Optimal foraging theory: Prey density and travel requirements in Rattus norvegicus..

Two male Wistar hooded rats were allowed to forage for food by climbing nail ladders to a box containing prey mixed with sand (a patch) to investigate how environmental contingencies (constraints) operate to affect Ss' foraging behavior and patterns of optimal foraging. The amount of food was varied, as was the distance each patch was placed above the ground. Results show that under conditions of constant patch height and differing locations of patch densities, both Ss showed optimal usage of the patches. When travel between patches was difficult, there was greater utilization of each patch than when travel was easy, in accord with optimality theory. Under conditions of variable patch-density locations and difficult travel requirements, optimal foraging theory was congruent with the data. Under conditions of fixed patch-density locations or easy travel requirements, optimal foraging theory did not fit the data. It is concluded that the degree of optimality of behavior is governed by proximal mechanisms, and components such as sampling environmental events and travel risk must be included for an understanding of foraging behavior. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Choice behavior of pigeons on progressive and multiple schedules: A test of optimal foraging theory.

16 pigeons were trained on a depleting progressive schedule and on a multiple schedule that produced food at 1 of 4 constant rates. Ss were then allowed to choose between the schedules presented concurrently to see if they switched from the progressive schedule to an alternate fixed component of the multiple schedule in a manner that maximized the benefit/cost ratio. The time of access to the food/number of pecks required to earn food (T/N) ratio was varied in 2 mathematically equivalent but procedurally different ways. Results reveal that the ratio group was more sensitive to the different T/N values than was the time group. For both groups, the number of reinforcers earned on the progressive schedule during choice tests was a decreasing function of the T/N value of the alternative fixed schedule. Predictions based on optimal foraging theory better approximated actual choice behavior than did those based on performance under the individual schedules. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Looking back and ahead in psychometrics.

Reviews developments in 5 areas of psychometrics (computers, testing, scaling, factor analysis, and mathematical learning theory) beginning with L. L. Thurstone's work in the 1930s through the present. Recommendations for further research in measurement in each area are presented, including improvements in (a) the criteria against which aptitude tests are evaluated (e.g., college grades and achievements after college); (b) factor analyses of areas in learning, memory, physiology, or political science; and (c) the relationship between aptitude tests and learning tasks. Characteristics of recently proposed learning models are discussed, and questions in need of experimental investigation are noted (e.g., the use of stochastic or finite step models with learning data, the development of meaningful learning parameters, parameter estimation for individual and group learning curves, and evidence on reliability by replication in learning studies). (2 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time horizons in rats foraging for food in temporally separated patches.

An important tenet of optimal foraging theory is that foragers compare prey densities in alternative patches to determine an optimal distribution of foraging behavior over time. A critical question is over what time period (time horizon) this integration of information and behavior occurs. Recent research has indicated that rats do not compare food density in a depleting patch with that in a rich patch delayed by an hour or more (Timberlake, 1984). In the present research we attempted to specify over what time period a future rich patch would affect current foraging. The effect of future food was measured by early entry into the rich patch (anticipation) and by a decrease in food obtained in the depleting patch (suppression). The rats showed anticipation of a rich patch up to an hour distant, but suppressed current feeding only if the rich patch was 16 min distant or less. The suppression effect appeared mediated by competition for expression between anticipatory entries into the rich patch and continued foraging in the depleting patch. These results suggest that optimal foraging is based on a variety of specific mechanisms rather than a general optimizing algorithm with a single time horizon. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Introduction to the special issue on animal memory.

The papers in this Special Issue represent a sample of the types of issues and questions being addressed in the area of animal memory. Two general categories of empirical studies and theoretical treatments are typically classified under the animal memory heading. The first category, rather obviously, is comprised of contributions concerned with the theoretical and empirical analysis of animal memory per se. Contributions of this type typically concern the specification of the mechanisms and processes responsible for retention and forgetting. The second category comprising the area of animal memory are contributions in which processes of memory are invoked in the analysis of some phenomenon which is at least potentially analyzable without such constructs. The twelve papers collected here can be divided approximately equally between these two categories. Falling into the first category are studies of spatial memory (Wilkie), memory for visual stimuli (Grant; Roberts & Kraemer; Santi), memory for auditory stimuli (D'Amato & Salmon), the role of expectancies as mediators of short-term retention (Honig, Matheson, & Dodd), and the nature of memory expression (Spear). The remaining papers consider the role of processes of memory in other phenomena: foraging behaviour (Sherry), sequence learning (Weisman, Gibson, & Rochford), auditory discrimination learning (D'Amato & Salmon), performance on reinforcement schedules (Shimp), the learning of ill-defined categories (Medin & Dewey), and place navigation (Sutherland & Dyck). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context, time, and memory retrieval in the interference paradigms of Pavlovian learning.

