Ergodic theorems and the basis of science

New results in ergodic theory show that averages of repeated measurements will typically diverge with probability one if there are random errors in the measurement of time. Since mean-square convergence of the averages is not so susceptible to these anomalies, we are led again to compare the mean and pointwise ergodic theorems and to reconsider efforts to determine properties of a stochastic process from the study of a generic sample path. There are also implications for models of time and the interaction between observer and observable.Supported in part by NSF Grant DMS-9203489. The author thanks Klaus Schmidt and Máté Wierdl for illuminating discussions.     

Effect of a reliability observer on the frequency of positive parent behavior recorded during naturalistic parent-child interactions

The purpose of the present study was to examine the effect of the presence of a reliability observer on the number of positive parent behaviors recorded by a primary observer during naturalistic parent-child interactions. Thirty parents and their young clinic-referred children served as subjects. After two initial home observations, a reliability observer was present to record data in observation session 3, but not session 4, for one-half the subjects. For the remaining subjects the reliability observer was present in session 4 but not session 3. The results of a 2 × 2 analysis of variance indicated a group by session interaction which resulted from an increase in maternal attention to the child in the presence of a reliability observer. Hypotheses to explain the finding are presented and implications of the results are discussed.This research was supported in part by NIMH Grant MH28859-01.     

Discrimination learning with and without “errors”

Responses to S− (“errors”) are not a necessary condition for the formation of an operant discrimination of color. Errors do not occur if discrimination training begins early in conditioning and if S+ and S− initially differ with respect to brightness, duration and wavelength. After training starts, S−'s duration and brightness is progressively increased until S+ and S− differ only with respect to wavelength. Errors do occur if training starts after much conditioning in the presence of S+ has occurred or if S+ and S− differ only with respect to wavelength throughout training. Performance following discrimination learning without errors lacks three characteristics that are found following learning with errors. Only those birds that learned the discrimination with errors showed (1) “emotional” responses in the presence of S−, (2) an increase in the rate (or a decrease in the latency) of its response to S+, and (3) occasional bursts of responses to S−.     

Active and passive scene recognition across views.

Recent evidence suggests that scene recognition across views is impaired when an array of objects rotates relative to a stationary observer, but not when the observer moves relative to a stationary display [Simons, D.J., Wang, R.F., 1998. Perceiving real-world viewpoint changes. Psychological Science 9, 315-320]. The experiments in this report examine whether the relatively poorer performance by stationary observers across view changes results from a lack of perceptual information for the rotation or from the lack of active control of the perspective change, both of which are present for viewpoint changes. Three experiments compared performance when observers passively experienced the view change and when they actively caused the change. Even with visual information and active control over the display rotation, change detection performance was still worse for orientation changes than for viewpoint changes. These findings suggest that observers can update a viewer-centered representation of a scene when they move to a different viewing position, but such updating does not occur during display rotations even with visual and motor information for the magnitude of the change. This experimental approach, using arrays of real objects rather than computer displays of isolated individual objects, can shed light on mechanisms that allow accurate recognition despite changes in the observer's position and orientation.     

Extinction of a discriminative operant following discrimination learning with and without errors

Different groups of pigeons were trained to respond to red and not to green with and without errors (responses to green) under a free operant procedure, in which responding to red was intermittently reinforced, and under a trial procedure in which all responses to red were reinforced. The response to red was then extinguished under a procedure in which the discriminative stimuli were successively alternated as during discrimination training. The performances of those birds that learned the discrimination without errors under the trial procedure were seriously disrupted during extinction; the birds persistently responded to green for the first time. The performances of those subjects that learned the discrimination without errors under the free operant procedure were not disrupted during extinction. In a second experiment, the same discrimination was trained without errors under a trial procedure in which the response to red was intermittently reinforced. Extinction did not disrupt discrimination performance. Thus, errorless discrimination performance was shown to remain intact during extinction so long as the response to red was intermittently reinforced during discrimination training.     

Chronic pain: a reformulation of the cognitive-behavioural model.

The last few decades has seen psychological theories of chronic pain dominated by behavioural concepts and particularly, by the operant model as described by Fordyce et al. (1968: Fordyce, W., Fowler, R., & DeLateur, B. (1968) An application of behavior modification technique to a problem of chronic pain. Behaviour Research and Therapy, 6, 105-107, 1976: Fordyce, W.E. (1976) Behavioral methods for chronic pain and illness. St Louis, MO: C. V Moseby). More recently, cognitive constructs have been included, giving the impression that the operant theory of chronic pain has been replaced by a cognitive-behavioural theory (CBT). Given the fact that CBTs were introduced essentially to overcome some inherent problems with operant theory, it is notable that they are still very much based on operant theory and continue to be founded upon operant principles. Further, the extent to which CBTs (at this stage) have included contemporary cognitive research has been limited. This paper argues that it is of questionable validity to continue to include problematic concepts (e.g., operant principles) into a revised theory (e.g., CBT). Instead, consistent with research from other areas (particularly the anxiety disorders), chronic pain and the problems associated with it may be better explained by a reformulated cognitive-behavioural theory which although not ignoring the observable behaviours of pain patients and their associations with social reinforcers, interprets these phenomena from a cognitive perspective. Thus, a modified CBT is proffered, focusing more directly on patients' thoughts about, and appraisals of, their pain. Evidence in support of such a theory is provided, as are suggestions for further research and the implications such a theory has for treatment.     

