title: Blocking by fixed and variable stimuli: Effects of stimulus distribution on blocking.
abstract: An experiment with rats compared the ability of fixed and variable duration cues to produce blocking. Rats in group B (Blocking) were trained that both fixed- (F) and variable- (V) duration cues would be followed by food delivery. In a subsequent training stage F and V continued to be reinforced, but F was accompanied by X, and V by Y. In the test phase responding to X and Y was examined. Control group O (Overshadowing) received identical treatment, except that F and V were nonreinforced in the first training stage. In group B there was evidence for blocking, but only of X, which had been conditioned in compound with the fixed-duration F; there was no evidence for blocking of Y, which had been conditioned in compound with the variable-duration V. It is suggested that this result may occur because fixed cues reach a higher, more stable asymptote of associative strength than do their variable equivalents.
authors.affiliation: a Institute of Neuroscience , Newcastle University , Newcastle upon Tyne , UK.
authors.forename: Dómhnall J
authors.initials: DJ
authors.lastname: Jennings
authors.affiliation: b School of Psychology , University of Nottingham , Nottingham , UK.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Bonardi
mesh_terms: D000161:Acoustic Stimulation; D000704:Analysis of Variance; D000818:Animals; D001245:Association Learning / Q000502:physiology*; D003214:Conditioning, Classical / Q000502:physiology*; D003463:Cues; D008297:Male; D051381:Rats; D012054:Reinforcement, Psychology
keywords: Associative learning; Blocking; Rats; Stimulus distribution form; Timing