John Loehlin

John Clinton Loehlin (1926–2020) was an American intelligence researcher, behavior geneticist, computer scientist, and psychologist. One of his groundbreaking achievements is the first attempt to endow a computer with emotion. In an effort to define and evaluate the major factors in “personality theory,” Loehlin wrote a computer program that was used to act as the intermediary between perception (input) and behavior (output).

In the early 1960s, Loehlin, a young professor at the University of Nebraska, became interested in computer models of personality. The idea originated in a paper presented by Loehlin at a conference on computer simulation and personality theory held at Princeton University, although the basic purposes and ideas in the computer simulation of psychological processes and behavior had been well defined by this time.

Initially, Loehlin basically created a small world of simulated automatons (termed Aldous after the author Aldous Huxley) and had them interact with one another to better understand what he had created. He defined each to have a “personality” or probabilistic way of reacting to threats–the “experiments” he ran with these different simulated creatures. Aldous was originally written on a Burroughs 205 Datatron computer entirely in assembly language. Burroughs 205 (see its Handbook) was a vacuum tube computer that cost a few hundred thousand dollars (equivalent to a few million today) and occupied an entire room.

Generally, Aldous was presented with a situation with certain characteristics and he responded based on some knowledge that had been previously acquired. Depending on the nature of the situation, Aldous may or may not receive further consequences. The Situation (external to Aldous) was defined with seven numbers. The first three were perceptual characteristics (0–9 for each of the three dimensions, thus there were 1000 possible perceptual situations). The next four numbers correspond to affective characteristics of the situation, based on Murray’s (1938) theory of situational “presses.” The four presses were defined as the relative probability of each situation to cause satisfaction, frustration, pain, and its power to do so. Thus there can be many combinations of stimulus perceptual characteristics.

Aldous had two storage locations—“immediate” and “permanent”,  to store information about how many times the present perceptual situation had been faced previously, how he responded to it each time before, and the class of perception and press to which this situation belongs. After Aldous responded, he had the capacity to adjust each of these memories to a degree that depended upon the reaction he produced, the consequence that the reaction produced, and the relative intensity of the response and the reaction. Aldous gave greater weight to recent memories and had the capacity to give a verbal (via a printout account) of his various memories at specific times. Loehlin called this “introspection.”

Once a stimulus situation had been introduced to Aldous he compared the situation with his memory. This included traces of previous encounters with the same and similar situations in the same perceptual classes. In addition, Aldous examined each press at essentially the same time for their individual attributes. Loehlin attempted to simulate human perceptual error by introducing a 6% error rate in this subsystem, so 6 out of every 100 stimulus characteristics were not recognized accurately by Aldous.

Once the situation was recognized by Aldous, an emotional reaction was developed based on the situational characteristics and the familiarity with the situation itself. For instance, if Aldous had never been exposed to a situation before, he would react based on any prior experience with similar classes of experience; Alternatively, if he has been exposed to that situation a few times before, he reacted based on this “experience.” In general, weight was given to the memories of that situation and to just the class of experiences but only if Aldous is familiar with the situation itself. In all, about 80% of responses were based on memory, and 20% were based on Aldous’s current mood (i.e., traces left from previous emotional characteristics). In terms of the reaction, Aldous had three possible emotional characteristics with which to react: (1) positively or with love; (2) with anger, or (3) with fear. Aldous calculated his own response predilection towards each of these. If one response was dominant, it interacted with its competitors to weaken them. If no response tendencies had been developed to a greater degree than another, Aldous developed emotional “conflicts.”

Aldous next selected an action based on the final emotion selected. He had three possible actions that corresponded to these emotional reactions: (1) approach; (2) attack; or (3) withdrawal. In addition, each of these could have two action strengths: (1) mild or (2) vigorous; or two non-action strengths (1) no action necessary, or (2) emotional “paralysis” (primarily caused by conflicts of relatively strong emotions). Thus, with all of the many possibilities of interactions, this behavior will be “physical” in only six ways. Only the verbal reports will show anything other than this.

