Concurrent Electrodermal and Eyeblink Conditioning With Masked and Unmasked Stimuli

The aim of this study was to determine if contingency awareness between the conditioned (CS) and unconditioned stimulus (US) is necessary for concurrent electrodermal and eyeblink conditioning to masked stimuli. An angry woman’s face (CS+) and a fearful face (CS−) were presented for 23 milliseconds (ms) and followed by a neutral face as a mask. A 98 dB noise burst (US) was administered 477 ms after CS+ offset to elicit both electrodermal and eyeblink responses. For the unmasking conditioning a 176 ms blank screen was inserted between the CS and the mask. Contingency awareness was assessed using trial-by-trial ratings of US-expectancy in a post-conditioning phase. The results showed acquisition of differential electrodermal and eyeblink conditioning in aware, but not in unaware participants. Acquisition of differential eyeblink conditioning required more trials than electrodermal conditioning. These results provided strong evidence of the causal role of contingency awareness on differential eyeblink and electrodermal conditioning.

A systematic review and meta-analysis of the evidence for unaware fear conditioning

Whether fear conditioning can take place without contingency awareness is a topic of continuing debate and conflicting findings have been reported in the literature. This systematic review provides a critical assessment of the available evidence. Specifically, a search was conducted to identify articles reporting fear conditioning studies in which the contingency between conditioned stimuli (CS) and the unconditioned stimulus (US) was masked, and in which CS-US contingency awareness was assessed. A systematic assessment of the methodological quality of the included studies (k = 41) indicated that most studies suffered from methodological limitations (i.e., poor masking procedures, poor awareness measures, researcher degrees of freedom, and trial-order effects), and that higher quality predicted lower odds of studies concluding in favor of contingency unaware fear conditioning. Furthermore, meta-analytic moderation analyses indicated no evidence for a specific set of conditions under which contingency unaware fear conditioning can be observed. Finally, funnel plot asymmetry and p-curve analysis indicated evidence for publication bias. We conclude that there is no convincing evidence for contingency unaware fear conditioning.

Sensory Preconditioning of Evaluation Requires Accurate Memory of the Co-occurrence between the Neutral Stimuli

Neutral "conditioned" stimuli (CS) acquire the valence of valent "unconditioned" stimuli (US) after the stimuli are paired. This effect has often been attributed to a low-level mechanism that occurs automatically, even without awareness of the CS-US pairing. However, recent research has failed to support this assumption. In three experiments (N = 1,541), we tested the possibility of attitude formation without awareness of pairing with a US using a sensory preconditioning paradigm. Previous research with that paradigm found attitude formation with no retrospective awareness of contingencies. However, retrospectively reported unawareness might be due to forgetting. Another weakness of retrospective measures is that people might show accurate memory of the CS-US pairing based on their evaluation of the CS. Our procedure circumvented these weaknesses. Participants observed co-occurrences between neutral nonwords and neutral faces, followed by a nonword-face co-occurrence memory test. After that test, participants observed co-occurrences between the faces and affective stimuli, indirectly pairing the nonwords with the affective stimuli. At that time, if participants previously failed to remember with which face a certain nonword co-occurred, then they were unaware of the indirect pairing of that nonword with affective stimuli. We found that indirect pairing influenced the evaluation of the nonwords only when memory for the nonword-face contingency was accurate. Contrary to past research, accurate memory in the present research cannot be explained by an effect of the change in evaluation on memory. Our results suggest that contingency awareness is necessary for the effect of stimulus pairing on evaluation.

Disentangling semantic and response learning effects in color-word contingency learning

It is easier to indicate the ink color of a color-neutral noun when it is presented in the color in which it had been shown frequently before, relative to print colors in which it had been shown less often. This phenomenon is known as color-word-contingency learning. It remains unclear whether participants actually learn semantic (word-color) associations or/and response (word-button) associations. We here present a novel variant of the paradigm that can disentangle semantic and response learning, because word-color and word-button associations are manipulated independently. In four experiments, each involving four daily sessions, novel words (pseudowords such as enas, fatu or imot) were probabilistically associated either with a particular color, a particular response-button position, or with both. Neutral trials were also included, and participants’ awareness of the contingencies was manipulated. The data showed no impact of explicit contingency awareness, but clear evidence both for response learning and for semantic learning, with effects emerging swiftly. Deeper processing of color information, with color words presented in black instead of color patches to indicate response-button positions, resulted in stronger effects, both for semantic and response learning. Our data add a crucial piece of evidence lacking so far in color-word contingency learning studies: Semantic learning effectively takes place even when associations are learned in an incidental way.