Higher order sequential effects in psychophysical judgments

We found that the depth of sequential effects depends on the judgment task. An experiment with squares indicated that stimulus-response pairs up to two trials back were included in the judgment process when subjects were required to make category judgments of size, whereas only the immediately preceding event was incorporated when subjects were making magnitude estimations. In the case of category judgment, interactions between the current stimulus and prior stimuli as well as configural effects indicated that events one and two trials back meet an equivalent function in the judgment process and that these events may jointly operate in one trial. These findings can be explained by a class of models that assume that the position of preceding stimuli relative to the current stimulus is decisive in the judgment process. The multiple-standards model is a representative of this class according to which there are two types of standards: (1) the endpoints of the range as long-term standards and (2) traces of preceding stimuli as short-term standards.     

Higher order sequential effects in psychophysical judgments

We found that the depth of sequential effects depends on the judgment task. An experiment with squares indicated that stimulus-response pairs up to two trials back were included in the judgment process when subjects were required to make category judgments of size, whereas only the immediately preceding event was incorporated when subjects were making magnitude estimations. In the case of category judgment, interactions between the current stimulus and prior stimuli as well as configural effects indicated that events one and two trials back meet an equivalent function in the judgment process and that these events may jointly operate in one trial. These findings can be explained by a class of models that assume that the position of preceding stimuli relative to the current stimulus is decisive in the judgment process. The multiple-standards model is a representative of this class according to which there are two types of standards: (1) the endpoints of the range as long-term standards and (2) traces of preceding stimuli as short-term standards.     

Sequential dependencies and response range in cross-modality matches of duration to loudness

Subjects matched durations of keypresses to loudnesses of pure tones. Resulting duration responses were found to be assimilated to the value of the immediately preceding stimulus and responses from one to at least six trials back in the sequence of loudness stimuli. Responses were contrasted with the values of stimuli two through six trials back in the sequence. These sequential dependencies and other properties of the data were predicted by a cognitive model in which cross-modality matches are mediated by category judgments of stimuli on both continua, and subjects use heuristic strategies to reduce response uncertainty.     

Immediately preceding stimuli increase the detection of a less detectable but not a more detectable stimulus

Both a small (S) and a large (L) stimulus occurred individually and randomly over trials. The task was to make the same speeded response to either stimulus. LSSS sequences on trials N-3, N-2, N-1, and N, respectively, resulted in a faster RT to S on trial N than to S on trial N-2. However, SLLL sequences did not produce a corresponding increase in detection. Also, overall, S was less detectable than L. Suppose that the physical S on trial N was lower in detectability-memorability than a memorial S produced by S on the immediately preceding trials N-1 and N-2. If so, the physical S may have assimilated in detectability-memorability to the memorial S, explaining why its detectability increased. In contrast, the physical L may have been sufficiently high in detectability-memorability to preclude a comparable assimilation. The theory: assimilation underlies detectability, regardless of whether two components are both physical (previous research), or whether one is physical and the other is memorial (the present research).     

Pure feedback effects in absolute identification

To reveal the pure effects of trial-by-trial feedback on judgmental accuracy and sequential dependencies independent of global anchoring effects and other influences, we presented subjects with sequences consisting alternately (within an experimental session) of short runs of trials with feedback (feedback sequences) and without feedback (no-feedback sequences). In Experiments 1 and 2 (absolute identification of sound intensity and sound frequency, respectively), judgmental accuracy was the same in the feedback and the no-feedback sequences, contrary to previous results. Also, in the feedback sequences, the dependency of the current response on the immediately preceding stimulus was larger than that in the no-feedback sequences, while the dependency on the previous response was larger in the no-feedback sequences. In Experiment 3 (absolute identification of sound frequency), we attempted to separate the effects of the number of response categories on sequential dependencies from the effects of the number of stimuli. The results showed that the number of response categories had a larger effect than the number of stimuli on most aspects of performance, but that both affected sequential dependencies. These results are generally consistent with a theory of absolute identification in which feedback affects judgmental accuracy by improving long-term memory for judgmental anchors, while feedback affects sequential dependencies by altering response biases.     

