Note on subjects' hypotheses in multiple-cue probability learning

Subjects' hypotheses in multiple-cue probability learning was studied by trial-by-trial verbal reports in tasks with linear and nonlinear cue-criterion relations. In accordance with earlier findings, the results of the present experiment show that subjects learned linear tasks rapidly, while nonlinear tasks were not learned at all. The subjects' verbal hypotheses show that the subjects were concerned with rules for combining cue values, rather than with cue-criterion functions. This explains why the subjects fail to learn nonlinear multiple-cue tasks. It also shows that, although the subjects seem to learn multiple-cue tasks through a hypothesis testing process of the same kind as in single-cue probability tasks, the hypotheses tested in multiple-cue tasks are different from those tested in single-cue tasks. Finally, the present results suggest that the picture of the subjects' cognitive models of multiple-cue probability learning tasks provided by the customary multiple regression analysis may be fundamentally misleading in that it suggests that the subjects learn the validity of each cue rather than a combination rule.     

The importance of alignment in blind subjects' use of tactual maps

An experiment was conducted to test for the presence of alignment effects (previously found in sighted map users) in blind and visually impaired subjects using tactual maps. The term 'alignment effects' refers to the fact that when points represented as further up on a map do not correspond to points forward from the user in the environment, errors in the directional judgments made by subjects are greatly increased. The results show that alignment effects do exist in blind and visually impaired map users. Blind subjects encoded maps using the 'up equals forward' rule, and demonstrated some similarity to sighted subjects in the types of errors made. There was also some indication of improved performance over repeated trials. Differences between blind and sighted subjects were also found and were tentatively attributed to visual experience with object transformations and/or representational variables. Subject background variables were also investigated and some relationships between background of the subject and performance were drawn.     

Individual differences in electrodermal activity as a function of subjects' anxiety

The present study examines the relationships between electrodermal activity (EDA) and anxiety in an attention demanding task, by looking at the neuropsychology of individual differences. 261 normal volunteer female students completed the Cattell anxiety form, and only subjects with extreme anxiety scores (deciles 0, 1 and 2 on the one hand, N = 22; deciles 9 and 10 on the other hand, N = 24) were retained. Subjects were presented a set of 16 stimuli (8 neutral and 8 emotional slides) in a randomized order (different for each subject), of 35 msec and 1 sec duration and a randomized inter-stimuli time of average 45 sec. Skin conductance levels (SCLs), interstimuli spontaneous fluctuations (SSCRs), skin conductance response (SCR) amplitudes and electrodermal latencies were recorded, as well as skin temperature (ST). Highly anxious subjects showed significantly lower SCLs, lower SCR amplitudes, fewer interstimuli SSCRs and longer latencies than subjects with low anxiety, whereas ST did not differ between groups. These results, showing that in normal subjects there are individual electrodermal differences as a function of trait-anxiety scores, are discussed both in terms of individual differences in self-regulatory neural processes and in reference to Gray's anxiety theory.     

The effects of context and subjects' perceived control in breaching posthypnotic amnesia

Subjects selected on the basis of being amnesic and experiencing their amnesia as “voluntary” or “involuntary” were subjected to two conditions designed to breach their amnesia: (1) lie detector, and (2) honesty instructions. A third group receiving relaxation instructions served as a control. Posthypnotic amnesia was breached under lie detection and honesty conditions. However, there appeared to be an interaction between how subjects reported their experience of amnesia (voluntary and involuntary) and the degree to which amnesia was breached. Voluntary subjects accounted for the majority of breaching. Implications for (1) studies on breaching, (2) theories and processes of breaching, Implications for (1) studies on breaching, (2) theories and processes of posthypnotic amnesia, and (3) studies in posthypnotic amnesia are discussed.     

Panic-disordered subjects' perceptions of film: a repertory grid study

Clinical research into panic attacks over the past two decades has led to the hypothesis that panic-disordered subjects may have a lower threshold to separation anxiety than normals. This hypothesis was investigated by measuring panic-disordered and normal subjects' reactions to viewing a film of a potentially anxiety-provoking situation. The extent to which individuals construe film through identification with the narrative's characters was also examined. To gauge these reactions a repertory grid was administered to 11 subjects with a history of panic disorder and 12 controls after they had watched a half-hour episode from a feature film in which a divorced couple fight acrimoniously over custody of their 17-yr.-old daughter. Five elements were characters mentioned in the film and two were of 'self,' one in a secure and another in an insecure situation. Ten constructs were elicited by a triadic sorting procedure and four were supplied. Ratings of elements on all constructs were subjected to a principal components analysis (INGRID). While the construals of the two groups were essentially similar, there were differences between them in terms of the perceived salience of the film's characters. Panic-disordered subjects also construed themselves as more insecure than did the normals. The results affirm the use of the repertory grid in the study of panic disorder and in the analysis of the perception of filmed events.     

