Conditional discrimination learning: A critique and amplification

Carter and Werner recently reviewed the literature on conditional discrimination learning by pigeons, which consists of studies of matching-to-sample and oddity-from-sample. They also discussed three models of such learning: the “multiple-rule” model (learning of stimulus-specific relations), the “configuration” model, and the “single-rule” model (concept learning). Although their treatment of the multiple-rule model, which seems most applicable to the pigeon data, is generally excellent, their discussion of the other two models is incomplete and sometimes inaccurate. Potential problems of terminology are discussed in the present paper, as are additional lines of research that deserve consideration by those interested in further work in this area. The issue of response versus stimulus selection (configuration versus compound-cue learning) is discussed in connection with the configuration model. Particular attention is given to Carter and Werner's criticism of the application, in studies with other species, of the learning set procedure in testing for single-rule learning. Some of the important related issues are: the bias for improvement on new problems in a series, the adequacy of a multiple-rule model to explain learning set formation, and evidence in favor of the single-rule model, at least in primates. Consideration of these additional contributions to the study of conditional discrimination learning emphasizes the usefulness of this task in the comparative study of cognitive processes.     

Formation of the sameness-difference concept by Japanese monkeys from a small number of color stimuli

Japanese monkeys were trained to form the sameness-difference concept. In Experiment 1, four monkeys were trained with two colors to discriminate matching stimulus pairs from nonmatching pairs by reinforcing only lever-pressing responses to matching pairs with a variable-interval schedule. Three monkeys showed successful transfer of this discrimination to two new colors, thus demonstrating that some Japanese monkeys are able to form this relational concept from a minimum number of stimuli. In Experiment 2, two monkeys were trained, in a Yes/No procedure with three colors, to press one lever under matching pairs and another lever under nonmatching pairs. Poor transfer performances to three new colors suggest that simultaneously establishing two different response patterns to matching and nonmatching pairs is ineffective in forming the concept. In Experiment 3, the amount of transfer to three new colors after mastering a standard three-color matching-to-sample task was compared with that of a modified task in which correct responses were reinforced with a within-trial variable-interval schedule. All three monkeys showed greater transfer with the modified procedure. The results suggest that the variable-interval schedule adopted within trials is effective in forming the sameness-difference concept.     

WHAT DOES A PIGEON SEE IN A PICASSO?

The present paper is primarily a response to Watanabe, Sakamoto, and Wakita's 1995 paper “Pigeons' Discrimination of Paintings by Monet and Picasso.” Our main criticism is that the key term concept, and in particular the way in which a class of stimuli is specified, remains equivocal. We argue that it is only useful to study categorization if the organism in question can be expected to have access to the information that is used in defining the classes, and that evidence for categorization requires selective responses that cannot be attributed to similarity in features that are not essential to the classification.     

Categorization of natural movements by pigeons: visual concept discrimination and biological motion

In three experiments, pigeons were exposed to a discriminated autoshaping procedure in which categories of moving stimuli, presented on videotape, were differentially associated with reinforcement. All stimuli depicted pigeons making defined responses. In Experiment 1, one category consisted of several different scenes of pecking and the other consisted of scenes of walking, flying, head movements, or standing still. Four of the 4 birds for which pecking scenes were positive stimuli discriminated successfully, whereas only 1 of the 4 for which pecking was the negative category did so. In the pecking-positive group, there were differences between the pecking rates in the presence of the four negative actions, and these differences were consistent across subjects. In Experiment 2, only the categories of walking and pecking were used; some but not all birds learned this discrimination, whichever category was positive, and these birds showed some transfer to new stimuli in which the same movements were represented only by a small number of point lights (Johansson's “biological motion” displays). In Experiment 3, discriminations between pecking and walking movement categories using point-light displays were trained. Four of the 8 birds discriminated successfully, but transfer to fully detailed displays could not be demonstrated. Pseudoconcept control groups, in which scenes from the same categories of motion were used in both the positive and negative stimulus sets, were used in Experiments 1 and 3. None of the 8 pigeons trained under these conditions showed discriminative responding. The results suggest that pigeons can respond differentially to moving stimuli on the basis of movement cues alone.     

从摩梭人的词汇看人类概念的发展

通过调查摩梭人的词汇研究人类概念的发展。摩梭人到本世纪七十年代还盛行母系家 庭,至今没有文字。调查方法是从小学汉语文课本中选出一批常用词汇,把当地摩梭和汉两种 语文水平最高的几个知识分子请到一起,逐词逐字地共同讨论,核实提供调查的词汇在摩梭 语中是否有对应词。不论有无对应词均以全体同意为准。结果表明,摩梭人词汇数量较少,范 围较窄,概括和具体化的程度都不高。作者认为,由摩梭词汇标志的概念发展状况,可作人类 概念发展早期的一个例证。     

Use of number by crows: investigation by matching and oddity learning

Hooded crows were trained in two-alternative simultaneous matching and oddity tasks with stimulus sets of three different categories: color (black and white), shape (Arabic Numerals 1 and 2, which were used as visual shapes only), and number of elements (arrays of one and two items). These three sets were used for training successively and repeatedly; the stimulus set was changed to the next one after the criterion (80% correct or better over 30 consecutive trials) was reached with the previous one. Training was continued until the criterion could be reached within the first 30 to 50 trials for each of the three training sets. During partial transfer tests, familiar stimuli (numerals and arrays in the range from 1 to 2) were paired with novel ones (numerals and arrays in the range from 3 to 4). At the final stage of testing only novel stimuli were presented (numerals and arrays in the range from 5 to 8). Four of 6 birds were able to transfer in these tests, and their performance was significantly above chance. Moreover, performance of the birds on the array stimuli did not differ from their performance on the color or shape stimuli. They were capable of recognizing the number of elements in arrays and comparing the stimuli by this attribute. It was concluded that crows were able to apply the matching (or oddity) concept to stimuli of numerical category.     