The effect of interstimulus interval on sequential effects in absolute identification

In absolute identification experiments, the participant is asked to identify stimuli drawn from a small set of items which differ on a single physical dimension (e.g., 10 tones which vary in frequency). Responses in these tasks show a striking pattern of sequential dependencies: The current response assimilates towards the immediately preceding stimulus but contrasts with the stimuli further back in the sequence. This pattern has been variously interpreted as resulting from confusion of items in memory, shifts in response criteria, or the action of selective attention, and these interpretations have been incorporated into competing formal models of absolute identification performance. In two experiments, we demonstrate that lengthening the time between trials increases contrast to both the previous stimulus and the stimulus two trials back. This surprising pattern of results is difficult to reconcile with the idea that sequential dependencies result from memory confusion or from criterion shifts, but is consistent with an account that emphasizes selective attention.     

Influence of gender membership on sequential decisions of face attractiveness

Responses in a current trial are biased by the stimulus and response in the preceding trial. In a mixed-category sequence, the sequential dependency is weaker when the stimuli of the current and preceding trials fall under different categories. In the present study, we investigated the influence of the gender membership of faces on the sequential dependency. Forty-eight pictures of male and female faces were presented successively. Participants rated the attractiveness, roundness, or intelligence of each face on a 7-point scale. The sequential effect was robustly observed, irrespective of the property to be judged. However, between-gender sequential dependency was weaker than within-gender dependency only in the attractiveness judgment. These findings suggest that the gender of faces serves as a cue for forming category representations when face attractiveness is of interest, and hence that the formation of categories in sequential decisions is an adaptive process that depends on the property to be judged.     

Sequence effects in the categorization of tones varying in frequency

In contrast to exemplar and decision-bound categorization models, the memory and contrast models described here do not assume that long-term representations of stimulus magnitudes are available. Instead, stimuli are assumed to be categorized using only their differences from a few recent stimuli. To test this alternative, the authors examined sequential effects in a binary categorization of 10 tones varying in frequency. Stimuli up to 2 trials back in the sequence had a significant effect on the response to the current stimulus. The effects of previous stimuli interacted with one another. A memory and contrast model, according to which only ordinal information about the differences between the current stimulus and recent preceding stimuli is used, best accounted for these data.     

Determinants of cumulative successive contrast in saltiness intensity judgments

When all stimuli elicit the same taste quality, solutions preceded by a high concentration level are judged to be significantly less intense than solutions preceded by a low concentration level. After repetitious stimulation with a different tasting stimulus, the intensity of the present stimulus is overestimated. This phenomenon is called “successive contrast.” In the present study, the cumulative effects of three identical stimuli on the saltiness ratings for a test stimulus are investigated. The preceding stimuli are manipulated with regard to taste quality, saltiness intensity, total taste intensity, and complexity. Whether the size of the cumulative contrast effect is associated with the degree of dissimilarity between preceding stimuli and test stimulus, or with the saltiness or total taste intensity of the preceding stimuli, is investigated. The size of the contrast effect depends on the type of preceding stimulus, its intensity, and the type of test stimulus. No association was found with judgments of the degree of dissimilarity between the preceding stimuli and the test stimulus. For nonsalty preceding stimuli, the contrast effects are independent of concentration level. When the preceding stimuli taste at least partly salty, the total intensity appears to determine the size of the contrast for an unmixed salty test stimulus.     

Signal recognition as influenced by presentation schedules

Performance in a recognition task involving two amplitudes of the same tone was investigaled over a wide range of presentation schedules. The task was arranged so that there was no trial-to-trial feedback or other information regarding the relative frequencies of the two tones. The hit and false alarm rates (the proportion of “loud” responses to loud and soft stimuli, respectively) on any given trial were strongly influenced by the stimulus and response on the preceding trial. In general, Ss tended to repeat the last response and were more accurate after a stimulus alternation than after a stimulus repetition. In addition, hit and false alarm rates were inversely related to the presentation probability of the loud tone, in contrast to the direct relation typically found in signal detection experiments and in recognition experiments with trial-to-trial feedback. A mathematical model incorporating three processes (memory, comparison, and decision) was shown to give a good account of these data.     

