Showing papers in "Journal of Experimental Psychology: General in 1976"

Learned helplessness: Theory and evidence.

Abstract: \, SUMMARY In 1967, Overmier and Seligman found that dogs exposed to inescapable and unavoidable electric shocks in one situation later failed to learn to escape shock in a different situation where escape was possible. Shortly thereafter Seligman and Maier (1967) demonstrated that this effect was caused by the uncontrollability of the original shocks. In this article we review the effects of exposing organisms to aversive events which they cannot control, and we review the explanations which have been offered. There seem to be motivational, cognitive, and emotional effects of uncontrollability. (a) Motivation. Dogs that have been exposed to inescapable shocks do not subsequently initiate escape response in the presence of shock. We review parallel phenomena in cats, fish, rats, and man. Of particular interest is the discussion of learned helplessness in rats and man. Rats are of interest because learned helplessness has been difficult to demonstrate in rats. However, we show that inescapably shocked rats do fail to learn to escape if the escape task is reasonably difficult. With regard to man, we review a variety of studies using inescapable noise and unsolvable problems as agents which produce learned helplessness effects on both instrumental and cognitive tasks, (b) Cognition. We argue that exposure to uncontrollabl e events interferes with the organism's tendency to perceive contingent relationships between its behavior and outcomes. Here we review a variety of studies showing such a cognitive set. (c) Emotion. We review a variety of experiments which show that uncontrollable aversive events produce greater emotional disruption than do controllable aversive events. We have proposed an explanation for these effects, which we call the learned helplessness hypothesis. It argues that when events are uncontrollable the organism learns that its behavior and outcomes are independent, and that this learning produces the motivational, cognitive, and emotional effects of uncontrollabi lity. We describe the learned helplessness hypothesis and research which supports it. Finally, we describe and discuss in detail alternative hypotheses which have been offered as accounts of the learned helplessness effect. One set of hypotheses argues that organisms learn motor responses during exposure to uncontrollabl e shock that compete with the response required in the test task. Another explanation holds that uncontrollable shock is a severe stressor and depletes a neurochemical necessary for the mediation of movement. We examine the logical structure of these explanations and present a variety of evidence which bears on them directly.

A fuzzy set approach to modifiers and vagueness in natural language.

Abstract: SUMMARY Recent developments in semantic theory, such as the work of Labov (1973) and Lakoff (1973), have brought into question the assumption that meanings are precise. It has been proposed that the meanings of all terms are to a lesser or greater degree vague, such that, the boundary of the application of a term is never a point but a region where the term gradually moves from being applicable to nonapplicable. Developments in fuzzy set theory have made it possible to offer a formal treatment of vagueness of natural language concepts. In this article, the proposition that natural language concepts are represented as fuzzy sets of meaning components and that language operators—adverbs, negative markers, and adjectives— can be considered as operators on fuzzy sets was assessed empirically. In a series of experiments, we explored the application of fuzzy set theory to the meaning of phrases such as very small, sort of large, and so on. In Experiment 1, subjects judged the applicability of the set of phrases to a set of squares of varying size. The results indicated that the group interpretation of the phrases can be characterized within the framework of fuzzy set theory. Similar results were obtained in Experiment 2, where each subject's responses were analyzed individually. Although the responses of the subjects, in general, could be interpreted in terms of fuzzy logical operations, one subject responded in a more idiomatic style. Experiments 3 and 4 were attempts to influence the logical-idiomatic distinction in interpretatio n by (a) varying the presentation mode of the phrases and by (b) giving subjects only a single phrase to judge. Overall, the results were consistent with the hypothesis that natural language concepts and operators can be described more completely and more precisely using the framework of fuzzy set theory.

The premise of equipotentiality in human classical conditioning: Conditioned electrodermal responses to potentially phobic stimuli.

