Are pictures good for learning new vocabulary in a foreign language? Only if you think they are not.

The current study explored whether new words in a foreign language are learned better from pictures than from native language translations. In both between-subjects and within-subject designs, Swahili words were not learned better from pictures than from English translations (Experiments 1-3). Judgments of learning revealed that participants exhibited greater overconfidence in their ability to recall a Swahili word from a picture than from a translation (Experiments 2-3), and Swahili words were also considered easier to process when paired with pictures rather than translations (Experiment 4). When this overconfidence bias was eliminated through retrieval practice (Experiment 2) and instructions warning participants to not be overconfident (Experiment 3), Swahili words were learned better from pictures than from translations. It appears, therefore, that pictures can facilitate learning of foreign language vocabulary--as long as participants are not too overconfident in the power of a picture to help them learn a new word.