Medical Informatics and the Concept of Disease

This paper attempts to address the general questionwhether information technologies, as applied in thearea of medicine and health care, have or are likelyto change fundamental concepts regarding disease andhealth. After a short excursion into the domain ofmedical informatics I provide a brief overview of someof the current theories of what a disease is from amore philosophical perspective, i.e. the ``valuefree' and ``value laden' view of disease. Next, Iconsider at some length, whether health careinformatics is currently modifying fundamentalconcepts of disease. To this question I will answerlargely in the negative, and I will provide the sketchof some arguments from current research programs inmedical informatics why I think this is the case. Thisargumentation is supported by a detailed account ofhow the disease profile for beriberi heart disease,used in one of the major medical informaticsdiagnostic programs, QMR (and its ancestorINTERNIST-1), was developed, and why at least thisprogram essentially follows received views oftraditional medicine.The one main exception to theconformity of this program to ``received' views of adisease occurs when the program's designers need tofine-tune a disease definition. This fine-tuning is tocomport with the expert's perspective on the disease,including his or her epistemic values, as well as theprogram's other resources for diagnosing components ofa disease.     

Cognitive control of action naming in adults who stutter

PurposeBased on previous evidence that cognitive control of lexical selection in object (noun) naming operates differently in adults who stutter (AWS) versus typically-fluent adults (TFA), the aim was to investigate cognitive control of lexical selection in action (verb) naming in AWS.Method12 AWS and 12 TFA named line drawings depicting actions using verbs. Half of the pictures had high-agreement action names and the other half low-agreement action names. Naming accuracy and reaction times (RT), and event-related potentials (ERPs) time-locked to picture onset, were compared between groups.ResultsNaming RTs were slower for low- versus high-agreement trials, and the magnitude of this effect was larger in AWS versus TFA. Delta-plot analysis of naming RTs revealed that individual differences in selective inhibition were associated with the agreement effect on naming RTs in AWS but not TFA. Action naming elicited frontal-central N2 activity in both agreement conditions in TFA but not AWS. Additionally, a later, posterior P3b component was affected by agreement in TFA only. In AWS, low-agreement action naming elicited frontal P3a activation.ConclusionsResults suggest that cognitive control of action name selection was qualitatively different between groups. In TFA, cognitive control of lexical selection in action naming involved nonselective inhibition, as well as more efficient working memory updating on high- versus low-agreement trials. In AWS, cognitive control of low-agreement action naming involved increased focal attention. Individual differences in selective inhibition may have moderated cognitive control of action naming in AWS.     

Simulating the Acquisition of Verb Inflection in Typically Developing Children and Children With Developmental Language Disorder in English and Spanish

Children with developmental language disorder (DLD) have significant deficits in language ability that cannot be attributed to neurological damage, hearing impairment, or intellectual disability. The symptoms displayed by children with DLD differ across languages. In English, DLD is often marked by severe difficulties acquiring verb inflection. Such difficulties are less apparent in languages with rich verb morphology like Spanish and Italian. Here we show how these differential profiles can be understood in terms of an interaction between properties of the input language, and the child's ability to learn predictive relations between linguistic elements that are separated within a sentence. We apply a simple associative learning model to sequential English and Spanish stimuli and show how the model's ability to associate cues occurring earlier in time with later outcomes affects the acquisition of verb inflection in English more than in Spanish. We relate this to the high frequency of the English bare form (which acts as a default) and the English process of question formation, which means that (unlike in Spanish) bare forms frequently occur in third-person singular contexts. Finally, we hypothesize that the pro-drop nature of Spanish makes it easier to associate person and number cues with the verb inflection than in English. Since the factors that conspire to make English verb inflection particularly challenging for learners with weak sequential learning abilities are much reduced or absent in Spanish, this provides an explanation for why learning Spanish verb inflection is relatively unaffected in children with DLD.     

Developmental stages,Piagetian stages in particular: A critical review

Developmental stages in general and Piaget's stages in particular have given rise to considerable controversy. Much of this controversy revolves around the responses that have been given to the following five central questions: (1) Do developmental stages exist? (2) If they exist, where are they? (3) What features define a developmental sequence as a sequence of developmental stages? (4) What psychological processes underlie developmental change? (5) Should we abandon the concept of developmental stages? The main goal of this paper is to present a critical review of such responses, while arguing for a strong conception of development and a “non-received” view of Piaget's theory. After an introduction section, we elaborate on each of the five questions. Finally, we present several reasons why this paper often appeals to Piaget's theory, and why his theory has been greatly misunderstood.