Reviews research and theory on the "interference paradigms" in Pavlovian learning. In these situations (e.g., extinction, counterconditioning, and latent inhibition), a CS is associated with different unconditioned stimulus/stimuli (UCS) or outcomes in different phases of the experiment; retroactive interference, proactive interference, or both are often observed. In all of the paradigms, contextual stimuli influence performance, and when information is available, so does the passage of time. Memories of both phases are retained, and performance may depend on which is retrieved. Despite the similarity of the paradigms, conditioning theories tend to explain them with separate mechanisms. They also do not provide an adequate account of the context's role, fail to predict the effects of time, and overemphasize the role of learning or storage deficits. By accepting 4 propositions about animal memory (i.e., contextual stimuli guide retrieval, time is a context, different memories are differentially dependent on context, and interference occurs at performance output), a memory retrieval framework can provide an integrated account of context, time, and performance in the various paradigms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A structural equation modeling approach to the multiple memory systems question.

Used linear structural equation modeling to test 2 models of declarative memory. A unitary model was compared with the semantic-episodic theory proposed by E. Tulving (e.g., 1972, 1983). The data consisted of performance scores of 300 Ss on 14 cognitive tests. The results of 2 sets of analyses suggest rejection of the unitary model but not the 2-factor model. Moreover, nested comparisons of the models revealed that the 2-factor model provided a significantly better fit to data than did the unitary model. Results support a division of declarative memory into memory for episodic information and memory for facts. This finding is discussed in terms of (1) different underlying memory systems mediating performance on semantic and episodic tests and (2) differences in the retrieval strategies that are required for accessing semantic and episodic information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Basic behavioral science research for mental health: Perception, attention, learning, and memory.

Examines the cognitive processes of sensation and perception, attention, learning, and memory to understand cognitive disorders seen in mental illnesses. The sensation and perception review includes recognizing patterns and shapes, perceiving words in reading and the "Where" and "When" Modules of the visual system. The focus on attention concerns it's important cognitive role to planned, adaptive behavior. Many aspects of learning are discussed, including learning and prediction, conditioning and addiction, instrumental learning, modulating and preserving behavior, and social learning of fears and phobias. Reconstructive memory, emotion and memory, forms of memory (working and implicit memory), and the cognitive unconscious are discussed. Directions for future research on perception, attention, learning, and memory are given. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rats (Rattus norvegicus) modulate eating speed and vigilance to optimize food consumption: Effects of cover, circadian rhythm, food deprivation, and individual differences.

The eating behavior of rats given food pellets of specified size was examined as a function of environmental, circadian, and experiential influences. Eating times were shorter in lighted, exposed environments than in dark, covered environments, even though in novel, exposed conditions the rats made many scanning movements as they ate. Eating time also varied as a function of the circadian cycle in that eating times were shorter in the night portion of the day–night cycle. Finally, eating times decreased if rats were food deprived, and deprivation had a small but enduring influence. Within the tests there were differences in the eating times of individual rats that were not attributable to the experimental manipulations. That rats can optimize food intake by varying eating speed is discussed in relation to physiological regulation of feeding and to optimal foraging theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Abram Amsel (1922-2006).

Presents an obituary for Abram Amsel who died on August 31, 2006, at 83 years of age. Abram Amsel's academic career spanned the second half of the 20th century, during which time he made seminal contributions to the theory and research of reward-schedule effects in mammals. In the first 20 years of his career, Amsel's behavioral research and theory of "frustrative nonreward" established aversive emotional consequences of nonreward as potent influences on behavior when certain reward schedules are in effect. During the next 30 years, he continued to pursue questions related to reward-schedule effects but this time from the perspectives of ontogeny and behavioral neuroscience. His work resulted in a much deeper understanding and a broader conceptualization of reward-schedule effects that he eventually came to characterize as "dispositional learning and memory." Amsel held several professional roles in his field. He was a member of the governing board of the Psychonomic Society (1973-1978) and the founding editor (1972-1976) of the Society's journal Animal Learning & Behavior (now Learning & Behavior). He also served as consulting editor for the Journal of Experimental Psychology (1964 -1969), editor of Psychonomic Science (1971-1972), and member of the editorial board of the International Journal of Psychophysiology (1982-1988). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于罚函数法的冷连轧轧制规程优化设计

 合理的轧制规程是使轧制过程达到最佳状态的重要保证。规程设定中采用具有自学习功能的BP神经网络取代传统轧制力数学模型,选用Levenberg Marquardt算法对轧制力进行预报。采用等相对负荷目标函数,考虑到现场和设备所受限制,确定约束条件。利用罚函数法将有约束的最优问题转换成无约束的最优问题,对某厂冷连轧现场规程进行了优化设计,并对优化前后的轧制规程进行了分析和比较,优化效果令人满意,满足实际生产要求。     

Posttrial d-amphetamine sulfate and one-trial learning in mice.

Conducted 3 experiments with a total of 216 male albino LACA mice to investigate the effect of dextroamphetamine sulfate on memory in such a way that (a) state-dependency learning effects were excluded, (b) the time of learning was known rather precisely, (c) the drug might be introduced rapidly after the learning trial if recovered, and (d) no previous learning experience or drug effects would be present to confound the interpretation of results. Results show that amphetamine (2 mg/Kg, iv) immediately after footshock on a 1-trial passive avoidance learning task impaired performance in retention tests 24 and 96 hrs later. When the injection was delayed by as little as 90 sec, no such impairment was seen. A similar injection immediately after the learning trial of a water-rewarded 1-trial appetitive task had no discernible effect on performance in retention trials 24 hrs and 6 wks later. It is argued that the effects of the amphetamines on learning behavior depend on whether reward or punishment is involved and, further, that all such effects could be accounted for in terms of the drugs' influence on memory mechanisms. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How experts' adaptations to representative task demands account for the expertise effect in memory recall: Comment on Vicente and Wang (1998).

