Maes, E., Boddez, Y., Alfei, J. M., Krypotos, A. M., D’Hooge, R., De Houwer, J., & Beckers, T. (2016). The elusive nature of the blocking effect: 15 failures to replicate. Journal of Experimental Psychology: General, 145, e49-e71.
With the discovery of the blocking effect, learning theory took a huge leap forward, because
blocking provided a crucial clue that surprise is what drives learning. This in turn stimulated the
development of novel association-formation theories of learning. Eventually, the ability to explain
blocking became nothing short of a touchstone for the validity of any theory of learning, including
propositional and other non-associative theories. The abundance of publications reporting a
blocking effect and the importance attributed to it suggest that it is a robust phenomenon. Yet, in
the current paper we report fifteen failures to observe a blocking effect despite the use of
procedures that are highly similar or identical to those used in published studies. Those failures raise
doubts regarding the canonical nature of the blocking effect and call for a reevaluation of the central
status of blocking in theories of learning. They may also illustrate how publication bias influences
our perspective towards the robustness and reliablilty of seemingly established effects in the
psychological literature.
De Houwer, J., & Hughes, S. (2016). Evaluative conditioning as a symbolic phenomenon: On the relation between evaluative conditioning, evaluative conditioning via instructions, and persuasion. Social Cognition, 34, 480-494.
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.
