We developed a computer model to simulate associative memory recall of patients with chronic schizophrenia. Model inputs consisted of words derived from normative data that differed in terms of connectivity and network size, with the former quantitatively represented by parametric weights and the latter by the specific number of word associates that formed a particular network. Previous behavioral studies of normal subjects indicated better recall for words of high connectivity-small network (HCSN), followed by low connectivity-small network (LCSN), high connectivity-large network (HCLN), and low connectivity-large network (LCLN). This pattern of recall differed from that observed in behavioral studies of schizophrenic patients, which showed better recall for high connectivity words, regardless of network size. Holding constant network size while manipulating connection weights effectively simulated this schizophrenic pattern of recall. That is, manipulation of parametric weights coupled with a slight increase in noise significantly and reliably elicited the response pattern of abnormal connectivity demonstrated in the prior behavioral study of patients with chronic schizophrenia. An increase in noise was a necessary, but insufficient step in modeling the response pattern of abnormal connectivity. These findings provide support for the use of computational models to investigate dynamics of associative word recall in patients with chronic schizophrenia.

How do children reward individual members of a team that has just won or lost a game? We know that from pre-school age, children consider agents' performance when allocating reward. Here we assess whether children can go further and appreciate performance in context: The same pattern of performance can contribute to a team outcome in different ways, depending on the underlying rule framework. Two experiments, with three age groups (4/5-year-olds, 6/7-year-olds, and adults), varied performance of team members, with the same performance patterns considered under three different game rules for winning or losing. These three rules created distinct underlying causal structures (additive, conjunctive, disjunctive), for how individual performance affected the overall team outcome. Even the youngest children differentiated between different game rules in their reward allocations. Rather than only rewarding individual performance, or whether the team won/lost, children were sensitive to the team structure and how players' performance contributed to the win/loss under each of the three game rules. Not only do young children consider it fair to allocate resources based on merit, but they are also sensitive to the causal structure of the situation which dictates how individual contributions combine to determine the team outcome.

There is fundamental debate about the nature of forgetting: some have argued that it represents the decay of the memory trace, others that the memory trace persists but becomes inaccessible because of retrieval failure. These different accounts of forgetting lead to different predictions about savings memory, the rapid re-learning of seemingly forgotten information. If forgetting is because of decay, then savings requires re-encoding and should thus involve the same mechanisms as initial learning. If forgetting is because of retrieval failure, then savings should be mechanistically distinct from encoding. In this registered report, we conducted a preregistered and rigorous test between these accounts of forgetting. Specifically, we used microarray to characterize the transcriptional correlates of a new memory (1 d after training), a forgotten memory (8 d after training), and a savings memory (8 d after training but with a reminder on day 7 to evoke a long-term savings memory) for sensitization in Aplysia californica ( n = 8 samples/group). We found that the reactivation of sensitization during savings does not involve a substantial transcriptional response. Thus, savings is transcriptionally distinct relative to a newer (1-d-old) memory, with no coregulated transcripts, negligible similarity in regulation-ranked ordering of transcripts, and a negligible correlation in training-induced changes in gene expression ( r = 0.04 95% confidence interval (CI) [–0.12, 0.20]). Overall, our results suggest that forgetting of sensitization memory represents retrieval failure.