The Tree of Knowledge System, described in the previous post, posits that there are four fundamental divisions in nature. The first division is between Energy and Matter, the second is between Matter and Life, the third is between Life and Mind, and the fourth being between Mind and Culture. These fundamental divisions between the dimensions are known as "joint points" in the lexicon of the ToK System.

Behavioral Investment Theory (BIT) is the third joint point on the ToK System. Technically, BIT provides a way to merge B.F. Skinner's theory of behavioral selection with computational neuroscience and ethology. In more straight forward terms, BIT frames animal behaviors in terms of invested work effort, specifically expenditures of time and energy calculated in terms of costs and benefits. For example, check out the following article from the NY Times on the sexual behavior of some deep sea squid.

The reason this research caught the of the media was because of the same -sex behavior. But for our purposes, what is notable is how the framing of the squid's behavior is consistent with BIT. The same-sex behavior gets attention from animal behavioral scientists not because of the issue, but because the scientists assume will follow along behavioral investment principles. And because the same-sex behavior had no initially obvious payoff in terms of survival or reproduction, the researchers questioned why the animals do it. In the article, the tentative answer is that the cost of releasing the sperm outweighs the complexity of determining the sex of the other squid in the dark depths of the ocean, so there have not been selection pressures resulting in sex-discriminating behaviors.

Here is another example. Crows on the west coast of Canada feed on whelks, which are a type of shellfish. The crows crack the shells of the whelks by picking them up and dropping them onto the rocks below. BIT makes the general prediction that animals will tend to spend the least amount of behavioral energy necessary predicted to achieve the motivated outcome (cf. La Cerra & Bingham, 2003), which in this case is a cracked shell that provides access to food. Researchers calculated the amount of energy required by the crows to lift the whelk to the point that optimizes the likelihood that the shell would break. If the crow does not lift the whelk high enough it will require several drops, yet flying it higher would result in the unnecessary expenditure of energy. The calculations found that the optimal expenditure of behavioral energy would be achieved by flying the shellfish to approximately five meters and this was in fact very close to the heights the birds actually dropped the whelks from.

BIT consists of six fundamental principles that are generally well known in animal behavioral science but are often not put together in a way that is effectively communicated to professional psychologists. They are as follows:

1) The Principle of Energy Economics is the fact that animals must, on the whole, acquire more workable energy from their behavioral investments than those behaviors cost; otherwise their complex arrangements will breakdown and eventually they will die.

2) The Evolutionary Principle is that inherited tendencies toward the behavioral expenditure of energy should be a function of ancestral inclusive fitness.

3) The Principle of is the notion that genetic differences result in differences in behavioral investment systems.

4) The Computational Control Principle is the idea that the is the organ of behavior and it functions as an information processing system.

5) The Learning Principle is the notion that behavioral investments that effectively move the animal toward animal-environment relationships that positively covaried with ancestral inclusive fitness are selected for (i.e., are reinforced), whereas behavioral investments that fail to do so are extinguished. The learning principle incorporates both associative and processes.

6) The Principle of Development states that there are various genetically and hormonally regulated life history stages that require different behavioral investment strategies.

BIT consolidates existing theoretical perspectives and, in conjunction with the holistic vision afforded by the unified theory, allows for previously separate lines of thought and research to be coherently integrated. Specifically, BIT allows for the assimilation and integration of major perspectives in mind, brain, and behavior, including: 1) evolutionary biology and genetics; 2) neuroscience; 3) behavioral science; 4) computational/cognitive science; and 5) developmental and dynamic systems theory. And, with its focus on investment and cost-benefit analysis, it also provides a framework for understanding animal and human behavior that is very congruent with economics. For example, Herb Gintis (2009), an economist who specializes in evolutionary biology and game theory, has argued that the central unifying principle underlying the behavioral sciences is the view that the mind is a organ that calculates costs and benefits to arrive at choices, suggesting that the principle has broad application across a wide variety of different disciplines.

There are several ways that BIT is valuable to the professional psychologist. First, it provides a conception of animal and human behavior as working to control the flow of resources, and this can guide clinicians in their functional understanding of mental behavior. Second, via the six principles, BIT grounds the clinician in basic brain and behavioral sciences and foundational concepts like associative and operant conditioning. Third, as articulated in the chapter, BIT provides the ground work for describing the architecture of the human mind and the relationship between perception, and emotion. Fourth, BIT provides a useful lens to look at certain disorders. For example, I have argued that can effectively be considered a state of behavioral shutdown via the lens of BIT. Specifically, BIT suggests that depression arises out of an evolved tendency to decrease behavioral expenditure in response to failing to chronically effectively control the flow of resources (i.e., in situations of prolonged danger, , or consistent failure to achieve one's goals it is best to shutdown rather that fruitlessly expend energy). This conception clarifies when and how it was appropriate to consider depression as a normal reaction, a psychological disorder, and a biological disease.