No evaluative conditioning effects with briefly presented stimuli

Abstract

Evaluative conditioning (EC) changes the preference towards a formerly neutral stimulus (Conditioned Stimulus; CS), by pairing it with a valent stimulus (Unconditioned Stimulus; US), in the direction of the valence of the US. When the CS is presented suboptimally (i.e., too briefly to be consciously perceived), contingency awareness between CS and US can be ruled out. Hence, EC effects with suboptimally presented CSs would support theories claiming that contingency awareness is not necessary for EC effects to occur. Recent studies reported the absence of EC with briefly presented CSs when both CS and US were presented in the visual modality, even though the CSs were identified at above-chance levels. Challenging this finding, Heycke and colleagues (2017) found some evidence for an EC effect with briefly presented visual stimuli in a cross-modal paradigm with auditory USs, but that study did not assess CS visibility. The present study realized a close replication of this study, while deviated from it by using different stimuli, introducing a brief practice phase, and adding a CS visibility check. Overall EC for briefly presented stimuli was absent, and results from the visibility check show that an EC effect with briefly presented CSs was only found, when the CSs were identified at above-chance levels.

Unconscious Knowledge of Rewards Guides Instrumental Behaviors via Conscious Judgments

“…The results of the present study seem to contradict the conclusions of most recent studies on subliminal instrumental and evaluative conditioning (e.g., Heycke & Stahl, 2020;Skora et al, 2021a, b), which found that conditioning does not occur when the stimuli are exposed subliminally. As explained in the introduction, a failure to find conditioning effects for unconsciously presented stimuli might mean that consciousness is necessary for learning and conditioning.…”

“…A first approach is to prevent the conscious perception of the predictive (conditioned) stimulus, during the conditioning procedure. Most recent studies that have exposed subliminally the conditioned stimuli, using improved methods for ensuring the unconscious character of exposure, have found evidence against instrumental conditioning outside of awareness (T Reber et al, 2018;Skora et al, 2021a, b; see also, e.g., Heycke & Stahl, 2020;Hogden et al, 2018 for similar results obtained in other conditioning paradigms; contrast Greenwald & De Houwer, 2017).…”

Unconscious knowledge of rewards guides instrumental behaviors via conscious judgments

“…Although conducted in a different paradigm, the results of the present study present a different picture compared to most recent studies on subliminal instrumental and evaluative conditioning (e.g., Heycke & Stahl, 2020;Skora et al, 2021a, b), which found that conditioning does not occur when the stimuli are exposed subliminally. The conclusion emerging from these studies point towards the necessity of consciousness for learning the appetitive value of stimuli.…”

Augmenting salivation, but not evaluations, through subliminal conditioning of eating-related words

“…The non-significant differences across CS evaluations reported here corroborates a recent report by Heycke and Stahl (2020), who found no evidence of subliminal conditioning on CS evaluations when CS were undetected. None of the CS presented here were detected during visibility checks, and CS evaluations were similarly unaffected by conditioning 2 .…”