A propositional perspective on context effects in human associative learning

Contingency inferences from base rates: A parsimonious strategy?

The pseudocontingency framework provides a parsimonious strategy for inferring the contingency between two variables by assessing the base rates. Frequently occurring levels are associated, as are rarely occurring levels. However, this strategy can lead to different contingency inferences in different contexts, depending on how the base rates vary across contexts. Here, we examine how base-rate consistency influences base-rate learning and reliance by contrasting consistent with inconsistent base rates. We hypothesized that base-rate learning is facilitated, and that people rely more on base rates if base rates are consistent. In Experiment 1, the base rates across four contexts implied the same (consistent) or different (inconsistent) contingencies. Base rates were learned equally accurately, and participants inferred contingencies that followed the base rates but deviated from the genuine contingencies within contexts, regardless of consistency. In Experiment 2, we additionally manipulated whether the context was a plausible moderator of the contingency. While we replicated the first experiment's results when the context was a plausible moderator, base-rate inferences were stronger for consistent base rates when the context was an implausible moderator. Possibly, when a moderation-by-context was implausible, participants also relied on the base-rate correlation across contexts, which implied the same contingency when base rates were consistent but was zero when the base rates were inconsistent. Thus, our findings suggest that contingency inferences from base rates involve top-down processes in which people decide how to use base-rate information.

The Influence of Packaging Color on Consumer Perceptions of Healthfulness: A Systematic Review and Theoretical Framework

When consumers evaluate a new product, packaging design plays a critical role. In particular, packaging color is a dominant design cue that influences consumer perception of a product. Several studies have investigated the influence of color on taste. However, there is limited research on the influence of packaging color on consumer health perception. As healthy eating is a focus for many consumers and public decision-makers, more knowledge is needed. The aim of this review is to provide an overview of empirical studies that have investigated the influence of packaging color on consumers' health perceptions and to provide a psychological explanation for the observed effects. The systematic review includes 20 empirical studies across different product groups. The results show that packaging color influences consumers' health perceptions. We argue that the influence of packaging color on consumer health perceptions can be explained by the following mechanisms, which are not mutually exclusive: (1) consumers rely on a color as an explicit signal for health; (2) colors are associated with beliefs that indirectly influence health assessments; and (3) colors trigger mental simulations that influence health assessments. In addition, we provide suggestions for further research that will contribute to a better understanding of when and how packaging color can help consumers make healthier food choices.

Do Task Sets Compete in the Stroop Task and Other Selective Attention Paradigms?

Task sets have been argued to play an important role in cognition, giving rise to the notions of needing to switch between active task sets and to control competing task sets in selective attention tasks. For example, it has been argued that Stroop interference results from two categories of conflict: informational and task (set) conflict. Informational conflict arises from processing the word and is resolved by a late selection mechanism; task conflict arises when two task sets (i.e., word reading and colour identification) compete for activation and can be construed as involving an early selection mechanism. However, recent work has argued that task set control might not be needed to explain all of the switching cost in task switching studies. Here we consider whether task conflict plays a role in selective attention tasks. In particular, we consider whether S-R associations, which lead to informational conflict, are enough on their own to explain findings attributed to task set conflict. We review and critically evaluate both the findings that provided the original impetus for proposing task conflict in selective attention tasks and more recent findings reporting negative facilitation (longer RTs to congruent than to neutral stimuli) - a unique marker of task conflict. We then provide a tentative alternative account of negative facilitation based on poor control over informational conflict and apply it to a number of paradigms including the Colour-Object interference and Affordances tasks. It is argued that invoking competition between task sets in selective attention tasks might not be necessary.

Controlled and implicit processes in evaluative conditioning on implicit and explicit attitudes toward alcohol and intentions to drink

Since implicit attitudes (i.e. evaluations occurring outside of complete awareness) are highly predictive of alcohol consumption, we tested an evaluative learning procedure based on repeated pairing to a critical stimulus (i.e. alcohol, the CS) with a valenced stimulus (the US) in order to modify implicit attitudes (i.e. evaluative conditioning; EC). We hypothesized that manipulating the learning context to bolster implicit affect misattribution should strengthen EC effects on implicit attitudes toward alcohol, while encouraging deliberate processing of CS-US pairs, should strengthen EC effects on explicit attitudes. In our study (n=114 students) we manipulated whether CS-US pairs were presented simultaneously or sequentially. Recollective memory was estimated with a Process Dissociation Procedure. Both implicit and explicit attitudes were assessed immediately after the procedure. Behavioral intentions were measured directly after and one week after the EC-procedure. We found that EC with sequential presentation had a stronger impact on implicit and explicit measures and on purchase intentions immediately after the procedure and one week after. The present findings provide new evidence that (i) EC is an effective way to change implicit attitudes toward alcohol and (ii) evidence that EC may be better described by propositional rather than dual process accounts.

