Under what conditions can human affective conditioning occur without contingency awareness? Test of the evaluative conditioning paradigm.

The role of conscious cognitive processes in human affective conditioning remains controversial, with several theories arguing that such conditioning can occur without awareness of the conditioned stimulus (CS)-unconditioned stimulus (UCS) contingency. One specific type of affective conditioning in which unaware conditioning is said to occur is "evaluative conditioning." The present experiment tested the role of contingency awareness by embedding an evaluative conditioning paradigm in a distracting masking task while obtaining, in addition to subjective ratings of affect, both psychophysiological (skin conductance and startle eyeblink) and indirect behavioral (affective priming) measures of conditioning, along with a trial-by-trial measure of awareness from 55 college student participants. Aware participants showed conditioning with all of the measures; unaware participants failed to show conditioning with all measures. The behavioral, neurophysiological, and therapeutic implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Resistance to extinction in evaluative conditioning.

A well-demonstrated phenomenon in traditional Pavlovian conditioning research with humans is that of experimental extinction. In contrast, human evaluative conditioning research suggests that evaluative learning shows marked resistance to extinction. Here, the authors replicate both findings concurrently. Two differential fear conditioning experiments with an electrocutaneous stimulus as the unconditioned stimulus evidenced (a) sensitivity to extinction using an autonomic skin-conductance measure and (b) complete resistance to extinction using an affective-priming measure. The results corroborate the idea that evaluative conditioning is more resistant to extinction than is expectancy learning (F. Baeyens, P. Eelen, & G. Crombez, 1995). (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Extinction in fear conditioning: effects on startle modulation and evaluative self-reports

gamma-Hydroxybutyric acid (GHB) is unfamiliar to many physicians in the United States but enjoys clinical use elsewhere for applications in resuscitation, anesthesia, and addiction therapy. Use within the United States is restricted to Food and Drug Administration-approved clinical trials for treatment of narcolepsy. Recently illicit use of GHB has emerged within the United States where it is distributed for purported euphoric and "fat-burning" metabolic effects. Clinical effects can be severe, progressing rapidly to respiratory arrest and death. We provide an updated comprehensive review of the literature with particular emphasis on toxicology, including GHB pharmacodynamics, clinical effects, and suggestions for overdose management. Recommended management of acute GHB intoxication includes prevention of aspiration, use of atropine for persistent symptomatic bradycardia, consideration of neostigmine as a reversal agent, and treatment for coingested substances. Emergency physicians are urged to become familiar with GHB because of its potential for severe morbidity as well as its potential use as a future resuscitative agent.     

Pseudoconditioning in earthworms (Lumbricus terrestris): Support for nonassociative explanations of classical conditioning phenomena through an olfactory paradigm.

Four experiments are reported that address conditioning effects in earthworms (Lumbricus terrestris) through an olfactory paradigm. Through the use of multiple control procedures, the authors demonstrate that much of what has been characterized as associative learning in earthworms is actually nonassociative in nature. Issues addressed include the role of pseudoconditioning and central excitatory state in explaining olfactory conditioning data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative and nonassociative theories of the UCS preexposure phenomenon: Implications for Pavlovian conditioning.

Excitatory Pavlovian conditioning of a discrete CS is attenuated by prior exposure to the UCS. The UCS preexposure phenomenon is observed in a variety of Pavlovian conditioning procedures as diverse as eyelid conditioning, the conditioned emotional response, and conditioned taste aversion learning. This article discusses the variables that affect the UCS preexposure phenomenon and uses this information in evaluating both associative and nonassociative accounts of the phenomenon. At least one associative account, based on context blocking, and at least one nonassociative account, based on central habituation of the emotional response to the UCS, remain viable. (71 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tolerance to morphine in the rat: Associative and nonassociative effects.

