Oren Hasson, Ph.D.

From Behavioral Research to Applied Evolutionary Psychology

Most of my website is in Hebrew and is devoted to my current work as a couple counselor in Israel. This English section is different. It presents part of my earlier career as an animal behaviorist — my work on animal signaling and, later, on human behavior — together with one unusual field observation: a hooded crow using bait to catch fish.

For professional animal behaviorists, these pages focus on concepts in animal signaling: amplifiers, indices, signal reliability, and signal design. They also recount my correspondence with the late John Maynard Smith, who wrote to me while he and David Harper were preparing their book Animal Signals, and they include my own letters from that exchange.

For specialists and enthusiasts alike, I also tell the story of a bait-fishing hooded crow — a rare and striking case of tool use in a wild bird.

Scientific Background

I completed my B.Sc. in Life Sciences and my M.Sc. in Zoology at Tel Aviv University in the 1970s. My master's thesis studied the white-spectacled bulbul (Pycnonotus xanthopygos), a bird that maintains persistent pair bonds even when a pair holds no breeding territory.

In 1987 I completed my Ph.D. at the Department of Ecology and Evolutionary Biology, University of Arizona, where I introduced the concept of "amplifiers": animal signals that are reliable by design, supported by genetic models. In 1990 I joined the Department of Entomology, Faculty of Agriculture, at the Hebrew University of Jerusalem, where I taught general and population ecology.

In a department of entomology, where birds were too large to be studied, it became natural for me to turn to jumping spiders — visually driven animals, and in many ways the most bird-like communicators I could find among land invertebrates. This also returned me to childhood memories of collecting jumping spiders from the walls of my home and watching them hunt and interact in jars. I later worked with David Clark, a jumping-spider specialist from Alma College, Michigan, and with Phil Taylor, who joined my laboratory as a postdoctoral researcher. Our study of the dark triangular abdominal mark of the male jumping spider Plexippus paykulli was later chosen by John Maynard Smith and David Harper, in Animal Signals, as a principal example of an honest signal that is not a handicap.

I left my academic position in 1997. Some time later I received a scholarship to study screenwriting at the Sam Spiegel Film and Television School in Jerusalem — an opportunity I had not sought, but enjoyed greatly — and I published two children's books.

From Animal Behavior to Human Behavior

Around that time I became increasingly interested in evolutionary psychology. My background in animal behavior, communication, and theoretical thinking gave me a natural foundation for understanding human behavior and interpersonal communication from an evolutionary perspective. I taught "The Evolution of Human Interpersonal Communication" at the Department of Communication and Journalism of the Hebrew University of Jerusalem and at Haifa University, using questionnaires and classroom exercises to help students think about human motivation, relationships, and communication strategies.

This eventually led to my current work as a couple therapist, applying evolutionary thinking to marriage, conflict, and communication. I later received training in cognitive behavioral therapy (CBT), which added practical tools to that theoretical foundation.

Later Research

In October 2006, Lewi Stone, Professor of Biomathematics in the Department of Zoology at Tel Aviv University, invited me to lead theoretical research on female extra-pair copulations in socially monogamous mating systems. I did this part-time, alongside teaching and my therapeutic work; it produced two theoretical papers on female infidelity in monogamous systems. Being active in academia again also gave me the opportunity to write my first paper in my new field — "Emotional Tears as Biological Signals" (2009), published in the journal Evolutionary Psychology. It proposed that emotional tears may act as a reliable biological signal that lowers defenses by blurring vision, and can thereby foster bonding or reduce aggression across several social contexts — an idea that has since become a widely cited explanation in research on human emotional tears.