judgement than instances in which the candidate is absent. Two experiments demonstrate how this model accounts for some recently published findings. A third experiment shows that it is possible to use the model to predict the occurrence of high causal judgements when the objective contingency is close to zero.     

Contiguity and the outcome density bias in action-outcome contingency judgements

In cause-outcome contingency judgement tasks, judgements often reflect the actual contingency but are also influenced by the overall probability of the outcome, P(O). Action-outcome instrumental learning tasks can foster a pattern in which judgements of positive contingencies become less positive as P(O) increases. Variable contiguity between the action and the outcome may produce this bias. Experiment 1 recorded judgements of positive contingencies that were largely uninfluenced by P(O) using an immediate contiguity procedure. Experiment 2 directly compared variable versus constant contiguity. The predicted interaction between contiguity and P(O) was observed for positive contingencies. These results stress the sensitivity of the causal learning mechanism to temporal contiguity.     

Cue interaction in human contingency judgment

Most studies of human contingency judgment have been based on the assumption that frequency information about one predictor is assessed in isolation of information about other predictors. Recent evidence, however, suggests that the judged predictive strength of one cue is influenced by the predictive strengths of other copresent cues. Two experiments demonstrate that stimuli with the same outcome contingencies may nonetheless have different predictive strengths as the result of cue interaction. The first experiment, in which a within-subject design was used, provides a demonstration of blocking. A stimulus presented in compound with a strong predictor was rated as less predictive than another stimulus that was presented in compound with a nonpredictive cue. In the second experiment, cue interactions in conditioned inhibition were examined. A stimulus gained negative predictive strength as the result of compound presentations with a positive predictor when the outcome was not presented. This negative predictor was compared with an otherwise analogous stimulus that was not presented in compound with a positive predictor. These results support the use of animal-conditioning models as accounts of human contingency learning.