Abstract: The premise of equipotentiality, which has been widely adhered to among learning theorists, states that the laws of learning should not vary with the use of particular stimuli, responses, or reinforcements. This premise has recently been challenged by some data originating within the learning tradition itself, for example, studies on the effects of verbal stimuli in eye-lid conditioning. More importantly, however, the premise of equipotentiality is incompatible with data from experiments carried out within a biological-ethological framework. The results of such studies indicate that a given species is prepared to associate certain stimuli, responses, and reinforcers but not others. In an attempt to examine the validity of this premise in human classical conditioning, we investigated the effect of pictures of potentially phobic objects as conditioned stimuli (CSs) for electrodermal responses, since it has been suggested that phobias may be instances of biologically prepared learning. Three experiments are reported, all of them involving a long interstimulus interval differential conditioning paradigm with different pictures as CSs and electric shock as the unconditioned stimulus (UCS). In Experiment 1 we established that different pictures are differentially effective as CSs. A groupconditioned to potentially phobic stimuli, snakes or spiders, showed greater resistance to extinction than a group conditioned to fear-irrelevant pictorial stimuli, that is, flowers or mushrooms. A third group conditioned to "representative laboratory stimuli," circles or triangles, fell in between thses two groups. Experuce similar effects to those observed with phobic and fear-irrelevant stimuli in Experiment 1. In Experiment 3 superior resistance to extinction for phobic stimuli was demonstrated when the UCS was an electric shock, but not when it was a tone to which the subject produced reaction times. Thus, the effect appears specific for aversive UCSs, and CS-UCS "belongingness" has been demonstrated. It was concluded that our data do challenge the premise of equipotentiality in human conditioning. There are several learning-theory accounts that could accommodate at least some aspects of the data, but they seem to be best explained in terms of biologically orsiented constructs, such as preparedness.

On the self-regulation of the occipital alpha rhythm: control strategies, states of consciousness, and the role of physiological feedback.

Abstract: In an experiment investigating the self-control of occipital alpha strength, a factorial design was employed with two levels of feedback (available or non-available), three levels of instruction (Cognitive, Oculomotor, and none), and two levels of lighting (on and off), except that the no-feedback-no-instruction group was not run. The Cognitive instructions were based on the strategies reported in the literature: To generate alpha, persons were instructed to relax, "let go", try to feel pleasant and serene, and allow themselves to review pleasant personal experiences; to suppress alpha, persons were instructed to concentrate, try hard, exert themselves mentally, and try to fell anxious or frustrated. The Oculomotor instructions to generate alpha were to visually blur and not focus, and to suppress alpha were to "look" and focus. The results led to the following conclusions: (a) Feedback-augmented enhancement and suppression of occipital alpha strength is always mediated by learned control of oculomotor processes, although sometimes persons are not aware that they are employing this strategy, especially in the case of alpha enhancement; alpha feedback trainees learn to "not look" in order to enhance alpha strength. (b) Whenever Cognitive strategies are successful in producing alpha strength changes, this is due to the fact that they can be efficient mediators of changes in oculomotor processes. (c) Feedback together with simple Oculomotor instructions leads to more successful alpha control than either alone. (d) High or enhanced levels of occipital alpha strength are not invariably accompanied by the "alpha experience", in fact, if a person is not led to expect it, the alpha experience will usually not occur during occipital alpha enhancement feedback. (e) States of nonsensory awareness, such as an absorption in thoughts and feelings, are reliably associated with enhanced occipital alpha strength. This association is what would be expected: Since vision is the dominant sensory modality in humans, it is reasonable that when visual processing is reduced during alpha enhancement feedback that there is also reduced sensory awareness in general and often greater attention to thoughts and feelings. (f) Alpha feedback per se is neither necessary for nor especially facilitative of the achievement of the alpha experience. Thus, if the alpha experience is more likely to occur with alpha feedback than without it, this is due to the special circumstances that make up the feedback situation and not due to alpha feedback per se.

Visual Processing of Nonlinguistic Strings: Redundancy Effects and Reading Ability.

Abstract: Visual redundancy effects were investigated in two experiments using nonalphabetic material. Experiment 1 had adult subjects search for the presence or absence of a predetermined target symbol through single six-symbol linear arrays. Reaction times were significantly faster in both a distributional redundancy and a spatial redundancy condition than in a no-redundancy condition. Experiment 2 had good and poor sixth-grade readers serve in the no-redundancy and spatial redundancy conditions of Experment 1. Poor readers were equivalent to good readers in the no-redundancy condition but were significantly slower in the spatial redundancy condition. Thus, spatial redundancy was shown to be operative in single symbol search time in a paradigm that avoided confounding by higher order linguistic variables. The present experiments, in conjunction with prior findings that good and poor readers differ in letter search time by their ability to use spatial redundancy, suggest that processes involved in the component skill of letter identification cannot be considered trivial to the reading process.