Considering the presses of the situation, and Aldous’ behavioral actions, the external situation could feedback and affect Aldous in several ways. In fact, if Aldous approached there was always some consequence. If Aldous did nothing the situation must have some ability or power to affect; if Aldous avoided or attacked mildly the situation might have relatively high power; and if Aldous avoided or attacked vigorously the situation a very high power to cause a consequence. If there was no consequence there is no change in memory, but if there was a consequence there is a change in memory (Loehlin called this change “learning”). The consequence affects the situation and the response tendencies depend on the experience. That is, the more familiar Aldous was with the situation the less any consequence could happen that changed his “ideas” about it. This affected the entire class in the same way but with less of an effect.

Loehlin experimented with several “worlds” for Aldous—a hostile world where the presses of all the stimuli were injurious or frustrating, and a benign world where all the presses were satisfying. He also developed several “types” of Aldouses.

Loehlin spoke of this whole enterprise as an attempt to develop a “model of personality”, and planned to improve upon Aldous’s (a) limited ability to plan based on more than one situation, (b) his rather limited perceptual system and memory, and (c) the use of too many constant values.

Biography of John Loehlin

John Clinton Loehlin was born in Ferozepur, India, on 13 January 1926, the firstborn of Presbyterian missionary parents, Clinton Herbert Loehlin (1897-1987) and Eunice (Cleland) Loehlin (1899-1983). Clinton and Eunice were sent to India in the fall of 1923 to work under the Presbyterian Board of Foreign Missions, met during the voyage, and married on 31 Oct 2024. John had four sisters and a brother, James Herbert.

John grew up mainly in the Punjab region of northern India and attended the Woodstock School, an international coeducational residential facility in Landour, graduating in 1942. He moved to the USA to go to college, first in Ohio and later at Harvard, where he completed a bachelor’s degree in English, cum laude, in 1947. In 1947-49 worked in the research department of McCann-Erickson, an advertising firm in Cleveland, then started his research and teaching assistantships, at the Psychology Department of the University of California (Berkeley). A member of the United States Naval Reserve, he was called up for active duty during the Korean War, interrupting his graduate studies. He served in the Pacific from 1951-53, as a lieutenant of the US Navy. John returned to complete his Ph.D. in Psychology at Berkeley in 1957, with a dissertation on time perception.

Loehlin began teaching at the University of Nebraska, Lincoln, in 1957, where he met Marjorie Leafdale (1921-2021), who taught in the English Department. They married on 2 January 1962, and had two children, Jennifer Ann and James Norris.

In 1964 Loehlins moved to Austin for a visiting year at the University of Texas. That post turned into a permanent position, a joint appointment in Psychology and Computer Science. John Loehlin taught at Austin from 1964 to 1992, apart from a visiting semester at the Institute for Behavioral Genetics at the University of Colorado and a year at the Center for Advanced Study in the Behavioral Sciences in Palo Alto. He chaired the Psychology Department from 1979-83. He also served as president of the Behavior Genetics Association and the Society for Multivariate Experimental Psychology. John received the Dobzhansky Award from the former in 1991, and a Festschrift was held in his honor at the 2011 BGA meetings. He was a Fellow of the American Association for the Advancement of Science and a Charter Fellow of the American Psychological Society.

As Professor Emeritus of Psychology from 1992 until his death, he continued to be active in research and publication. His research was mainly on the interaction of genes and environment, especially on personality development. He also worked on the computer analysis of complex scientific data. He published seven scholarly books, some in multiple editions, and dozens of articles. He also enjoyed writing poetry, and brought out two volumes of verse; as a young man, he had poems published in The Cleveland Plain Dealer, Harper’s, and The New Yorker.

John Clinton Loehlin died on 9 August 2020 (aged 94), at his home in Austin, Texas.

Note: Material is based on the article “Loehlin’s Original Models and Model Contributions”, author: John J. McArdle, publisher: Behavior Genetics volume 44, 2014.