Beyond associations: Do implicit beliefs play a role in smoking addiction?

BACKGROUND AND OBJECTIVES

Influential dual-system models of addiction suggest that an automatic system that is associative and habitual promotes drug use, whereas a controlled system that is propositional and rational inhibits drug use. It is assumed that effects on the Implicit Association Test (IAT) reflect the automatic processes that guide drug seeking. However, results have been inconsistent, challenging: (1) the validity of addiction IATs; and (2) the assumption that the automatic system contains only simple associative information. We aimed to further test the validity of IATs that are used within this field of research using an experimental design. Second, we introduced a new procedure aimed at examining the automatic activation of complex propositional knowledge, the Relational Responding Task (RRT) and examine the validity of RRT effects in the context of smoking.

METHODS

In two experiments, smokers performed two different tasks: an approach/avoid IAT and a liking IAT in Experiment 1, and a smoking urges RRT and a valence IAT in Experiment 2. Smokers were tested once immediately after smoking and once after 10 hours of nicotine-deprivation.

RESULTS

None of the IAT scores were affected by the deprivation manipulation. RRT scores revealed a stronger implicit desire for smoking in the deprivation condition compared to the satiation condition.

CONCLUSIONS

IATs that are currently used to assess automatic processes in addiction have serious drawbacks. Furthermore, the automatic system may contain not only associations but complex drug-related beliefs as well. The RRT may be a useful and valid tool to examine these beliefs.

The impact of a context switch and context instructions on the return of verbally conditioned fear

BACKGROUND AND OBJECTIVES

Repeated exposure to a conditioned stimulus can lead to a reduction of conditioned fear responses towards this stimulus (i.e., extinction). However, this reduction is often fragile and sensitive to contextual changes. In the current study, we investigated whether extinction of fear responses established through verbal threat instructions is also sensitive to contextual changes. We additionally examined whether verbal instructions can strengthen the effects of a context change.

METHODS

Fifty-two participants were informed that one colored rectangle would be predictive of an electrocutaneous stimulus, while another colored rectangle was instructed to be safe. Half of these participants were additionally informed that this contingency would only hold when the background of the computer screen had a particular color but not when it had another color. After these instructions, the participants went through an unannounced extinction phase that was followed by a context switch.

RESULTS

Results indicate that extinguished verbally conditioned fear responses can return after a context switch, although only as indexed by self-reported expectancy ratings. This effect was stronger when participants were told that CS-US contingency would depend on the background color, in which case a return of fear was also observed on physiological measures of fear.

LIMITATIONS

Extinction was not very pronounced in this study, possibly limiting the extent to which return of fear could be observed on physiological measures.

CONCLUSIONS

Contextual cues can impact the return of fear established via verbal instructions. Verbal instructions can further strengthen the contextual control of fear.

Chronic Stress During Adolescence Impairs and Improves Learning and Memory in Adulthood

HIGHLIGHTS This study tested the effects of adolescent-stress on adult learning and memory.Adolescent-stressed rats had enhanced reversal learning compared to unstressed rats.Adolescent-stress exposure made working memory more vulnerable to disturbance.Adolescent-stress did not affect adult associative learning or reference memory. Exposure to acute stress can cause a myriad of cognitive impairments, but whether negative experiences continue to hinder individual as they age is not as well understood. We determined how chronic unpredictable stress during adolescence affects multiple learning and memory processes in adulthood. Using male Sprague Dawley rats, we measured learning (both associative and reversal) and memory (both reference and working) starting 110 days after completion of an adolescent-stress treatment. We found that adolescent-stress affected adult cognitive abilities in a context-dependent way. Compared to rats reared without stress, adolescent-stressed rats exhibited enhanced reversal learning, an indicator of behavioral flexibility, but showed no change in associative learning and reference memory abilities. Working memory, which in humans is thought to underpin reasoning, mathematical skills, and reading comprehension, may be enhanced by exposure to adolescent-stress. However, when adolescent-stressed animals were tested after a novel disturbance, they exhibited a 5-fold decrease in working memory performance while unstressed rats continued to exhibit a linear learning curve. These results emphasize the capacity for stress during adolescence to transform the cognitive abilities of adult animals, even after stress exposure has ceased and animals have resided in safe environments for the majority of their lifespans.