Iontophoretically applied potassium ions as an experimental pain stimulus for investigating pain mechanisms

The present study investigated the psychophysical characteristics of potassium iontophoresis and its suitability as an experimental pain stimulus. Experiment 1 investigated the optimal duration of the pain stimulus for reliable reporting across repeated trials and whether the relationship between stimulus and subject response was linear, logarithmic, or a power function. In Experiment 2, the optimal interstimulus interval (ISI) was determined for reliable pain reporting, and stimulus history effects, both in terms of session effects and the effects of immediately preceding stimuli, were evaluated. In Experiment 3, potassium iontophoresis was compared with a sodium iontophoresis control. Linear functions described the stimulus-pain relationship best. No significant differences in the goodness-of-fit coefficients of determination, correlations, or coefficients of variation were found for the stimulus durations of 1, 2, and 4 sec. Significant stimulus history effects were found across a session, with adaptation and enhancement of responding for low- and moderate-intensity stimuli, respectively. The effects of the immediately preceding stimuli were suppression or enhancement of pain response, depending on the ISI, the preceding stimulus intensity, and the present stimulus intensity. Potassium iontophoresis was a significantly more effective pain stimulus than was sodium iontophoresis. It was concluded that potassium iontophoresis is a convenient and reliable experimental pain stimulus, which can be presented rapidly and repeatedly with minimal loss in consistency of subject pain report. Potassium iontophoresis provides a tool for investigating the neural modulation of pain in the relative absence of inflammation processes and tissue damage.     

Visual awareness judgments are sensitive to accuracy feedback in stimulus discrimination tasks

In this study we tested the hypothesis that perceptual awareness judgments are sensitive to accuracy feedback about the previous action. We used a perceptual discrimination task in which participants reported their stimulus awareness. We created two conditions: No-feedback and Feedback (discrimination accuracy feedback was provided at the end of each trial). The results showed that visual awareness judgments are related to the accuracy of current and previous responses. Participants reported lower stimulus awareness for incorrectly versus correctly discriminated stimuli in both conditions; they also reported lower stimulus awareness in trials preceded by incorrect discrimination responses, compared to trials preceded by correct discrimination responses. This difference was significantly stronger in the Feedback condition, in which we also observed post-error slowing for PAS ratings. We discuss the relation between visual awareness and the effects of performance monitoring and interpret the results in the context of current theories of consciousness.     

A developmental study of differences in initial coding and recoding of hypothesis information

Coding and recoding of hypothesis information was studied in children in Grades 3, 5, and 7, and college students. Each S was tested on several two-choice discrimination problems. A problem consisted of two trials, a training trial and a test trial. The information available for coding on the first trial was varied in three series of problems by using pairs of stimuli differing in 3, 4, or 6 dimensions. Recoding after an error was facilitated in half of the problems in each series by allowing the stimuli to persist briefly after response and feedback. The stimuli terminated immediately after response and feedback in the remaining problems. The second trial of a problem, in which the stimuli differed on only one dimension, was used to probe for the information coded or recoded on the first trial. On the average, fewer dimensions were coded per trial by the younger Ss than by the older Ss. Neither the effects of negative feedback nor the effects of stimulus persistence were found to be related to developmental level. It was concluded that a deficiency in young children's ability to code, but not recode, hypothesis information contributes to their less efficient performance in discrimination problems.     

Two types of serial dependence in visual working memory

Stimulus representations in working memory depend on memory traces of past stimuli both from previous trials and from the current trial. However, it is unclear whether the same or different mechanisms underlie this serial dependence across and within trials. We directly contrasted estimates of bias for pairs of immediately successive stimuli across and within trials. In each trial, participants memorized two consecutive motion direction stimuli (S1 and S2) and after a short delay were cued to report one of them. We found serial dependence across trials: The current S1 was attracted towards the preceding S2 when the latter had been cued for report. In contrast, within the same trial S2 was repulsed from S1. In addition, repulsion within a trial occurred for a broader range of motion direction differences between stimuli than attraction across trials. A second experiment in which 25% of trials did not require a response demonstrated that across‐trial attraction did not depend on whether the previous S2 actually had to be reported. Our findings provide evidence for two types of serial dependence operating across and within trials. They support the notion of different mechanisms integrating or segregating current from similar past memory contents depending on their task relevance.     

Taking a bright view of negative priming in the light of dim stimuli: further evidence for memory confusion during episodic retrieval.

