DOCUMENTS

We investigated whether instructions have the potential to generate memory-independent
attitude acquisition as indexed by a stochastic model of evaluative conditioning that distinguishes
between memory-dependent and memory-independent learning. For that purpose, we instructed
participants about pairings of conditioned and unconditioned stimuli without having participants
experience them. We obtained a significant contribution of memory-independent learning that
depended on whether instructions emphasized the importance of memorization at learning or the
importance of feelings at either learning or retrieval. Our findings call for caution when
interpreting the memory-independent contribution as an indicator of association formation on the
one hand and unaware learning on the other hand. Our research demonstrates the need to clearly
distinguish between processes operating at encoding and processes operating at retrieval in
empirical and theoretical research on evaluative conditioning.

Unpronounceable strings of 4 consonants (conditioned stimuli: CSs) were consistently
followed by familiar words belonging to one of two opposed semantic categories
(unconditioned stimuli: USs). Conditioning, in the form of greater accuracy in rapidly
classifying USs into their categories, was found when visually imperceptible (to most
subjects) CSs occupied ≥ 58 ms of a 75-ms CS–US interval. When clearly visible CSs
were presented in a 375 ms CS–US interval, conditioning was strongly correlated with
measures of contingency awareness, and did not occur in the absence of that awareness.
These experiments delineated two forms of conditioning: Unconscious conditioning
occurred with a brief CS–US interval, with an effectively masked CS, and with no
reportable knowledge of the contingent CS–US relation. Conscious conditioning
occurred with a substantially longer CS–US interval, a perceptible CS, and with subjects’
reportable knowledge of the contingent CS–US relation.

Maes, E., De Filippo, G., Inkster, A., Lea, S.E.G., De Houwer, J., D'Hooge, R., Beckers, T., Wills, A.J. (2015). Animal Cognition

Humans can spontaneously create rules that allow them to efficiently generalize what they have learned to novel situations. An enduring question is whether rule-based generalization is uniquely human or whether other animals can also abstract rules and apply them to novel situations. In recent years, there have been a number of high-profile claims that animals such as rats can learn rules. Most of those claims are quite weak because it is possible to demonstrate that simple associative systems (which do not learn rules) can account for the behavior in those tasks. Using a procedure that allows us to clearly distinguish feature-based from rule-based generalization (the Shanks-Darby procedure), we demonstrate that adult humans show rule-based generalization in this task, while generalization in rats and pigeons was based on featural overlap between stimuli. In brief, when learning that a stimulus made of two components (“AB”) predicts a different outcome than its elements (“A” and “B”), people spontaneously abstract an opposites rule and apply it to new stimuli (e.g. knowing that “C” and “D” predict one outcome, they will predict that “CD” predicts the opposite outcome). Rats and pigeons show the reverse behavior – they generalize what they have learned, but on the basis of similarity (e.g. “CD” is similar to “C” and “D”, so the same outcome is predicted for the compound stimulus as for the components). Genuinely rule-based behavior is observed in humans, but not in rats and pigeons, in the current procedure.

Mertens, G., Kuhn, M., Raes, A. K., Kalisch, R., De Houwer, J., & Lonsdorf, T. B. (In press). Fear expression and the return of fear following threat instruction with or without direct contingency experience. Cognition and Emotion.

Prior research showed that mere instructions about the contingency between a Conditioned Stimulus (CS) and an Unconditioned Stimulus (US) can generate fear reactions to the CS. Little is known, however, about the extent to which actual CS-US contingency experience adds anything beyond the effect of contingency instructions. Our results extend previous studies on this topic in that it included fear potentiated startle as an additional dependent variable and examined return of fear following reinstatement. We observed that CS-US pairings can enhance fear reactions beyond the effect of contingency instructions. Moreover, for all measures of fear, instructions elicited immediate fear reactions that could not be completely overridden by subsequent situational safety information. Finally, return of fear following reinstatement for instructed CS+s was unaffected by actual experience. In sum, our results demonstrate the power of contingency instructions and reveal the additional impact of actual experience of CS-US pairings.

Van Dessel, P. , De Houwer, J., Roets, A., & Gast, A. (2016). Failures to change stimulus evaluations by means of subliminal approach and avoidance training. Journal of Social and Personality Psychology, 110, e1-e15.

