Brain and Physiological Needs

One motivated brain

This weeks material made me think about how hard it is to separate biological processes from environmental factors and visa versa. As Reeve (2009) suggests, specific brain structures generate motivational states after input from bio-chemical agents. However, the production of these biochemical agents are also influenced by environmental factors, i.e. one’s behaviour and events occurring in their environment. Therefore, although we consider some drives or motivational forces to be biological, they are still being influenced by environmental and psychological factors. For example people’s appetite drives are affected by their emotional state such ias in depression and anxiety, one may have increased or decreased desires to eat.

Maslow’s hierarchy of needs suggests that physiological needs must be satisfied to be able to move on to higher psychological and social needs. Reeve also suggests there is a lack of cortical or conscious control of physiological motivations. This seems to be particularly evident when discussing dieting and trying to ignore hunger signals. However, in the case of anorexia, as mentioned in the first lecture, an individual has such strong psychological and social forces compelling them not to eat that they do mange to override the physiological motivators which are telling them to eat. Over eating is also interesting to consider, as eating far beyond what the body requires also involves overriding physiological drives to cease eating. Despite these examples, for most of us most of the time, our physiological drives do have the power to occupy all of our attention despite our efforts to ignore them in favour of other motivational forces.

The drive of thirst is seemingly quiet simple, but I found the experimental methods used to discover where in the body one perceives dehydration and sends signals to the hypothalamus to create the perception of thirst, was clever. It makes sense that the sensory system for dehydration to be mainly confined to intra-cellular senses but I thought it was interesting to have that confirmed through experiments.

Sexual drives and motivations were also interesting to learn about, particularly considering the differences in men and women’s sexual motivation. Again it is hard to separate biological differences and social cultural differences between gender. I was reminded at this time of a talk we had last year from Dr. Cordelia Fine in the physiological psychology unit. In it she discussed her book Delusions of Gender in which she discusses the over exaggeration in published literature of physiological differences between male and female brains. She suggested that slight but statistically significant differences in neuro-physiological studies between genders are often published while the many studies that find non-significant differences are either not published or ignored. I found this might need to be considered when talking about evolutionary reasons why women might prefer one partner with the ability to provide for her long term while males want lots of young healthy women to be able to “sow their seed”. Although these gender differences are partly physiological, they are also highly influenced by culture, gender stereotypes and other social and psychological factors.

Testosterone levels are one major difference between females and males which effects sexual motivation. I remember reading in the past that testosterone levels relate to whether one is likely to be married or in a committed relationship with men higher in testosterone being more likely to be single or to cheat on their partners (McInyre et al., 2006). This might explain why females, with lower testosterone levels, are more likely to want more intimate long-term sexual relationship than males. In males, testosterone peaks in their 20s and slowly declines with age, thus as males get older they may be more likely to want a committed relationship as they have less and less testosterone circulating in their bodies and thus they may be more motivated to gain intimacy.

I personally find physiological aspects of motivation and emotion fascinating and am excited to research further the physiological aspects of emotion for my book chapter assignment.

References

Fine, C. (2010) Delusions of Gender. W W Norton & Co.

McIntyre, M., Gangestad, S. W., Gray, P. B., Chapman, J. F., Burnham, T. C., O'Rourke, M. T., et al. (2006). Romantic involvement often reduces men's testosterone levels--but not always: The moderating role of extrapair sexual interest. Journal of Personality and Social Psychology, 91(4), 642-651. doi:10.1037/0022-3514.91.4.642

Reeve, J. (2009). Understanding motivation and emotion (5th ed.). Hoboken, NJ: Wiley.