Finding locations in the environment: the map as mediator.

When an observer (O) uses a map (M) whose orientation does not correspond to the orientation of the environment (E) in which performance occurs, substantial errors occur: these are called map alignment effects. Much of the prior research on map/environment (M/E) alignment has involved maps of simple paths, although alignment effects have also been demonstrated for you-are-here (YAH) maps. A study is reported in which simple YAH maps were used to test the hypothesis that errors with misaligned maps would fall into categories predictable from the application of inappropriate cognitive operations to the misaligned maps, as demonstrated earlier by Rossano and Warren. Further, performance under conditions of M/E misalignment was compared with performance under map/observer (M/O) misalignment, the situation in which the map is sideways or upside-down with respect to the observer. The major hypothesis was supported: predictable errors occurred under conditions of M/E misalignment. Errors under conditions of M/O misalignment were significantly smaller. Furthermore, when given the choice of using M/E or M/O alignment, each at the expense of the other, the overwhelming choice was to retain M/E rather than M/O alignment. This pattern of results occurred even when environmental features were represented by words rather than by lines and shapes on the map. The results underscore the robustness of map alignment effects.     

What can prosody tell a parser?

In this paper, I consider how a sentence processor might use specific prosodic cues at various points in the processing of particular sentences containing (at least temporary) syntactic ambiguity. In principle, the usefulness of prosodic information depends on what a given cluster of prosodic cues typically signifies, and on which syntactic options exist for a given string: in only some instances can prosodic information provide useful disambiguating information.This work was supported by Grant #DC-01409, a Research and Training Grant funded by the National Institute on Deafness and Other Communicative Disorders to the National Center for Neurogenic Communication Disorders, University of Arizona. I wish to thank Andrew Barss for very helpful comments on an earlier draft of this paper.     

Effects of clausal structure on subject-verb agreement errors

This paper explores the effect of manipulating the internal structure of a complex subject on the incidence of subject-verb agreement errors. Using the sentence completion task (Bock & Miller, 1991), this study followed up on Vigliocco and Nicol's (1995) finding that the syntactic distance between a head noun and a number-mismatching noun contained within a modifier has an impact on error incidence: the greater the distance, the lower the error rate. The study presented in this paper investigated whether this distance effect is purely syntactic; if so, then it would be expected that there would be fewer errors followingThe owner of the house which charmed the realtor... than followingThe owner of the house who charmed the realtors..., since in the latter, the mismatch is syntactically nearer the head noun. Results show no hint of a difference between the two, suggesting that the distance effect is more likely due totemporal distance rather than syntactic distance per se.This research was supported by grant 5 P60 DC 01409-05, a Research and Training Grant funded by the National Institute on Deafness and Other Communicative Disorders, National Institutes of Health, to the National Center for Neurogenic Communication Disorders, University of Arizona. I am grateful to Danielle Cvitanovic, Nicole Diamond and Brad Greenwell for their assistance in testing subjects and scoring responses. I wish to thank Merrill Garrett for reviewing an earlier draft of this paper.     

Response cost and impulsive word recognition errors in reading-disabled children

Subjects were 30 fourth grade children with average intellectual ability but reading achievement at least 1.5 years below grade level. Each child was given two word-recognition lists, the first one as a pretest and the second list under one of three different experimental conditions: control, positive reinforcement (1 nickel for each word read correctly), and response cost (1 of 40 nickels taken back for each word read incorrectly). Relative to the control condition, positive reinforcement led to a significant increase in response latency but no change in errors, while response cost led to both a significant increase in latency and a significant decrease in reading errors. The entire group was found to be impulsive on the Matching Familiar Figures test. The successful reduction in impulsive reading errors was interpreted as support for Kagan's hypothesis that the impulsive child evidences low concern about errors on such academic tasks.This report is based on a senior honors thesis by D. E. B., which was the 1977 winner of the Dashiell-Thurstone Prize for the best undergraduate honors thesis in psychology at the University of North Carolina at Chapel Hill Appreciation is expressed to the following persons for their assistance or comments: Dr. W. Anderson, Ms. D. Crew, Ms. C. Earp, Ms. N. Hardy, Dr. K. Jens, Dr. K. Fleishman, Dr. B. Martin, Dr. G. Mesibov, Mr. S. Muller, Ms. E. Pritchett, Mr. Wall, Ms. Wall, and Ms. M. Walton. The research was supported in part by U. S. Public Health Service, Maternal and Child Health Project No. 916, and by Grants HD-03110 and ES-01104 from the National Institutes of Health.     

