Fixed Interval
fixed interval
Time as its own representation? Exploring a link between timing of cognition and time perception
The way we represent and perceive time has crucial implications for studying temporality in conscious experience. Contrasting positions posit that temporal information is separately abstracted out like any other perceptual property, or that time is represented through representations having temporal properties themselves. To add to this debate, we investigated alterations in felt time in conditions where only conscious visual experience is altered while a bistable figure remains physically unchanged. In this talk, I will discuss two studies that we have done in relation to answering this question. In study 1, we investigated whether perceptual switches in fixed intervals altered felt time. In three experiments we showed that a break in visual experience (via a perceptual switch) also leads to a break in felt time. In study 2, we are currently looking at figure-ground perception in ambigous displays. Here, in experiment 1 we show that differences in flicker frequencies on ambigous regions can induce figure-ground segregation. To see if a reverse complementarity exists for felt time, we ask participants to view ambigous regions as figure/ground and show that they have different temporal resolutions for the same region based on whether it is seen as figure or background. Overall, the two studies provide evidence for temporal mirroring and isomorphism in visual experience, arguing for a link between the timing of experience and time perception.
The structure of behavior entrained to long intervals
Interpretation of interval timing data generated from animal models is complicated by ostensible motivational effects which arise from the delay-to-reward imposed by interval timing tasks, as well as overlap between timed and non-timed responses. These factors become increasingly prevalent at longer intervals. To address these concerns, two adjustments to long interval timing tasks are proposed. First, subjects should be afforded with reinforced non-timing behaviors concurrent with timing. Second, subjects should initiate the onset of timed stimuli. Under these conditions, interference by extraneous behavior would be detected in the rate of concurrent non- timing behaviors, and changes in motivation would be detected in the rate at which timed stimuli are initiated. In a task with these characteristics, rats initiated a concurrent fixed-interval (FI) random-ratio (RR) schedule of reinforcement. This design facilitated response-initiated timing behavior, even at increasingly long delays. Pre-feeding manipulations revealed an effect on the number of initiated trials, but not on the timing peak function.