experimental psychology

The current experiment looks at a variation of the lexical decision paradigm that involves priming. Priming means that two words are presented, one typically shortly before the other. Participants are instructed to respond only to the second word, but if the first word is a close associate of the second (e.g. doctor-nurse), reaction time to the second word is faster (Meyer & Schvaneveldt, 1971). The goal of the current experiment is to examine the time-course of the priming effect—that is, what is the optimal time period between presentation of the first (priming) word and second (target) word.

The basic idea is that as soon as the prime is presented and processed in the brain, activation spreads from the mental representation of that word to the mental representations of associated words. This process, unsurprisingly, is known as “spreading activation” (Collins & Loftus, 1975; Anderson & Pirolli, 1984). Therefore by studying the optimal time period between presentation of the prime and target, we may be studying the dynamics of spreading activation (Bueno & Frenck-Mestre, 2002).

It may seem that the answer to the optimal time period is “the longer the better” since longer durations give the participant more time to think about the priming word and to therefore activate related words. However, the process seems not to rely on conscious activation but rather on automatic sub-conscious activation. In fact the optimal time periods may be very short (Fischler & Goodman , 1978; Perea & Gotor, 1997).

This experiment will study word pairs in three categories (Related Prime, Unrelated (neutral) prime, and random word prime with nonsense word target). The last category is necessary so that participants will not know whether to press ‘1’ for real word or ‘2’ for nonsense word. We will only be analyzing the results for the first two categories: Related vs. Neutral primes.

The following shows the results from an experiment from a previous class.

As can be seen here, words with associated primes are responded to almost 80 ms faster than words with neutral primes. Also, having a slower time difference between the onset of the two words (200 ms SOA) has a bout a 60 ms advantage, reinforcing the point made earlier that shorter SOAs may actually be helpful. However, the lines on the graph are almost perfectly parallel, meaning that the priming effect of 80 ms is virtually the same, regardless of whether the SOA is 200 ms or 1000 ms. Had the lines not been parallel, there would have been the possibility of a significant interaction between SOA and Relatedness, and we might have been able to say more about the time course for priming.

The current experiment will be quite similar to the one graphed above. However, we will focus in on shorter SOAs, using SOAs of 100, 200 and 500 ms. We will be looking to see whether we can replicate the “Main Effects” for Relatedness and SOA as shown above, but also whether or not an interaction between Relatedness and SOA appears for these shorter SOAs.

For example, a graph like the following would indicate that the ideal SOA is around 200 ms. Statistically, the ANOVA might indicate a significant interaction between Relatedness and SOA, as the lines are obviously not parallel.

Some applications of these results may be to see whether or not the same temporal (time-related) dynamics apply to bilinguals, in which the prime and target words may be in different languages (Grainger & Beauvillain, 1988).

Note: For more details on ANOVAs and graphs with more than one independent variables, refer to the information document on memory scanning.

Statistical Analysis

Use ezANOVA. The design screen should look like the following:

This gives you a data entry screen like

The analysis will produce three F values. Report on each one:

1. F for Relatedness, indicating whether (overall) target words with related primes are responded to faster or slower than target words with neutral primes.

2. F for SOA, whether (overall) target words with shorter SOAs are responded to faster or slower than target words with longer SOAs.

3. F for interaction, indicating whether the effect of Relatedness depends on the SOA.

References

Anderson, J. R., & Pirolli, P. L. (1984). Spread of activation. Journal of Experimental Psychology: Learning, Memory, and Cognition, 10(4), 791-798. doi:10.1037/0278-7393.10.4.791

Bueno, S., & Frenck-Mestre, C. (2002). Rapid activation of the lexicon: A further investigation with behavioral and computational results. Brain and Language.Special Issue: Mental Lexicon II, 81(1-3), 120-130. doi:10.1006/brln.2001.2511

Collins, A. M., & Loftus, E. F. (1975). A spreading-activation theory of semantic processing. Psychological Review, 82(6), 407-428. doi:10.1037/0033-295X.82.6.407

Fischler, I., & Goodman, G. O. (1978). Latency of associative activation in memory. Journal of Experimental Psychology: Human Perception and Performance, 4(3), 455-470. doi:10.1037/0096-1523.4.3.455

Grainger, J., & Beauvillain, C. (1988). Associative priming in bilinguals: Some limits of interlingual facilitation effects. Canadian Journal of Psychology/Revue Canadienne De Psychologie, 42(3), 261-273. doi:10.1037/h0084193

Krueger, L. E. (1975). Familiarity effects in visual information processing. Psychological Bulletin, 82(6), 949-974. doi:10.1037/0033-2909.82.6.949

Meyer, D. E., & Schvaneveldt, R. W. (1971). Facilitation in recognizing pairs of words: Evidence of a dependence between retrieval operations. Journal of Experimental Psychology, 90(2), 227-234. doi:10.1037/h0031564

Perea, M., & Gotor, A. (1997). Associative and semantic priming effects occur at very short stimulus-onset asynchronies in lexical decision and naming. Cognition, 62(2), 223-240. doi:10.1016/S0010-0277(96)00782-2

Data from Psych 465 class (2008)

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050010001500

Stimulus Onset Asynchrony (SOA), ms

Reaction Time (RT), ms

Associated

Neutral

Hypothetical Results

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0200400600

Stimulus Onset Asynchrony (SOA), ms

Reaction time (RT), ms

Associated

Neutral