Rating norms for semantic attributes (e.g., concreteness, dominance, familiarity, and valence) are widely used in many psychological literatures to study the effects of processing specific types of semantic content. Word and picture norms for many attributes are available for thousands of items, but there is a contamination problem in experimentation. When an attribute's ratings are varied, how the semantic content that people process changes is unclear because ratings of individual attributes are correlated with ratings of so many other attributes. To solve this problem, the psychological space that 20 attributes occupy has been mapped, and factor score norms have been published for the latent attributes that generate that space (emotional valence, age-of-acquisition, and symbolic size). These latent attributes have yet to be manipulated in experimentation, and hence, their effects are unknown. We conducted a series of experiments that focused on whether they affect accuracy, memory organization, and specific retrieval processes. We found that (a) all three latent attributes affected recall accuracy, (b) all three affected memory organization in recall protocols, and (c) all three affected direct verbatim access, rather than reconstruction or familiarity. The memory effects of two of them (valence and age-of-acquisition) were unconditional, but memory effects were only detected for the third at particular levels of the other two. The key implications are that semantic attributes can now be cleanly manipulated, and when they are, they have broad downstream effects on memory.
Public Significance StatementA fundamental principle of human memory is that meaning is crucial: Information that is more meaningful to people is more easily learned, more easily remembered, and more easily retained over time. Meaning has many components, and hence, we must understand the effects of specific components to use this principle to optimize memory. That question has traditionally been investigated by studying the effects of distinct semantic attributes, such as categorization, concreteness, imagery, familiarity, and valence. However, we know that these attributes are not actually distinct and, instead, are substantially correlated. This problem has recently been solved by analyzing a large collection of semantic attributes and extracting three latent attributes (emotional valence, age-of-acquisition, and symbolic size) that are actually distinct from each other. Our experiments show that people process each of these latent attributes because each has broad memory effects. In particular, each latent attribute affects recall accuracy, the organization of memory, and people's ability to recover literal verbatim memories of experience.