Two experiments were conducted to examine the impact of dose level and interdose interval (IDI) on the development of tolerance to the analgesic effect of morphine. In Exp I, rats were administered a series of low- (5 mg/kg) or high- (30 mg/kg) dose injections of morphine either explicitly paired or unpaired with a distinctive context at a 48-hr IDI. The development of tolerance following this regimen was assessed by shifts in dose-response curves to the right when animals were tested on a tail-flick device in the distinctive context. Only animals that had received morphine paired with the distinctive context were tolerant to morphine; the magnitude of this associative tolerance was a positive function of the level of the conditioning dose. In Exp II, rats were exposed to a high dose of morphine (30 mg/kg) either paired or unpaired with a distinctive context at one of two IDIs (24 or 96 hr). Tolerance testing revealed that at the long IDI, only associative tolerance was evident, whereas at the short IDI, tolerance in the unpaired condition was more pronounced with a corresponding decline in the development of associative tolerance. The relevance of these findings for psychological theories of drug tolerance are discussed. Results are consistent with the predictions of an habituation model of drug tolerance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

List-context effects in evaluative priming.

Evaluative priming effects are often found in the evaluative decision task, in which persons judge the affective connotation (positive vs. negative) of a target word. The present experiments examined list-context effects to test whether evaluative and semantic priming follow the same laws. In Experiment 1, evaluative priming was found at prime-target stimulus onset asynchronies (SOAs) of 0 ms and 100 ms, but not at SOAs of -100, 200, 600, and 1,200 ms. Experiment 2 manipulated SOA (0, 200, and 1,200 ms) and the proportion (25%, 50%, and 75%) of the prime-target pairs that were evaluatively related. Contrary to the typical finding that increases in the proportion of related prime-target pairs lead to increased priming at long but not short SOAs, an effect of consistency proportion was found at SOAs of 0 ms (for reaction times) and 200 ms (in the accuracy data), but not at the 1,200-ms SOA. The pattern of results is discussed in relation to possible explanatory mechanisms of evaluative priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A physiological explanation of infants' early visual development.

Proposes a physiological explanation of infants' early visual development based on recent evidence that the cat's visual system contains at least 3 separate pathways that subserve different functions and develop at different rates. Several lines of evidence suggest the same is true in humans. Data from human newborns suggest that at birth, 2 of these pathways (the X-pathway to the cortex and the Y-pathway directly to the superior colliculus and pretecturm) are functional, but that the third, the Y-pathway to the cortex, is not. Striking changes at 2 mo appear to reflect the dawning influence of that Y-pathway to the cortex. (French abstract) (5 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Avoidance conditioning of verbal behavior without awareness: A paradigm of repression.

31 male college students responded to a 15-item word association list receiving an electric shock immediately after 5 arbitrarily selected response words. A number of additional trials were given with shock administered every time as S responded with one of the 5 first-trial punished responses. They were then asked to chain-associate to each of the stimulus words with no shock administered. At the conclusion of the experiment Ss could be classified into insight and non-insight groups on the basis of their levels of verbal awareness as to the reasons for the shocks and what they had done to avoid them. Both groups showed a rapid and marked learning of avoidance behavior and a significant decrement in the number of punished responses occurring during chained associations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociation of associative and nonassociative concomitants of classical fear conditioning in the freely behaving rat.

In this article we describe three experiments aimed at determining why the conditioned stimulus/stimuli (CS) elicits similar increases in heart rate in groups given paired and random training. The first study demonstrates that regardless of the pseudoconditioning control procedure used (random, backwards, shock-alone, or naive), the same pattern of results is obtained: the increases in arterial pressure are greater in the paired than in each control group, but the heart rate rises to the same extent in all groups. The second study determined that the context in which the responses are tested (conditioning apparatus vs novel test chamber) does not affect the general pattern of results obtained. The third study demonstrates that the superficially similar increases in heart rate in conditioned and pseudoconditioned rats are achieved by different physiological mechanisms: coactivation of the sympathethic and parasympathetic nervous systems in conditioned rats and sympathetic excitation alone in pseudoconditioned rats. Thus, the heart is influenced by associative emotional processes, but heart rate is not, under these conditions, a particularly useful index of those influences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The restricting effects of awareness: A paradox and explanation.

