Cognitive mechanisms for transitive inference performance in rhesus monkeys: Measuring the influence of associative strength and inferred order.

Abstract

If Ben is taller than Emily and Emily is taller than Dina, one can accurately infer that Ben is taller than Dina. This process of inferring relations between stimuli based on shared relations with other stimuli is called transitive inference (TI). Many species solve TI tasks in which they learn pairs of overlapping stimulus discriminations (A+B−, B+C−, etc.) and are tested with non-adjacent novel test pairings (e.g. BD). When relations between stimuli are determined by reinforcement (i.e., A is reinforced when paired with B, B when paired with C), performance can be controlled by the associative values of individual stimuli or by logical inference. In Experiment 1 rhesus monkeys (Macaca mulatta) chose the higher ranked item on non-adjacent test trials after training on a 7-image TI task. In Experiment 2 we measured the associative values of 7 TI images and found that these values did not correlate with choice in TI tests. In Experiment 3 large experimental manipulations of the associative value of images did influence performance in some TI test pairings, but performance on other pairs was consistent with the implied order. In Experiment 4 monkeys linked two previously learned 7-item lists into one 14 item list after training with a single linking pair. Linking cannot be explained by associative values. Associative value can control choice in TI tests in at least some extreme circumstances. Implied order better explains most TI choices in monkeys, and is a more viable mechanism for TI in social dominance hierarchies, which has been observed in birds and fish.

Direct and relational representation during transitive list linking in pinyon jays (Gymnorhinus cyanocephalus).

“…3, the birds showed no preference for either stimulus during Block 1 of probe testing but then rapidly developed a clear preference for C during the later blocks (Figure 2f). In their list-linking study of rhesus macaques, Gazes et al (2012) also found above-chance performance on far-between pairs. Because they used longer lists, there were more far-between exemplars to analyze.…”

“…In Treichler's studies the error rates for pairs below the link were roughly double those of corresponding pairs above it (Table 2 in Treichler & Van Tilburg, 1996;Figure 12.3 in Treichler, 2007). In Gazes et al (2012), multiple comparisons were analogous to B ? D versus 2 ?…”

“…The results of these experiments clearly demonstrated the influence of the implied order of the transitive series above and beyond any effects of associative value. In their fourth experiment, Gazes et al (2012) tested the monkeys with two seven-item lists that were linked and again found clear evidence of effects of relational representation. We will describe the results of this listlinking experiment in some detail for comparison with our results in the discussion below.…”

“…Many of these difficulties were avoided by Gazes, Chee, and Hampton (2012). They conducted a series of experiments explicitly testing the adequacy of associative models to predict TI performance in rhesus monkeys (Macaca mulatta).…”

“…They conducted a series of experiments explicitly testing the adequacy of associative models to predict TI performance in rhesus monkeys (Macaca mulatta). Once the monkeys had learned a single list and demonstrated transfer to novel pairs (Experiment 1), Gazes et al (2012) directly measured (Experiment 2) and experimentally manipulated (Experiment 3) the associative values of the stimuli. The results of these experiments clearly demonstrated the influence of the implied order of the transitive series above and beyond any effects of associative value.…”