K. A. Ericsson and W. Kintsch's (1995) theoretical framework of long-term working memory (LTWM) accounts for how experts acquire encoding and retrieval mechanisms to adapt to real-time demands of working memory during representative interactions with their natural environments. The transfer of the same LTWM mechanisms is shown to account for the expertise effect in unrepresentative "contrived" memory tests. Therefore, K. J. Vicente and J. H. Wang's critique of the generalizability of the LTWM framework is rejected. Their proposed refutation of LTWM accounts is found to be based on misrepresented facts. The process-based framework of LTWM is shown to be superior to their product theory because it can explain interactions of the expertise effect in "contrived" recall under several testing conditions differing in presentation rate, instructions, and memory procedures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conditioning, remembering, and forgetting.

Argues that the separation of theories of learning and of memory should be abandoned. Remembering and forgetting play an important role in simple conditioning experiments. For example, conditioned performance can readily recover after extinction because extinction is susceptible to forgetting. Memory itself involves the kind of associative learning that conditioning experiments are designed to investigate (e.g., conditioning experiments provide insight into the mechanisms of memory retrieval). Learning, remembering, and forgetting all occur within the same biological context; their adaptive functions are therefore intertwined. Taken together, they shed light on some of the mechanisms of clinical relapse. Conditioning theory enriches, and is enriched by, the field of memory as well as other fields of behavioral science. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Schema training in analogical reasoning.

In 3 experiments, college students learned how to solve 20 verbal analogy problems and took transfer and memory tests. Ss learned from worked-out examples that emphasized relational terms such as "part-to-whole" or under 3 other instructional conditions that required responding to examples or that excluded mention of relational terms. The former Ss were more accurate and faster then other Ss on solving new problems involving the same relations but less accurate in recognizing words from previous problems. This pattern is inconsistent with active responding theory, which predicts students learn best by generating answers and receiving feedback to problems, and is consistent with active learning theory, which predicts that students learn best by inducing schemas for particular problem types. Results indicate that schema induction is maximized when the schemas are made salient and the cognitive system is not overloaded. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the whats and hows of retrieval in the acquisition of a simple skill.

Two general views on the role of memory in cognitive skills—an instance-based theory and an associative perspective—were compared with respect to their general assumptions about the information involved and the processes that operate on that information. Characteristics of memory information were examined in terms of predictions for transfer to various stimulus forms as a function of 2 types of learning conditions. Characteristics of memory processes were examined using a set of general process models. Results of 4 experiments indicate that (a) neither theoretical perspective was capable of accounting for all the observed transfer effects, indicating needed refinements to informational assumptions, and that (b) 1 class of process assumptions was consistently supported, whereas other classes were consistently contradicted, indicating a general set of process characteristics that can be used in further model development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The dynamics of operant conditioning.

Existing models of operant learning are relatively insensitive to historical properties of behavior and applicable to only limited data sets. This article proposes a minimal set of principles based on short-term and long-term memory mechanisms that can explain the major static and dynamic properties of operant behavior in both single-choice and multiresponse situations. The critical features of the theory are as follows: (a) The key property of conditioning is assessment of the degree of association between responses and reinforcement and between stimuli and reinforcement; (b) the contingent reinforcement is represented by learning expectancy, which is the combined prediction of response–reinforcement and stimulus–reinforcement associations; (c) the operant response is controlled by the interplay between facilitatory and suppressive variables that integrate differences between expected (long-term) and experienced (short-term) events; and (d) very-long-term effects are encoded by a consolidated memory that is sensitive to the entire reinforcement history. The model predicts the major qualitative features of operant phenomena and then suggests an experimental test of theoretical predictions about the joint effects of reinforcement probability and amount of training on operant choice. We hypothesize that the set of elementary principles that we propose may help resolve the long-standing debate about the fundamental variables controlling operant conditioning. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Feeding diversity in deer mice.

Compared the foraging behavior of 2 geographically isolated subspecies of deer mice. Laboratory-reared Peromyscus maniculatus borealis from the prairies of Alberta, Canada and P. m. blandus from the deserts of Arizona were studied in 3 tests emphasizing different aspects of foraging: approach, acquisition, and consumption. Two measures were used to compare feeding: diversity, an index of the breadth of the diet, and preference, an index of what Ss ate most. A consistent difference found between the 2 subspecies in individuals' feeding diversity suggests that this subspecific effect is due to genetic differences, as predicted by evolutionary theory. At the same time that individuals of each subspecies had roughly the same diversity, they had different preferences, which suggests that they are more variable or opportunistic in their foraging choices than predicted by theories of optimal foraging. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)