Errors of Omission in English-Speaking Children's Production of Plurals and the Past Tense: The Effects of Frequency, Phonology, and Competition

How do English‐speaking children inflect nouns for plurality and verbs for the past tense? We assess theoretical answers to this question by considering errors of omission, which occur when children produce a stem in place of its inflected counterpart (e.g., saying “dress” to refer to 5 dresses). A total of 307 children (aged 3;11–9;9) participated in 3 inflection studies. In Study 1, we show that errors of omission occur until the age of 7 and are more likely with both sibilant regular nouns (e.g., dress) and irregular nouns (e.g., man) than regular nouns (e.g., dog). Sibilant nouns are more likely to be inflected if they are high frequency. In Studies 2 and 3, we show that similar effects apply to the inflection of verbs and that there is an advantage for “regular‐like” irregulars whose inflected form, but not stem form, ends in d/t. The results imply that (a) stems and inflected forms compete for production and (b) children generalize both product‐oriented and source‐oriented schemas when learning about inflectional morphology.     

Slope estimation and viewing distance of the observer

The overestimation of geographical slant is one of the most sizable visual illusions. However, in some cases estimates of close-by slopes within the range of the observer’s personal space have been found to be rather accurate. We propose that the seemingly diverse findings can be reconciled when taking the viewing distance of the observer into account. The latter involves the distance of the observer from the slope (personal space, action space, and vista space) and also the eye-point relative to the slope. We separated these factors and compared outdoor judgments to those collected with a three-dimensional (3D) model of natural terrain, which was within arm’s reach of the observer. Slope was overestimated in the outdoors at viewing distances between 2 m and 138 m. The 3D model reproduced the errors in monocular viewing; however, performance was accurate with stereoscopic viewing. We conclude that accurate slant perception breaks down as soon as the situation exits personal space, be it physically or be it by closing one eye.     

The relationship between external variables and common factors

A theorem is presented which gives the range of possible correlations between a common factor and an external variable (i.e., a variable not included in the test battery factor analyzed). Analogous expressions for component (and regression component) theory are also derived. Some situations involving external correlations are then discussed which dramatize the theoretical differences between components and common factors.Support by the National Research Council of Canada (NRC Grant No. A4640) and the University of British Columbia (UBC Humanities and Social Sciences Grant 26-9718) is gratefully acknowledged.This paper is based in part on the author's Ph.D. dissertation. I am particularly grateful to my dissertation advisor, Dr. Peter H. Schönemann. Thanks also to the editor and the anonymous reviewers, who contributed many helpful comments and suggestions.     

A feasible method for standard errors of estimate in maximum likelihood factor analysis

A jackknife-like procedure is developed for producing standard errors of estimate in maximum likelihood factor analysis. Unlike earlier methods based on information theory, the procedure developed is computationally feasible on larger problems. Unlike earlier methods based on the jackknife, the present procedure is not plagued by the factor alignment problem, the Heywood case problem, or the necessity to jackknife by groups. Standard errors may be produced for rotated and unrotated loading estimates using either orthogonal or oblique rotation as well as for estimates of unique factor variances and common factor correlations. The total cost for larger problems is a small multiple of the square of the number of variables times the number of observations used in the analysis. Examples are given to demonstrate the feasibility of the method.The research done by R. I. Jennrich was supported in part by NSF Grant MCS 77-02121. The research done by D. B. Clarkson was supported in part by NSERC Grant A3109.     

Precue effects in visual search: Data or resource limited?

Precuing an observer as to where a target is more likely to occur in a subsequent visual array can increase the detectability (d′) of a target at that location. This is often attributed to the observer’s increased allocation of some limited cognitive resource (“attention”) to the cued location. Two experiments are reported which are difficult to interpret in this way even though they involve similar cue effects. The first involves postcuing a location well after the array but before the observer responds, so that the cue can influence the response but not the observation. The second involves precuing, but with slow sequential presentation of array elements prior to the response, so the observer need not share any limited resource while processing each element in turn. Enhanced detectability similar to that produced with precues and simultaneous presentation of elements is shown to occur in each experiment. An alternative data-limited (rather than resource-limited) interpretation of these effects is provided by a mathematical model in which the observer integrates equally noisy or degraded internal representations of the array elements, but gives more weight to cued elements in selecting a response. Theoretical parameters of the model are shown to provide separate measures of both an observer’s overall sensitivity and precue effects in cost-benefit analyses of cuing data.     

