Are there laws of psychology?

One of the factors that led Mjøset (2001) to differentiate social science from physical science was that the latter had succeeded in formulating laws of nature such as the second law of thermodynamics. (Those laws are undisputed, universal statements about how nature works.) He noted that many early psychologists hoped to formulate similar laws of nature within psychology. Unfortunately, no such laws have yet been discovered, nor may they ever be. In some ways, then, the physical sciences have far surpassed the social sciences because of the presence and reality of physical laws. The situation is somewhat similar between the biological sciences and the physical sciences too. It is impossible to find biological laws either. Some social scientists, notably Merton (1949), simply decided to continue practicing science and forgo any hope of discovering universal laws. In psychology, a similar story exists. It is impossible to find results that apply in any situation. Instead, results must be carefully couched within a disciplinary, subdisciplinary, or finer-grained contexts. There are no laws of psychology.

All is not lost however. Some results have stood the tests of time and of multiple replications. While the examples to follow fail to reach the criterion of a scientific law they serve to illustrate real and reliable psychological data. The first example is Ebbinghaus’ research on human memory. His 1885 book, Über das Gedächnis (Concerning Memory) caused a sensation when first published. He was the first to show the relationship between memory and the passage of time. Simply put, we forget much more quickly soon after learning and forget much more slowly thereafter. The figure below shows the relationship between memory and time.

Ebbinghaus’ discovery does not rise to the level of a scientific law because other conditions (e.g., practice) can alter the relationship between memory and time. So, the relationship is real and reproducible but it does not apply to all types of memory. A second example is Shepard and Metzler’s (1971) mental rotation research. In a laboratory setting, they projected pairs of geometric stimuli to human participants. While the stimuli were projected in two dimensions, they were designed to convey information in all three dimensions. Participants had to decide quickly whether the two stimuli were alike or different. The stimuli which were alike were presented from 0° up to 180° of rotation from each other in any plane. Like Ebbinghaus, they discovered a remarkably straightforward relationship between the amount of rotation and the time it took to decide. As the rotation approached 180°, participants took longer to decide. Moreover, the relationship was linear. See the figures below for examples of the stimuli used and the results Shepard and Metzler found. Pigeons, too, have been tested for their abilities to



mentally rotate objects. Unlike humans, pigeons are able make accurate mental rotations from various points of view (Köhler, Hoffman, Dehnhardt, & Mauck, 2005). Humans perform mental rotations best while in a normal, upright position. Pigeons, on the other, hand perform mental rotations equally well regardless of their spatial relationship to the stimulus. Flying, apparently, affects how pigeons make mental rotations. Thus, the results show that different species make mental rotations differently. Again, while the results of mental rotation experiments are replicable, they are not universal. The species tested makes a difference.

References

Köhler, C., Hoffmann, K. P., Dehnhardt, G., & Mauck, B. (2005). Mental rotation and rotational invariance in the rhesus monkey. Brain, Behavior, and Evolution, 66(3), 158-166.

Merton, R. K. (1949). Social theory and social structure. Glencoe, IL: Free Press.

Mjøset, L. (2001). Theories: Conceptions in the social sciences. In N. J. Smelser & P. B. Baltes, (Eds.). International encyclopedia of the social and behavioral sciences. 23, 15,641–15,647.

Shepard, R. N., & Metzler, J. (1971). Mental rotation of three-dimensional objects. Science, 171(3972), 701-703.

Psychology's Borders

Gray (2008) notes that psychology fits neatly in the middle of nearly every academic discipline. The figure below shows how Gray places psychology in a central position with the natural sciences, social sciences, and humanities arrayed around it. He adds, “It would be impossible for people from any other department to draw a diagram nearly as elegant as mine that put their discipline in the center.” (p.30) I agree. The centrality of psychology creates borders between it and many nearby disciplines. Four disciplines: sociology, biology, computer science, and philosophy have especially intimate borders with psychology. Over time those borders have moved as well. Those border realignments are historically important to understanding 21st century psychology.

Psychology's central position in the academy is probably one reason why psychology courses and the psychology major are so popular.

Gray, P. (2008). The value of Psychology 101 in liberal arts education: A psychocentric theory of the university. Observer, 21(9), 29-32.

Zeitgeist of the Middle Ages

I spent the Christmas holiday working on a book proposal and playing golf (also a little tennis). One of the things I'm sending publishers is a description of what it might have been like to live in the Middle Ages. The textbook is for the history of psychology course, in case you are wondering.

For those who do not know, zeitgeist is a German word that describes what it feels like to live in a particular time and place.

Here goes:

The Zeitgeist of the Middle Ages

Religion was probably the most important difference between then and now. For during the medieval period, religion thoroughly permeated every aspect of life to a degree almost unimaginable today. Yet, at the same time, daily life contradicted those same religious principles. Violence was endemic and justice uncertain. Life was seen as a temporary state, a trial leading to eternal salvation or damnation. Thus, efforts were few to reform social structures or to change behavior because, for the blessed, salvation awaited; and, for the wicked, damnation. Religion also stifled creative thought because God's plan had already been revealed. All human explanations had to account for Biblical truth and for religious dogma. The world and humankind were unique reflections of God's creation. The gradual sense of a loss of uniqueness caused later by Copernicus, Galileo, and Darwin were still far in the future.

Throughout the period, evidence of earlier Roman civilization still stood. Early in the period, a belief that the world was in decline must have been universal. Later, however, as new towns grew, and great cathedrals and castles were built such feelings probably abated some. However, our notions of constant and universal progress would probably have been unrecognizable. Instead of progress, stasis was a hallmark of the period. But, some technological change did take place, slowly. For example, the invention of the chimney allowed for the heating of individual rooms and served to separate the classes from the great common rooms before, where all huddled overnight around the only fire. Town clocks were built, and changed forever perception of time. In the service of war, metallurgy advanced.

Socially, the world was highly structured. The three estates consisted of the clergy, the nobility, and the rest of humanity. Within each estate, of course, large differences existed. The clergy had a special role given the religiosity of the period. The nobility are our main source of information about the period, because of their status. Comparatively little is known about the daily existence of peasants, but their lives can probably be safely assumed to reflect best the stasis of the period. Later in the period, as towns and commerce grew, a middle class developed. Jews, excluded from "proper" occupations, suffered throughout the period. Massacres, exiles, and discrimination were both common and viewed as righteous, given the Jews' alleged role as "Christ killers" and their subsequent refusal to adopt Christianity. In the same light, the Crusades seemed to make abstract sense, even though in a practical sense they were no testimony to Christian principles.

The universities of the Middle Ages were established to reconcile philosophy and theology. Early on in the history of universities, many of the religious orders opened houses of study. The course of study at the medieval university was much different than today's curriculum. The trivium, or introductory curriculum, consisted of three courses: grammar, logic, and rhetoric, while the quadrivium, or advanced curriculum, consisted of geometry, astronomy, arithmetic, and music. Books were all produced by hand and were, consequently, rare. Relatively few attended the university, and those came from the clergy or the nobility. (As an aside, the oldest universities are: Bologna, Paris, and Oxford)

So, life was far different during the medieval period than it is today. Yet, some of its vestiges still remain, such as superstitions and nursery rhymes. Zeitgeist yourself back to a medieval village. Imagine the smell of raw sewage flowing through the gutter in the center of the street. Think of the rigid class structure, the status of women, and the lives of children. Finally, examine how modern culture is descended from medieval culture, and what things have changed and what have not.