Dissociating Processes Supporting Causal Perception and Causal Inference in the Brain.

An understanding of relations between causes and effects is essential for making sense of the dynamic physical world. It has been argued that this understanding of causality depends on both perceptual and inferential components. To investigate whether causal perception and causal inference rely on common or on distinct processes, the authors tested 2 callosotomy (split-brain) patients and a group of neurologically intact participants. The authors show that the direct perception of causality and the ability to infer causality depend on different hemispheres of the divided brain. This finding implies that understanding causality is not a unitary process and that causal perception and causal inference can proceed independently. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Congruency proportion reveals asymmetric processing of irrelevant physical and numerical dimensions in the size congruity paradigm.

When the proportion of congruent trials in conflict tasks is manipulated (e.g., Stroop, Simon), the typical result is that the magnitude of the conflict effect increases as the proportion of congruent trials increases. The present experiment investigated the influence of Congruency Proportion in the context of the Size Congruity Paradigm. Congruency Proportion had a significant impact on the Numerical Judgement Task (judging which of two numbers is numerically larger), but not on the Physical Judgement Task (judging which of two numbers is printed in a larger font). These data support the inference that physical size information is processed before, and more fluently than, numerical size information. The implications of this asymmetry are discussed in terms of the relative role of semantic and physical size information in representations of magnitude, and the role they play in both of these tasks. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Theory and Data Interactions of the Scientific Mind: Evidence From the Molecular and the Cognitive Laboratory.

A number of researchers and scholars have stressed the importance of disconfirmation in the quest for the development of scientific knowledge (e.g., Popper, 1959). Paradoxically, studies examining human reasoning in the laboratory have typically found that people display a confirmation bias in that they are more likely to seek out and attend to data consistent rather than data inconsistent with their initial theory (Wason, 1968). We examine the strategies that scientists and students use to evaluate data that are either consistent or inconsistent with their expectations. First, we present findings from scientists reasoning "live" in their laboratory meetings. We show that scientists often show an initial reluctance to consider inconsistent data as "real." However, this initial reluctance is often overcome with repeated observations of the inconsistent data such that they modify their theories to account for the new data. We further examine these issues in a controlled scientific causal thinking simulation specifically developed to examine the reasoning strategies we observed in the natural scientific environment. Like the scientists, we found that participants in our simulation initially displayed a propensity to discount data inconsistent with a theory provided. However, with... (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Belief-Based and covariation-based cues affect causal discounting.

Examined the extent to which individuals' a priori beliefs contribute to the degree of causal discounting and how those beliefs are combined with covariation-based cues. Ss were 72 university students who made causality judgments on multiple causal candidates for a single given effect in 6 stories. Each candidate varied in terms of the degree to which it covaried with the effect and the degree to which it was a believable precursor to the observed effect. The 1st cause, was of neutral belief and was moderately contingent with the effect. The 2nd cause was either highly believable or highly unbelievable and was either less, the same, or more contingent than the 1st cause. Ss made their judgments before and after being presented with the 2nd cause. The results indicate that the degree to which a causal candidate is discounted depends not only on the degree to which an alternative cause covaries with the effect, but also on whether the alternative is a believable or unbelievable candidate. Specifically, the results show that a highly believable alternative will produce the discounted effect, even if it is a weaker covariate than the original candidate. These findings suggest the need to incorporate both belief-based and covariation-based cues into models of causal attribution. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of lexicality and distinctiveness on repetition blindness.

The repetition blindness (RB) paradigm developed by K. M. Arnell and P. Jolic?ur (1997) was used to examine effects of lexicality (word vs. nonword target pairs) and target distinctiveness on RB. Distinctiveness was manipulated by having both targets (Experiments 1 and 2) or only the first target (Experiment 3) brighter than nontarget items. All 3 experiments demonstrated strong RB for word targets but no RB for nonword targets. This confirms that RB depends on pre-existing memory representations. In fact, there was repetition facilitation for nonwords in Experiments 2 and 3. These experiments also demonstrated that RB is reduced when targets are distinctive. This finding is better understood in terms of RB as a failure of memory rather than as a failure of perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Remembering makes evidence compelling: Retrieval from memory can give rise to the illusion of truth.

The illusion of truth is traditionally described as the increase in perceived validity of statements when they are repeated (Hasher, Goldstein, & Toppino, 1977). However, subsequent work has demonstrated that the effect can arise due to the increased familiarity or fluency afforded by repetition and not necessarily to repetition per se. We examine the case of information retrieved from memory. Recently experienced information is expected to be subsequently reexperienced as more fluent and familiar than novel information (Jacoby, 1983; Jacoby & Dallas, 1981). Therefore, the possibility exists that information retrieved from memory, because it is subjectively reexperienced at retrieval, would be more fluent or familiar than when it was first learned and would thus lead to an increase in perceived validity. Using a method to indirectly poll the perceived truth of factual statements, our experiment demonstrated that information retrieved from memory does indeed give rise to an illusion of truth. The effect was larger than when statements were explicitly repeated twice and was of comparable size to when statements were repeated 4 times. We conclude that memory retrieval is a powerful method for increasing the perceived validity of statements (and subsequent illusion of truth) and that the illusion of truth is a robust effect that can be observed even without directly polling the factual statements in question. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strategy selection in causal reasoning: When beliefs and covariation collide.

Investigated how people combine covariation information with pre-existing beliefs when evaluating causal hypotheses. Ss were 752 college students (aged 17–52 yrs). Three experiments, using both within- and between-Ss designs, found that the use of covariation information and beliefs interacted, such that the effects of covariation were larger when people assessed hypotheses about believable than about unbelievable causal candidates. In Exp 2, this interaction was observed when Ss made judgments in stages (e.g., first evaluating covariation information about a causal candidate and then evaluating the believability of a candidate), as well as when the information was presented simultaneously. Exp 3 demonstrated that this pattern was also reflected in Ss' metacognitive judgments: Ss indicated that they weighed covariation information more heavily for believable than unbelievable candidates. Finally, Exps 1 and 2 demonstrated the presence of individual differences in the use of covariation- and belief-based views. That is, individuals who tended to base their causality judgments primarily on belief were less likely to make use of covariation information and vice versa. (PsycINFO Database Record (c) 2010 APA, all rights reserved)