Ss were shown tachistoscopically-presented word stimuli to test the distinction between the perceptual processes of registration (what could be called physiological or sensory threshold) and awareness (or the cognitive threshold). The presentation consisted of a stimulus word followed by series of words associated to the stimulus word either in terms of meaning or structural resemblance. Recall of words presented subliminally or supraliminally was facilitated with degree of awareness of actual stimulus word; with greater awareness of the word, associational recall was for words that structurally resembled S word; without awareness, recall was determined by associative meaning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interpersonal attraction in aversive environments: A problem for the classical conditioning paradigm?

Several studies have found decreased attraction for a stranger rated under aversive conditions, and these studies have been used to support a model that views attraction as a function of generalization of affect. A number of studies, however, have failed to support such a model, not only failing to show decreases in attraction as a function of negative circumstances but often showing the reverse, that is, enhanced attraction under aversive conditions. It is suggested that studies that have supported the affective generalization model may be limited in ecological validity as a function of their use of a "simulated stranger" paradigm and that results from studies in which "real" strangers are rated can be understood within a negative reinforcement model. Original data from a study in which 60 undergraduate females rated both a fellow S and a bogus stranger under conditions of either aversive noise or low-level noise are presented to support such a resolution. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Association learning of likes and dislikes: A review of 25 years of research on human evaluative conditioning.

Evaluative conditioning refers to changes in the liking of a stimulus that are due to the fact that the stimulus has been paired with other, positive or negative stimuli. Although evaluative conditioning appears to be subjected to certain boundary conditions, significant evaluative conditioning effects have been obtained using a large variety of stimuli and procedures. Some data suggest that evaluative conditioning can occur under conditions that do not support other forms of Pavlovian conditioning, and several models have been proposed to account for these differences. In the present article, the authors summarize the available literature, draw conclusions where possible, and provide suggestions for future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A new paradigm for operant conditioning of Drosophila melanogaster

A freely walking single fly (Drosophila melanogaster) can be conditioned to avoid one side of a small test chamber if the chamber is heated whenever the fly enters this side. In a subsequent memory test without heat it keeps avoiding the heat-associated side. The memory mutants dunce and rutabaga successfully avoid the heated side but show no avoidance in the memory test. Wildtype flies can be trained to successively avoid alternating sides in a reversal conditioning experiment. Every single fly shows strong avoidance and a positive memory score. The new conditioning apparatus has several advantages: (1) Statistically significant learning scores can be obtained for individual flies. (2) Learning scores are obtained fully automatically without interference of the experimenter. (3) The procedure is fast, robust and requires little handling. Therefore the apparatus is suitable for largescale mutant screening. (4) Animals are not attached to a hook and thus can easily be used for breeding.     

Development of food recognition in young chicks: IV. Associative and nonassociative effects of experience.

In 4 experiments, 3-day-old Burmese Red Junglefowl chicks were allowed to peck food, sand, or mealworms or were force-fed liquid food, glucose water, or water and were tested later on either food or sand. Only experience that involved pecking led to the development of a discrimination between food and sand based on short-term metabolic feedback. These and previous results can be accounted for by postulating that the act of pecking and a hunger coordinating mechanism develop independently but experience is necessary for the association of pecking with the hunger system (i.e., chicks must learn that pecking leads to ingestion). After this association is formed, unlearned physiological mechanisms could modulate the rate of pecking directly. Immediate discrimination between food and sand, based on taste cues, occurred when chicks had 3 separate experiences in ingesting food. This result can be accounted for by using a standard discrimination learning paradigm. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative and nonassociative tolerance: the effects of dose and interdose interval

Two experiments examined the effects of dose and interdose interval (IDI) on associative and nonassociative tolerance to morphine analgesia in rats. Associative contingencies were manipulated by administering low (5 mg/kg) or high (20 mg/kg) doses of morphine explicitly paired or unpaired with a distinctive context. Nonassociative processes were manipulated by administering morphine at a short (6-h) or long (96-h) IDI. Tolerance was assessed as shifts in morphine dose-response curves on the tail-flick test. Animals in the long IDI conditions showed considerable context-specific tolerance. Tolerance in the short IDI conditions was not influenced by contextual contingencies at the immediate test (Experiment 1) and showed no retention over a 30-day interval (Experiment 2), suggesting this tolerance was nonassociative. The impact of massed exposure to morphine and context on the disruption of learning at the short IDI is discussed.     

