Disinhibition account of the conditioned response (DACR).

Pavlovian conditioning is widely used to study the substrates of learning and memory in the mammalian brain. In a standard protocol, subjects are exposed to pairings of a conditioned stimulus (CS; e.g., a tone) with an unconditioned stimulus (US; e.g., an electric shock). Subsequent presentations of the CS elicit a range of behaviors that relate to the US (e.g., freezing) showing that animals learned the CS-US relation. However, it is still unclear how neuronal activity pertaining to the CS comes to excite a representation of the US, and thereby, conditioned responses. The current analysis of this problem, based on neurophysiological evidence, views Pavlovian conditioning as a process of facilitating the disinhibition, rather than the excitation, of neuronal responses representing the US. Conversely, Pavlovian extinction is viewed as a process of relearning to inhibit neuronal responses representing the US. We propose a mathematical equation that confirms the predictions made by this novel perspective on Pavlovian conditioning when applied to conditioning phenomena that fall beyond classic associative learning theories. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Mere Exposure Effect Is Sometimes Insensitive to Mood Inductions.

The mere exposure effect (MEE) is defined as repeated exposures to a stimulus enhancing affective evaluations of that stimulus (Zajonc, 1968). The three prominent explanations of the MEE are Zajonc's "neophobia" account, the uncertainty reduction account, and the perceptual fluency approach. Zajonc's "neophobia" account posits that people have an inherent low level of fear of novel objects and exposure to the objects partially extinguishes this novelty-based fear. The uncertainty reduction account asserts that people find uncertainty aversive and habituation reduces uncertainty. The fluency account postulates that people "like" representations of things with which they are fluent. In four experiments, we induced positive and negative moods before or after target exposures. In addition to assessing the MEE in each condition, we assessed the mood induction. The central hypothesis assessed in this series was that there would be an interaction between mood and the MEE. Although the three accounts of the MEE generated divergent predictions, none of the accounts were well supported by the data. Tests for mood induction demonstrated the efficacy of the induction procedures and the MEE was consistently observed, but Bayesian analysis indicated that at least in the present preparation mood had no effect on the MEE.

Spatial inference without a cognitive map: the role of higher-order path integration.

The cognitive map has been taken as the standard model for how agents infer the most efficient route to a goal location. Alternatively, path integration - maintaining a homing vector during navigation - constitutes a primitive and presumably less-flexible strategy than cognitive mapping because path integration relies primarily on vestibular stimuli and pace counting. The historical debate as to whether complex spatial navigation is ruled by associative learning or cognitive map mechanisms has been challenged by experimental difficulties in successfully neutralizing path integration. To our knowledge, there are only three studies that have succeeded in resolving this issue, all showing clear evidence of novel route taking, a behaviour outside the scope of traditional associative learning accounts. Nevertheless, there is no mechanistic explanation as to how animals perform novel route taking. We propose here a new model of spatial learning that combines path integration with higher-order associative learning, and demonstrate how it can account for novel route taking without a cognitive map, thus resolving this long-standing debate. We show how our higher-order path integration (HOPI) model can explain spatial inferences, such as novel detours and shortcuts. Our analysis suggests that a phylogenetically ancient, vector-based navigational strategy utilizing associative processes is powerful enough to support complex spatial inferences.

Associative structure of second-order conditioning in humans.

Second-order conditioning (SOC; i.e., conditioned responding to S2 as a result of S1-US pairings followed by S2-S1 pairings) is generally explained by either a direct S2→US association or by an associative chain (i.e., S2→S1→US). Previous research found that differences in responses to S2 after S1 was extinguished often depended on the nature of the S2-S1 pairings (i.e., sequential or simultaneous). In two experiments with human participants, we examined the possibility that such differences result from S1 evoking S2 during extinction of S1 following simultaneous but not sequential S2-S1 pairings. This evocation of S2 by S1 following simultaneous pairings may have paired the evoked representation of S2 with absence of the outcome, thereby facilitating mediated extinction of S2. Using sequential S2-S1 pairings, both Experiments 1 and 2 failed to support this account of how extinction of S1 reduced responding to S2. Experiment 1 found that extinguishing S1 reduced responding to S2, while extinguishing S2 had little effect on responses to S1, although forward evocation of S1 during extinction of S2 paired the evoked representation of S1 with absence of the outcome. In Experiment 2, evocation of S2 during S1 nonreinforced trials was prevented because S2-S1 pairings followed (rather than proceeded) S1-alone exposures. Nevertheless, responding to S2 at test mimicked S1 responding. Responding to S2 was high in the context in which S1 had been reinforced and low in the context in which S1 had been nonreinforced. Collectively, these experiments provide additional support for the associative-chain account of SOC.

Recovery of attention with renewal.

One experiment determined the relationship between renewed associative strength and attention. Following cue1-outcome pairings in Context A, cue1 was extinguished in Context B while cue2 was conditioned. On test cue2 was chosen as a predictor of the outcome in Context B. Both cues were chosen equally often as predictors in Context A. Consistent with attributing attention to effective associative strength (as noted in a previous study), participants could locate only cue2 in Context B while both were located in Context A, regardless of having been chosen as a predictor. Attention varied as a function of both cues' associative strengths across contexts.

