Howard Liddell (psychologist)

Howard Scott Liddell (1895-1962) was an American psychologist best known for his work on experimental neurosis and conditioned reflexes in animals, particularly sheep. Liddell's research significantly contributed to the understanding of the physiological and psychological effects of stress and anxiety.

Liddell received his Ph.D. from the University of Michigan in 1923. He subsequently joined the faculty at Cornell University, where he remained for the duration of his career. At Cornell, he established the Behavior Farm Laboratory, which provided a controlled environment for studying animal behavior.

His research focused on the development of experimental neurosis in sheep, observing their responses to aversive conditioning. By pairing a conditioned stimulus, such as a tone, with an unconditioned stimulus, such as a mild shock, Liddell induced neurotic-like behaviors in the animals. These behaviors included restlessness, anxiety, and physiological changes such as increased heart rate. Liddell's work demonstrated that prolonged exposure to unpredictable or uncontrollable stressors could lead to maladaptive behavioral patterns.

Liddell's work had important implications for understanding the etiology of anxiety disorders in humans. He argued that early childhood experiences, particularly those involving inconsistent or unpredictable parental behavior, could predispose individuals to developing anxiety-related problems later in life.

His major publications include Conditioned Reflex Method and Experimental Neurosis (1934) and Emotional Hazards in Animals and Man (1956). His research was influential in the development of behavior therapy and stress management techniques. Liddell also served as a consultant to the military during World War II, applying his knowledge of stress and anxiety to help soldiers cope with the psychological demands of combat.