Psychology Commons^™

Mirror Use By African Grey Parrots (Psittacus Erithacus), Irene M. Pepperberg, Sean E. Garcia, Eric C. Jackson, Sharon Marconi

Sentience Collection

No abstract provided.

Indicating Acts During Counting By A Chimpanzee (Pan Troglodytes), Sarah T. Boysen, Gary G. Berntson, Traci A. Shreyer, Michelle B. Hannan

Sentience Collection

A chimpanzee (Pan troglodytes) experienced in counting arrays of 0-7 items and trained for comprehension of number symbols, spontaneously displayed a variety of indicating acts (e.g., pointing, touching, and rearranging items) during counting. Twenty-five sessions were videotaped, and all trials were evaluated for the relations among number of items presented, number of indicating acts displayed, and the Arabic number selected to represent the array. Significant correlations included the relations between number of items and the cardinal number selected by the animal, between the number of items and indicating acts displayed by the chimpanzee, and between the number of indicating acts …

Elephants, Robert H.I. Dale

Scholarship and Professional Work - LAS

Book review for the following title:

Elephants. By Clive Spinage, Kent, UK: Harcourt Brace & Co., 1994, 319 pages. £27.45.

Calling By Domestic Piglets: Reliable Signals Of Need?, Daniel M. Weary, David Fraser

Communication Skills Collection

Two manipulations were performed on domestic piglets to determine whether differences in calling during periods of separation from the mother can indicate differences in need. In both cases, the aim was to manipulate the piglet's need for the sow's attention. In the first manipulation a 'thriving' piglet (i.e. the piglet with the heaviest weight and most rapid weight gain) and a 'non-thriving' one (lightest and slowest weight gain) were selected from each of 15 litters. The two piglets were removed from the sow and litter and recorded for 13 min in separate isolated enclosures. For the second manipulation, two piglets …

Responses To Quantity: Perceptual Versus Cognitive Mechanisms In Chimpanzees (Pan Troglodytes), Sarah T. Boysen, Gary G. Berntson

Sentience Collection

Two chimpanzees were trained to select among 2 different amounts of candy (1-6 items). The task was designed so that selection of either array by the active (selector) chimpanzee resulted in that array being given to the passive (observer) animal, with the remaining (nonselected) array going to the selector. Neither animal was able to select consistently the smaller array, which would reap the larger reward. Rather, both animals preferentially selected the larger array, thereby receiving the smaller number of reinforcers. When Arabic numerals were substituted for the food arrays, however, the selector animal evidenced more optimal performance, immediately selecting the …

Comprehension Of Cause-Effect Relations In A Tool-Using Task By Chimpanzees (Pan Troglodytes), Luca Limongelli, Sarah T. Boysen, Elisabetta Visalberghi

Sentience Collection

Five chimpanzees (Pan troglodytes) were tested to assess their understanding of causality in a tool task. The task consisted of a transparent tube with a trap-hole drilled in its middle. A reward was randomly placed on either side of the hole. Depending on which side the chimpanzee inserted the stick into, the candy was either pushed out of the tube or into the trap. In Experiment 1, the success rate of 2 chimpanzees rose highly above chance, but that of the other subjects did not. Results show that the 2 successful chimpanzees selected the correct side for insertion beforehand. Experiment …