Modeling semantic memory: Effects of presenting semantic information in different modalities

How is semantic information from different modalities integrated and stored? If related ideas are encountered in French and English, or in pictures and sentences, is the result a single representation in memory, or two modality-dependent ones? Subjects were presented with items in different modalities, then were asked whether or not subsequently presented items were identical with the former ones. Subjects frequently accepted translations and items semantically consistent with those presented earlier as identical, although not as often as they accepted items actually seen previously. The same pattern of results was found when the items were French and English sentences, and when they were pictures and sentences. The results can be explained by the hypothesis that subjects integrate information across modalities into a single underlying semantic representation. A computer model, embodying this hypothesis, made predictions in close agreement with the data.     

The effects of divided attention on encoding and retrieval processes: The resiliency of retrieval processes

We have recently cast doubt (Craik, Govoni, Naveh-Benjamin, & Anderson, 1996; Naveh-Benjamin, Craik, Guez, & Dori, 1998) on the view that encoding and retrieval processes in human memory are similar. Divided attention at encoding was shown to reduce memory performance significantly, whereas divided attention at retrieval affected memory performance only minimally. In this article we examined this asymmetry further by using more difficult retrieval tasks, which require substantial effort. In one experiment, subjects had to encode and retrieve lists of unfamiliar name-nouns combinations attached to people's photographs, and in the other, subjects had to encode words that were either strong or weak associates of the cues presented with them and then to retrieve those words with either intra- or extra-list cues. The results of both experiments showed that unlike division of attention at encoding, which reduces memory performance markedly, division of attention at retrieval has almost no effect on memory performance, but was accompanied by an increase in secondary-task cost. Such findings again illustrated the resiliency of retrieval processes to manipulations involving the withdrawal of attention. We contend that retrieval processes are obligatory or protected, but that they require attentional resources for their execution.     

Human social defeat and approach–avoidance: Escalating social-evaluative threat and threat of aggression increases social avoidance

Basic research on avoidance by Murray Sidman laid the foundation for advances in the classification, conceptualization and treatment of avoidance in psychological disorders. Contemporary avoidance research is explicitly translational and increasingly focused on how competing appetitive and aversive contingencies influence avoidance. In this laboratory investigation, we examined the effects of escalating social-evaluative threat and threat of social aggression on avoidance of social interactions. During social-defeat learning, 38 adults learned to associate 9 virtual peers with an increasing probability of receiving negative evaluations. Additionally, 1 virtual peer was associated with positive evaluations. Next, in an approach–avoidance task with social-evaluative threat, 1 peer associated with negative evaluations was presented alongside the peer associated with positive evaluations. Approaching peers produced a positive or a probabilistic negative evaluation, while avoiding peers prevented a negative evaluation (and forfeited a positive evaluation). In an approach–avoidance task with social aggression, virtual peers gave and took money away from participants. Escalating social-evaluative threat and aggression increased avoidance, ratings of feeling threatened and threat expectancy and decreased ratings of peer favorableness. These findings underscore the potential of coupling social defeat and approach–avoidance paradigms for translational research on the neurobehavioral mechanisms of social approach–avoidance decision-making and anxiety.