Previous research suggests that the repeated performance of approach and avoidance (AA) actions in response to a stimulus causes changes in stimulus evaluations. Kawakami, Phills, Steele, and Dovidio (2007) and Jones, Vilensky, Vasey, and Fazio (2013) provided evidence that these AA training effects occur even when stimuli are presented only subliminally. We also examined whether reliable AA training effects can be observed with subliminal stimulus presentations but added more sensitive checks of perceptual stimulus discriminability. Three experiments, including a direct replication of the study by Kawakami et al. (2007), failed to provide any evidence for effects of subliminal AA training on implicit or explicit evaluations. Bayesian analyses indicated that our data provide robust evidence that subliminal AA training does not cause changes in evaluations. In contrast, we observed changes in evaluations when participants were provided with (either correct or incorrect) information about the stimulus-action contingencies in the subliminal AA training task and when participants performed a supraliminal AA training task that allowed participants to detect these contingencies. These findings support the idea that contingency awareness is necessary for the occurrence of AA training effects.

Bardi, L., Bundt, C., Notebaert, W. & Brass, M. (2015). Eliminating mirror responses via instructions. Cortex, 70, 128-136.

The observation of an action leads to the activation of the corresponding motor plan in the observer. This phenomenon of motor resonance has an important role in social interaction, promoting imitation, learning and action understanding. However, mirror responses not always have a positive impact on our behavior. An automatic tendency to imitate others can introduce interference in action execution and non-imitative or opposite responses have an advantage in some contexts. Previous studies suggest that mirror tendencies can be suppressed after extensive practice or in complementary joint action situations revealing that mirror responses are more flexible than previously thought. The aim of the present study was to gain insight into the mechanisms that allow response flexibility of motor mirroring. Here we show that the mere instruction of a counter-imitative mapping changes mirror responses as indexed by motor evoked potentials (MEPs) enhancement induced by transcranial magnetic stimulation (TMS). Importantly, mirror activation was measured while participants were passively watching finger movements, without having the opportunity to execute the task. This result suggests that the implementation of task instructions activates stimulus-response association that can overwrite the mirror representations. Our outcome reveals one of the crucial mechanisms that might allow flexible adjustments of mirror responses in different contexts. The implications of this outcome are discussed.

Raes, A. K., De Houwer, J., De Schryver, M., Brass, M., & Kalisch, R. (2014). Do CS-US pairings actually matter? A within-subject comparison of instructed fear conditioning with and without actual CS-US pairings. PLoS ONE 9(1): e84888. doi:10.1371/journal.pone.0084888

Previous research showed that instructions about CS-US pairings can lead to fear of the CS even when the pairings are never presented.In the present study, we examined whether the experience of CS-US pairings adds to the effect of instructions by comparing instructed conditioning with and without actual CS-US pairings in a within-subject design. Thirty-two participants saw three fractals as CSs (CS+1, CS+2, CS-) and received electric shocks as USs. Before the start of a so-called training phase, participants were instructed that both CS+1 and CS+2 would be followed by the US, but only CS+1 was actually paired with the US. The absence of the US after CS+2 was explained in such a way that participants would not doubt the instructions about the CS+2-US relation. After the training phase, a test phase was carried out. In this phase, participants expected the US after both CS+s but none of the CS+s was actually paired with the US. During test, self-reported fear was initially higher for CS+1 than for CS+2, which indicates that the experience of actual CS-US pairings adds to instructions about these pairings. On the other hand, the CS+s elicited similar skin conductance responses and US expectancies. Theoretical and clinical implications are discussed.

Instructions are known to have a profound impact on human behavior. Nevertheless, research
on the effects of instructions is relatively scarce and scattered across different areas of
research in psychology and neuroscience. The current issue of this journal contains six papers
that review research on instructions in different research areas. In this introduction to the
special section, we provide the outline of a framework that focuses on five components that
can be varied in research on this topic (sender, message, receiver, context, and outcome). The
framework brings order to the boundless potential variability in research on the effects of
messages (i.e., it has heuristic value) and highlights that past research explored only a tiny
fraction of what is possible (i.e., it has predictive value). Moreover, it reveals that research in
different areas tends to examine different instantiations of the five components. The latter
observation implies that much can be gained from closer interactions between researchers
from different areas.

Evaluative conditioning (EC) is sometimes portrayed as a primitive way of changing attitudes
that is fundamentally different from persuasion via arguments. We provide a new perspective
on the nature of EC and its relation to persuasion by exploring the idea that stimulus pairings
can function as a symbol that conveys the nature of the relation between stimuli. We put
forward the concept of symbolic EC to refer to changes in liking that occur because stimulus
pairings function as symbols. The idea of symbolic EC is consistent with at least some current
theories of persuasion. It clarifies what EC research can add to the understanding of the origins
of our preferences and has implications for how (symbolic and non-symbolic) EC can be
established, the boundaries of EC research, and cognitive and functional models of EC.

Powerpoint slides used for the progress report of WP3 at the annual IUAP meeting, Leuven, 11 December 2014