Hick’s law equivalent for reaction time to individual stimuli

Hick’s law, one of the few law-like relationships involving human performance, expresses choice reaction time as a linear function of the mutual information between the stimulus and response events. However, since this law was first proposed in 1952, its validity has been challenged by the fact that it only holds for the overall reaction time (RT) across all the stimuli, and does not hold for the reaction time (RT_i) for each individual stimulus. This paper introduces a new formulation in which RT_i is a linear function of (1) the mutual information between the event that stimulus i occurs and the set of all potential response events and (2) the overall mutual information for all stimuli and responses. Then Hick’s law for RT follows as the weighted mean of each side of the RT_i equation using the stimulus probabilities as the weights. The new RT_i equation incorporates the important speed–accuracy trade-off characteristic. When the performance is error-free, RT_i becomes a linear function of two entropies as measures of stimulus uncertainty or unexpectancy. Reanalysis of empirical data from a variety of sources provide support for the new law-like relationship.     

Effects of Number of Alternatives on the Psychological Refractoriness of an Extended Movement,

The single-channel prediction that delays in RT₂ should be proportional to RT₁ was examined by varying the number of alternatives (one, two, or three) in the primary response which was an extended arm swing at maximal speed. The second response was a thumb key release. Foreperiods were 2, 3, or 4 sec., and interstimulus intervals (ISIs) ranged from .10:50 sec. in .10-sec. steps. General support for the single-channel model was found in that RT₂ paralleled changes in RT₁. However, RT₂ was greater than predicted when the second signal (S₂) occurred during the execution of the primary response. In addition, while delays in RT₂ as a function of ISI – RT₁ showed corresponding differences between choice conditions, most values were greater than predicted. The deviations from the single-channel model appeared to be explained best in terms of a decrease in readiness to respond to the second signal as ISI lengthened.     

Varying temporal placement during CS of an added stimulus correlated with non-delivery of UCS

This experiment extends Pavlov’s method of contrasts for training a stimulus discrimination to the case of the cardiac conditional response in the rhesus monkey. It explores the parameter of temporal placement of an additional stimulus (“CS₂”) within a 10-sec CS (or “CS₁”), with the appearance of the former stimulus on any trial signalling the absence of UCS (electric shock) on that trial. This experimental paradigm is a parallel to that of the “intruded stimulus” studies in operant conditioning. In both cases, several ways of describing the function of the added stimulus are possible, but all seem reducible to the same operational terms. Data were taken in the present study with respect to the form and latency of the cardiac rate changes produced by intrusion of CS₂ (light), across a range of placements varying from simultaneity with CS₁ (a different light) onset to two sec before UCS would have been delivered. The control of CS₂ over the cardiac rate CR was occasionally exhibited with a latency as short as three beats after stimulus onset. The order of CS₂ temporal placements to which a subject was exposed was a factor in determining the form of the conditioned cardiac rate response to CS₁.     

Intersensory effects in the psychological refractory period

Two experiments examined reaction time (RT) to each of two stimulus events separated by short interstimulus intervals (1SI). The essential contrast was RT to the second visual signal, RT₂, in auditory-visual (A-V) vs visual-visual (V-V) sequences. With response, certain pairings in Experiment 1, an effect apparently demonstrating a single-channel process (Welford, 1952), was noted. RT₂ was generally faster for A-V as opposed to V-V sequences especially when Ss were uncertain as to the sequence that would occur. At 0-msec ISI, the RT₂ difference between sequences approached the RT! difference. More rapid RT₂ to A-V sequences was also observed with go vs no-go pairings in Experiment 2 when the initial event was a go signal. However, the RT difference disappeared upon error correction, making the RT₂ sequence difference of questionable relevance to the hypothetical single-channel process. RT₂ was more rapid following a null no-go signal when the no-go signal was contrasted with a visual as opposed to auditory go signal. The latter effect was independent of error and is consistent with channel-switching theory (Kristofferson, 1967).     

Storage mode of geometrical dimensions in a two-stimulus matching paradigm

In a two-stimulus matching paradigm requiring “same” and “different” responses to simple geometric dimensions, the successive stimulus presentation mode with several retention intervals was compared to a simultaneous stimulus presentation mode. For the simultaneous condition, the data suggested a wholistic template matching process, but in none of the successive conditions was template matching indicated. The retention interval of the successive condition allows the subject to analyze out the target dimension from the first two-dimensional stimulus. The ability to anticipate the value of the target dimension in the second stimulus could also influence the representation of the first stimulus. The findings shed some light upon the perceptual interactions between dimensions that constitute the stimulus. In particular, an outside-to-inside order of iconic scanning appeared to be supported by the data.     

