Emergent equivalence relations between interoceptive (drug) and exteroceptive (visual) stimuli.

Conditional "if-then" relations between drug (interoceptive) stimuli and visual (exteroceptive) stimuli were taught to 4 normal humans. Interoceptive stimuli were the effects produced by 0.32 mg/70 kg triazolam (a prototypical benzodiazepine) and placebo (lactose-filled capsules); exteroceptive stimuli were black symbols on white flash cards. Following the training of the prerequisite conditional relations, tests of emergent relations were conducted between exteroceptive stimuli and between interoceptive and exteroceptive stimuli. Equivalence relations emerged immediately without explicit training for all 4 subjects. Accuracy of responding during the interoceptive-exteroceptive equivalence tests and subjects' self-reports showed consistent discrimination between the drug effects of triazolam and placebo. Finally, a generalization test assessed whether a novel visual stimulus presented in the context of the placebo (i.e., no drug) would generalize to visual stimuli belonging to the placebo stimulus class. All 3 subjects who completed this test reliably chose the visual stimuli belonging to the placebo class and not the visual stimuli belonging to the triazolam stimulus class. The development of equivalence relations between interoceptive and exteroceptive stimuli demonstrates that private and public stimulus events can emerge as members of the same equivalence class. Theoretical and clinical implications are discussed.     

Personality Psychology in Europe (Vol. 3) (Book)

This study explored the effect of defensive (i. e., fake-good) responding by substance-abusing patients on the scale scores of the Millon Clinical Multiaxial Inventory (MCMI-II; Millon, 1987). Patients asked to respond honestly (N = 62) had significantly higher scores on most of the scales than patients who were instructed to respond defensively (N = 62) and forensic subjects suspected of abusing psychoactive substances (N = 54). Significantly fewer subjects in the defensive responding simulation and the forensic group had elevated the Drug Dependence and Alcohol Dependence scales compared to the honestly responding patients. These results indicate that most drug-abusing individuals can conceal the presence of a substance-related disorder, as reflected by scale scores on the MCMI-II, if motivated to do so.     

Lessons From Markey et al. (2015) and Bushman et al. (2015): Sensationalism and Integrity in Media Research

This article presents a response to the comment by B. J. Bushman, D. Romer, and P. E. Jamieson (2015). This reply addresses 2 issues raised by the commenters. First, they claim they and others have not made sensationalistic statements linking violent media to horrific acts of real‐world violence. In response, we supply numerous examples of sensationalistic statements made by them and others. Second, they claim they did not expect violence in films to be related to violent behavior among adults, but only among youths. However, by examining homicide arrests and homicide gun mortality rates among youths, we found that as films have become increasingly violent over time, both homicide arrests and gun‐related homicides have tended to decrease among this age group.     

Comparison of scotopic sensitivity in diurnal (Anas platyrhynchos) and crepuscular (Dendrocygna autumnalis) ducks.

Scotopic visual adaptation curves were obtained from 4 mallard ducks. A curve of best fit was used to compare the mallards' mean adaptation curve to the curve previously reported for the black-bellied tree duck, a crepuscular species. The curves did not differ significantly in either their slopes or base levels (thresholds). The mallards curve had a rod-cone "break" at approximately 25 min. This break is evident in the scotopic curve for pigeons, but is absent from the black-bellied tree ducks' curve. Examination of retinal tissues indicated that the black-bellied tree ducks had significantly more rods and cones, and a larger rod:cone ratio than the mallards. The mallards' scotopic visual threshold is exceeded by the natural illumination present under several nocturnal conditions.     

Spontaneous class grouping behavior by bonobos (Pan paniscus) and common chimpanzees (P. troglodytes)

Two experiments investigated spontaneous class grouping behavior by human-enculturated and language-reared bonobos (Pan paniscus) and common chimpanzees (P. troglodytes). In experiment 1, three chimpanzees ranging in age from 6 to 18 years were presented with six objects. The objects embodied three conditions: additive, multiplicative and disjoint classes. All chimpanzees spontaneously produced single- and two-category classifying. In experiment 2, six chimpanzees ranging in age from 6 to 21 years were presented with 12 objects in the same class conditions. Chimpanzees mainly produced single-category classifying. Their two-category classifying was more rudimentary than that found in experiment 1. Chimpanzees did not produce any three-category classifying which would be necessary to construct the hierarchies that humans begin to construct during early childhood. Received: 1 February 1999 / Accepted after revision: 9 August 1999     

Octopuses (Octopus bimaculoides) and cuttlefishes (Sepia pharaonis, S. officinalis) can conditionally discriminate

In complex navigation using landmarks, an animal must discriminate between potential cues and show context (condition) sensitivity. Such conditional discrimination is considered a form of complex learning and has been associated primarily with vertebrates. We tested the hypothesis that octopuses and cuttlefish are capable of conditional discrimination. Subjects were trained in two maze configurations (the conditions) in which they were required to select one of two particular escape routes within each maze (the discrimination). Conditional discrimination could be demonstrated by selecting the correct escape route in each maze. Six of ten mud-flat octopuses (Octopus bimaculoides), 6 of 13 pharaoh cuttlefish (Sepia pharaonis), and one of four common cuttlefish (S. officinalis) demonstrated conditional discrimination by successfully solving both mazes. These experiments demonstrate that cephalopods are capable of conditional discrimination and extend the limits of invertebrate complex learning.