Derek was laying on the couch and had fallen asleep when all of a sudden his body jerked and he woke up because he felt like he was falling. Derek was most likely in which stage of sleep?

The theorist who believed that children learn language when they are reinforced by parental attention was

Jean Piaget. B. F. Skinner. Noam Chomsky. Lev Vygotsky.

Dr. Muhammed wants to know if people will rate facial photographs more or less favorably based on the skin color and facial features of the pictures. He digitally alters photographs and mixes the features on each picture,

so that participants in his study do not know exactly what they are looking at. Keeping participants unaware of the exact nature of the study in which they are participating helps reduce __________ effects. a. criterion b. subject-expectancy c. placebo d. observer bias