Negative priming without ignoring

Negative priming is conventionally defined by slowed responses to a target item that appeared previously as a distractor. As a result, it is widely assumed that negative priming is caused by an act of ignoring. Three experiments are reported in which novel abstract shapes were studied with either “shallow” or “deep” encoding instructions. This study phase was followed by asame-different discrimination task similar to that employed by DeSchepper and Treisman (1996). Same-different discrimination was slower for old than for new target shapes, and this negative priming effect depended on the difficulty of the discrimination task. The results suggest that negative priming may not be caused by the ignoring of a prime stimulus.     

Concurrence costs in double stimulation tasks

Seven experiments are described on reaction time (RT₁) to a first auditory stimulus in a double stimulation paradigm, where the response to a second visual stimulus was explicitly non-speeded. In all studies it was found that, compared to a single stimulus control condition, RT₁ showed a constant delay of about 20–30 msec. The effect occurred irrespective of (a) the viewing conditions of the second stimulus in terms of either duration, processing demands or presence vs absence of a backward masking signal (experiments 1, 4, 5, 6, 7); (b) the duration of the interstimulus interval ranging from -200 msec up to at least a second (experiments 2, 3, 5); and (c) the processing demands of the first task (experiment 7). It is suggested that the delay reflects a basic concurrence cost which remains when two reactions can be time-shared.     

Negative priming and stimulus-response compatibility

The subjects in this study made incongruent naming responses to words and pictures that were presented on alternate trials (e.g., say “car” toBIKE). Their response time was longer if the correct response for the current trial was the name of the stimulus presented on the preceding trial, as compared with a control condition. These results suggest that the tendency to produce the (congruent) name of the stimulus is automatically activated and then inhibited. The “negative priming” effects appeared stronger for words where pictures were primes than for pictures where words were primes. The implications of these results for negative priming and stimulus-response compatibility are discussed.     

Getting one step closer to deduction: Introducing an alternative paradigm for transitive inference

Transitive inference is claimed to be “deductive”. Yet every group/species ever reported apparently uses it. We asked 58 adults to solve five-term transitive tasks, requiring neither training nor premise learning. A computer-based procedure ensured all premises were continually visible. Response accuracy and RT (non-discriminative nRT) were measured as is typically done. We also measured RT confined to correct responses (cRT). Overall, very few typical transitive phenomena emerged. The symbolic distance effect never extended to premise recall and was not at all evident for nRT; suggesting the use of non-deductive end-anchor strategies. For overall performance, and particularly the critical B?D inference, our findings indicate that deductive transitive inference is far more intellectually challenging than previously thought. Contrasts of our present findings against previous findings suggest at least two distinct transitive inference modes, with most research and most computational models to date targeting an associative mode rather than their desired deductive mode. This conclusion fits well with the growing number of theories embracing a “dual process” conception of reasoning. Finally, our differing findings for nRT versus cRT suggest that researchers should give closer consideration to matching the RT measure they use to the particular conception of transitive inference they pre-held.     

Pulsation patterns of sinusoids vs. critical band noise

Pulsation patterns of both sinusoidal and critical band “maskers” at f_M = 400 Hz, 1 kHz, 2 kHz, and 4 kHz are compared. At the slope towards low frequencies, the pulsation pattern of a sinusoid is up to 30 dB lower than the pattern of a critical band noise; at the upper slope, only small differences (4 dB) are noticed. Variations in the temporal configuration of the stimulus yield a great variety of pulsation patterns for one and the same “masker.” Therefore, the interpretation of pulsation patterns as a quantitative measure of the ear’s frequency selectivity is still obscure. On the other hand, a comparison of pulsation patterns of different “maskers,” measured with one and thesame stimulus paradigm, seems to be useful.

     

Configural-like effects observed in the course of second-order conditioning in rats

After receiving first-order CER (conditioned emotional response) conditioning, four groups of rats were exposed to the first-order conditioned stimulus (CS₁) and a new stimulus (CS₂) according to one of three paradigms. For different groups, CS₂ preceded CS₁, was simultaneously compounded with it, or was explicitly unpaired with it. There was evidence of second-order conditioning (SOC) only when CS₂ preceded CS₁, with the effect diminishing when SOC training was continued for a long time. Though suppression to CS₁ extinguished in the course of SOC training, animals which had experienced CS₂ preceding CS₁ suppressed almost completely when later tested with CS₁ alone. This “protection-from-extinction” is formally similar to an analogous effect observed in the simultaneous compound group. Animals appear to “configure” elements of both simultaneous and successive compounds.     