Sensitization and habituation regulate reinforcer effectiveness

We argue that sensitization and habituation occur to the sensory properties of reinforcers when those reinforcers are presented repeatedly or for a prolonged time. Sensitization increases, and habituation decreases, the ability of a reinforcer to control behavior. Supporting this argument, the rate of operant responding changes systematically within experimental sessions even when the programmed rate of reinforcement is held constant across the session. These within-session changes in operant responding are produced by repeated delivery of the reinforcer, and their empirical characteristics correspond to the characteristics of behavior undergoing sensitization and habituation. Two characteristics of habituation (dishabituation, stimulus specificity) are particularly useful in separating habituation from alternative explanations. Arguing that habituation occurs to reinforcers expands the domain of habituation. The argument implies that habituation occurs to biologically important, not just to neutral, stimuli. The argument also implies that habituation may be observed in “voluntary” (operant), not just in reflexive, behavior. Expanding the domain of habituation has important implications for understanding operant and classical conditioning. Habituation may also contribute to the regulation of motivated behaviors. Habituation provides a more accurate and a less cumbersome explanation for motivated behaviors than homeostasis. Habituation also has some surprising, and easily testable, implications for the control of motivated behaviors.     

Operant conditioning permits voluntary,noninvasive measurement of blood pressure in conscious,unrestrained baboons (Papio cynocephalus)

This report describes a computerized apparatus and procedure for completely automated noninvasive measurement of systolic, diastolic, and mean arterial blood pressure in conscious, unrestrained nonhuman primates. We used a specially constructed, cage-mounted oscillometric blood pressure instrument and operant reward conditioning methods to train adult baboons(Papio cynocephalus) to submit voluntarily to frequent self-initiated determinations of their blood pressures in the absence of a human operator/observer. Details concerning the operant training procedure and illustrative blood pressure data are presented. The accuracy of the method was evaluated by comparing the noninvasive blood pressure readings with simultaneously taken direct measurements obtained by means of chronically indwelling arterial catheters.     

Idiosyncratic profiles of collinearity error using segments and dot pairs

It is well known that judgments of oblique line segments are more variable and less accurate than are judgments of horizontal or vertical segments, i.e., the “oblique effect.” A prior study from our laboratories confirmed these differentials for a task in which the collinearity of segments at various angular positions was judged. Further, that study found that each observer manifests a distinct, idiosyncratic profile of errors across the 360° range. These error tendencies are conspicuous in models derived by harmonic analysis, and we describe significant excursions of a given model as “delta errors.” The present experiments found complex profiles of delta error with various stimulus and test conditions. A given subject manifested similar models of delta error when judging collinearity of dot pairs versus line segments. In the prior work the segments to be judged were asymmetrically positioned upon the test sheet. However, the asymmetric positioning is not responsible for the errors, as the present work found errors excursions with a round display field. Similar profiles of delta error were found when subjects were allowed to mark an open space, versus being required to respond at a specific distance (indicated by a target circle). This addresses questions of whether the error should be measured as an angle. In the two final experiments, we present evidence that the source of delta error within the nervous system is at the point of binocular synthesis of the information from the two eyes, or beyond, and the effects are not due to errors of reaching. Potential neural substrates for these complex, idiosyncratic error tendencies are discussed. Received: 16 June 2000 / Accepted: 10 March 2001     

Visual perceptual learning by operant conditioning training follows rules of contingency

Visual perceptual learning (VPL) can occur as a result of a repetitive stimulus-reward pairing in the absence of any task. This suggests that rules that guide Conditioning, such as stimulus-reward contingency (e.g., that stimulus predicts the likelihood of reward), may also guide the formation of VPL. To address this question, we trained subjects with an operant conditioning task in which there were contingencies between the response to one of three orientations and the presence of reward. Results showed that VPL only occurred for positive contingencies, but not for neutral or negative contingencies. These results suggest that the formation of VPL is influenced by similar rules that guide the process of Conditioning.     

Memory for metaphors

Three experiments examined memory for metaphorical sentences. No differences between metaphors and nonmetaphorical equivalents (e.g.,The ivy cuddled up to the window vs.The ivy grew up to the window) in the number of correct recalls or recognitions were found. There was, however, a significant trend for recall errors that were meaning-preseving to be less metaphorical than the input sentence. The results supported hypotheses that metaphors and nonmetaphors are equally easy to remember and that the stored memory representation does not distinguish whether its antecedent linguistic input was metaphorical or not.This research was supported by Grant MH 28493-01 from NIMH and by a grant from the Kansas State University Bureau of General Research.Some of the data were reported at the Meeting of the Psychonomic Society, Denver, November 1975.