Reinforcement and substitution in humans: a multiple-response analysis

Three adult human subjects engaged in activities such as reading, sewing, artwork, and candlemaking while living alone in a laboratory apartment 24 hours per day for several weeks. After a baseline period in which the activities were fully available, access to a particular activity (contingent response) was made dependent on engaging in another less-preferred activity (instrumental response). The contingencies produced substantial increases in instrumental responding, and responding decreased toward baseline levels when the dependency was removed. Under the contingent conditions, time earned for the concurrent activity was always less than the baseline level. To determine the contribution of this reduction to the instrumental increase, access to the contingent activity was restricted in the absence of any dependency. The results indicated that increases among responses that filled the newly available time could be selective, e.g., artwork increased when reading was restricted but candlemaking did not. It was concluded that the reductions in the contingent response that accompany contingencies usually do not exclusively determine instrumental increases, but selective increases can contribute to the increase in time devoted to the instrumental response.     

Conditioning Method Dramatically Alters the Role of Amygdala in Taste Aversion Learning

Although an important role for the amygdala in taste aversion learning has been suggested by work in a number of laboratories, results have been inconsistent and interpretations varied. The present series of studies reevaluated the role of the amygdala in taste aversion learning by examining the extent to which conditioning methods, testing methods and lesioning methods, influence whether amygdala lesions dramatically affect conditioned taste aversion (CTA) learning. Results indicated that when animals are conditioned with an intraoral (I/O) taste presentation, lesions of amygdala eliminate evidence of conditioning whether animals are tested intraorally or with a two-bottle solution presentation. Dramatic effects of amygdala lesions on CTA learning were seen whether lesions were made electrolytically or using an excitotoxin. In contrast, when animals were conditioned using bottle presentation of the taste, electrolytic lesions attenuated CTAs but did not eliminate them, and excitotoxic lesions had no effect. These results are consistent with the hypothesis that neural structures critical for CTA learning may differ depending on the extent to which the method of conditioned stimulus delivery incorporates a response component.     

Panic-relevant predictability preferences: a laboratory test

In the present investigation the authors evaluated the role of verbally instructed safety periods as they relate to predictability preference within a single-session challenge paradigm involving recurrent administrations of 20% carbon dioxide (CO-sub-2) enriched air. Participants included 160 nonclinical young adults (91 women, 69 men) between the ages of 18 and 59 (M=21.6 years; SD=7.23). Results indicated that equivalent levels of anxiety were experienced during predictable and unpredictable administrations of 20% CO-sub-2, yet participants preferred predictable compared with unpredictable trials, with women showing a stronger predictability preference than men. Lower anxiety was reported during known safety periods (predictable room air trials) but not during predictable compared with unpredictable administrations of 20% CO-sub-2. Findings are discussed in relation to theoretical and applied implications for the role of predictability in the nature of anxiety and its disorders.     

Foraging and associative learning of visual signals in a parasitic wasp

To cope with environmental variability, animals should gather and use information to reduce uncertainty. In insect parasitoids, associative learning has been widely documented in the context of host foraging. However, despite its potential adaptive value, the insect food searching strategy and cues used to search are poorly understood. In this study, we examined the ability of hymenopteran Venturia canescens females to associate food to a visual cue. To broaden the scope of our results, experiments were performed with both arrhenotokous (sexual) and thelytokous (asexual) individuals. The wasps showed innate attraction for yellow and orange stimuli when presented versus blue stimuli. When trained to associate a food reward with one of the attractive colours (orange), they significantly moved from a distance towards the colour previously associated with food. The choice of the innately preferred colour (yellow) was not modified by associative learning. In the context of food foraging, this study is the first to show associative learning using visual stimuli in a parasitoid and active choice of this colour. This ability gives new insights concerning potential food sources for V. canescens in the field, since flowers are sugar sources, which emit colour signals.     

Changing abilities in recognition of unfamiliar face photographs through childhood and adolescence: Performance on a test of non‐verbal immediate memory (Warrington RMF) from 6 to 16 years

A commonly used test of non‐verbal memory, which measures recognition for unfamiliar face pictures, was developed by Warrington (1984) , the Recognition Memory for Faces (RMF) test. The task has been widely used in adults in relation to neurological impairment of face recognition. We examined the relationship of RMF scores to age in 500 young people aged between 6 and 16 years. A linear relationship obtained between 6 and 10 years, followed by a ‘plateau’ between the ages of 10 and 13, followed by further improvement. Abilities on the test correlated with both verbal and non‐verbal intelligence, but the nonlinear function relating age and RMF survived partialling for intelligence in the younger age groups. The improvement of the adolescents compared with older children also survived partialling for IQ. We found no significant influence of gender or reported pubertal status (which was not obtained for all participants) on RMF once age was taken into account. Performance on other face‐processing tasks (emotion classification and accuracy in line of sight detection) correlated significantly, if moderately, with RMF scores. Despite its age and imperfections, RMF test may nevertheless be a useful indicator of ‘face expertise’ in a developmental context.     

Integrating Anxiety Sensitivity, Distress Tolerance, and Discomfort Intolerance: A Hierarchical Model of Affect Sensitivity and Tolerance

The purpose of the present investigation was to concurrently examine the latent dimensional and hierarchical structure of anxiety sensitivity (AS) and two key theoretically relevant and related affect (in)tolerance and sensitivity constructs: distress tolerance and discomfort intolerance. These constructs were measured using the Anxiety Sensitivity Index (Reiss, Peterson, Gursky, & McNally, 1986), the Distress Tolerance Scale (Simons & Gaher, 2005), and the Discomfort Intolerance Scale (Schmidt, Richey, & Fitzpatrick, 2006). A total of 229 individuals (124 females; M_age = 21.0 years, SD = 7.5) without current Axis I psychopathology participated by completing a battery of self-report questionnaires. A two-stage exploratory factor analysis was conducted to examine the lower- and higher-order latent structural relations among the variables. The factor solution was subsequently evaluated in relation to negative affectivity, anxious arousal, and anhedonic depression. AS and distress tolerance appeared to be related to one another as distinct lower-order facets of a common higher-order affect tolerance and sensitivity factor, whereas discomfort intolerance did not appear to demonstrate similar relations with either AS or distress tolerance at the lower-order or higher-order levels. A unique pattern of association with theoretically-relevant criterion variables was observed between the affect tolerance and sensitivity higher-order factor, the AS and distress tolerance lower-order factors, and the discomfort intolerance factor. Findings are discussed in the context of theoretical and clinical implications and future directions for the study of affect tolerance and sensitivity in relation to emotional vulnerability.     

The Consequences of False Memories for Food Preferences and Choices

ABSTRACT— False memories, or memories for events that never occurred, have been documented in the real world and in the laboratory. In the real world, false memories involving trauma and abuse have resulted in real-life consequences. In the laboratory, researchers have just begun to study the consequences of false memories. We review this laboratory-based work and show how false memories for food-related experiences (e.g., becoming ill after eating egg salad) can lead to attitudinal and behavioral consequences (e.g., lowered self-reported preference for and decreased consumption of egg salad).