Encoding the levels of information in pictures and words.

Abstract: From a levels-of -processing framework (e.g., Craik & Lockhart, 1972), we derive the idea that the levels of information implicit in a stimulus, such as its physical configuration, its name, and the category to which it belongs, may become available for subsequent processing at different times after stimulus onset. In particular, tasks which allow the use of physical codes should be performed more rapidly than those which require "deeper" information. There are two important implications here: The first is that the ability to use a code does not mean that that code has been "matched to" a representation in memory. The second is that "depth" effects (i.e., physical less than name less than conceptual) should be demonstrable within both pictorial and verbal materials. The approach as a whole may be contrasted with current dual-coding approaches (e.g., Paivio, Note 1), which, while they allow for different levels of meaning in both verbal and imaginal symbolic systems, seem forced to assume that certain types of cenceptual information are more easily accommodated within the verbal system. This leads to the prediction that some kinds of conceptual information will not be directly available from pictures, but must instead become available to the subject via an interaction between the symbolic systems. We tested these assumptions with a speeded-inference task (Van Rijn, 1973), which has properties that allow for unambiguous interpretation of reaction time differences across stimulus materials which require processing to the same explicit depth. Briefly, we found that pictures yield faster inferences than do words when the same semantic information is required for performance (Experiments 1 and 2), and that physical information is available sooner than conceptual information for both pictures (Experiment 4) and words (Experiment 5). Moreover, some types of pictorial materials (e.g., representations of proper nouns) function symbolically to the extent that they do not have an advantage in discriminability over words (Experiments 6 and 7), unless physical features are added to them which are redundant with the conceptual information the subject needs to perform (Experiment 8). The results are best interpreted within a levels-of-processing framework, in which multiple codes or representations do not exist to be activated by the appropriate stimuli, but rather the stimuli themselves embody levels of information which are encoded and used as needed.

Some considerations of two alleged kinds of selective attention.

Abstract: The present article deals with selective attention phenomena and elaborates on a stimulus material classification, "stimulus set" versus "response set," proposed by Broadbent (1970, 1971)9 Stimulus set is defined by some distinct and conspicuous physical properties that are inherent in the stimulus. Response set is characterized by the meaning it conveys, and thus its properties are determined by cognitive processing on the part of the organism. Broadbent's framework is related to Neisser's (1967) distinction between two perceptual-cognitive processes, namely, preattentive control and focal attention. Three experiments are reported. A before-after paradigm was employed in Experiment 1, together with a sptial arrangement manipulation of relevant versus irrelevant stimuli (being grouped or mixed). The results indicated that before-after instruction had a stronger effect under stimulus set than under response set conditions. Spatial arrangement, on the other hand, affected performances under response set but not under stimulus set conditions. These results were interpreted as supporting the idea that stimulus set material, which is handled by preattentive mechanisms, may be processed in parallel, while response set material requires focal attention that is probably serial in nature. Experiment 2 used a search task with different levels of noise elements. Although subjects were not able to avoid completely the processing of noise elements, they had much more control under stimulus set than under response set conditions. Experiment 3 dealt with memory functions and suggests differential levels of perceptual processing depending on the nature of the stimulus material. This extends the memory framework suggested by Craik and Lockhart (1972). The results of these experiments, together with evidence from other behavioral and physiological studies, lend strong support to the proposed theory. At the theoretical level, it is suggested that the distinction between stimulus and response set, and the corresponding one between preattentive mechanisms and focal attention, are on a continuum rather than being an all-or-none classification. Thus, it permits greater congnitive flexibility on the part of the organism, which is reflected through the assumption that both preattentive mechanisms and focal attention may operate simultaneously and differ only in the salience of their functioning. From a methodological point of view, the distinction between stimulus material and organismic processes is emphasized. It is argued that researchers have not given sufficient attention to the properties of the stimulus materials that they have used, and as a consequence have reached unwarranted conclusions, as exemplified by a few studies that are briefly discussed.

