Textbook Notes (367,757)
Canada (161,373)
Psychology (1,949)
PS264 (24)
Chapter 3

Motivation and Emotion - Chapter 3

8 Pages
Unlock Document

Camie Condon

Motivation and Emotion – Chapter 3  Eat for 3 basic reasons o Source of energy o Necessary elements for rebuilding cells and manufacturing various chemicals, hormones and enzymes that make it possible for body to perform variety of functions o Need to be able to remove toxins that are often a by-product of eating various foods  Also eat for social or psychological reasons  How do humans avoid toxins? o Biological component  Humans have evolved a number of mechanisms to guard against eating natural toxins  Smell and taste often a source of toxins  Gagging, spitting and vomiting is the second line of defense  Nausea also a protective mechanism  Instead of digesting foods that are toxic, our body rejects it, and simple conditioning teaches us to avoid similar foods  Research to support food sensitivity in pregnant women  Plant toxins that can be tolerated by adults are linked to birth defects and spontaneous abortion  Sickness is at highest when embryo’s organ systems are being laid down and wane when nearing completion  Tend to avoid bitter, pungent, highly flavoured and novel foods  Sense of smell is hypersensitive  Universal across all cultures  Greater pregnancy sickness less likely to bear offspring with birth defects o Learned component  Organisms learn to avoid things that make them sick  Animals are biologically prepared to make certain associations and not others  Potentially toxic foods taken in small amounts might only make us sick, and will not result in death  Highly adaptive behaviour  Will result in learning to avoid these foods in the future  Important that food supply not be too restrictive, equipping brain with ability to potentially avoid toxic foods has potential of doing that  Sampling helps to avoid potentially toxic foods o Cooking foods can take out toxins  Cooking may be cultural conditioning  Food preferences largely learned and mechanism that governs these preferences is taste o Learning to only eat foods caretakers give us  Trying novel foods may take more time to adapt to o Cognitive component  As more toxins are being artificially created, it creates the problem of how to avoid the chemicals that may kills us  Warnings help to deter us from eating toxic foods  Toxins exist in small amounts in foods we eat, which is not harmful  In larger amounts, it builds up in the body  Food selection o Food and energy: fats, carbohydrates and proteins  Stomach and intestines breaks down food into more basic units that can be used for energy  Carbohydrates – starches and sugars  Glucose, fructose, galactose 1 Motivation and Emotion – Chapter 3  Glucose that is not used converts into glycerol, and if body does not have enough carbs in diet, then body will break down the stored glycerol stores  If there is not enough glucose/sugars for body to use, then muscles will start to be digested  Fats  Get from meats, milk products and seeds/grains (ones used to make cooking oils) and broken down into fatty acids  Converted into energy through fatty acid oxidation o Not as efficient as converting glucose into glycerol  Fatty acids not used for immediate energy are stored under the skin in places such as the stomach, hips, thighs and arms  Fat can be made from excessive glucose o This conversion does not allow for immediate access of this fat o Can be a source of long-term energy  Proteins  Meats, beans, nuts and seeds  Broken down into amino acids, which convert into glucose or fat  20 different amino acids o Used for growth, repair and energy  Takes body a couple of hours after a meal to digest and absorb  Intestine act as an energy storehouse for energy during this  Amino acids and sugars go directly into the liver  Liver regulates amino acid levels in the blood o Food and nutrients  Balanced diet involves 50-60% carbohydrates, 10-20% fats, 10-20% proteins o Humans evolved as meat eaters  Distinct advantage to becoming omnivores, means we will not be dependent on one food source  Being an omnivore increases odds of being poisoned  More foods that one eats, greater the likelihood of being poisoned  Evidence that suggests meat /protein is essential to our diet  Extremely difficult for humans to get all the essential nutrients from an exclusively vegetarian diet  Human body cannot produce all the vitamins/nutrients by itself, and meat/protein provides body with the lacking nutrients  Amino acids contained in proteins provide body basic components to manufacture neurotransmitters  Small intestine’s job is to break down and absorb proteins (unique to humans)  Teeth built to eat meat (incisors)  Ancestors ate meat o Biological component  Role of taste in food selection  Two important unlearned taste preferences o Sweet and fatty o Born with preference for sweet foods and fatty foods  Sweet foods tend to be non-toxic and good source