The sparing is far from spurious: Reevaluating within-trial contingency effects in the attentional blink.

The attentional blink is the marked deficit in awareness of a 2nd target (T2) when it is presented shortly after the 1st target (T1) in a stream of distractors. When the distractors between T1 and T2 are replaced by even more targets, the attentional blink is reduced or absent, indicating that the attentional blink results from online selection mechanisms that act in response to distracting input rather than being the result of T1-induced cognitive resource depletion. However, Dell'Acqua, Jolicoeur, Luria, and Pluchino (2009) recently contended that an attentional blink is found in the multiple-target case as long as the appropriate trial context and analyses are used, thus reinstating resource-based explanations of the attentional blink and challenging the selection account. Specifically, an attentional blink reemerges when target performance is analyzed contingent on previous target accuracy. We argue on theoretical and empirical grounds that neither the trial context nor the type of analysis poses a serious problem for selection accounts. We show that the attentional blink and previous target contingency effects can be dissociated, with the latter depending more on low-level, short-range competition. We conclude that selection mechanisms involved in filtering for targets still provide a strong and coherent explanation of the attentional blink. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Letter encoding in visual word identification: More evidence for a word-integration explanation for parafoveal preview effects in reading.

A letter string presented briefly in the parafovea facilitates naming a foveally presented word provided that the two stimuli are orthographically similar. The facilitation is asymmetrical in that to obtain it, both letter strings must have the first letters in common. One possible explanation, a letter-integration hypothesis, proposes that readers only identify the letters at the beginning of the parafoveal stimulus, an action that facilitates processing the target. Another explanation, a word-integration hypothesis, postulates that all the letters of the parafoveal stimulus are identified and that the asymmetry occurs because the first letters of the parafoveal stimulus are weighted more heavily than the later ones. The two accounts differ in the way the position of the first letter is determined. To distinguish the views, English and Hebrew stimuli were presented to 7 bilingual readers. 12 normal students participated as controls. Readers could not anticipate the position of the first letters; hence, if the letter-integration explanation is correct, the asymmetry in the priming should be attenuated. Consistent with the word-integration explanation, however, priming occurred when the target shared the beginning letters with the prime in both languages. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Congruity effects in the survival processing paradigm.

Five experiments were conducted to investigate a proposal by Butler, Kang, and Roediger (2009) that congruity (or fit) between target items and processing tasks might contribute, at least partly, to the mnemonic advantages typically produced by survival processing. In their research, no significant survival advantages were found when words were preselected to be highly congruent or incongruent with a survival and control (robbery) scenario. Experiments 1a and 1b of the present report show that survival advantages, in fact, generalize across a wide set of selected target words; each participant received a unique set of words, sampled without replacement from a large pool, yet significant survival advantages remained. In Experiment 2, we found a significant survival advantage using words that had been preselected by Butler et al. to be highly unrelated (or irrelevant) to both the survival and control scenarios. Experiment 3 showed a significant survival advantage using word sets that had been preselected to be highly congruent with both scenarios. Finally, Experiment 4 mixed congruent and incongruent words in the same list, more closely replicating the design used by Butler et al., and a highly reliable main effect of survival processing was still obtained (although the survival advantage for the congruent words did not reach conventional levels of statistical significance). Our results suggest that the null effects of survival processing obtained by Butler et al. may not generalize beyond their particular experimental design. (PsycINFO Database Record (c) 2011 APA, all rights reserved)