Effects of diagnostician prestige and sex upon subjects' acceptance of genuine personality feedback

Examined subjects' acceptance of genuine, test-based personality feedback as a function of diagnostician prestige and sex, subject sex, and diagnostician. It was found that subjects of both sexes rated the feedback provided by female diagnosticians as significantly more accurate than that provided by male diagnosticians. This was attributable in part to a tendency for subjects to greatly devalue the feedback provided, by low prestige, male diagnosticians, Support for the generalizability of the present results from the social psychological literature was noted and suggestions for future research were provided.     

Agrammatic aphasic subjects' comprehension of subject and object extracted Wh questions

This study attempted to replicate the unusual wh question comprehension pattern of Hickok and Avrutin's (1996) subjects who showed an expected subject/object extraction asymmetry for which NP questions, but not for who questions. We also examined comprehension of what and which one questions, which are similar to who and which NP questions, respectively, and we examined passivized wh questions in order to test predictions of Grodzinsky's (1995) restrictive theory of trace deletion, the Trace-Based Account (TBA). Results, using both a figurine manipulation task and a picture pointing task, showed that only one of four agrammatic (Broca's) aphasic subjects showed the pattern reported by Hickok and Avrutin and that this pattern extended to comprehension of what and which one questions. One of the subjects showed subject/object asymmetry for all wh questions tested, as would be predicted by the original trace deletion hypothesis (Grodzinsky, 1984), and two subjects showed neither pattern. None of our subjects demonstrated ability to comprehend passivized wh questions as predicted by the TBA. We discuss our findings in terms of the lack of homogeneity of wh question comprehension among individuals with agrammatic aphasia and we explore alternatives to the syntactic explanation for differences between who and which NP question comprehension advanced by Hickok and Avrutin.     

Unraveling subjects' perceptions of paraprofessionals and professionals: a pilot study

This study examined 75 undergraduate women's perceptions of paraprofessional and professional therapists in an analogy study. The data indicated subjects were more willing to seek treatment from paraprofessional than professional therapists; no differences were found in predicted success of treatment. Subjects' perceptions of paraprofessional and professional expertness, attractiveness, and trustworthiness were also examined; the findings were nonsignificant.     

Star-triangle equivalence in two-dimensional soap froths

In two-dimensional foams at equilibrium, triangular bubbles can be freely exchanged with threefold stars, three edges ending at a central vertex. This theorem is deduced here from Moukarzel's duality. Moreover, to probe the method, a few related properties are established: under slow gas diffusion, cell extinction is a continuous process for triangles but not for other types of bubble. In general, the gas flow results in different configurations in the presence of a triangle from those in the presence of a star.     

Power equivalence in structural equation modelling

Implementing large‐scale empirical studies can be very expensive. Therefore, it is useful to optimize study designs without losing statistical power. In this paper, we show how study designs can be improved without changing statistical power by defining power equivalence, a relation between structural equation models (SEMs) that holds true if two SEMs have the same power on a likelihood ratio test to detect a given effect. We show systematic operations of SEMs that maintain power, and give an algorithm that efficiently reduces SEMs to power‐equivalent models with a minimal number of observed parameters. In this way, optimal study designs can be found without reducing statistical power. Furthermore, the algorithm can be used to drastically increase the speed of power computations when using Monte Carlo simulations or approximation methods.     

