Demand and Consumer Choice

Chapter 2: Demand and Consumer Choice

1. Individual Demand: What You Want, at Each Price

  • Individual Demand Curve:

    • Definition: A graph that plots the quantity of an item that an individual plans to purchase at each price.

    • Characteristics:

    • Visual representation of buying plans.

    • Varies with price changes.

    • Example: If my favorite cookies are cheaper, I will buy more cookies.

2. Your Decisions and Your Demand Curve

  • Importance of personal decisions on individual demand:

    • Individual buying plans are shaped by personal circumstances and economic conditions.

  • Marginal Principle: A breakdown of buying decisions into smaller marginal choices.

3. Market Demand: What the Market Wants

  • Market Demand Curve:

    • Definition: A graph of the total quantity of an item demanded by the entire market at each price.

    • It reflects the aggregate behavior of all consumers.

  • Estimating Market Demand:

    • Four-step process:

    1. Survey: Inquire about quantities to purchase at various prices.

    2. Sum Total Quantities: At each price, aggregate how many units all customers plan to buy.

    3. Scale Up: Adjust findings to represent the entire market.

    4. Plot Curve: Graph the total quantity demanded at each price point.

4. What Shifts Demand Curves?

  • Demand Shifters:

    • 1. Income:

    • Normal Goods: Demand increases as income rises (e.g., smartphones, organic produce).

    • Inferior Goods: Demand decreases as income rises (e.g., instant noodles, generic brands).

    • 2. Preferences:

    • Life events or social trends can affect demand (e.g., a new trend for organic foods).

    • 3. Prices of Related Goods:

    • Complementary Goods: Demand falls if the price rises (e.g., hot dogs and buns).

    • Substitute Goods: Demand rises if the substitute's price rises (e.g., Coca-Cola vs. Pepsi).

    • 4. Expectations:

    • Anticipated future price changes can affect current demand.

    • 5. Congestion and Network Effects:

    • Network Effect: Demand rises as more use the product (e.g., social media).

    • Congestion Effect: Demand falls if product use creates congestion (e.g., busy roads).

    • 6. Type and Number of Buyers:

    • Changes in demographics can affect market demand (e.g., aging population leads to increased healthcare demand).

5. Shifts versus Movements Along Demand Curves

  • Movement Along Demand Curve:

    • Caused by changes in the price of the good itself.

    • Results in a change in quantity demanded (not demand).

  • Shift of Demand Curve:

    • Caused by changes in factors other than the price of the good (like income or preferences).

    • Results in a change in demand itself.

The Law of Demand

  • As price decreases, quantity demanded increases:

    • This fundamental relationship gives demand curves their downward slope.

Creating and Interpreting an Individual Demand Curve: Darren’s Example

  • Example of gas demand:

    • Price per gallon:

    • $5: 1 gallon,

    • $4: 2 gallons,

    • $3: 3 gallons,

    • $2: 5 gallons,

    • $1: 7 gallons.

    • The lower the price, the higher the quantity demanded.

The Rational Rule for Buyers

  • Definition: Consumers should continue purchasing until the price equals marginal benefit.

  • Application: Assessing the marginal benefit of each gallon of gas Darren considers buying.

Understanding Demand Curves: Marginal Benefit

  • The demand curve represents both price and marginal benefit:

    • Diminishing marginal benefit: Each additional item yields a smaller benefit than the previous one (e.g., slices of pizza).

Applying Demand Principles

  • Choosing the best quantity to buy involves:

    • Employing the marginal principle and cost-benefit analysis to maximize economic surplus.

Real-World Applications and Implications

  • Importance of understanding demand for business strategies, including pricing, sales forecasting, and market competition.