Stimulus control over sex-typed play in cross-gender identified boys.

Discriminative stimulus control over masculine and feminine sex-typed play behaviors was investigated in five boys, aged 5–8 yr, with “childhood crossgender identification.” Reliable observational measures of play were obtained with two sets of toys: (a) “dress-up toys” (girls' apparel vs boys' apparel), and (b) “affect toys” (maternal-nurturance play vs masculine-aggression play). With an ABA reversal intrasubject design, certain stimulus conditions (e.g., presence of father, mother, male, or female stranger) were found to be discriminative for reliable changes in sex-typed play. Sex-typed play was found to vary as a function of the social stimulus situation and as a function of the type of play response required. All children played predominantly feminine while alone in the playroom. While no single environmental stimulus was consistently discriminative for masculine play across children, at least one stimulus condition was found for each subject under which he played predominantly masculine.     

1966 and All That: James Gibson and Bottom-Down Theory

ABSTRACT

The “later” James Gibson is widely misrepresented as an extreme stimulus–response theorist. In fact, Gibson's 1966 book presents a radical alternative to stimulus–response theory. “Perceptual systems” are not passive and receptive but “organs of active attention” (1966/1968, p. 58). Perceivers “reach out” into the world. This commentary examines some of the implications of Gibson's systems-cum-functionalist-cum-ecological approach, including the relations between the senses; the concept of “sensationless” perception; and most fundamentally, the nature of perceptual systems as extending beyond the body. I conclude that an adequate understanding of perception cannot be limited to the already severely limited domain of psychology. If Gibson is right, “ecological psychology” is a contradiction in terms.     

Infants’ representations of same and different in match- and non-match-to-sample

Three experiments investigated the representations that underlie 14-month-old infants’ and adults’ success at match-to-sample (MTS) and non-match-to-sample (NMTS) tasks. In Experiment 1, 14-month-old infants were able to learn rules based on abstract representations of sameness and/or difference. When presented with one of eighteen sample stimuli (A) and a choice between a stimulus that was the same as the sample (A) and a different stimulus (B), infants learned to choose A in MTS and B in NMTS. In Experiments 2 and 3, we began to explore the nature of the representations at play in these paradigms. Experiment 2 confirmed that abstract representations were at play, as infants generalized the MTS and NMTS rules to stimuli unseen during familiarization. Experiment 2 also showed that infants tested in MTS learned to seek the stimulus that was the same as the sample, whereas infants tested in NMTS did not learn to seek the different stimulus, but instead learned to avoid the stimulus that was the same as the sample. Infants appeared to only use an abstract representation of the relation same in these experiments. Experiment 3 showed that adult participants, despite knowing the words “same” and “different”, also relied on representations of sameness in both MTS and NMTS in a paradigm modeled on that of Experiment 2. We conclude with a discussion of how young infants may possibly represent the abstract relation same.     

Expertise effects on decision-making in sport are constrained by requisite response behaviours – A meta-analysis

ObjectivesA quantitative review of the effects of requisite responses and methods of stimulus presentation for assessing decision-making expertise in sport was undertaken.DesignAn electronic literature search was conducted in the online databases: SPORTDiscus with Full Text and ISI Web Knowledge All Databases. Articles for analysis were selected according to prior defined criteria.MethodsWe considered 111 effect sizes in studies involving 882 expert and non-expert participants. Effect sizes were calculated for six common protocols for measures responses: verbalized knowledge, eye movement measures, decision time, response accuracy, movement accuracy, and movement time. Two moderator variables were also considered to assess effects of research protocols on the dependent variables: “the requisite response” and “stimulus presentation”. A random effect model was used to calculate effect sizes.ResultsAnalysis of moderator variables suggested that expertise effects were more apparent for “requisite responses” when participants were required to actually perform sporting actions and for “stimulus presentation” under in situ task constraints than for other conditions.ConclusionsFuture empirical work on expertise and decision-making needs to consider task representativeness in considering requisite responses of participants in simulating performance environment conditions. Use of representative task constraints with performers required to perform sport actions in in situ conditions appeared the most functional empirical protocols to enhance validity of data.     

