We [Lazareva, O. F., Freiburger, K. L., & Wasserman, E. A. (2004). "Pigeons concurrently categorize photographs at both basic and superordinate levels." "Psychonomic Bulletin and Review," 11, 1111-1117] previously trained four pigeons to classify color photographs into their basic-level categories (cars, chairs, flowers, or people) or into their…

Conditioned taste aversions (CTAs) may be acquired when an animal consumes a novel taste (CS) and then experiences the symptoms of poisoning (US). This aversion may be extinguished by repeated exposure to the CS alone. However, following a latency period in which the CS is not presented, the CTA will spontaneously recover (SR). In the current…

Two studies examined whether nonreinforcement of a stimulus in multiple contexts, instead of a single context, would decrease renewal of conditioned fear in rats (as assessed by conditioned suppression of lever pressing). In Experiment 1, renewal was measured after 36 nonreinforced CS trials delivered during six extinction sessions in a single…

The failure to discriminate between a pattern consisting of four orthogonal bars and the same pattern rotated by 45 degrees has been interpreted in the literature as evidence against pictorial representations in honeybees. This study determines whether prior training can facilitate the discrimination. In Experiment 1, one group of bumblebees was…

Adults searched for or cached three objects in nine hiding locations in a virtual room or a real-space room. In both rooms, the locations selected by participants differed systematically between searching and hiding. Specifically, participants moved farther from origin and dispersed their choices more when hiding objects than when searching for…

Morris water maze data are most commonly analyzed using repeated measures analysis of variance in which daily test sessions are analyzed as an unordered categorical variable. This approach, however, may lack power, relies heavily on post hoc tests of daily performance that can complicate interpretation, and does not target the nonlinear trends…

In three experiments, four chimpanzees made choices between two visible food options to assess the validity of the "selective value effect" (the assignment of value to only the most preferred type of food presented in a comparison). In Experiment 1, we established that all chimpanzees preferred single banana pieces to single apple pieces before…

Three experiments examined the effect of motivational variables on timing in the peak procedure. In Experiment 1, rats received a 60-s peak procedure that was coupled with long-term, between-phase changes in reinforcer magnitude. Increases in reinforcer magnitude produced a leftward shift in the peak that persisted for 20 sessions of training. In…

Four- to 10-year-old children (n = 50) participated in a 2D search task that included geometry (with- and without lines) and feature conditions. During each of 27 trials, participants watched as a cartoon character hid behind one of three landmarks arranged in a triangle on a computer screen. During feature condition trials, participants could use…

In avoidance learning studies, a warning signal (Sd) is directly paired with an aversive unconditioned stimulus (US) unless a particular response is performed. Research by Augustson and Dougher (1997) demonstrated that not only warning signals but also stimuli that are indirectly paired with the aversive event are capable of affecting the…

Three Pavlovian fear conditioning experiments with rats as subjects explored the effect of extinction in the presence of a concurrent excitor. Our aim was to explore this particular treatment, documented in previous studies to deepen extinction, with novel control groups to shed light on the processes involved in extinction. Relative to subjects…

The pioneering work by Kirk-Smith, Van Toller, and Dodd [Kirk-Smith, M. D., Van Toller, C., & Dodd, G. H. (1983). "Unconscious odour conditioning in human subjects." "Biological Psychology," 17, 221-231], established that an unnoticed odorant paired with an emotionally meaningful task can influence mood and attitudes when the odorant alone is…

Behavioral data suggest that distinguishable orientations may be necessary for place learning even when distal cues define different start points in the room and a unique goal location. We examined whether changes in orientation are also important in place learning and navigation in a water T-maze. In Experiment 1, rats were trained to locate a…

To test the hypothesis that pigeons will only code the more salient sample when samples differ markedly in salience, pigeons were trained with samples consisting of a 2-s presentation of food (highly salient sample) and an 8-s presentation of keylight (less salient sample). During retention testing, pigeons tended to respond at longer delays as if…

Appetitive contextual excitation supported by intertrial unconditioned stimuli was more easily overcome by timed conditioned responding in rats using quiet (Experiment 1) rather than noisy (Experiment 2) food pellet deliveries. Head-entry responding in acquisition peaked above the contextual baseline when pellet delivery occurred 10, 30, 60, or 90…