Modeling response signal and response time data

The diffusion model (Ratcliff, 1978) and the leaky competing accumulator model (LCA, Usher & McClelland, 2001) were tested against two-choice data collected from the same subjects with the standard response time procedure and the response signal procedure. In the response signal procedure, a stimulus is presented and then, at one of a number of experimenter-determined times, a signal to respond is presented. The models were fit to the data from the two procedures simultaneously under the assumption that responses in the response signal procedure were based on a mixture of decision processes that had already terminated at response boundaries before the signal and decision processes that had not yet terminated. In the latter case, decisions were based on partial information in one variant of each model or on guessing in a second variant. Both variants of the diffusion model fit the data well and both fit better than either variant of the LCA model, although the differences in numerical goodness-of-fit measures were not large enough to allow decisive selection between the models.     

Automatic sequential response priming and intentional response preparation in choice reaction tasks: Evidence from response repetition and response cuing

This study examined the interaction of response repetition and response cuing in a finger cuing task with a short and a long cue-stimulus interval (CSI). We observed shorter reaction times (RTs) with increasing CSI and a substantial response repetition benefit. However, this benefit was abolished at the long CSI, suggesting that response cuing neutralized the repetition effect. According to additive-factors logic, the observed interaction suggests that both repetition and cuing exert their influence on a common processing stage, which we identify as the response selection stage. We argue that cuing and repetition effects are expressions of distinct mental operations: cuing is based on intentional response code activation, whereas repetition is based on sequential, automatic response code priming. Cue-based intentional code activation starts slowly and increases with CSI, but sequential response priming is independent of CSI, explaining why cuing abolishes the response repetition benefit at the long CSI.     

A comparison of chinchilla auditory evoked response and behavioral response thresholds

The auditory sensitivity of the chinchilla was measured by both a behavioral and auditory evoked-response (AER) procedure. There was no significant difference in either the waveform or the threshold of the AER recorded over the tentorium from awake and anesthetized chinchillas. The chinchilla threshold for pure tones appears to be more sensitive when measured by the behavioral technique than by the AER method. Both the AER and behavioral response of three chinchillas exposed to a 105 dB SPL octave band of noise centered at 2 KHz for 3 h shifted markedly after the exposure. However, the difference between the AER and behavioral response threshold was reduced or absent. During the process of recovery the difference between the two responses begins to reappear.     

The interaction between response effects during the acquisition of response priming

In three experiments we investigated the role of associative learning in the acquisition of response priming by effect stimuli, by examining their interaction during response-effect learning. Having replicated the ability of visual effect stimuli to prime their associated responses, we paired a response with a compound consisting of visual and auditory effects before assessing the ability of the auditory effect stimulus to prime the response. This priming was reduced if the visual stimulus had been pre-trained as an effect of the response. By contrast, priming by the visual effect stimulus was potentiated when the auditory effect had been pre-trained. We interpret these interactions in terms of contemporary associative learning theory derived from studies of conditioning.     

Author's response

The year 1996 was regarded by a considerable part of contemporary literature on global political economy as a definite turning point in modern history. The majority of experts tended to see the starting point of take‐off that year, but others—not a negligible minority—saw omens of disastrous recession and lasting depression. It appears the time has not yet come. The question is now that of the incalculable resultant of runaway (deregulated) forces of the international financial “whirlpool”, of a random process of global, regional and local accumulation of capital. The year 1997 will set in with a foreseeable and calculable agrarian and related cycle and it may find an outlet for accumulated tensions of capital accumulation at the high tide of unemployment (demographic or migratory) wave with unforeseeable and incalculable effects and side‐effects. This will be just the beginning of the end and a Black Weekday still lies ahead of us. There can be no doubt that we live in a transition period but we do not know where this transition leads to. Loose talk about “post‐industrial society”, “post‐modern age” and “postsomething anything” has limited interpretative power. Very few students of social sciences venture to see and verify secular trends in world history.     

Author's response

In Search of Philosophic Understanding E. A. Burtt Mentor Book. New York: New American Library, 1967 Pp.xvii+350,$1.25     

Switching of response modalities

When participants perform a sequence of different tasks, it is assumed that the engagement in one task leads to the inhibition of the previous task. This inhibition persists and impairs performance when participants switch back to this (still inhibited) task after only one intermediate trial. Previous task-switching studies on this issue have defined different tasks at the level of stimulus categorization. In our experiments we used different response modalities to define tasks. Participants always used the same stimulus categorization (e.g., categorize a digit as odd vs. even), but had to give a vocal, finger, or foot response (A, B, or C). Our results showed a higher reaction time and error rate in ABA sequences than in CBA sequences, indicating n - 2 repetition cost as a marker for persisting task inhibition. We assume that different response modalities can define a task and are inhibited in a “task switch” in the same way as stimulus categories are inhibited.