Cognitive performance in rhesus monkeys varies by sex and prenatal androgen exposure

• Published in: Hormones and behavior Vol. 51; no. 4; pp. 496 - 507
• Main Authors: Herman, Rebecca A., Wallen, Kim
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.04.2007; Elsevier; Elsevier BV
• Subjects: Analysis of Variance; Androgen Antagonists - pharmacology; Androgens; Androgens - physiology; Animal cognition; Animals; Behavioral psychophysiology; Biological and medical sciences; Discrimination Learning - physiology; Endocrinology; Female; Flutamide; Flutamide - pharmacology; Fundamental and applied biological sciences. Psychology; Gender differences; Hormones and behavior; Landmarks; Macaca mulatta; Male; Maze Learning - physiology; Monkeys & apes; Pregnancy; Prenatal; Prenatal Exposure Delayed Effects; Primates; Problem Solving - physiology; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rhesus monkey; Sex differences; Sex Factors; Space Perception - physiology; Spatial Behavior - physiology; Spatial cognition; Testosterone; Prenatal; Rhesus monkey; Testosterone; Flutamide; Spatial cognition; Sex differences; Landmarks; Antineoplastic agent; Androgen; Physical performance; Sex; Monkey; Antiandrogen; Exposure; Antihormone; Vertebrata; Mammalia; Animal; Primates; Testicular hormone; Sex steroid hormone; Non steroid compound
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/j.yhbeh.2007.01.005

Men and women differ on performance and strategy on several spatial tasks. Rodents display similar sex differences, and manipulations of early hormone exposure alter the direction of these differences. However, most cognitive testing of nonhuman primates has utilized sample sizes too small to investigate sexually differentiated behaviors. This study presents an investigation of sex differences and the effects of prenatal androgen on spatial memory and strategy use in rhesus monkeys. Monkeys prenatally exposed to vehicle, testosterone, or the androgen receptor blocker flutamide performed a search task in which 5 of 12 goal boxes contained food rewards. Spatial consistency and the presence of local landmarks were varied. Performance when both spatial and marker cues were available did not differ by sex or prenatal treatment. Contrary to predictions, females easily solved the task when local markers were removed, and their performance outscored males. Although eliminating spatial consistency and requiring subjects to use local markers impaired performance by all monkeys, females continued to locate correct goal boxes at higher than chance levels and scored better than males. Blocking prenatal androgen exposure in males improved use of local markers. These findings suggest that the tendency to attend to landmarks and to use them in solving spatial problems is typical of females across many species, including rodents, humans, and rhesus monkeys. In rhesus monkeys and rodents, developmental androgen eliminates this specialization. However, these results are the only known example of better performance of females than males when salient markers are removed.