Impact of planned movement direction on judgments of visual locations

The present study examined if and how the direction of planned hand movements affects the perceived direction of visual stimuli. In three experiments participants prepared hand movements that deviated regarding direction (“Experiment 1” and “2”) or distance relative to a visual target position (“Experiment 3”). Before actual execution of the movement, the direction of the visual stimulus had to be estimated by means of a method of adjustment. The perception of stimulus direction was biased away from planned movement direction, such that with leftward movements stimuli appeared somewhat more rightward than with rightward movements. Control conditions revealed that this effect was neither a mere response bias, nor a result of processing or memorizing movement cues. Also, shifting the focus of attention toward a cued location in space was not sufficient to induce the perceptual bias observed under conditions of movement preparation (“Experiment 4”). These results confirm that characteristics of planned actions bias visual perception, with the direction of bias (contrast or assimilation) possibly depending on the type of the representations (categorical or metric) involved.     

Age‐related change of location‐based visual selectivity depending on conflict frequency

Age‐related change in cognitive control for visual selectivity was examined using a conflict adaptation effect (CAE). The CAE reflects an increased stimulus compatibility effect for low levels of conflict frequency within blocks of trials. Younger (n = 20) and elderly (n = 20) adults received an Eriksen‐type flanker task involving compatible (e.g., “44444”) or incompatible (e.g., “44644”) arrays presented to either the left or right visual field (VF). The participants identified the central digit of an array. Relative frequency of conflict (incompatible) trials varied as a function of the VF. Also manipulated was the presentation order of more‐conflict VF and less‐conflict VF conditions over trial blocks. The results showed that a location‐based CAE appeared for both age groups in the first set of trial blocks, whereas in the final set of trial blocks the location‐based CAE appeared only for the younger adults. These results suggested that cognitive flexibility related to context‐dependent cognitive control diminishes with age.     

Evaluation of a dynamical model of speech perception

Previous work (Tuller, Case, Ding, & Kelso, 1994) has revealed signature properties of nonlinear dynamical systems in how people categorize speech sounds. The data were modeled by using a twowell potential function that deformed with stimulus properties and was sensitive to context. Here we evaluate one prediction of the model—namely, that the rate of change of the potential’s slope should increase when the category is repeatedly perceived. Judged goodness of category membership was used as an index of the slope of the potential. Stimuli from a “say”-“stay” continuum were presented with gap duration changing sequentially throughout the range from 0 to 76 to 0 msec, or from 76 to 0 to 76 msec. Subjects identified each token as either “say” or “stay” and rated how good an exemplar it was of the identified category. As predicted, the same physical stimulus presented at the end of a sequence was judged a better exemplar of the category than was the identical stimulus presented at the beginning of the sequence. In contrast, stimuli presented twice near the middle of a sequence with few (or no) stimuli between them, as well as stimuli presented with an intervening random set, showed no such differences. These results confirm the hypothesis of a context-sensitive dynamical representation underlying speech.     

Loudness and reaction time: II Identification of detection components at different intensities and frequencies

Equal-loudness contours were first obtained for five stimulus frequencies at four stimulus intensities. These 20 stimuli were then presented as reaction-time signals in a Donders C paradigm. The Z-transform method of convolution, as applied in linear systems identification, was used to deconvolve an empirically generated response (or “residual”) distribution (T_R) from each of the 20 reaction-time (RT) distributions obtained at different intensities and frequencies. The resulting sensory-detection (t_d) models formed exponential densities at strong intensities (60 and 80 phons), but their shapes were either gamma or normal at relatively weak intensities (20 and 40 phons). Our analyses support the idea that the simple reactiontime process (RT) is a convolution (or sum) of two component stages: stimulus detection (t_d), followed by response evocation (t_r). Based on the shapes of t_d, a neural-impulse theory is offered to account for the detection of simple auditory RT signals.     

The effects of delay and exposure duration in a face recognition task

Face recognition was investigated in a successive comparison task. Subjects were required to makesame/different judgments about pairs of Photo-fit faces that were either identical or differed by a single feature. Picture information extraction and retention were examined by manipulating stimulus delay and exposure duration. Results indicated that overall performance was better for the top of the face. The eyes and mouth were more vulnerable than the rest of the face to recognition decrement after a delay, possibly due to their role in facial expression. When features were ranked in order of processing difficulty for each subject, it appeared that features were processed serially and delay affected a retrieval stage, while short exposure affected a visual comparison stage of processing. For the feature ranks, a single dimension of “salience” appeared to be both perceptual and mnemonic.