A same-different letter-matching task was used to examine the effects of stimulus intensity on negative priming, which is poorer performance when target letters have been presented as distractor letters on the immediately preceding trial. In Experiment 1, stimulus intensity was manipulated between-participants, whereas in Experiment 2, it varied randomly from trial-to-trial within-participants. In Experiment 1, negative priming was equivalent for both stimulus intensities. In Experiment 2, negative priming effects were larger for repeated intensity stimuli than for nonrepeated intensity stimuli, when stimulus intensity was dim. Furthermore, for repeated intensity stimuli, negative priming effects were enhanced when the overt response required to the stimulus was repeated from prime to probe trial. These results are consistent with the hypothesis that negative priming may be due to memory confusion, rather than to inhibition of the distractor stimuli.     

Sequential effects in face-attractiveness judgment

A number of studies have shown that current-trial responses are biased toward the response of the preceding trial in perceptual decisionmaking tasks (the sequential effect-Holland and Lockhead, 1968 Perception & Psychophysics 3 409-414). The sequential effect has been widely observed in evaluation of the physical properties of stimuli as well as more complex properties. However, it is unclear whether subjective decisions (e.g., attractiveness judgments) are also susceptible to the sequential effect. Here, we examined whether the sequential effect would occur in face-attractiveness judgments. Forty-eight pictures of male and female faces were presented successively. Participants rated the attractiveness of each face on a 7-point scale. The results showed that the attractiveness rating of a given face assimilated toward the rating of the preceding trial. In a separate experiment, we provided the average attractiveness rating by others for each trial as feedback. The feedback weakened the sequential effect. These findings suggest that attractiveness judgment is also biased toward the preceding judgment, and hence the sequential effect can be extended into the domain of subjective decisionmaking.     

A limited-capacity response process in absolute identification

In two absolute identification experiments, the dependency of the current response, Rn, on the immediately preceding stimulus, Sn-1, and response, Rn-1, was measured by means of multivariate information transmission (see McGill, 1954). In these experiments, the amount of stimulus information available to subjects, measured as the amount of information transmission from a current stimulus, Sn, to Rn, was manipulated. The magnitude of the dependency of Rn on Sn-1 and Rn-1 was inversely proportional to that of information transmission from Sn to Rn, supporting the argument of Ward and Lockhead (1971) that the less stimulus information the subjects get, the more their responses will be likely to depend on previous stimuli and responses. Interestingly, the sum of information transmission from Sn, Sn-1, and Rn-1 to Rn was always about 2.5 bits, without respect to the variance of each term. This result could have arisen from the operation of a limited-capacity response process.     

The reversed work‐ethic effect: Monkeys avoid stimuli associated with high‐effort1

We investigated how different numbers of responses prior to the presentation of a stimulus influenced preferences for the stimulus in three Japanese monkeys (Macaca fuscata). Monkeys were trained for two kinds of simultaneous discriminations that followed a high‐effort or a low‐effort response. In probe test trials, the stimulus that followed the high‐effort and the stimulus that followed the low‐effort response during discriminations were presented simultaneously. All monkeys chose stimuli that in training followed a low‐effort response. This result suggested that monkeys avoided stimuli that followed high‐effort responses because of the association between those stimuli and the preceding greater effort. The present result is consistent with our previous study conducted with humans, but contradicts analogous studies carried out with pigeons that reported either opposite results (i.e. pigeons preferred the stimuli after high‐effort) or non‐biased preferences. The differences between mammals and birds are discussed in terms of the lack of a successive negative contrast effect in birds.     

Conflict adaptation is reflected by response interference

The conflict monitoring theory suggests that the occurrence of conflict in previous trials leads to a reduction in interference in current trials through conflict adaption. The present study included two experiments that used a colour-based flanker task and a Stroop task in combination with a 2:1 stimulus-to-response mapping manipulation and a crossing of transition types (Previous trial type×Current trial type) with stimuli to investigate conflict adaption in relation to stimulus and response interference. The results demonstrate that response interference, but not stimulus interference, was reduced following both stimuli and response conflicts in previous trials. In contrast to some recent evidence, we conclude that conflict adaptation is limited to response interference.     

Response scales and sequential effects in judgment

There are persistent sequential effects in judgment tasks. For example, responses tend to be similar to the value of the just-prior stimulus. This is called assimilation. Also, if feedback is or is not provided after each trial, then responses contrast with or assimilate to, respectively, each of several earlier stimuli in the sequence. These context effects have been shown to be independent of stimulus modality and of the range of stimulus values within a modality. By providing different sets of feedback in order to affect the responses used, this article shows that these sequential effects in judgment data are also independent of the form and range of the scale of responses used to label stimuli.