Role of spatial contiguity in sensory preconditioning with humans.

The present study demonstrates the contribution of spatial contiguity in the formation of associations between two neutral stimuli. Using human participants, we used visual conditioned stimuli (CSs) in a sensory preconditioning design in which simultaneous CS2-CS1 pairings and CS4-CS3 pairings were interspersed during Phase 1, followed by sequential CS1-US+ (i.e., CS1-pleasant US) and CS3-US-- (i.e., CS3-unpleasant US) pairings during Phase 2. The conditioned response was a shift in the gaze of the participants to the location where the US+ (i.e., short video clip) appeared. Distances between CS2 and CS1 and between CS4 and CS3 were manipulated. Our results showed a greater response to CS2 when the Phase 1 stimuli were adjacent rather than separated by 100 pixels. Implications for the role of spatial contiguity in associative learning are discussed.

Attenuating social affective learning effects with Memory Suppression manipulations.

People can form opinions of other individuals based on information about their good or bad behavior. The present study investigated whether this affective learning might depend on memory links formed between initially neutral people and valenced information. First, participants viewed neutral faces paired with sentences describing prosocial or antisocial behaviors. Second, memory suppression manipulations with the potential to aid in the forgetting of valenced information were administered. Using the Think/No think paradigm, the effectiveness of four different suppression instructions was compared: Unguided Suppression, Guided Suppression, Distraction, and Thought Substitution. Overall, all the tasks appreciably reduced affective learning based on prosocial information, but only the Guided Suppression and Thought Substitution tasks reduced affective learning based on antisocial information. These results suggest that weakening the putative memory link between initially neutral people and valenced information can decrease the effect of learned associations on the evaluation of other people. We interpreted this as indicative that social affective learning may rely on declarative memories.

Integration of multiple memories in sensory preconditioning.

The present study demonstrates that humans' response to a single stimulus (S1) is determined by what follows S1's associates. The experiment used a sensory preconditioning (SPC) design where S1 was associated with both S2 and S3 on separate trials before establishing relationships between these latter stimuli with an outcome or its absence in a second phase. When S2 and S3 were associated with the same consequence, either an outcome or its absence, strong consequence-based responding to S1 was observed in a reaction time test. Participants responded quickly to indicate that the outcome was, or was not, predicted by S1. When S2 predicted the outcome and S3 did not, SPC was weaker although participants were not slower to respond to S1. Implications on the understanding of the mechanisms that allow for the response to S1 to emerge are discussed.

Attention as an acquisition and performance variable (AAPV).

This article introduces a new model of Pavlovian conditioning, attention as an acquisition and performance variable (AAPV), which, like several other so-called attentional models, emphasizes the role of variation of cue salience, together with associative strength, in accounting for conditioning phenomena. AAPV is primarily (but not exclusively) a performance-focused model in that it assumes not only that both the saliences and associative strengths of cue representations change during acquisition, but also that they are both influential at the time of test in determining responding. Different weights are given to the representations' associative strengths according to the representations' respective saliences at test. The model also treats the representation of a stimulus that is directly activated by presentation of that stimulus as distinct from the representation of the same stimulus that is activated by presenting a companion of the stimulus. Additionally, extinction is viewed as resulting from a decrease in the salience of the cue's representation, rather than a decrease in associative strength. Simulations of several Pavlovian phenomena are presented in order to illustrate the model and assess its robustness.

Spatial integration of boundaries in a 3D virtual environment.

Prior research, using two- and three-dimensional environments, has found that when both human and nonhuman animals independently acquire two associations between landmarks with a common landmark (e.g., LM1-LM2 and LM2-LM3), each with its own spatial relationship, they behave as if the two unique LMs have a known spatial relationship despite their never having been paired. Seemingly, they have integrated the two associations to create a third association with its own spatial relationship (LM1-LM3). Using sensory preconditioning (Experiment 1) and second-order conditioning (Experiment 2) procedures, we found that human participants integrated information about the boundaries of pathways to locate a goal within a three-dimensional virtual environment in the absence of any relevant landmarks. Spatial integration depended on the participant experiencing a common boundary feature with which to link the pathways. These results suggest that the principles of associative learning also apply to the boundaries of an environment.

Reaction time as a measure of human associative learning.

Studies of human associative learning have often used causal/predictive learning preparations in which participants decide whether or not a first event is effective in causing or predicting a second event (i.e., an outcome). Those preparations have proved successful in replicating many Pavlovian phenomena. In the present paper we tested a novel associative learning preparation in which visually presented letters were paired with a visual outcome. Reaction times (RTs) were recorded to assess associative strength between specific cues and the outcome. Combining two different dependent variables (RTs and type of response given), we propose a rule for evaluating the associative strength between two events. The preparation and the data transformation rule were successful in producing several Pavlovian phenomena including excitatory acquisition, extinction, overshadowing, and latent inhibition, as well as established summation effects. Advantages and limitations of this new preparation based on the use of RT are discussed.