Effects of orientation and differential reinforcement on transitive stimulus control

Intra-group differences in skin tone influence evaluative and perceptual face processing

In an exploration of colorist biases across native Melanesian participants, we employed a multi-method approach across three studies to examine evaluative and perceptual processing of 'lighter' and 'darker' non-Melanesian facial targets controlled for attractiveness, sex, and ethnicity. In Study 1, 305 participants evaluated facial attractiveness using surveys. In Study 2, 153 participants alternately mapped lighter and darker faces with positive and neutral attributes across brief Implicit Association Tests. In Study 3, 61 participants underwent a manual sorting task followed by a 'breaking' continuous flash suppression (b-CFS) paradigm to probe 'non-conscious' perceptual biases. Across evaluative measures, male and female respondents consistently preferred lighter-skinned, highly attractive male faces. During b-CFS, lighter and attractive opposite-sex faces entered awareness ('broke suppression') faster than their darker counterparts. We speculate that skin tone may operate as a perceptually salient cue in the presence of facial configurations signaling high reproductive potential.

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

Correlating eating-related words (CS) with positively valenced words (US+) may augment eating-associated motivational responses (e.g., preingestive salivation) with minimal CS knowledge. We tested this claim using a subliminal conditioning procedure, where CS and US were presented under subliminal and supraliminal visual conditions. Three groups of Brazilian undergraduates (N = 69) viewed eating-related words (CS) or their scrambled counterparts (non-CS) followed by positive (US+) or neutral (US-) words. A free-selection visibility check confirmed that subliminally presented CS and non-CS had not been detected by any group. Participants exposed to CS/US+ pairings produced significantly more saliva relative to participants exposed to CS/US- and non-CS/US+ pairings. Reliable induction of salivation, coupled with null outcomes across evaluation measures, suggests that affective information related to eating can subliminally augment preingestive salivation with minimal deliberation.

Auditory sentence comprehension in children with cochlear implants after simple visual discrimination training with specific auditory-visual consequences

The present study evaluated the effects of simple discrimination training with specific consequences on auditory comprehension in children with cochlear implants (CIs). Demonstration of auditory comprehension was based on derived conditional relations and the formation of equivalence relations. Participants learned two sets of three simple visual discriminations in which the positive stimulus (S⁺) was a written pseudo-sentence (C1, C2, or C3) or a compound abstract picture (D1, D2, or D3), displayed in the correct orientation. Each trial presented the S⁺ simultaneously with two S^- which were the same sentence or picture as the positive stimulus but were displayed in either an upside-down or an inverse orientation. Correct responses were followed by specific consequences with two components presented simultaneously: a dictated pseudo-sentence (A) and a representative picture (B). Probes of arbitrary matching to sample assessed derived auditory-visual (AB, AC, and AD) and visual-visual (BC, CB, BD, DB, CD, and DC) conditional relations. All three participants learned the simple discriminations; two of them showed derived conditional relations, demonstrating the formation of three ABCD classes. The present study replicated and extended previous results on sentence learning in children with CIs, suggesting the simple discrimination training with specific consequences as an efficient procedure to generate auditory-visual and symbolic relations in this population.

Dissociating preferences from evaluations following subliminal conditioning

Preferences towards unfamiliar drink brands may be influenced through subliminal conditioning. This can involve associating unfamiliar brands (CS) with positively valenced attributes (US) under constrained visual conditions to prevent the former's conscious detection. According to learning theory, CS associated with positive US should become increasingly preferred as the latter's positive valences generalizes (transfer) across associated CS. Similarly, correlating CS with negative US should reduce CS-associated preferences. There is some evidence that CS-associated preferences can be reliably influenced through subliminal conditioning (Elgendi et al., 2018). Conversely, there is also evidence that subliminal conditioning does not effectively alter evaluations of CS valence (Heycke et al., 2018). Those works suggest CS preferences may be more susceptible to subliminal valence transfer relative to CS evaluations. We explored this hypothesis presently, where four pairs of supraliminal/visible and subliminal trigrams (CS) were respectively associated with four US categories varied along aggregate valence (100% positive, 80% positive, 20% positive, 0% positive). CS evaluations and preferences were recorded before and after conditioning. Bayesian analyses revealed US valence manipulations were likely to shift preferences, but not evaluations, of subliminal CS. Across supraliminal CS, Bayesian and frequentist analyses indicated US valence was significant and likely to shift preferences and evaluations. The present study demonstrates preferences may be influenced through subliminal conditioning even as evaluations are not.

Neurophysiological Effects Associated With Subliminal Conditioning of Appetite Motivations

When attempting to encourage eating, explicitly providing statements like "eating is pleasant" may produce little effect. This may be due to subjective, negatively-valenced narratives evoked by perception of the verb "eating" (e.g., eating →fat →lonely), overriding any explicitly provided eating-pleasant valence information. In our study, we presented eating-related verbs under subliminal visual conditions to mitigate the onset of eating-associated deliberation. Verbs were linked with neutral or positively valenced terms across independent blocks. Modulations of event-related magnetoencephalographic (MEG) components and parietal activations in the alpha range (8-12 Hz) illustrated a significant effect of valence during pre-lexical time windows. We found significantly greater saliva production and declarations of increasing hunger after eating-related verbs were linked with positive terms. Orally reported preferences did not vary between conditions.

Effects of orientation and differential reinforcement II: transitivity and transfer across five-member sets

A recent report by Amd et al. (2017) demonstrated that orienting towards successively presented stimulus-stimulus pairs yielded significantly more transitive relations then when those same pairs were differentially reinforced following training for three, 3-member stimulus sets. We build on that work in four important ways. First, transitivity yields produced by Pavlovian and instrumental procedures were compared following training for three 5-member sets (A1-B1-C1-D1-E1, A2-B2-C2-D2-E2, A3-B3-C3-D3-E3), where the 'A' stimuli were emotional faces and all remaining stimuli were nonsense words. Second, our instrumental task here required two orienting/observing responses per trial. Third, we compared differences in multi-nodal transfer following Pavlovian and instrumental relational learning procedures. Finally, we tested whether functioning as 'end terms' in a relational series can mitigate transfer following instrumental conditioning. Transitivity, as measured by sorting tests, was significantly more pronounced following Pavlovian training. Transfer, assessed before and after relational training with two visual analog scales corresponding to valence and arousal dimensions, appeared marginally more robust observed for participants exposed to the Pavlovian condition. Transfer magnitude was positively related with demonstrations of transitivity, regardless of type of conditioning.