Chapter 4 Time and Number Multiple times for multiple time scales o Millisecond timing very quick speech music motor control o Interval timing second 1 second 1 day classical conditioning taste aversion learning forging dicison making conscious time estimation o Circadian timing 24 hour rhythms of hours sleep wake cycle times to eat Time of Day Circadian Rhythms o Latin circa around and dies a day circadian rhythms are cycles of roughly 24 hour periods in physiological processes of plants animal fungi and some bacteria o In most animals they free run at somewhat longer than 24 hours o Can be entrained by external stimulus called Zeitgeber German for o Synchronize animals behavior and physiology with natural rhythms in timegiver the environment o Give animals internal sense of passage of time on long time scale o Melatonin levels provide signal to body for circadian rhythm Actograms in rats o Rats in tubes in dark and light phases of daily light dark cycle o Charges of counts of locomotor activity over time called actograms o Activity over days is higher in dark than light phase of dark light cycle Short time intervals Timing and the Internal Clock o Timing and the peak procedure peak procedure for studying animal timing was developed by Russel Church and his students Seth Roberts and Warren Meck peak procedure discrete trail Fixed Interval extended probe trail without reinforcement for example with fixed interval at 20s rats peak response rate is just after the 20s have expired prove trial test to see what the animal does rats can tell us when 20 s are up o Scalar Timing theory Church and Gibbon Time is like other stimulus dimensions in that it obeys Weber s Law To be judged as different stimuli must differ by a minimum constant proportion scalar If a stimulus varies geometrically if its multiplied by a fixed factor the corresponding perception follows an arithmetic progression it will be perceived as progressing by adding constant amounts o Temporal Bisection and the Geometric Mean Temporal bisection 10s vs 50s Play 2 different tones will respond at mean Different kinds of averages o Arithmetic mean 30s o Geometric mean 22 4s responded to this evidence for Weber s law Information Processing model of timing handwritten notes Connectionist models of timing Neural oscillators with different periods as the pacemaker Blackout procedure Learned to respond most at 40s Turn off apparatus for 10s Time up until blackout stop for 10 seconds finish timing Causes shift The Internal Clock Shows good control of internal clock Internal clock is like a stopwatch o Measures elapsed time o Runs at a constant rate Drugs can alter speed of clock Methamphetamine speeds up clock Haloperidol slows clock o Can be stopped and started Information Processing Model Timing and Counting If clock switch allows one tick per event the number of ticks number of events Brain automatically tells difference in small numbers Subitizing rapid assessment of a number from a small number of simultaneously presented items usually 1 4 o Not necessarily enumerated or counted o Thought to be perceived and apprehended as much as we perceive features of objects such as color o Disagreement whether developmentally counting grows out of subitizing or reverse New born guppies o Can distinguish between 7 and 4 spots on cards for reinforcement o Distinguish between large vs small shoals of fish o More precise for 3 vs 4 Different types of numerical competence o Where do animals fall on this scale Relative number judgment relative numerosity Absolute number judgment Counting Mental tagging o Applying number labeling in a given order to items o Order of applying labels is not critical but the order of items to which that are applied is relevant o Ordinality John Capaldi Purdue University o Rats routinely count items such as food pellets o Counting trials in a runway 0 0 0 0 20 vs 20 0 o Counting quantities in a runway o Rats can learn to use discimant clues as tags for 0 0 0 quantities Herbert S Terrace Columbia University o Showed that monkeys can count to 9 and possibly beyond o Trained rhesus monkeys to choose objects in ascending order of number o Controlled size and distrution of objects Irane Pepperber MIT and Alex the African Grey Parrot o Alex was bought from a pet store o Alex was trained daily almost constantly using model rival technique Observed an instructor student pair and spontaneously joins in the social interaction o Alex was taught to comprehend and produce words to Count up to 6 items Count items in categories Count items in superordinate categories How many red and green blocks Sally Boysen Ohio State University o Showed apes can count fruits using digits o Can add go find number that is total o Sumbolic counting add 2 symbol numbers pick digit that shows addition of both