Introduction to Biological Psychology: Foundations, History, and Methodology

Introduction to Biological Psychology and Professor Profile

The course is led by Dr. Janosch A. Priebe (PhD), who identifies as a neuroscientist, researcher, and expert in scientific methods. Dr. Priebe is active in science communication (WissKomm) through platforms like Instagram (@dr.jap_ and @dr.jap) and YouTube (@dr.JAP), where he provides scientific advice, academic sponsoring, and critical evaluations of studies, such as those regarding sucralose with Christian Wolf or gender topics. His professional background emphasizes the application of scientific rigor to various social and biological phenomena, including violence against officials and the health implications of obesity.

Course Objectives and Interaction Guidelines

The primary goals of the semester are to provide students with a deeper understanding of brain structure and function, to demonstrate why psychology cannot function without biology, and to enable students to explain selected biopsychological processes. Proficiency in these areas will be assessed via a final exam (Klausur). Regarding classroom interaction, Dr. Priebe established that the lecture is a "professional safe space." He emphasizes punctuality and requests that private conversations take place outside the lecture hall to maintain a focused learning environment.

Philosophical Framework and Core Questions

The course adopts a specific world view (Menschenbild) encapsulated by a quote from Stephen Hawking: "We are just an advanced breed of monkeys on a minor planet of a very average star… But we can understand the Universe. That makes us something very special." To gauge foundational knowledge, several introductory questions are posed to students: What is the central nervous system? What constitutes the cortex (specifically the bark or cerebrum)? What is a neuron ($\text{Nervenzelle}$) and how many do humans possess? Other inquiries involve the percentage of active brain power during tasks, the mechanisms of excitation transmission between neurons, and the similarities between human and animal brains. The course also touches on complex topics like the objective measurement of sexual preference, the debate over free will versus determinism, the valence of addiction-associated stimuli, the neurological processes occurring during sleep, and the identification of neurological disorders.

Historical Context: Localizationism vs. Equipotentiality

Karl S. Lashley (1880–1958), an American psychologist, conducted experiments training rats to respond to two different light stimuli with specific behavioral responses (e.g., pressing with one paw for stimulus A and another for stimulus B). After learning was established, Lashley severed various connections within the cortex. He found that even after massive destruction of cortical regions, the animals could still perform the learned behaviors. This led Lashley to conclude that there are no specific "centers" for learning and memory in the cortex; instead, all cortical areas are equally suitable ($\text{äquipotenzial}$) for establishing memory traces (engrams). This theory of Equipotentiality ($\text{Äquipotenzialität}$) was strongly opposed by neurosurgeons W. Penfield and T. Rasmussen. During brain surgeries on human patients, they observed that even minor stimulation or destruction in temporal regions led to significant memory impairments. These contradictory findings—Localizationism ($\text{Lokationismus}$) stating there is one specific area for one function versus Equipotentiality stating all areas can perform all functions—remained unresolved for much of the 19th and 20th centuries. The conflict was eventually attributed to different methodological approaches: Lashley only interrupted intra-cortical connections, whereas the neurosurgeons also damaged connections to subcortical regions. Modern biopsychology recognizes that while specialized areas (like language centers) exist, functions can often be partially assumed by other areas due to plasticity.

Formal Definitions and Subfields of Biopsychology

Biological Psychology is defined as the study of the connections between biological processes and behavior, considering the life processes of all organs, not just the brain (Birbaumer & Schmidt, 2006). Janke (1993) defines Biopsychology as a branch of psychology concerned with linking "biological" and "psychological" states. Physiological Psychology, depending on the specific definition, is a subfield investigating the relationship between the brain and behavior. Other related fields include Genetic Psychology (e.g., investigating intelligence), Evolutionary Psychology, Comparative Psychology, Animal Psychology, and Human Ethology. The core interest of these disciplines is the relationship between physiology/biology (the soma) and experience/behavior (psychology).

Research Methodologies: Neuropsychology, Psychophysiology, and Correlation

There are three primary research approaches used to study the link between biology and psychology. In Neuropsychology, the Independent Variable (UV) is the physiological or somatic state (e.g., brain injury, drug administration), and the Dependent Variable (AV) is the psychological state (e.g., concentration, mood). This allows for causal conclusions (Soma $\rightarrow$ Psychology). For example, administering Ritalin to observe its effect on concentration or observing the consequences of alcohol on reaction times ($\text{Reaktionszeittest or RT}$). In Psychophysiology, the UV is a psychological condition (e.g., stress induction, training), and the AV is a physiological response (e.g., heart rate, sweat gland activity), also allowing for causal conclusions (Psychology $\rightarrow$ Soma). Examples include measuring heart rate after shouting at a subject or observing changes in neuron form after training. Finally, the Correlative Strategy looks for relationships without establishing causality. An example is the study by Johnstone et al. (1976), which examined cerebral ventricular size and cognitive impairment in chronic schizophrenia. This strategy shows a relationship between variables (e.g., IQ and nerve cell quantity) but cannot determine if a change in one leads to a change in the other. For instance, declaring that "ventricle enlargement leads to schizophrenia" based on correlation is scientifically invalid.

Practical Examples and Studies in Biopsychology

A notable study in Psychophysiology by Serra et al. (2005) titled "Social isolation-induced changes in the hypothalamic-pituitary-adrenal axis in the rat" examined how social factors influence physical stress systems. Rats were kept either in isolation or in groups for $30\,\text{days}$. Afterward, they were given CRH ($\text{Corticotropin-releasing hormone}$), a hormone that activates the stress system. The researchers questioned whether the stress levels (AV) of the isolated rats reacted more strongly than those in the group setting (UV). Another common example in the correlative domain is the study of addiction, where researchers look for connections between transmitter concentrations and addictive behavior. In lectures, students are encouraged to brainstorm their own experimental questions, such as how the induction of bad mood ($\text{Psychology}$) affects physical parameters like heart rate or nociception ($\text{Physiology}$).