Eating and appetite Flashcards
What does Keesey and Powley’s (1986) set point theory of hunger state?
That hunger is a consequence of an energy deficit - each individual has an optimal level of energy resources (set point) which the body seeks to return to = homeostasis.
What are the main criticisms of the set point theory of hunger?
- Evolutionarily unlikely and potentially incompatible (inconsistent resources, winter)
- Not supported by evidence (blood glucose reduction would have to be substantial, consuming calories before a meal doesn’t affect what you eat)
- Ignores environmental factors - effects of learning, preference and social factors.
What did Lowe (1993) find about drinking a high calorie drink before a meal?
That it’s the participant’s belief about the drink that affects what they eat.
Who came up with an example of a positive-incentive theory?
Berridge, 2004.
Outline the positive-incentive theory.
- Anticipation (expected pleasure = +ve incentive)
- Craving initiates eating (enables you to take advantage of good food when available)
- Multiple factors affect eating
According to positive-incentive theory, what factors influence how much we eat?
Flavour, knowledge of food i.e. learning, time since last meal, food in gut, blood glucose levels etc.
What determines what we eat?
- Learned taste preferences and aversions, e.g. Sclafani (1990), Dwyer, Haselgrove and Jones (2011).
- Social acquisition (Galef, 1995)
What did Sclafani (1990) and Dwyer, Haselgrove and Jones (2011) do?
Training: - Flavour A + glucose/ Flavour B Test - A>B Training 2 - A + lithium chloride (ill)/ B Test 2 - A was avoided.
Therefore we acquire preferences.
What did Fudim (1976) find about associating salt with flavours?
All animals Almond+Salt and Banana+sugar. No injection = prefer banana. Formalin (induces salt craving) = prefer almond.
Given Fudim (1976)’s findings, why do people have such a poor diet?
Our diets are too complex to be fixed by this paradigm - e.g. Harris et al. (1993) thyamine depleted rats learned to eat complete diet but effect weakened when choice was between 10 diets.
What determines when we eat?
Collier (1986):
- Most mammals eat many small meals.
Initiated mainly by environmental cues, which cause physiological ones.
How does Woods (1991) explain pre-meal hunger?
- Eating a meal stresses the body - influx of fuel moves it away from homeostasis.
- Signals for a meal evoke a cephalic phase in which insulin is released into the blood causing a decrease in blood glucose.
- Thus, hunger is the body preparing for homeostatic disruption.
How did Weingarten (1983) investigate conditional hunger in rats?
Buzzer+Light–>food.
Light = CS, rats ate more when subsequently presented.
What parts of the hypothalamus are involved in eating?
- Ventromedial = satiety centre
- Lateral = feeding centre
What is the role of the ventralmedial area of the hypothalamus in eating?
- Hetherington and Ranson (1940) lesioned = hyperphagia (overeating)
- VMH syndrome (dynamic and static phase, lazy and picky.