of calories  People who restrict carbohydrate diets develop condition called ketosis o Developed when body can no longer supply brain with glucose and forced to burn ketone bodies  During diets, many people lose weight in muscle mass, rather than fat o Learned component 2 Motivation and Emotion – Chapter 3  Eating preferences of different ethnic groups provide evidence that learning plays important role in diet  Food selection comes from learning to avoid all foods that produce some type of aversive state  Modeling parents and developing preferences, eliminate process of trial-and-error learning  Due to availability of food, learning process is flexible  Many of the new preferences linked to taste/texture more than nutritional value  Humans prefer salt  Deprivation of salt produces highly aversive and life-threatening state  Much of the junk food we eat are high in sugar/fat and salt, but low in nutrients o Cognitive component  Our modern society depends on ability to think and reason  Most fast foods and junk foods taste good because they are sweet, fatty or salty, but don’t provide basic nutrients  Ingredients are now listed on foods so people can make conscious efforts to eat foods that are nutritious  Distinguishing between hunger and eating o Important to distinguish between concepts of hunger and eating  Hunger is a biological need o We don’t eat just because we’re hungry, but behaviour also affects it o Satiety is a biological state  We sometimes eat more than we need to  Often eats more than our satiety o Eating as a sensory experience  Not only eat for taste, but because of texture as well  Eat for positive-incentive value of foods  If taste is enhanced, humans eat more, regardless of how hungry  Greater variety – eat more  People tend to eat more when surrounded by other people  Experiment where consumption of liquid diet was in situations with no social interactions o Nonobese individuals kept diet to 2400 calories o Obese individuals droped diet to 500 per day (3000 less than otherwise)  Question of overweight and obesity o Individuals are categorized as obese if they exceed average weight b a given percentage o Within us, there lives potential obese person, ready to emerge if given the opportunity o Insulin levels at the centre of explaining digesting and eating o Failure to produce sufficient insulin – diabetes  Serious disorder that can lead to vascular and retinal damage o Insulin helps glucose from blood enter the cells of the body o Diabetics have difficulty breaking down carbohydrates  Daily injections of insulin and restricted intake of carbohydrates can help with this o Too much insulin can also lead to obesity  Hypoglycemia o When people become overweight, develop condition called hyperinsulinemia  Chronically low blood glucose and constant hunger o Biological component  Genetic factor  Adopted children look more like their biological parents in weight than their adoptive parents 3 Motivation and Emotion – Chapter 3  Identical twins more similar in weight than fraternal twins  Substantial heritability for obesity and binge eating  Energy expenditure  Three components o Basal metabolic rate (BMR)  Amount of energy we use in given period relative to body size o Physical activity o Specific dynamic action  Increase in energy expenditure following the ingestion of food  Actual proportions of energy expended in exercise and metabolism depend on individual exercise patterns  Obesity and anorexia as malfunctions of the hypothalamus  Hypothalamus involved in variety of motivational functions, includes hunger and eating  Two areas linked to eating o Lesions of ventromedial nuclei (VMN)  Produce over eating, obesity  Showed these characteristics  Unresponsive to normal satiety cues  Will not work as hard to obtain food  Stop eating adulterated foods before animals without lesion  Eat large amounts of palatable foods o Lesions of lateral hypothalamus  Failure to eat, anorexia  Lesions of the ventromedial nuclei o Obese people characterized with chronic hyperinsulinemia o Satiety linked with high levels of leptin in the VMN  Lesions destroy leptin receptors  Obese people have high levels of leptin in brain o People born with different rates of metabolism  Lesions of the lateral hypothalamus o Shown to produce effects of eating cessations o Body loses weight o Degree of anorexia displayed related to size of the lesion  Set point theory  Proposed set-point theory of weight level o Hypothalamus sets our weight  People with high points are inclined to be overweight o Feel hungry and to satisfy their hunger, would be inclined to overeat  Weight would match set point, and food consumption would level off  Positive-incentive theory  When exposed to environment that allows for unlimited access to food, they are inclined to become overweight  Tend to eat more when food tastes good, even when th
More Less

Related notes for PS264

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.