Emotionality in male and female rodents: a reply to Archer.

Archer (1979) has complained that his criticisms (Archer, 1971, 1973, 1975) of Gray's (1971 a, b) views on emotionality and on sex differences in fearfulness in rodents have not been answered. These criticisms are shown to lack substance and to depend on confused arguments and misleading reviews of the literature.     

Effects of medial and lateral septal lesions on the partial reinforcement extinction effect at short inter-trial intervals

Rats sustained electrolytic lesions either in the medial septal (MS) area (of a kind known to eliminate the hippocampal theta rhythm) or in the dorso-lateral septal (LS) area (of a kind known to spare theta) and were compared to sham-operated controls in three experiments in the straight alley with food reward on continuous (CRF) or partial (PRF) reinforcement and inter-trial intervals of 3-8 min. With 6 acquisition trials MS lesions increased resistance to extinction and enhanced the partial reinforcement extinction effect (PREE). With 48 acquisition trials MS lesions did not alter resistance to extinction after either CRF or PRF training, but LS lesions abolished the PREE by increasing resistance to extinction in rats trained with CRF and decreasing it in rats trained with PRF. With 96 acquisition trials LS lesions were without effect on resistance to extinction after either CRF or PRF training, as previously reported by Henke (1974) using total septal lesions. Thus the impairment in the PREE previously shown after large septal lesions is due to damage to the lateral, not the medial, septal area.     

The right tool for the job: what strategies do wild New Caledonian crows use?

New Caledonian crows Corvus moneduloides (NC crows) display sophisticated tool manufacture in the wild, but the cognitive strategy underlying these skills is poorly understood. Here, we investigate what strategy two free-living NC crows used in response to a tool-length task. The crows manufactured tools to extract food from vertical holes of different depths. The first tools they made in visits were of a similar length regardless of the hole depth. The typical length was usually too short to extract food from the deep holes, which ruled out a strategy of immediate causal inference on the first attempt in a trial. When the first tool failed, the crows made second tools significantly longer than the unsuccessful first tools. There was no evidence that the crows made the lengths of first tools to directly match hole depth. We argue that NC crows may generally use a two-stage heuristic strategy to solve tool problems and that performance on the first attempt in a trial is not necessarily the ‘gold standard’ for assessing folk physics.This contribution is part of the special issue ‘Animal Logics’ (Watanabe and Huber 2006).     

Suboptimal tradeoffs in information seeking

Explicit information-seeking actions are needed to evaluate alternative actions in problem-solving tasks. Information-seeking costs are often traded off against the utility of information. We present three experiments that show how subjects adapt to the cost and information structures of environments in a map-navigation task. We found that subjects often stabilize at suboptimal levels of performance. A Bayesian satisficing model (BSM) is proposed and implemented in the ACT-R architecture to predict information-seeking behavior. The BSM uses a local decision rule and a global Bayesian learning mechanism to decide when to stop seeking information. The model matched the human data well, suggesting that adaptation to cost and information structures can be achieved by a simple local decision rule. The local decision rule, however, often limits exploration of the environment and leads to suboptimal performance. We propose that suboptimal performance is an emergent property of the dynamic interactions between cognition and the environment.     

Children's understanding of the arithmetic concepts of inversion and associativity

Previous studies have shown that even preschoolers can solve inversion problems of the form a+b-b by using the knowledge that addition and subtraction are inverse operations. In this study, a new type of inversion problem of the form d x e/e was also examined. Grade 6 and 8 students solved inversion problems of both types as well as standard problems of the form a+b-c and d x e/f. Students in both grades used the inversion concept on both types of inversion problems, although older students used inversion more frequently and inversion was used most frequently on the addition/subtraction problems. No transfer effects were found from one type of inversion problem to the other. Students who used the concept of associativity on the addition/subtraction standard problems (e.g., a+b-c=[b-c]+a) were more likely to use the concept of inversion on the inversion problems, although overall implementation of the associativity concept was infrequent. The findings suggest that further study of inversion and associativity is important for understanding conceptual development in arithmetic.     

Gender differences in the effect of visual sexual stimulation on the perceived covariation between freedom and responsibility

The authors replicated and extended a test of Epstein's cognitive-experiential self-theory (CEST; S. Epstein, 1973, 1980, 1985, 1994, 2003) regarding subjective estimates of the relationship between freedom and responsibility. CEST predicts that information in the form of sexually provocative images is likely to be processed by the experiential system. The authors' hypothesis was that such experiential processing would cause an increase in the likelihood of participants endorsing as true a statement that proposed a negative correlation between freedom and responsibility. University students (N = 97) in introductory psychology classes viewed 25 images of either men or women in provocative clothing, or a control consisting of academic journal covers, after which they responded to 24 statements proposing either a positive, negative, or noncontingent relationship between freedom and responsibility. Judgments were analyzed according to perceiver gender and target gender, as well as the framing of the proposition and its contingency category. The hypothesis was supported for the men and to a lesser extent for the women. Although priming the experiential system by exposing participants to sexually provocative images did not change endorsement rates of positive contingencies, it did lead to an increase in the likelihood of simultaneously endorsing negative contingencies.     

Performance determined instruction for training in remedial reading

A system called Performance Determined Instruction (PDI) is presented as a methodological tactic for training in remedial reading. The system incorporates aspects of binary logic, instrumental conditioning, and programmed instruction. Results suggest that PDI is a high-precision instructional procedure effective in obtaining desired changes in reading-task performance.