Maintained nodal-distance effects in equivalence classes

Twelve subjects were trained to select one of two stimuli from a pair (the B pair) when presented with one of two stimuli from another pair (the A pair), thus establishing two AB relations, A1-B1 and A2-B2. In a similar fashion, additional stimuli were used to establish BC, CD, and DE relations. Trials used to train all relations occurred in each session. Once performances were established, probe trials were introduced that tested for the emergence of untrained relations (e.g., B1-D1 or A1-E1). These emergent relations were categorized according to nodal distance (i.e., the number of stimuli across which transitivity would have to hold in order for the relation to emerge). For example, a test for A2-C2 crosses one node (B2), whereas a test for A1-E1 crosses three nodes (B1, C1, and D1). Only 2 of the subjects formed equivalence classes. The evocation of class-appropriate responding by each emergent-relation probe was an inverse function of nodal distance for all 12 subjects. In addition, performance on the originally trained relations was disrupted by the introduction of probes. The 2 subjects who exhibited equivalence classes were then trained to make different numbers of key presses in the presence of each of the four A and E stimuli. In a response-transfer test, the B, C, and D stimuli evoked the responses trained to the A and E stimuli in the same equivalence class. Likelihood of class-appropriate responses was an inverse function of nodal distance, and this pattern persisted across testing. Reaction times in the transfer test were an inverted U-shaped function of nodal distance. Because training of the baseline relations occurred concurrently and the B, C, and D stimuli were presented an equal number of times before the transfer test, the test performances illustrate effects of nodal distance that were not confounded by order or amount of experience with the stimuli. The results imply that ordered, sequential exposure to individual stimulus relations may facilitate the development of equivalence classes and that the relatedness of stimuli within an equivalence class is a relatively permanent inverse function of nodal distance.     

Subitizing speed,subitizing range,counting speed,the Stroop effect,and aging: capacity differences and speed equivalence

Thirty younger and 29 older adults were tested on reaction times for set size of a display of 1 to 9 digits. On half of the trials, the nominal value of the digits was equal to the size of the set displayed; on the other half, the value differed by 1 from the set size (Stroop interference). We found evidence for age differences in subitizing span (2.83 vs. 2.07). Once individual differences in subitizing range were taken into account, no age differences were found in the rate of either subitizing or counting, and no individual differences were apparent in subitizing speed. There was no age difference in the susceptibility to the Stroop effect. The results suggest that, with advancing age, the size of the focus of attention may shrink, but speed of access to elements in the focus of attention may remain constant.     

Effects of victim's and defendant's physical attractiveness on subjects' judgments in a rape case

Physical attractiveness of the victim and defendant in a rape case were varied along with sex of subject in a 2×2×2 factorial design. It was found that both the attractive defendant and the rapist of an unattractive victim were less likely to be seen as guilty and that the attractive defendant received a shorter recommended prison term than the unattractive defendant. Victim attractiveness had no effect on attributions of her degree of responsibility. Females were more likely to see the defendant as guilty and recommended longer prison terms than males. Results are discussed in terms of specificity of victim and defendant and the beauty is good stereotype.     

Stability of functional equivalence and stimulus equivalence: effects of baseline reversals

Functional equivalence and stimulus equivalence classes were established, reversed, and tested for stability with college students. Functional stimulus classes were established using a task in which students were trained to say nonsense words in the presence of arbitrarily assigned sets of symbols. Computer-controlled speech-recognition technology was used to record and analyze students' vocal responses for accuracy. After the establishment of stimulus classes was demonstrated with a transfer-of-function test, the effects of reversing selected baseline simple discriminations were assessed during an additional transfer-of-function test and a follow-up test that occurred several weeks later. With the same students, stimulus equivalence classes were established and demonstrated with computerized matching-to-sample procedures. The effects of reversing selected baseline conditional discriminations also were assessed during a postreversal equivalence test and a follow-up test. Both functional stimulus classes and stimulus equivalence were sensitive to contingency reversals, but the reversals with stimulus equivalence closses affected stimulus class organization whereas reversals with functional stimulus classes did not. Follow-up performances were largely consistent with the original baseline contingencies. The similarities and differences between stimulus equivalence and functional equivalence are related to the specific contingencies that select responding in the presence of the stimuli that form the classes.     

Parsimony and predictive equivalence

If a parsimony criterion may be used to choose between theories that make different predictions, may the same criterion be used to choose between theories that are predictively equivalent? The work of the statistician H. Akaike (1973) is discussed in connection with this question. The results are applied to two examples in which parsimony has been invoked to choose between philosophical theories-Shoemaker's (1969) discussion of the possibility of time without change and the discussion by Smart (1959) and Brandt and Kim (1967) of mind/body dualism and the identity theory.