Residual fear of the conditioned stimulus as a function of response prevention after avoidance or classical defensive conditioning in the rat.

Abstract: Studies employing response prevention (RP) are reviewed. Considering assessment difficulties and conflicting findings, it is questionable whether RP actually reduces fear to a conditioned stimulus (CS). This study measured fear after RP via a conditioned emotional response (CER) paradigm. Hypotheses were that fear of an auditory CS (conditioned in an avoidance paradigm) is reduced during RP, and that fear conditioning would occur to aspects of the conditioning environment per se. Also evaluated was the effectiveness of RP when fear had been learned under two different conditions: (a) avoidance or (b) classical defensive conditioning. Seven groups of 10 experimentally naive female rats were run. Animals were initially trained to bar press for food pellets on a variable interval (VI) 2 schedule. Three groups were then avoidance trained in a two-way shuttle box to a criterion of 10 successive avoidances. Immediately following acquisition, one group received RP (blocking) in the shuttle box (Condition A-B). This consisted of placing a door between the two sides of the box and presenting the 85 dB (A) white noise CS for 15 20-sec periods with a variable 1-min interstimulus interval. One group did not receive RP (nonblocked) and was instead immediately returned to its home cage (Condition A-NBHC). The third group was treated as was A-B except the CS was not presented (Condition A-NBSB). Two other groups were trained in a classical defensive paradigm. These animals were matched to A-B animals in terms of number, order, and duration of CSs and USs. Following conditioning, one group received the same treatment as A-B (Condition CD-B), and the other received the same treatment as A-NBHC (Condition CD-NBHC). Two groups served as controls. A backward control (Condition BC-NBHC) was matched to A-NBHC in terms of number, order, and duration of CSs and USs. A sensitization control (Condition SC-NBHC) was matched to A-NBHC in terms of number, order, and duration of CS presentations. Immediately following conditioning trials, control animals received the same treatment as A-NBHC animals. After differential treatments all animals were immediately returned to the lever box in which they had learned to bar press, a VI 2 schedule was reinstated, and the CER was measured. A-B showed significant suppression initially but significantly less than A-NBHC, suggesting that although RP was effective in reducing fear to the CS, some fear remained. Controls showed essentially no suppression and did not differ. A-B did not differ from A-NBSB, suggesting that conditioning of fear did occur to the environment and that this fear was subsequently reduced in A-NBSB. A-B suppressed significantly more than CD-B, suggesting that RP was more effective when fear was learned in a classical as compared to an avoidance paradigm. Theoretical implications and generalizations to implosive therapy are discussed.

Limulus psychophysics: spectral sensitivity of the ventral eye.

Abstract: The ventral eye of Limulus contains only one type of photoreceptor. Behaviors mediated by the ventral eye provide an unambiguous representation of the function of that single-receptor type. Such behaviors can be compared with the results of acute, single-cell investigations to assay for the contributions of candidate neural codes in the regulation of behavior (cf. Uttal, 1973). Using an unconditioned tail movement as the response, the psychophysical spectral sensitivity function mediated by the ventral eye of Limulus was measured. This psychophysical function peaked at 525 nm and showed evidence of strong absorption by the cuticle in the short-wavelength portion of the spectrum. Under the conditions of the present experiment, the threshold was 4.5 quanta absorbed per receptor per msec at 525 nm. The spectral transmission of the ventral eye cuticle was also measured. After correction for cuticle absorption, the psychophysical spectral sensitivity function was compared with previously reported spectral sensitivity functions obtained either from electrophysiologic (Millecchia, Bradbury, and Mauro, 1966; Nolte and Brown, 1970) or from microspectrophotometric (Murry, 1966) recordings from single, isolated ventral eye photoreceptor cells. All three functions exhibit a sensitivity peak near 525 nm; the corrected psychophysical and microspectrophotometric functions both display a second peak near 425 nm. A second experiment confirmed the reliability and validity of the 425-nm peak. The coding implications of these findings were explored. A preliminary finding is that, in dichromatic or trichromatic visual systems, two-peaked receptor spectral sensitivity functions produce central, opponent response systems that are qualitatively the same as those produced by single-peaked receptors.