Aligning Spinoza with Descartes: An informed Cartesian account of the truth bias

Remembering the truth or falsity of advertising claims: A preregistered model-based test of three competing theoretical accounts

Given the large amount of information that people process daily, it is important to understand memory for the truth and falsity of information. The most prominent theoretical models in this regard are the Cartesian model and the Spinozan model. The former assumes that both "true" and "false" tags may be added to the memory representation of encoded information; the latter assumes that only falsity is tagged. In the present work, we contrasted these two models with an expectation-violation model hypothesizing that truth or falsity tags are assigned when expectations about truth or falsity must be revised in light of new information. An interesting implication of the expectation-violation model is that a context with predominantly false information leads to the tagging of truth whereas a context with predominantly true information leads to the tagging of falsity. To test the three theoretical models against each other, veracity expectations were manipulated between participants by varying the base rates of allegedly true and false advertising claims. Memory for the veracity of these claims was assessed using a model-based analysis. To increase methodological rigor and transparency in the specification of the measurement model, we preregistered, a priori, the details of the model-based analysis test. Despite a large sample size (N = 208), memory for truth and falsity did not differ, regardless of the base rates of true and false claims. The results thus support the Cartesian model and provide evidence against the Spinozan model and the expectation-violation model.

The effect of value on context and target recollection in memory for truth and falsity

Memory for truth and falsity has recently been investigated from the perspective of the dual-recollection theory, showing better context and target recollection for truth than falsity. In this paper, we examine whether these memory effects obtained for true statements are similar to the value effect, whereby true statements are given higher priority in encoding. For this purpose, we implemented value-directed remembering (VDR) into the conjoint-recognition paradigm. In our first experiment, the primary goal was to verify how VDR influences the processes defined by dual-recollection theory. At study, prioritized/important items were linked to higher numerical values (e.g., 10), while unimportant ones had lower values (e.g., 1). At test, the participants' task was to recognize whether a particular sentence was important, unimportant, or new. We found that both context and target recollection were better for important items. In the second experiment, the main goal was to study the combined effects of importance and veracity on memory. In the between-subjects design, participants were monetarily rewarded for memorizing true or false sentences. The results demonstrated differences in the ability to prioritize truth over falsity. Specifically, we found a substantial increase in context recollection for prioritized true information but not for prioritized false information. Moreover, we found higher context recollection for true than false sentences in the true-prioritized condition, but not in the false-prioritized condition. These results indicated that people are able to prioritize true information better than false, and suggested that memory for truth may be a special case of the value effect.

Evidence for Spinozan "Unbelieving" in the Right Inferior Prefrontal Cortex

Humans can think about possible states of the world without believing in them, an important capacity for high-level cognition. Here, we use fMRI and a novel "shell game" task to test two competing theories about the nature of belief and its neural basis. According to the Cartesian theory, information is first understood, then assessed for veracity, and ultimately encoded as either believed or not believed. According to the Spinozan theory, comprehension entails belief by default, such that understanding without believing requires an additional process of "unbelieving." Participants (n = 70) were experimentally induced to have beliefs, desires, or mere thoughts about hidden states of the shell game (e.g., believing that the dog is hidden in the upper right corner). That is, participants were induced to have specific "propositional attitudes" toward specific "propositions" in a controlled way. Consistent with the Spinozan theory, we found that thinking about a proposition without believing it is associated with increased activation of the right inferior frontal gyrus. This was true whether the hidden state was desired by the participant (because of reward) or merely thought about. These findings are consistent with a version of the Spinozan theory whereby unbelieving is an inhibitory control process. We consider potential implications of these results for the phenomena of delusional belief and wishful thinking.

Plausibility matters: A challenge to Gilbert's "Spinozan" account of belief formation

Most of the claims we encounter in real life can be assigned some degree of plausibility, even if they are new to us. On Gilbert's (1991) influential account of belief formation, whereby understanding a sentence implies representing it as true, all new propositions are initially accepted, before any assessment of their veracity. As a result, plausibility cannot have any role in initial belief formation on this account. In order to isolate belief formation experimentally, Gilbert, Krull, and Malone (1990) employed a dual-task design: if a secondary task disrupts participants' evaluation of novel claims presented to them, then the initial encoding should be all there is, and if that initial encoding consistently renders claims 'true' (even where participants were told in the learning phase that the claims they had seen were false), then Gilbert's account is confirmed. In this pre-registered study, we replicate one of Gilbert et al.'s (1990) seminal studies ("The Hopi Language Experiment") while additionally introducing a plausibility variable. Our results show that Gilbert's 'truth bias' does not hold for implausible statements - instead, initial encoding seemingly renders implausible statements 'false'. As alternative explanations of this finding that would be compatible with Gilbert's account can be ruled out, it questions Gilbert's account.

Recollection of "true" feedback is better than "false" feedback independently of a priori beliefs: an investigation from the perspective of dual-recollection theory

The processes underlying memory for truth and falsity have been explored and discussed in experimental psychology for over thirty years now. Psychologists have often referred to the Spinozan and Cartesian models about truth-value information "tagging" but, so far, experimental results have been inconsistent. This paper investigates memory for truth and falsity from the new perspective of the dual-recollection theory. We conducted two experiments using the conjoint recognition paradigm and multinomial modelling as a measurement model. Both our experiments confirmed a satisfactory goodness of fit of the data to the dual-recollection multinomial model. In Experiment 1, the context recollection parameter representing memory for feedback information was significantly higher for true than for false statements. This finding was replicated in the second experiment, which controlled the potential impact of participants' previous knowledge on memory performance. Experiment 2 indicated that the target recollection parameter representing memory for the sentence itself was significantly higher for true than for false sentences solely when participants believed this sentence to be true but not when they perceived it as false before the memory experiment. Our research was the first attempt to look at memory for truth and falsity from the perspective of the recently developed dual-recollection theory.

More evidence against the Spinozan model: Cognitive load diminishes memory for "true" feedback

We tested two competing models on the memory representation of truth-value information: the Spinozan model and the Cartesian model. Both models assume that truth-value information is represented with memory "tags," but the models differ in their coding scheme. According to the Cartesian model, true information is stored with a "true" tag, and false information is stored with a "false" tag. In contrast, the Spinozan model proposes that only false information receives "false" tags. All other (i.e., untagged) information is considered as true by default. Hence, in case of cognitive load during feedback encoding, the latter model predicts a load effect on memory for "false" feedback, but not on memory for "true" feedback. To test this prediction, participants studied trivia statements (Experiment 1) or nonsense statements that allegedly represented foreign-language translations (Experiment 2). After each statement, participants received feedback on the (alleged) truth value of the statement. Importantly, half of the participants experienced cognitive load during feedback processing. For the trivia statements of Experiment 1, we observed a load effect on memory for both "false" and "true" feedback. In contrast, for the nonsense statements of Experiment 2, we found a load effect on memory for "true" feedback only. Both findings clearly contradict the Spinozan model. However, our results are also only partially in line with the predictions of the Cartesian model. For this reason, we suggest a more flexible model that allows for an optional and context-dependent encoding of "true" tags and "false" tags.